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            PC LAB

          APPROVED BY A.I.C.T.E

            Submitted By:-
                       Name:-Manish Gupta
                       Roll No:-11364
                       Group:- A


This is to certify that Mr.Manish Gupta   Roll No.11364   is

student of IIIrd Semester(Information Technology) has

completed the practical file under the guidance and

supervision of undersigned.

Mr. Jitender Yadav               Ms. Maneela Tuteja
(HOD CSE & IT)                    (Lab Faculty)


Sr.                 Name of Program                     Date   SIGN.
1     To make a comparative study of
2     To describe features of MS Word, Prepare
      your Cover Letter & Resume using MS-
3     To describe features of MS Excel & prepare a
      list of marks obtained by students in different
      subjects and show with the help of
      chart/graph the average, min and max marks
      in each subject.
4     To describe features of MS Power Point &
      Prepare a presentation explaining the
      facilities/ infrastructure available in your
      college/ institute.
      To describe features of MS Access & Create a
5     database of books in the library on a mini
      scale w.r.t. Computers and manipulate the
      database using different forms & Reports

6     To study remove and replace Switch Mode
      Power Supply (SMPS)
7     To study various cards used in a system viz.
      Display Card, LAN Card etc

8     To remove, study and replace Hard Disk
9     To remove, study and replace CD ROM
10    To study parts of Mouse

11   To study parts of Keyboard
12   Trouble-shooting exercises related to various
     components of drive?
13   Trouble-shooting exercises related to various
     components of memory?
14   Trouble-shooting exercises related to various
     components of printers?
15   Trouble-shooting exercises related to various
     components of CD ROM Drive?

16   How to assemble a PC

17   To observe and study various cable
     connections and parts used in computer
18   To study monitor, its circuitry and various
     presents and some elementary fault detection.

19   To study printer assembly and elementary
     fault detection of DMP and laser printer.

20   To observe various cables and connectors
     used in Networking.

21   Trouble-shooting exercises related to various
     components of Monitor?

22   To remove, study and replace USB Drive

                        EXPERIMENT No.1

Aim:- To make comparative study of motherboards.

Requirements:- Tester, screw driver, multimeter, a motherboard,
connectors, wires.

Theory:-A motherboard is the central printed circuit board (PCB) in many
modern computers, and holds many of the crucial components of the system,
while providing connectors for other peripherals. The motherboard is
sometimes alternatively known as the main board, system board, or, on
Apple computers, the logic board.[1] It is also sometimes casually shortened
to mobo.[2]


An Acer E360 motherboard made by Foxconn, from 2005, with a large
number of integrated peripherals. This board's nForce3 chipset lacks `a
traditional northbridge.

Most computer motherboards produced today are designed for IBM-
compatible computers, which currently account for around 90% of global PC
sales. A motherboard, like a backplane, provides the electrical connections
by which the other components of the system communicate, but unlike a

Backplane, it also hosts the central processing unit, and other subsystems
and devices.

Motherboards are also used in many other electronics devices such as mobile
phones, stop-watches, clocks, and other small electronic devices.

A typical desktop computer has its microprocessor, main memory, and other
essential components on the motherboard. Other components such as
external storage, controllers for video display and sound, and peripheral
devices may be attached to the motherboard as plug-in cards or via cables,
although in modern computers it is increasingly common to integrate some
of these peripherals into the motherboard itself.

An important component of a motherboard is the microprocessor's
supporting chipset, which provides the supporting interfaces between the
CPU and the various buses and external components. This chipset
determines, to an extent, the features and capabilities of the motherboard.

Modern motherboards include, at a minimum:

      sockets (or slots) in which one or more microprocessors are installed[3]
      slots into which the system's main memory is installed (typically in
       the form of DIMM modules containing DRAM chips)
      a chipset which forms an interface between the CPU's front-side bus,
       main memory, and peripheral buses
      non-volatile memory chips (usually Flash ROM in modern
       motherboards) containing the system's firmware or BIOS
      a clock generator which produces the system clock signal to
       synchronize the various components
      slots for expansion cards (these interface to the system via the buses
       supported by the chipset)
      power connectors flickers, which receive electrical power from the
       computer power supply and distribute it to the CPU, chipset, main
       memory, and expansion cards.[4]

The Octek Jaguar V motherboard from 1993.[5] This board has 6 ISA slots
but few onboard peripherals, as evidenced by the lack of external

Additionally, nearly all motherboards include logic and connectors to
support commonly-used input devices, such as PS/2 connectors for a mouse
and keyboard. Early personal computers such as the Apple II or IBM PC
included only this minimal peripheral support on the motherboard.
Occasionally video interface hardware was also integrated into the
motherboard; for example on the Apple II, and rarely on IBM-compatible
computers such as the IBM PC Jr. Additional peripherals such as disk
controllers and serial ports were provided as expansion cards.

Given the high thermal design power of high-speed computer CPUs and
components, modern motherboards nearly always include heat sinks and
mounting points for fans to dissipate excess heat.

CPU sockets

A CPU socket or CPU slot is an electrical component that attaches to a
printed circuit board (PCB) and is designed to house a CPU (also called a
microprocessor). It is a special type of integrated circuit socket designed for
very high pin counts. A CPU socket provides many functions, including
providing a physical structure to support the CPU, providing support for a
heat sink, facilitating replacement (as well as reducing cost) and most
importantly forming an electrical interface both with the CPU and the PCB.
CPU sockets can most often be found in most desktop and server computers
(laptops typically use surface mount CPUs), particularly those based on the
Intel x86 architecture on the motherboard.

Integrated peripherals

Block diagram of a modern motherboard, which supports many on-board
peripheral functions as well as several expansion slots.

Peripheral card slots

A typical motherboard of 2009 will have a different number of connections
depending on its standard.

A standard ATX motherboard will typically have: - 1x PCI-E 16x
connection for a graphics card. - 2x PCI slots for various expansion cards. -
1x PCI-E 1x (which will eventually supersede PCI). A standard Super ATX
motherboard will have: - 1x PCI-E 16x connection for a graphics card. - a
varying number of PCI and PCI-E 1x slots. - It can sometimes also have a
PCI-E 4x slot (This varies between brands and models).Some motherboards
have 2x PCI-E 16x slots, to allow more than 2 monitors without special
hardware or to allow use of a special graphics technology called SLI (for
Nvidia) and Crossfire (for ATI). These allow 2 graphics

cards to be linked together, to allow better performance in intensive
graphical computing tasks, such as gaming and video-editing.

As of 2007, virtually all motherboards come with at least 4x USB ports on
the rear, with at least 2 connections on the board internally for wiring
additional front ports that are built into the computer's case. Ethernet is also
included now. This is a standard networking cable for connecting the
computer to a network or a modem. A sound chip is always included on the
motherboard, to allow sound to be output without the need for any extra
components. This allows computers to be far more multimedia-based than
before. Cheaper machines now often have their graphics chip built into the
motherboard rather than a separate card.

Temperature and reliability

Motherboards are generally air cooled with heat sinks often mounted on
larger chips, such as the northbridge, in modern motherboards. If the
motherboard is not cooled properly, it can cause the computer to crash.
Passive cooling, or a single fan mounted on the power supply, was sufficient
for many desktop computer CPUs until the late 1990s; since then, most have
required CPU fans mounted on their heat sinks, due to rising clock speeds
and power consumption. Most motherboards have connectors for additional
case fans as well. Newer motherboards have integrated temperature sensors
to detect motherboard and CPU temperatures, and controllable fan
connectors which the BIOS or operating system can use to regulate fan
speed. Some higher-powered computers (which typically have high-
performance processors and large amounts of RAM, as well as high-
performance video cards) use a water-cooling system instead of many fans.

                2.MICROSOFT WORD
Microsoft Word is a popular and commonly used word processing program.
It is one of the most popular word processing programs, if not the most
popular. Microsoft Word is often used in businesses, schools and
universities. Below, you can learn more about Microsoft Word, how it can
be beneficial to you and how you can obtain your own Microsoft Word

 On September 29, 1983, the first version of Microsoft Word came on the
market. Its original name was "Multi-Tool Word." Several other versions
followed, including Word 95, 97, 2000, XP, 2003 and 2007.

 Microsoft Word allows users to type, format and edit text to create
documents that can be printed or viewed electronically.

 The formatting styles feature available in Word make it easy to set up an
entire document. Formatting styles include everything from font, paragraph
settings and alignment. Users can also create custom fonts in Word.

 Microsoft Word is an affordable word processing application. Word offers
numerous tools.

                                COVER LETTER
Dear Madam/Sir


I am Manish Gupta,I have done Bachelor of Technology specializing in Information Technology
from Maharishi Dayanad University,one of the leading university in India. I am writing this to
apply for job in your esteemed and progressive organization where I can learn and apply myself.

I have worked as a trainee in Infosys,Gurgaon(Haryana) during my curricular practical training
where I worked on the software project called Employee Management System,which was based
upon C++ technologies. I also have the knowledge of Java,C and Data Structure.

In addition to the above mentioned skills,I believe that my hard work,dedication,honesty,sincerity
and passion towards work will prove to be an asset for your organisaton. I would be grateful to if
you could grant me an opportunity to work with your esteemed organization.

If you have any queries,I would be obliged to answer them.I appreciate your concideration and
request for a personal interview to discuss my qualifications and to learn more about this

Thanks and Regards

Manish Gupta
Tel No: +91-9818293103(M)

                                  Manish Gupta
                           Garhi Harsaru, Gurgaon, India
Personal Details
Date of Birth                                       22-06-1990
Father’s Name                                       Sh. K.P.Gupta


  To obtain a responsible,respected and challenging position in an organization where I
  can apply my knowledge and education skills towards the development of the

Summary Profile

  I have done bachelor of Technology with specialization in Information Technology,
 from Dronacharya College Of Engineering,Gurgaon,which is affiliated to Maharishi
 Dayanad University,one of the esteemed and leading universities of India. I have
 always maintained a good balance between academics and extra curricular activites
 throughout my school as well as my college years.I would like to join a progressive
 organization where I can learn and apply myself.

Industrial Training

  PayRoll Management System – 8 weeks
    IBM ltd. Gurgaon, Haryana- 122022

Educational Qualifications

 Bachelor Of Technolgy in Information Technology 2004-2008(79%)
  Dronacharya College Of Engineering,Gurgaon,Haryana – Maharishi Dayanand

 Senior Secondary Examination 2004(75%)
   Chiranjiv Bharati School, Palam Vihar, Gurgaon

 Secondary Examination 2002(86%)
   Chiranjiv Bharati School, Palam Vihar, Gurgaon

 Additional Qualifications

                  Learned C++ from F-Tec institute,Janak Puri,New Delhi in2004-2005
                  Done a certified course in Data Structure from NIIT in 2005-2006

Computer Proficiency
     Software Languages : C,C++.
     Operating System : Windows 98,XP,Vista
Software Projects

  1. In my final year of engineering ,I had an opportunity to work on a project
     “Library Manegement” in which the records of library is managed.
     It involved the application of Java and C++.

Honors and Awards

      Won the first prize in Procom Quiz Contest at zonal level.
      Prizes in various events at the College Tech Fest.
      Played for my school cricket team and won many prizes at various levels.

Extra Curricular Activites

      Took part in various technical events held at uviversity level.
      Participated in various cultural events in school and college.
      Participated in sports meet in school and college.
      Lead my team to victory in various cricket tournaments in school.


   Listening music,sports,internet surfing,traveling.


      Honest,dedicated,decent and deciplined person.
      Clear about my goals in life.
      Optimistic and positive attitude toward everything.
      Willingness to work the extra mile to achieve success.

Career Aspirations

   I wish to associate myself with a esteemed organization and would like to grow
   along the organization I serve

                Available on request

(Manish Gupta)

                          COVER LETTER

Dear Madam/Sir


I am Manish Gupta, I have done Bachelor of Technology specializing in
Information Technology from Maharshi Dayanand University, one of the
Leading Universities in India. I am writing this to apply for a job in your
esteemed organization where I can learn and apply myself.

I worked as a trainee,In Patni computers,Mumbai as a software tester which
was based On PHP. I also have knowledge of Core Java, J2EE

In addition to the above skills, I sincerely believe that my hard work,
dedication, sincerity and passion towards work in hand will prove to be an
asset for you. I would be grateful if you could grant me an opportunity to
work with you.

If you have any queries, I would be obliged to answer them. I appreciate
your consideration and request for a personal interview to discuss my
qualifications and to learn more about this opportunity.

Thanks & Regards

Manish Gupta
Tel No: +91-9818293103 (M)

                            3.MS EXCEL

Microsoft Excel (full name Microsoft Office Excel) is a spreadsheet-
application written and distributed by Microsoft for Microsoft Windows and
Mac OS X. It features calculation, graphing tools, pivot tables and a macro
programming language called VBA (Visual Basic for Applications).


Microsoft Excel up until 2007 version used a proprietary binary file format
called Binary Interchange File Format (BIFF) as its primary format. Excel
2007 uses Office Open XML as its primary file format, an XML-based
format that followed after a previous XML-based format called "XML
Spreadsheet" ("XMLSS"), first introduced in Excel 2002. The latter format
is not able to encode VBA macros.

Although supporting and encouraging the use of new XML-based formats as
replacements, Excel 2007 remained backwards-compatible with the
traditional, binary formats. In addition, most versions of Microsoft Excel can
read CSV, DBF, SYLK, DIF, and other legacy formats. Support for some
older file formats were removed in Excel 2007. The file formats were mainly
from DOS based programs.

Software errors

Criticisms of spreadsheets in general also apply to Excel. See Spreadsheet
shortcomings Errors specific to Excel include accuracy, date limitations and
the (now resolved) Excel 2007 display error.


Due to Excel's foundation on floating point calculations, the statistical
accuracy of Excel has been criticized, as lacking certain statistical tools.

Excel MOD function error

Excel has issues with modulo operations In the case of excessively large
results; Excel will return the incorrect answer of #NUM! Error

                     4. MS POWERPOINT
Microsoft PowerPoint is a presentation program developed by Microsoft. It
is part of the Microsoft Office suite, and runs on Microsoft Windows and
Apple's Mac OS X computer operating systems.

PowerPoint is widely used by business people, educators, students, and
trainers and among the most prevalent forms of persuasive technology.

PowerPoint presentations consist of a number of individual pages or
"slides". The "slide" analogy is a reference to the slide projector, a device
that has become obsolete with the use of PowerPoint and other presentation
software. Slides may contain text, graphics, movies, and other objects, which
may be arranged freely on the slide. PowerPoint, however, facilitates the use
of a consistent style in a presentation using a template or "Slide Master".

The presentation can be printed, displayed live on a computer, or navigated
through at the command of the presenter. For larger audiences the computer
display is often projected using a video projector. Slides can also form the
basis of webcasts.

PowerPoint provides three types of movements:

   1. Entrance, emphasis, and exit of elements on a slide itself are
      controlled by what PowerPoint calls Custom Animations.
   2. Transitions, on the other hand are movements between slides. These
      can be animated in a variety of ways.
   3. Custom animation can be used to create small story boards by
      animating pictures to enter, exit or move features, and many users are
      familiar and comfortable with its Microsoft toolbar.

                            5.MS ACCESS

Microsoft Office Access, previously known as Microsoft Access, is a
relational database management system from Microsoft that combines the
relational Microsoft Jet Database Engine with a graphical user interface and
software development tools. It is a member of the Microsoft Office suite of
applications and is included in the Professional and higher versions for
Windows and also sold separately.

Access stores data in its own format based on the Access Jet Database
Engine. It can also import or link directly to data stored in other Access
databases, Excel, SharePoint lists, text, XML, Outlook, HTML, dBase,
Paradox, Lotus 1-2-3, or any ODBC-compliant data container including
Microsoft SQL Server, Oracle, My SQL and PostgreSQL. Software
developers and data architects can use it to develop application software and
non-programmer "power users" can use it to build simple applications. Like
other Office applications Access is supported by Visual Basic for
Applications, an object-oriented programming language that can reference a
wide variety of objects, including DAO (Data Access Objects) and ActiveX
Data Objects, and many other ActiveX components provided by Microsoft
or by third parties. Visual objects used in forms and reports expose their
methods and properties gracefully in the VBA programming environment,
and a huge selection of Windows operating system functions can be declared
and called from VBA code modules, making Access a rich programming

                   EXPERIMENT NO.6
Aim:- To make comparative study of SMPS (Switch mode power

Requirements:- Multimeter, tester, screw driver, electric board, SMPS.


 A switched-mode power supply (also switching-mode power supply,
SMPS, or simply switcher) is an electronic power supply unit (PSU) that
incorporates a switching regulator in order to provide the required output

Interior view of an ATX SMPS:
Below A - input EMI filtering
A - Bridge rectifier
B - Input filter capacitors
Between B and C - Primary side heat sink
C - Transformer
Between C and D - Secondary side heat sink
D - Output filter coil
E - Output filter capacitors
The coil and large yellow capacitor below E are additional input filtering

components that are mounted directly on the power input connector and are
not part of the main circuit board.

Wires and their related voltages

   ORANGE:- It supplies +5V dc and acts as a good power signal.

   RED:- It supplies +5V dc. This is the basic supply voltage for nearly
    all electronic components.

   YELLOW:- It supplies +12V dc to the devices. This line supplies
    power to most of the devices.

   BLUE:- It supplies -12V. This line is usually used for some of the
    communication circuits.

   WHITE:- It supplies -5V. This voltage is used by any device and is
    retained only for the purpose of background compatibility.

                        EXPERIMENT NO.7

AIM: - To study various cards used in a system viz. Display Card, LAN
Card etc

PCI-It is a slower bus for communicating with things like hard disks and
sound cards. One very common bus of this type is known as the PCI bus.
These slower buses connect to the system bus through a bridge, which is a
part of the computer's chipset and acts as a traffic cop, integrating the data
from the other buses to the system bus.

Accelerated Graphics Port. AGP enables your computer to have a
dedicated way to communicate with the graphics card, enhancing both the
look and speed of your computer's graphics.

SOUND CARD-The sound card is an expansion card that allows the
computer to send audio information to any compatible audio device such as
a set of speakers.

A sound card is rectangular in shape with numerous contacts on the bottom of the card
and multiple ports on the side for connection to audio devices such as speakers. The
sound card installs in a PCI slot on the motherboard.

LAN-A Local Area Network (LAN) card is used to provide wireless Internet access to
computer users in home or roaming networks. It works by exchanging signals with a
router, which transmits the signals over a physically wired line. The LAN card became
ubiquitous in Western society in the early part of the twenty first century, when the cards
became affordable due to wireless networks springing up everywhere, from coffee shops
to airports.

                               Experiment No. 8
       To study remove and replace HARD DISK DRIVES
Function - The hard disk drive is a permanent storage area for data and the programs
used to create the data. Inside the hard disk drive are individual platters covered on
both sides with a special magnetic material. Drives work by writing small magnetic
charges onto the surface of the disk platter. These platters spin at thousands of
Revolution per Minute (RPM).

Description: HDD systems consist of a hard disk drive, a disk controller, jumpers,
and a cable. On some PC's the controller is a separate expansion board that interfaces
the system through an expansion slot. Power is supplied by direct cabling to the power
supply. There are different hard drive interfaces, such as, IDE, EIDE, SCSI, etc.,
which will be discussed below.

Hard disks are measured by their capacity, that is, how many megabytes it can store.
Older drives hold up to 20 - 500 MB. Newer models hold 1 - 6 gigabyte (GB) and

more. The best drives are physically small, spin fast, have fast seek times, have large
buffers, and a long warranty. The rule of thumb today is $.10 (cents) a megabyte.

Special purpose drives that sit outside your computer and are connected by a cable to
a special port are called external drives. The most popular are the Zip and Jazz drives

                          Hard Drive Physical Components

A hard disk had a certain number of heads, tracks per surface or platters, and sectors
per track. These were entered into the BIOS set up so the PC knows how to access the
drive. Many higher-end drives do use more than three or four platters, but most
mainstream drives keep the number of platters small. The physical components then
are Platters, Heads, a Spindle Motor, the hard disk drive controller of the hard
(Input/Output) Card that sits in the computer.


      THE PHYSICAL MATERIAL: Aluminun alloy comprises the physical
       material of the platter. It is rigid, easy to work with, lightweight, stable,
       inexpensive and readily available. As technology advances the gap between the
       heads and the platter is decreasing, and the speed that the platters spin at is
       increasing, creating more demands on the platter material itself.
      MEDIA LAYER: The physical material of which the platters are made forms
       the base upon which the actual recording media is deposited. The media layer
       is a very thin coating of magnetic material which is where the actual data is
       stored, typically only a few microinches in thickness. The media layer is
       usually comprised of a special alloy.
      PROTECTIVE LAYER: The surface of each platter is normally covered with
       an extra-thin, protective, lubricating layer, on top of the magnetic media
       layer itself. This material is used to protect the disk from damage caused by
       accidental contact from the heads or other foreign matter that might get into the
      PLATTER DIVISIONS: The platter is divided into Tracks and Sectors and is
       read by Zone Recording or Clusters.

    TRACKS: Platters are organized into specific structures to enable the
     organized storage and retrieval of data. Each platter is broken into several
     thousand tracks, which are tightly-packed concentric circles. (These are similar
     in structure to the annual rings of a tree.)
    SECTORS: Each track is further broken down into sectors. A sector is
     normally the smallest individually-addressable unit of information stored on a
     hard disk, and in most cases holds 512 bytes of information. Each track
     typically holds between 100 and 300 sectors. In modern drives the larger outer
     tracks hold more sectors than the smaller inner ones. All information stored on
     a hard disk is recorded in tracks. The tracks are numbered, starting from zero,
     starting at the outside of the platter and increasing as you go in. A modern hard
     disk has several thousand tracks on each platter.
    BLOCK MODE: More than one sector can be transferred on each interrupt
     notification. Newer drives allow you to transfer as many as 16 or 32 sectors at a
     time. These sectors are known as CLUSTERS

2. HEADS: Each platter is accessed for read and write operations using two
read/write heads, one mounted on the top of the platter and another on the bottom.
These heads are mounted onto arms that allow them to be moved from the outer tracks
of the hard drive to the inner tracks and back again. The arms are controlled using a
device called an actuator that positions the arms to the appropriate track on the disk.
The read/write heads don't touch the platter when the platter is spinning at full speed;
instead, they float on an extremely thin cushion of air (10 millionths of an inch).

3. THE SPINDLE MOTOR: The spindle motor is responsible for turning the hard
disk platters, allowing the hard drive to operate. Many drive failures are actually
failures with the spindle motor.

4. HARD DISK DRIVE CONTROLLER: Since digital information is a stream of
ones and zeros, hard disks store information in the form of magnetic pulses. In order
for the PC's data to be stored on the hard disk, therefore, it must be converted to
magnetic information. When it is read from the disk, it must be converted back to
digital information. This work is done by the integrated controller built into the hard
drive, in combination with sense and amplification circuits that are used to interpret
the weak signals read from the platters themselves.

5. HARD DRIVE SPEED: At one time all hard disks spun at 3,600 RPM; this is now
considered unacceptable in a modern disk drive. Most consumer drives today spin at
around 5,200 to 5,400 RPM. High end drives spin at 7,200 RPM and the newest ones

actually go up to 10,000 RPM.

6. HARD DRIVE POWER CONNECTOR: Hard disk drives use a standard, 4-pin
male connector plug, that takes one of the power connectors coming from the power
supply. This keyed, 4-wire plastic connector provides +5 and +12 voltage to the hard

7. DATA INTERFACE CONNECTOR OR CARD: Modern hard disk drives use
one of two interfaces: IDE (ATA) - INTEGRATED DRIVE ELECTRONICS (also
called ST506 drives) and its variants (EIDE - ENHANCED INTEGRATED DRIVE
can tell immediately by looking at the back of the hard disk which interface is being

      IDE hard disks use a 40-pin connector, and SCSI hard disks normally use
       either a 50-pin or a 68-pin connector.
       INTERFACE) hard disks used two data connectors, one 34 pins and the other
       20 pins.
      The cable usually has a red stripe to indicate wire #1 and the hard disk uses
       markers to indicate the matching pin #1.

8. LED CONNECTOR: Originally, hard disks shipped with a faceplate (or bezel) on
the front. The hard disk was mounted into an external hard drive bay (in place of a
floppy disk drive) and an LED was visible on the front of the drive to indicate when
the disk was in use. It was quickly realized that having the disks mounted internally to
the case made more sense, but the LED was still desirable. So an LED was mounted
to the case and a wire run to a two-pin connector on the hard disk itself. On newer
systems that run with integrated IDE controllers on the motherboard, the LED is
connected to a special connector on the motherboard itself.

9. DRIVE BAY: The entire hard disk is mounted into a physical enclosure designed
to protect it and also keep its internal environment sealed from the outside air. This is
necessary because of the requirement of keeping the internal environment free of dust
and other contamination that could get between the read/write heads and the platters
over which they float, and possibly lead to head crashes.

DRIVE BAYS are where internal hard drives are mounted inside the PC. They come
in internal and external versions, based on whether they allow access from the exterior

of the case, and also in two standard sizes: 5.25" and 3.5".

expensive and faster. It is allows the addition of up to seven devices, scanners, or
printers that use SCSI. There is also SCSCI II, Fast SCSCI, and Wide SCSCI drives.

Each SCSI device on the SCSI bus requires a unique SCSI number, from 1 to 7. The
computer's SCSI number is 0. SCSI devices are daisy chained together by cabling, and
the device at the end of the daisy chain must be terminated with a terminator resistor.

The SCSI interface comes in several types. 8-bit (50 wire data cable) or 16-bit (68
wire data cable, Wide SCSI). The clock can be 5 MHz (SCSI 1), 10 MHz (Fast SCSI),
20 MHz (Fast-20 or Ultra SCSI) or 40 MHz (Ultra-2 SCSI).

Performance Specifications and Their Meanings

1. SEEK TIME: The amount of time it takes the arm to move the read/write head
between tracks is called seek time. Seek time is measured in milliseconds (ms).

2. AVERAGE SEEK TIME: This is the time it takes to position the drive's
read/write heads for a randomly located request. For today's drives this range is from
8 to 14 ms. Seek time is one specification used for comparing relative drive
performance in benchmark studies.

3. QBENCH: Quantam, a hard drive manufacturer, developed a measurement
standard called data access time and a benchmark called QBench to measure it. This
benchmark uses data access time along with data transfer rate to provide a measure of
overall disk drive performance.

      ACCESS TIME is a measure of how long it takes to position a read/write head
       over a particular track and find a sector(s) within the track for reading or
      DATA TRANSFER RATE entails a data transfer between the disk and the
       CPU. The faster the data transfer, the less time the user has to wait for a
       software program to operate. The data transfer rate is measured in megabytes
       (MB) and megabytes per second (MB/s).

QBench is used widely throughout the industry as a standard for drive performance


The BIOS has an entry in the Standard Setup menu for each of the four IDE/ATA
devices supported in a modern system - primary master, primary slave, secondary
master, and secondary slave. This allows at least 4 hard drive devices to be connected
to your computer, such as, removable cartridges, tape drives, floppy drives, CD ROM,
and Magneto-opticals.


      PIO MODE (PROGRAMMED I/O): Data transfer is performed by the
       system CPU. The system processor is responsible for executing the instructions
       that transfer the data to and from the drive. The mode channels available are 0,
       1, 2, 3, and 4. EIDE and Fast-SCSI hard drives demand modes 3 a,d 4.
      DMA (DIRECT MEMORY ACCESS) is the term used to refer to a transfer
       protocol where a peripheral device transfers information directly to or from
       memory, without the system processor being required to perform the
       transaction. Most newer hard disks support the use of DMA modes over the
       IDE/ATA interface, which means that the built-in controller on the hard disk
       can do transfers to memory without the system processor's involvement. DMAs
       are used most commonly today by floppy disk drives, tape drives, and sound

Factfile: Hard disk drive
A hard disk drive is the device used to store large amounts of digital
information in computers and related equipment like iPods and games
consoles such as the Xbox 360 and PS3.

A typical hard disk drive consists of a motor, spindle, platters, read/write
heads, actuator and electronics. Click on the links below to see how these
components work.


A hard disk has one or more platters - or disks - and each platter usually has
a head on each of its sides.

In modern drives the platters are made from glass or ceramic. The platters
themselves are non-magnetic but have a magnetic coating which holds the
magnetic impulses which represent the data.

A typical hard drive will have three or four platters and modern varieties
can hold 20GB per disk.


The read/write heads float on a cushion of air only nanometers above the
surface of the platters.

As the read/write heads pass over the spinning platters they magnetize the
surface in a pattern which represents the data in digital form.

The data is stored digitally as tiny magnetized regions, called bits, on the


A magnetic orientation in one direction on the disk could represent a "1",
while an orientation in the opposite direction could represent a "0".

Data is arranged in sectors along a number of concentric tracks. These
tracks are arranged from the inner diameter of the disk to its outer edge.

When reading data on a disk, a similar process occurs in reverse.


The platters are mounted on the spindle which is turned by the drive motor.
Most current hard disk drives spin at between 5,400 and 10,000 RPM.

Modern hard drives can transfer 80 megabytes of data per second.


The triangular-shaped head arm holds the read/write heads and is able to
move the heads from the hub to the edge of the drive.

There is one hard arm per read/write head and all of them are lined up and
mounted to the acuator as a single unit.


The head arm is controlled by an actuator - which has to be incredibly
accurate. 30,000 tracks can be stored within one inch of space on a platter.

The hard disk's electronics control the movement of the actuator and the
rotation of the disk, and perform reads and writes on demand from the disk
controller via its interface to the computer.


Hard drives are typically air-sealed to enable the heads to float and to avoid
contamination from dust.

The air inside the the hard drive enclosure is in constant motion and passes
through the filter to remove any leftover contaminants from the

manufacturing process and any particles or chemicals that may have
somehow entered the enclosure.

                          Experiment No. 9
           To study remove and replace CD-ROMS
Function: Most computers now come standard with a CD ROM drive.
Many programs are now being put on CD¹s. A CD drive reads data from a
CD that looks much like a music CD. CD¹s make it possible to add features
like sound and video to programs and games since they will hold between
527 and 742 megabytes of data depending on the number of sectors and the
format used. Standard discs used in a computer CD drive stores 650 MB
using 333,000 sectors. CD's has a shelf life of over 100 years.

Description: CD ROM drives can be internal or external. A headphone jack
sits on the front of the player. All CD drives are capable of playing music. If
the computer has a sound card, the music can be amplified and played
through speakers. CD drives come in various transfer speeds - 2X, 3X, 4X,
etc. The higher the speed the faster the CD plays.

CD-ROMS are either EIDI, SCSI, or the proprietary (has manufacturer's
special card) older CD-ROMS. The older computers used a 16 bit expansion
card or a sound/CD-ROM drive controller card.


      A reflecting mirror reflects a beam of light from a laser diode to a
       track on the CD-ROM. The reflecting mirror is positioned by a
      The beam bounces of the track and is sent through focussing lenses
       and a beam splitter to a photodetector.
      The photodetector changes the light to an electronic signal or data.
      Data is "burned" from the inside track out.

CD-ROM drives rotate faster when accessing the inner tracks and slower
when accessing the outer tracts. This is called COnstant Linear Velocity
(CLV). The reduce the changing spin rates, Constant Angular Velocity
(CAV) was created. CAV moves head across the disc at a constant speed.
Some use both methods using CAV for innner 2/3's of disc, and CLV for the
outer portion.

Salient Characteristics

      1. High information density -- With the density achievable using
       optical encoding, the CD can contain some 540 megabytes of data on
       a disc less than five inches in diameter.
      2. Low unit cost -- Because CDs are manufactured by a well-
       developed process similar to that used to stamp out LP records, unit
       cost in large quantities is less than two dollars.
      3. Read only medium -- CD-ROM is read only; it cannot be written on
       or erased. It is an electronic publishing, distribution, and access
       medium; it cannot replace magnetic disks.
      4. Modest random access performance -- Due to optical read head
       mass and data encoding methods, random access ("seek time")
       performance of CD is better than floppies but not as good as magnetic
       hard disks.
      5. Robust, removable medium -- The CD itself is comprised mostly
       of, and completely coated by, durable plastic. This fact and the data
       encoding method allow the CD to be resistant to scratches and other
       handling damage. Media lifetime is expected to be long, well beyond
       that of magnetic media such as tape. In addition, the optical servo
       scanning mechanism allows CDs to be removed from their drives.
      6. Multimedia storage -- Because all CD data is stored digitally, it is
       inherently multimedia in that it can store text, images, graphics,
       sound, and any other information expressed in digital form. Its only
       limit in this area is the rate at which data can be read from the disc,
       currently about 150 KBytes/second. This is sufficient for all but
       uncompressed, full motion color video.

How to set Jumper Pin settings on a CD rom or hard drive

When installing a CD/DVD rom drive or even a hard drive, there are some
tiny little pins at the back that sometimes need to be adjusted. If you do not
have the jumper in the correct position, your device will not be recognised
by the computer.

There are three basic jumper pin settings
     1.    Cable Select
     2.    Master
     3.    Slave

Cable Select To use this setting you will need a cable select compatible
IDE cable. They have a blue end. This will allow you to connect Two
devices on the same cable. The cable decides which is master and which is
slave. By default the device plugged in on the end of the IDE will be the
master. For Example: If you installed two hard drives you will definitely
want your computer to boot to the main one with the operating system on
it. Therefore that harddrive will be plugged in on the last connection and
the slave hard drive will be on the middle connection. The other end will be
connected to the motherboard.
Master If you do not have a cable select cable, set your main hard drive to
master. This also applies if you have two CD Roms.
Slave Use this setting when you install a second harddrive or cd rom and
use the same cable for both. The main is the master..

Note: Don't put a cd rom on the same cable as a hard drive. But you can
have two hard drives together or two CD roms.

How do you find the Jumper pin settings combination?

The Jumper pin order of a CD rom or hard drive is usually written
somewhere on the drive. It could be at the back, like in the picture below,
or it could be on the top or sides. Sometimes there is an elaborate diagram
which confuses some people, however if you look for a familiar word or
letter, you will know that it is the pin order. Below they have abbreviated
the settings to CS (cable select), SL (slave), MA (master).


     A blue end on the IDE cable means it is a cable select. A normal
      black one means you have to set the hard drive jumper pins to either
      master or slave. The blue end connects to the motherboard.
      Sometimes the connection on the motherboard is blue also.
     A master gets plugged into the end of the IDE cable.
     If you wanted to add another hard drive you should have a master
      and a slave, selected with the jumper pins at the back of the harddrive.
      However the easiest way is to set them both to cable select. Then
      connect them on the same IDE Cable( they usually have two
      connections) but put the main hard drive on the last or end connection
      of the IDE cable. This way the one connected on the lower is the
     Now days the default settings are cable select. All new cables,
      devices, and motherboards are compatible.

                         Experiment No. 10
              To study various parts of MOUSE
The computer Mouse was invented in 1963 by a Mr Douglas Englebart.His
hardware invention is an input device which allows us to control a cursor
which in turn,allows us to input data in the computer.

The Mouse controls the pointer on the screen and is used to perform such
tasks as selecting icons,pointing and moving objects on the screen.Inside
the Mouse
are moving components allowing the input of data
making your computing easier and more fun.

The get the mouse to perform the desired task,you place the pointer in the
desired location and press one of the buttons to start the operation of the
you selected.

The mouse is moved on a mouse pad and this movement is tracked by four
components inside.As you can well image,this device get its name by the
shape and the cable or tail it has.

Function: The mouse is an input device that makes getting around on the
computer easier. The mouse controls an pointer on the screen which can be
moved anywhere. The mouse is used for doing tasks such as moving,
pointing to, or selecting objects on the screen. Once the mouse pointer is in
the correct position on the screen, pressing or clicking one of the buttons
will initiate an action or operation.

Most mice are mechanical. One mechanical part is the ball on the bottom
of the mouse. Turning and removing the retaining ring will allow the ball to
fall out. Inside there are three little wheels that move when the ball moves
against them. Two of these wheels are monitored electronically. As they
turn, they transmit how much they turned to the computer. One wheel tracks
the X-axis motion while the other tracks the Y-axis motion. The third is just
a wheel.

A PC mouse can have two or three buttons. A two button mouse is usually
standard. The middle button on a three button mouse can be programmed to
do certain tasks like double clicking. Pushing the middle button once would
be like trying to double click the left button on a two button mouse. A Mac
mouse has one button for navigating.

An Optical Mouse shines a beam of infrared light on a special mouse pad
with a grid. One roller measures movement in the X direction, and the other
in the Y direction. Each roller drives an axle with a plastic disk attached to
it. The plastic disk has a series of slots arranged radially at the outer edge of
the disk. A light emitting diode (LED) is placed on one side of the disk, and
a transducer on the other side.

As the mouse is moved, the plastic disk turns, creating pulses of light. The
transducer's signal is counted and converted into X and Y movement that
can be reported to the CPU. The optical mouse shoots two beams of
infrared light at right angles to each other onto the mouse pad. The beam is
reflected from the pad into a photo detector. The light beam is broken by
non-reflective patches on the mouse pad.

Serial mice connect directly to an RS-232C serial port or a PS/2 port. This
is the simplest and oldest type of connection. PS/2 mice connect to a PS/2
port. USB mice collect to a USB port.

Other Types: There are several types of mice as well as other input devices
similar to mice, such as a trackball, touchpad, and touchscreen.

      Cordless Infrared Mice
      The trackball has a ball on the top instead of on the bottom. The ball
       is moved with the thumb or palm. An advantages to this type of
       device is that once the mouse is in position, the grasp of the ball can
       be released to click the button and the mouse arrow will usually not
      The touchpad and touchscreen are very similar. A finger is used to
       move the cursor on the screen. With a touchpad, the finger is on a
       pad, while with a touchscreen, the finger is on the screen.

      Pen Input Devices
      Digitizing Pads

Different types of Mouse

                       Mini USB mouse for notepads

                            Mouse shaped like
                              a car for kids

                             Cordless Mouse

                               USB Mouse




Radio Frequency Cordless

      Pen Mouse

                                  Mechanical Mouse

                                 Three Button Mouse


This device normally will have two or three buttons on the top that we push down to give
middle button on a three button mouse can be used to do such tasks as double clicking

Instead of double clicking the left button on the standard two button mouse,you can click
the center button on the three button mouse which may be a little faster.

The movement of the move is sent to the computer by way of Four Pin Interface
Cable.This is where
information is transferred from the mouse to the PC.


When we move the mouse,a ball underneath rolls in the direction of the movement.This
moves a roller which moves the chopper gear.These components are housed inside a
cavity underneath the mouse.The mouse ball is the main component inside and allows
the user to move the mouse cursor on the screen.

The cursor would be motionless without the ball.And the ball uses two Choppers and
Gears to transmit
its movement to the computer.


When you purchase your mouse,it will, in most cases, come with a floppy disk containing
the device driver.This software communicates with the computer and your operating
system will most likely have this utility installed within its database.

Use the software on the diskette over any utility that your operating system may
offer.Once your mouse
is performing the way it should,visit its supporting web site and download any new
device driver for
your particular mouse.

Special software may be needed for the Optical, and the cordless mouse.As with the
mouse,download updates from their supporting web sites once you are up and running.

While understanding your mouse may seen to be such a big deal,learning about each
and every
component of your computer will boost your PC know how and help you save big on
future PC
repair costs.

                        Experiment No. 11
          To study various parts of KEYBOARDS
Description: A keyboard is a typewriter-like set of keys used to input data
                and control commands into a computer.

       Original PC boards came with 84 keys. Although several versions of
        the keyboard exist, the most common PC keyboard is the Enhanced
         Keyboard (101 Keyboard and the Window's 95 104 Keyboard).
       The two main varieties of Macintosh keyboards are the standard
          keyboard and the extended keyboard, which has 15 additional
       special-function keys. All of them are called ADB keyboards because
                  they connect to the Apple Desktop bus (ADB).

OTHER TYPES OF KEYBOARDS are the Ergonomic Keyboards, which
 look like they are broken in half, and keyboards with trackballs or finger
   pads. These keyboards use a QWERTY layout, have a calculator-type
            numeric keypad, and a set of cursor-movement keys.

                           Ergonomic Keyboard

                              Split Keyboard

Dvorak Keyboard: In addition their is another keyboard called the Dvorak
Keyboard. The Dvorak keymap is carefully adapted to the English language,
unlike the QWERTY. It groups all vowels and punctuation marks on the left
  side of the keyboard and common consonants on the right. For example,
  most typing in Dvorak takes place on the home row, so your fingers and
hands don't have to move around so much. Dvorak also divides words more
evenly between hands, so one hand isn't typing whole words like agree, fact,
    grass, greater, opinion, regard... Dvorak has alleviated some people's
  repetitive-stress injury (RSI) symptoms. In spite of these advantages, the
             DVORAK keyboard has never been fully accepted.

                    The Dvorak Keyboard


        There are two kinds of keyboard technologies.

   Capacitive technology generally is used in more expensive
keyboards. They have fewer moving parts, making them less prone to
  Switches are used in less expensive keyboards. Switch-type
  keyboards have a switch for every key, increasing the number of
moving parts. When a switch in the keyboard fails, it may be replaced
                    by soldering in a new key.

                     Experiment No.13
             Troubleshoot memory chip problems
This portion is one that is very difficult to outline in a study guide and is
where your experience is really being tested. There are far too many
different errors and solutions to be written here. We have included some
general troubleshooting information and common problems for various
components, however, this is by no means a comprehensive list. This is
where your on the job experience and work in your home lab are necessary.

Below is a list of useful tools for hardware troubleshooting:

      Standard and Phillips Screwdrivers - various sizes
      IC ROM Puller - For upgrading BIOS chips
      Multimeter - A necessary tool for troubleshooting electrical issues
       such as the power supply. It can also be used to do a resistance test.
       When performing this test make sure that the power to the system is

The following table shows the readings that you should see for various
multimeter tests:

                           Test           Good reading
                   Speaker Resistance 8 ohms
                   Fuse Resistance       0 ohms
                   Capacitors(DC)        5V (most of them)

Some components of a PC are field replaceable and some are not. Common
Field Replaceable Units(FRUs) are below:

      Monitor
      Keyboard
      Mouse
      Floppy Drive

      CDROM
      Hard Drives
      Printer
      Video Adapter
      Sound Card
      Network Card
      Motherboard
      Power Supply
      Processor
      CMOS Battery
      RAM

Beep codes vary depending on the manufacturer of the BIOS. Below are
some of the common beep codes for an Award BIOS.

                   Beep Code                  Meaning
               1 long                 System memory failure
               1 long then 2 short Video controller failure
               1 long then 3 short Video controller failure
               Continuous             Video or memory failure

Below are the IBM error code families and the component that the error
code relates to:
Error Code Family                        Error Type
1xx                    System board errors
2xx                    Memory (RAM) errors
3xx                    Keyboard errors
4xx                    Monochrome monitor errors
5xx                    Color monitor errors
6xx                    Game control adapter errors
7xx                    8087 or 80287 math coprocessor errors
9xx                    Parallel printer adapter errors

10xx                  Reserved for parallel printer adapter
11xx                  Asynchronous communications adapter errors
12xx                  Alternate asynchronous communications adapter errors
13xx                  Parallel printer adapter errors

      Lost BIOS password - Most newer motherboards have a jumper that
       can be used to clear the CMOS memory. Typically this involves
       opening the PC, changing the jumper to a special setting, and then
       booting the PC. If the memory has been cleared, you power the PC
       down and put the jumper back to its previous position
      System clock is not keeping correct time - This is typically caused by
       the CMOS battery failing or running low voltage. Usually, replacing
       the CMOS battery will fix this.
      System locks up consistently a few minutes after power up - This is
       usually associated with a failed processor fan or general overheating.
       Boot the system with the case off and see if the fan is running. If not,
       the fan and likely the processor will need to be replaced.
      System appears completely dead(no visible activity during powerup) -
       Check the external power cable and make sure that it is plugged into a
       working outlet and securely plugged into the unit. Next, make sure
       that the on/off switch is set to "On" and that the 115/230 switch is set
       to the appropriate setting for your location. Verify that the internal
       power connection from the power supply to the motherboard is firmly
       connected. A multimeter can be used to narrow determine how far the
       power is getting. Start at the outlet and work your way inside. Finally,
       remove all unnecessary components from the motherboard to see if
       one of them is overloading the power supply.
      Front panel lights come on and the power supply fan runs, but no
       other activity is present - Try swapping out the power supply. If this
       doesn't fix the problem, remove all unnecessary components from the
       motherboard to see if one of them is overloading part of the power

There are 2 types of memory errors:

          Soft-memory errors - These are occasional strange behaviors that can
           usually be cleared by rebooting.
          Hard-memory errors - Caused by a hardware failure related to the
           RAM and will usually display a message on the screen or create a
           beep code. Can be isolated by removing memory chips 1 at a time.

          System locks up while counting RAM - Usually requires that the
           processor be replaced

    Takeaway: Seldom do memory chips actually fail, but memory-related
    problems are all too common. Here are some tips to help you solve memory-
    related errors quickly and easily.

    Physical memory chips rarely go bad, but memory-related errors are some of
    the most common problems faced by the support pro. Learn how to
    accurately diagnose and troubleshoot various memory problems so that
    memory errors become less of a hassle and more of a quick fix.

    Is it really the memory?
    So often, reported memory problems are actually due to software or other
    component issues. To eliminate this possibility and save myself some time, I
    ask the following questions before doing anything else:
           Is the computer brand new? In this case, get your computer vendor
     to fix the problem under warranty. If this isn’t an option, read on.
           Were new memory chips recently installed? Check for incorrect or
     incompatible chips and make sure that they are correctly configured and
     seated properly in their sockets.
           Has any new software been installed? If the problems occurred
     soon after new software was installed, this could be the cause. Make sure
     the latest patches have been installed. Sometimes just reinstalling
     software will fix the problem. Since newer software tends to be more
     memory-intensive, older machines may not be able to handle the
     increased load. In this case, your only option may be to replace or
     upgrade the machine.

         Was new hardware installed or removed? Check the computer’s
     components for any loose connections and make sure that the new
     hardware is working properly.
         Did it happen on a computer that was previously working? Most
     perplexing memory problems tend to be of this kind. First of all, if the
     computer does not boot but merely beeps, usually this means that the
     CPU is not able to communicate with the hardware. Ensure that all
     components are properly installed and that you have the latest BIOS.

    Beware when installing new RAM chips
    Incorrect handling of chips can cause electrostatic discharge (ESD). This is
    where static from your body can damage the chips. Try to hold the chips by
    the edges, never touch the contacts, and ground yourself often by touching
    the metal part of your computer. Use a grounded antistatic wrist strap if

    True memory problems
    Once you’ve eliminated all other possibilities, it’s time to check for an actual
    memory problem. The following list is comprised of several potential
    memory problems and how to resolve them.
          The screen is blank: Check that the VGA card and memory chips
     are seated properly. Check compatibility between the motherboard and
     the chips.
          Not all memory is counted: This often means incompatible RAM
     chips have been installed. On many machines, chips are installed in pairs.
     If a new pair is not counted, check for compatibility with the motherboard
     and/or the existing chips. Error checking and correction (ECC) chips also
     have the habit of gradually counting less and less when there are
     problems. If the missing memory count is small, such as less than 10 MB,
     I usually leave it alone for the time being. After all, a 10-MB loss in a
     computer with 128 MB of memory is really not a cause for alarm.
          Computer hangs or suddenly reboots: Check that there is
     sufficient memory. Check for possible corrosion between each socket and
     chip. A faulty power supply can also be the culprit.
          General-protection faults: This is often caused by two pieces of
     software trying to occupy the same memory address. Rebooting usually
     solves the problem. If the problem occurs immediately after installing

     new memory, replace the chips. If the problem does not reappear, check
     with the manufacturer of the problem chips for known difficulties. I
     usually fix this problem by making sure that all the chips belong to the
     same batch from the same manufacturer.
          Memory errors reported by computer: If you get a “memory
     mismatch” error, make sure that settings are correct in CMOS
     (complementary metal-oxide semiconductor). Other errors such as
     “memory parity interrupt…,” “memory address error…,” “memory
     failure…,” and “memory verification error…” tend to occur when written
     information is not read back correctly from memory. The best way to
     check for incompatible chips is to remove the new chips and see if the
     problem goes away. If it does, your old and new chips may be
     incompatible. Install all new chips to solve the problem.
          Memory errors reported by server system manager: System
     managers are usually shipped with servers to monitor and report
     component abnormalities. Unless you are using ECC chips that
     automatically correct soft errors, a system manager will report a memory
     error if the rate of soft errors is greater than acceptable levels. I take this
     problem very seriously, as it can lead to server failure. Replace all the
     chips as soon as possible. Also make sure you have the latest BIOS.

    Since memory problems can be caused by components other than the chips,
    they need to be resolved through a process of elimination. If quality brands
    are used, chances are good that you will not encounter defective chips or
    corroded slots. However, incompatibility, dirty sockets, outdated BIOS, and
    newly released software will always require your investigative expertise.
    Hail to your job security!

                             Experiment No. 14

Trouble-shooting experiment related to various components of printers

PRINTER INTERFACE: The most common printer cable is for a parallel
port with a 25 pin male DB25 connector at one end and a 36 pin male
Centronics on the other and follows the IEEE 1284 standard. Serial printers
use a 9 pin male DB9 and follows the RS232C standard.

      Parallel connections are faster and more efficient, as eight wires can
       send information, one byte at a time. Parallel printers typically use a
       Centronics connector and their ports are referred to as LPT1 and
       LPT2 ports.

       Parallel ports can be unidirectional which is a 4-bit standard port
       which by factory default did not have the capability of transfering
       data both ways or bidirectional or capable of sending 8-bits input
       and output. Parallel cables used by printers today are bidirectional.
       Be sure your cable is bidirectional following the IEEE 1284

                      DB25 male             Centronics

      Serial cables can be longer than parallel ones. The maximum
       recommended length for a
          o serial cable is 50 feet.
          o parallel cable is 10 feet.

       Serial ports are not common for today's printers, but were frequently
       used with older printers and plotters. Serial ports are more
       commonly used for modems and are referred to as COM1 and


      IMPACT PRINTERS: Printers that form images by print wires

    striking a ribbon and pressing it against the paper.
        o Daisy Wheel: Old printers that were friction-fed, single-sheet
           printers, and had characters on a wheel.
        o Dot matrix printers are measured by how many pins are on the
           print heads. 9, 18, 24 pins are common. This type of printer
           employs movable print heads with pins or wires that shoot and
           strike the ribbon placing a dot on the paper with hundreds of
           dots forming images or text. Rated in character per second.
           They treat characters as raster (bitmap) images.
                Keep platen (roller on which the pins contact) clean
                  with denatured alcohol. Lubricate gears and pulleys.
                White bars going through text may mean you ned a new
                Chopped off characters mean the print head may need to
                Paper has dots and small smudges, the printhead is dirty.
                With faded image replace ribbon or move printhead
                  closer to platen.
                If images are light on one side, maybe the platen is out
                  of adjustment.
   NON-IMPACT printers place the ink, or print media, on the paper
    by some means other than impact, such as ink nozzles or high heat.
        o DIRECT THERMAL PRINTERS: use heat to burn images
           on paper. Here the printhead heats the paper instead of hitting
           it. Fax machine printers use this technology. Requires special
           thermal paper. Thermal paper is chemically treated so that the
           print head can heat it in the dotted patterns of letters.
           are formed by melting wax that then cools and binds the ink to
           the paper. Also requires special paper. Supports up to 300 dpi,
           but are slow. Also referred to as Color PostScript or Dye
           Sublimation printers.
        o INKJET PRINTERS - Printer forms letters and images on the
           paper by spraying small streams of quick-drying ink through a
           nozzle, using several different technologies. Some ink-jets use
           a piezo-electric crystal that squeezes the ink out by applying
           electrical current. Other printers use a small heating element
           that boils the ink, developing steam that forces the ink out of
           the nozzle.

o   LASER PRINTERS: Uses a heat transfer process. Placetoner
    that is heated until they bond with the paper. Toner Powder is
    a combination of plastic, metal (iron), and organic compounds.
    EP is short for electrophotographic. In the EP drum or toner
    cartridge images are created. Uses a laser beam to draw the
    image onto a photosensitive drum of aluminum. 300 dpi inch
    to over 1000 dpi. Rated in ppm (pages per minute).
         Requires 1,000 volts to create static electricity charge
            that moves toner.
         Heat and pressure fuses the toner to paper.
         Laser beam writes an image to photosenstive drum first.
         A mirror and motor direct the reflected light beam.
         The Main logic assembly is called ECP (electronic
            control package). It is the circuitry for talking to the
            CPU, control panel, and printer memory.
         Has 2 power supplies.High voltage power supply
            provides power to primary corona. The primary power
            supply provides power to motors that move paper,
            system electronics, the


    1. CLEANING and ERASING: A rubber cleaning blade is used to
       scrape the drum clean of toner. THIS STEP REMOVES IMAGE
       has no electrical charge. (The image is printed by positive dots
       against a negative surface and stored on drum.) Erase lights provide
       wavelength that bleeds away electrical charge from drum. Once the
       drum is erased it is neutral. The ERASE LAMP then resets the
       photosensitive lamp to clear.
    2. CONDITIONING: Is when the drum receives a negative (-6000
       volt) charge and spread by a thin wire called the PRIMARY
       CORONA WIRE (corona wire charges drum to attract toner).
       The drum becomes photoconductive. THIS STEP APPLIES
    3. WRITING: When beam of light or LASER touches surface of
       drum, the dot is less negative and more positive than the drum. It

        creates holes that develop into images. Software program controls
        what is sent. IN THIS STEP A LASER LIGHT WRITES TO
   4.   DEVELOPING: There is high charge where the light misses. The
        TONER CYLINDER (DEVELOPER ROLLER)is a long metal
        sleeve with a permanent magnet in it. It turns and attracts particles
        of toners to the sleeve. With no light, the high negative charge repels
        the negative charged toner particles. Where the light touches, there
        is less of a charge than the toner particles, and the toner is attracted
        to the drum. Toner has an attraction to holes that form images. Turns
        until the image is finished. THE TONER IS IONIZED WITH A
        charges the paper with a high positive charge to pull the the toner
        from the drum. THE TONER IS TRANSFERRED TO THE
   6.   FUSING: The FUSER includes 2 rollers. The fusing assembly is a
        quartz heating lamp inside a roller tube above a rubber pressure
        roller made of non-stick material. Paper is drawn between the heated
        upper roller and rubber lower roller, and subjected to enough heat to
        melt it (180 degress Celcius) and pressed into the paper by bottom
        roller. The fuser roller heats the toner sufficiently to cause it to melt;
        then, the pressure roller presses the melted toner into the paper,
        causing it to bond to the paper. There is a temperature sensor on
        heated fuser roller to stop fires. HEAT AND PRESSURE ARE
   7.   Back to Cleaning and Erasing.

Printer resolution is measured in DPI - dots per inch and PPM - pages per


       Common troubleshooting problems occur when more than one paper
        is feeding through the paper separation pad and when paper is being

    lifted by the pick up roller. Fan paper before placing in laser printer.

   "Insure that your printer is on. Generally your printer will have
    some type of light (generally green) which will indicate that the
    printer is on.
   ECP printer mode - Several printers do not work well with ECP
    mode. It is recommended that you check CMOS and insure that your
    printer mode is not set to ECP.
   Insure paper is loaded - Without paper your printer will not be able
    to print. Insure that you paper is loaded properly into the computer
    and that it is not in anyway jammed.
   Insure no blinking or orange lights - Blinking and or Orange
    lights generally indicate that your printer has some type of error. It
    is recommended that if you are getting any flashing lights that you
    refer to your manual to determine what these lights may mean.
   If new ink cartridges / Inkjet printer/ Laser - Insure that the
    protective film protective layer is still not on the Ink cartridge.
   Print self test - Most printers have a way of printing a test page.
    This page allows you to determine if the printer is physically
    working or not. This test is usually accomplished by holding down a
    series of keys. If you are not sure if your printer has this feature
    refer to your manual or visit your printer manufacturers web site.
   Printer software test - If you are running MS-DOS, Windows 3.x,
    Windows 95, Windows 98, or Windows NT you can attempt the
    following software test:
        o Get to a MS-DOS prompt - If you are running Windows 3.x
           click File then Exit / If you are running Windows 95, 98, or
           NT click Start - Shutdown - Restart the computer in MS-DOS
           mode. Get to the root directory
        o Type cd\ Reroute dir to printer - Type dir > lpt1 The above
           should take the directory listing and print to the printer. If this
           does refer to your operating system trouble shooting section.
   Paper will not feed - therefore press your FF or PP or manually
    eject the paper."
   Clean platen with denatured alcohol. Do not use alchohol on
    printheads (may smudge).
   In a laser, clean the transfer corona wires with carefully with soft


Troubleshooting Different types of Printers

There are several different types of printers and you will need to know their
print processes and common issues.

Feed Mechanisms:

      Pin Feed - Paper has perforated strip on each side that contains holes
       that fit onto pins that are rotated by a motor in the printer.
      Friction Feed - Typically uses rollers that press against the platen or
       drum that rotate forcing the paper through the printer.

Thermal Wax - Thermal wax printers use a roll of cellophane like film that
has colored panels on it. The file is rolled past a print head containing
thousands of heated elements that burn the wax from the film onto the paper.

Dye-Sublimation - The print process is very similar to the thermal wax
printers, however, there are a few differences. Dye-sublimation printers use
film that contains dye rather than wax and must be used with specially
coated paper. More importantly, they offer extremely high quality due to
their continuous tone printing. Continuous tone refers to the fact that the dots
put down by the printer can vary in size and intensity rather than using a
dithering process like other print processes. For this reason, dye-sub printers
can product photographic quality output.

Dot Matrix - Uses an impact printing process whereby a matrix of pins
imprint an image. Uses a Ribbon. ROM programs the Fonts.


      Smudges can be caused by the ribbon tension being too high
      Broken printhead pins can cause incomplete or missing characters.
      If the tops of characters are missing, the printhead is misaligned with
       the platen and needs to be reseated or the printhead carriage may need
       to be adjusted.

      If the print gets lighter on the page from left to right, the printhead
       distance from the plate is uneven and will need to be adjusted.

Ink Jet(or Bubble Jet) - No contact therefore quiet. Works by spraying ink
onto the paper in a sequential fashion. Similar in operation to a dot matrix


      Never refill cartridges which are causing problems. The head is part of
       the cartridge so replace the entire cartridge.
      If the output is disfigured or wavy, make sure that the paper thickness
       level is in the correct position. If it is, then the paper feed rollers
       probably need to be replaced.

Laser Printers - Uses a Page Description Language (PDL) to print a page at
a time. Main components are:

      Cleaning Blade - This rubber blade removes excess toner off the drum
       after the print process has completed.
      Photosensitive Drum - The core of the electrophotographic process.
       This component should not be exposed to light.
      Primary Corona Wire - Highly negatively charged wire erases the
       charge on the Photosensitive drum to make it ready for another image.
      Transfer Corona - A roller that contains a positively charged wire to
       pull the toner off the photosensitive drum and place it on the page.
      Toner - Plastic Resin. Naturally Negatively charged
      Fusing Rollers - Bonds the toner particles to prevent smearing. Uses
       heat to bond. A thermal fuse prevents the fuser from overheating.


      Blank Pages - Can be caused by No Toner, Transfer Corona Failure or
       HVPS Failure.
      Speckled Pages - Due to a failure in the cleaning step of the EP
       Process. Or a scratch on the EP drum.
      Ghosted Images - Caused if the erasure lamp doesn’t erase all of the
       image from the EP drum before the next page is printed.
      Smudged Images - The fusing process must have failed. The heating
       elements in the fusing rollers may be faulty.

      Dark spots - Can indicated toner buildup at some point in the paper
       path. Running blank sheets through it may clear problem.
      Jams in laser printers usually occur in the paper pickup area, the fuser
       or the registration area. They can be caused by incorrect paper settings
       or media types.

Electrophotographic Print Process(EP):
The process concerned with putting the image on the page. Follows Six

   1. Cleaning - The Drum is cleaned and electrically erased.
   2. Charging - The Drum is negatively charged to -5000Vdc. Done by the
      Primary Corona.
   3. Writing - The Laser sweeps the length of the drum applying the
      image. The Laser reduces the negative charge on the drum where the
      image is going to be.
   4. Developing - The Toner is transferred to the area on the drum which
      has been swept by the laser.
   5. Transferring - Once the image is on the drum the paper is fed through
      and the transfer corona wire attracts the image from the drum to the
   6. Fusing - The Fusing rollers heat up and pass the paper through
      bonding the toner to the paper. Uses a Non stick roller surface.

Physical Connections:
Older printers utilize a RS-232 connection that can either be 9 or 25 pin
serial port and cable. The cable should be less than 50 feet long (15.25
meters). Serial configuration requires that the port be configured with parity
type, speed, protocol and character frame must be configured.

                         Parallel connections utilize a DB-25 port(left) on
                         the computer to connect to the printer. Parallel
                         cables should be less than 10 feet(3 meters). Most
                         parallel ports are now Extended Capability Ports
                         (ECP) which offers increased performance over
                         previous standards. Both the computer's parallel
                         port and the peripheral's port must support ECP in
                         order to use it.

Many newer printers use USB connections and higher-end printers have rj-
45 network connections and can be integrated with standard networks. Older
models may have coaxial network connections. Another popular connection
solution is the print server such as a Jet-Direct interface that connects to the
printers parallel port and has an RJ-45 connection at the other end.

The Basics: Static Electricity

The primary principle at work in a laser printer is static electricity, the same
energy that makes clothes in the dryer stick together or a lightning bolt travel
from a thundercloud to the ground. Static electricity is simply an electrical
charge built up on an insulated object, such as a balloon or your body.
Since oppositely charged atoms are attracted to each other, objects with
opposite static electricity fields cling together.

               The path of a piece of paper through a laser

A laser printer uses this phenomenon as a sort of "temporary glue." The core
component of this system is the photoreceptor, typically a revolving drum
or cylinder. This drum assembly is made out of highly photoconductive
material that is discharged by light photons.

The basic components of a laser printer

                              Experiment No.15
          Trouble-shooting experiment related to various
                components of CD-ROM Drive?
OBJECTIVE: Determine whether the CD or the DVD drive is located on
the Hardware Compatibility List.

Locate the manufacturer and part number of your CD or your DVD drive on
the Hardware Compatibility List. If your drive is not listed on the Hardware
Compatibility List, contact the manufacturer of the drive. To check whether
your CD or your DVD drive is located on the Hardware Compatibility List,
follow these steps

      1. In the Devices left navigation pane, point to Storage, and then
         click Optical Disk Drive.
      2. Select the manufacturer of your CD or your DVD drive from the
         Company drop-down list, and then click GO.
      3. Locate your CD or your DVD drive part number from the product

         If your CD or your DVD drive is not listed, contact the device
         manufacturer for a Windows device driver or for compatibility

         If your CD or your DVD drive is listed, click the name of the drive
         in the Product Name column to see the notes about certification
         and driver availability.

As soon as you have determined that the CD or the DVD drive and the SCSI
controller are compatible with Windows XP, follow these steps to
troubleshoot issues that you are still experience with the drive:

1. Verify that the CD or the DVD drive is installed according to the
   manufacturer's specifications.
2. If you installed a SCSI CD or DVD drive:
       a. Verify that the SCSI bus is stopped correctly. On a SCSI
          bus, the last SCSI device should be stopped by using a
          terminator that is provided by the manufacturer. For more
          information about termination, see the documentation for the
          SCSI adapter.
       b. Verify the CD or the DVD SCSI ID. The SCSI ID of the CD
          or the DVD drive is typically set to SCSI ID 2 or higher.
          Make sure that the CD or the DVD drive is not configured to
          use the same SCSI ID that another device is using. For
          information about how to set or how to change the SCSI ID
          of your CD or your DVD drive, see the documentation for
          the CD or the DVD drive.
       c. Verify that the SCSI ID of the SCSI controller is set to SCSI
          ID 7.
       d. Verify that no other adapters are configured by using settings
          that conflict with the SCSI controller settings.
       e. Look in the Microsoft Windows Event Viewer for error
          messages that apply to the CD or the DVD drive or the SCSI
          controller. To do this, follow these steps:
              1. Click Start, and then click Control Panel.
              2. Double-click Administrative Tools, and then double-
                 click Computer Management.
              3. In the left pane, expand Event Viewer, and then click
                 System to view the system log in the right pane for
                 error messages that apply to the CD or the DVD drive
                 or the SCSI controller.
       f. Verify that Device Manager detects the SCSI controller and
          the CD or the DVD drive, and that your device is working
          correctly. To do this, follow these steps:
              1. Click Start, right-click My Computer, and then click
              2. Click the Hardware tab.
              3. Under Device Manager, click Device Manager.

                   4. Find your device on the list of devices.

Troubleshooting the installation of an IDE CD or DVD drive
If you installed an IDE CD or DVD drive, follow these steps:

      1. Make sure that you are using a device driver that is designed for
         the IDE controller to which the CD or the DVD drive is attached.
         To do this, follow these steps:
             a. See the product documentation that is included with your CD
                or your DVD drive, and note the device drivers that the
                manufacturer recommends.
             b. In Device Manager, verify that the device driver that the
                manufacturer recommends matches the device driver that is
             c. If the device driver does not match, contact the manufacturer
                of the CD or the DVD drive to obtain a device driver that is
                designed for the IDE controller to which the CD or the DVD
                drive is attached.
      2. If the manufacturer does not provide a specific driver for your IDE
         controller, install the IDE controller driver that is included with
         Windows XP. This driver is compatible only with IDE CD or DVD
         drives that are ATAPI 1.2-compliant. To verify the ATAPI
         compliance level of your CD or your DVD drive, contact the
         manufacturer of the CD or the DVD drive. To install the IDE
         controller driver that is included with Windows XP, follow these
      . Right-click the IDE controller driver that you want to replace, and
         then click Update Driver.
             a. Follow the instructions that appear on the screen to update
                the driver.

Troubleshooting the installation of a CD or a DVD drive that uses a
proprietary, non-SCSI interface
If you try to install a CD or a DVD drive that uses a proprietary, non-SCSI
interface, follow these steps:

1. Verify that the correct device driver is installed. To do this, run
   Windows XP Setup and select Add/Remove SCSI Adapters on
   the Options menu.

   Note You must have your original device driver disk available to
   install during this procedure.
2. Check the Windows XP Read Me file (Readme.wri) and the
   Windows XP HCL for notes that apply to your proprietary, non-
   SCSI interface CD or DVD drive.

                        Experiment No.16
                      How to assemble a PC
If you have purchased all the necessary hardware your are ready assemble
your PC. Before unpacking your components from its original anti-static
bags you must put on your anti-static wrist strap, which will discharge your
self. It is important that you discharge yourself or there is a danger that you
can damage your components by anti-static shock by touching the
components. If you don't have an anti-static wrist strap you can discharge
your self by touching the metal edges of your ATX case, although this is not
recommended. Be careful not to cut yourself as some ATX cases have sharp
edges. Have all the mounting screws that come with the motherboard and a
philips screw driver handy as you would need them during the later stages.

Now you can proceed to the first step:

Step 1 - Motherboard Installation

Install Motherboard

The first thing you should do is unpack your ATX case. Take off the cover
of your case so that you can access the inside. Place the case on a desk so
that you are looking down towards the open case. Your case should come
with motherboard mounting screws. If your ATX back plate it not already
fitted you can fit it by placing your plate near the ATX back plate cut out
and pushing the plate outwards, it should clip on.

Now place your motherboard on top of the mounting screw holes. Make sure
your ATX devices on the motherboard such as PS/2 and parallel port are
facing towards ATX back plate cut out. Gently push your motherboard
towards the cut out, every devices should fit easily into its corresponding cut
out, as shown below.

The screw holes on your motherboard should align with the screw holes on
your case. Place your screws that came with the case into the appropriate
holes and gently screw it on using a screw driver.

The motherboard is now securely mounted to the case. You can now place
the ATX power connector to the motherboard. Your ATX case should come
with a power supply unit (PSU) and should already be mounted to the case.
The ATX power connector is shown on image below.

Place the ATX power connector on top of the power socket on the
motherboard. Push down the power connector and it should clip onto the
socket. If you try to fit the power connector the wrong way round, it won't
fit, it will only fit one way. So, if the power connector does not go in, it
should go in the other way round.

Next - Processor (CPU) Installation

Install a Processor (CPU)

Locate the processor socket on your motherboard. I am installing an Intel
PIII 866 processor on a socket 370 as shown on the following image. The
installation would be slightly different if you have a different processor i.e.
Slot1 PIII CPU, P4 Socket 478, Core 2 Duo Socket 775, AMD Slot A /
Socket A, Socket AM2 CPU etc.

Raise the brown lever on the socket and slowly put the processor in place.
You have to make sure the pin 1 of your CPU goes into the pin 1 of your
CPU socket otherwise the CPU would not get into the socket, so don't try to
force it in. It will go in gently if you fit it correctly. Now close the brown
lever which will securely hold the CPU in place.

If you bought a retail boxed CPU it would include a heatsink + fan. If you
bought an OEM CPU make sure you got a fan that is correct for the speed of
your CPU, otherwise your CPU will overheat and behave abnormally or
could be damaged. Take off the plastic cover from the bottom of the CPU
fan that covers the heat transfer pad. Now place the CPU fan on top the CPU
and push down the metal clips on the fan so that it clips onto the CPU

CPU fan has a power connector which needs to be connected to CPU fan
power socket on your motherboard as shown on the image above.

Finally, you have to specify what frequency (speed) your CPU is running at.
This can be done using jumper settings, or on some modern motherboard it
can be done in the BIOS, or your motherboard may have automatic detection
for your CPU frequency. Please refer to your motherboard manual for more
details. The motherboard I am using (Abit BX133) has a dip-stick jumper
setting and it can be setup in the BIOS. I have left the jumper setting to
default as I will use the BIOS to specify the CPU frequency. The CPU runs
at the bus speed of 133Mhz therefore I will use the settings 133 *
6.5(multiplier) under the BIOS, which will the run the CPU at 866Mhz.

Next - Memory Installation (SDRAM)

Install Memory - SDRAM

Installing memory is quite simple. Find the SDRAM banks on your
motherboard, they should look similar to the banks below. Notice the
memory banks has a white clip on each side. Make sure you release the clips
so it bends to each side.

Hold each corner of the SDRAM placing it on top of the bank 1. You will
notice that the SDRAM has a cut at the bottom side, it is there to prevent the
memoy going in the wrong way round. If you are holding the SDRAM the
incorrect way you will not be able insert it. Gently push down the SDRAM

and it should clip on to the memory bank. The two white clips will now
become straight holding each corner of the memory. If you have more that
one SDRAM perform same steps as above but placing the SDRAM in
memory bank 2 and so on.

Next - Hard Disk Drive Installation

IDE or SATA Hard drive

Please choose the type of hard drive you will be using to build the system. If
you have an IDE hard drive (also known as ATA or PATA) then choose
IDE. If you have SATA ( Serial ATA) hard drive then choose SATA. If you
don't know what type hard drive you have, then look at the image below and
choose the one that matches your hard drive.

Install IDE Hard Drive

If you look at the rear side of an IDE hard drive it should look similar to the
image below.

The IDE/ATA connector is on the left hand side which consists of many
pins. Next to the IDE connector is the jumper setting for the drive. The
jumper should be set to Master, which is the default setting for a new HDD.
Any other device sharing the same IDE cable should be set to Slave.
Different HDD has different jumper settings, please refer to your HDD
manual for more information. On the right hand side, next to the jumpers is

the power connector. Every device except FDD uses this type of power

Figure 1 and 2 below shows what an ATA 66 and a power cable looks like.
The ATA 66 cable which is also known as UDMA 66 cable is an advance
IDE cable, which offers higher performance and data integrity than the
standard IDE cable. ATA 66 cable consists of 80 conductor cable where as
the standard IDE cable consists of 40 conductor cable. I am using an ATA
66 cable because the above HDD is an ATA 100 drive which requires an
ATA 66 cable.

                        Figure 1 - ATA 66 Cable

                           Figure 2 - Power cable

Install IDE Hard Drive

Place your hard drive into the HDD mounting slot of your case, make sure
the IDE/ATA connector is facing outwards. Screw the HDD to the case
using screws provided with the HDD or the ATX case.

Insert the ATA 66 cable into the ATA connector of the HDD. Make sure the
pin 1 on the cable is connected to pin 1 on the HDD connector. Pin 1 is the
red or pink strip on the edge of an ATA cable. Most new IDE/ATA cables
are designed so that it will only go in one way which will correspond to pin

Push the power cable into the power connector as shown. The power cable is
designed to go in one way, so you shouldn't have any problems.

Connect the other end of the ATA 66 cable to the primary ATA socket of
your motherboard as shown. Make sure the pin 1 on the cable connects to
the pin 1 on the ATA socket.

That's it you have successfully installed a HDD.

Install Floppy Disk Drive

The rear side of a floppy drive looks similar to the following image.

The black connector on the left hand side is the floppy disk connector. It is
different from the IDE connector and uses a different cable. The small white
connector on the right hand side is the power connector for the floppy drive.
Figure 1 and 2 below shows what a floppy drive cable and floppy drive
power connector looks like.

                      Figure 1 - Floppy drive cable.

                   Figure 2 - Floppy drive power cable

Install Floppy Disk Drive

Place the floppy drive into the FDD mounting slot as shown. Screw the drive
securely into place.

Insert the floppy drive cable into the floppy drive connector. Make sure the
pin 1 on the cable connects to the pin 1 on the floppy drive connector. As
you already know by now that pin 1 is the red or pink strip on the edge of
the floppy drive cable. Most floppy drive cables are designed so that it will
only go in on way, so you can not connect it incorrectly.

Push the floppy drive power cable to the power connector. This will only go
in on way.

Finally connect the other end of the floppy drive cable to floppy drive
connector on your motherboard. Make sure pin 1 on the cable connects to
pin 1 on the connector.

Next - CD-ROM/DVD-ROM Installation

Install CD / DVD-ROM

If you look at the rear side of your CD / DVD-ROM it should look similar to
image shown on figure 1.

On the right hand side you have the power connector. Next to power
connector you have the IDE connector. On the left hand side near the IDE
connector you have the jumper settings for the DVD-ROM. The jumper is
set to Master by default. I am connecting the DVD-ROM on a separate IDE
cable therefore I will leave the jumper setting to Master. However if you are
sharing an IDE cable with another device like HDD, then you would have to
set jumper to Slave, as your HDD would be set to Master. Next to the
jumpers you have the CD Audio-Out socket. One side of your audio cable
connects to this socket and other side connects to the sound card cd-in
socket. This would allow you to listen to Audio CD's on your computer.

                               Figure 1

                               Figure 2

Mount your CD/DVD-ROM drive into its mounting slot. Use the supplied
screws to screw the drive into position.

                               Figure 3

Connect the IDE cable to the drives IDE connector. Make sure the pin 1 on
the cable is connected to pin 1 on the drives IDE connector. Pin 1 is the red
or pink strip on the edge of an IDE cable. Connect the other end of the IDE
cable to the IDE socket on your motherboard as shown in figure 4. Again,
make sure you conncet the cable to pin 1. The IDE socket could be your
primary or secondary socket depending which socket you choose. If your
HDD is on the primary IDE socket and your secondary IDE socket is free,
then it is better to use your secondary IDE socket for the CD/DVD-ROM.

                                    Figure 4

Finally connect the power cable to power connector and connect the audio
cable to the CD Audio-Out socket as shown on figure 3.

Next - Graphics card installation

Install Graphics Card

Most modern graphics cards are AGP based and connects to the AGP bus of
the motherboard. An AGP bus (slot) looks like the following image. The
brown slot is where you connect your AGP graphics card.

Place your AGP card on top of the slot and gently push it down. The card
should firmly sit into position.

All you need to do now is to screw the metal plate on the front of the card to
the ATX case. Use the screws supplied with case and screw the card to the

Next - Sound card Installation

Install Sound Card

Most modern sound cards are designed with the PCI interface and connects
to the PCI slot of your motherboard. A PCI slot looks like the slots on the
following image.

Place your sound card on top of a chosen slot. Gently push down the card so
it sits into position. Once the card is seated correctly into position, screw the
card on to the case

Finally insert the audio cable into the CD-IN socket. The other end of the
cable should be connected to Audio-out socket on your CD/DVD-ROM

Next - Modem Installation

Install Modem

Find a free PCI slot on your motherboard (assuming your modem is a PCI
modem). Place your modem card on top of the slot and gently push it down
into position.

Once the card has seated correctly into position, screw the card to the case
using the screws supplied with the case.

Now you have installed all the prerequisite hardware devices. You can either
proceed to the finalising stage, or you may want to install optional devices
like a ZIP drive, CD-RW drive or a TV-Card. If you do not want to install
these devices you can now proceed to the finalising stage.

Install CD Writer

The rear end of your CD-RW drive should look similar to the image below.

It contains all the usual connectors such an IDE connector, a power
connector, audio connector, and a place to set the jumpers. Set the jumpers
so the drive is configured to run as a Master device. It is best to connect your
CD-RW on separate IDE cable. This would avoid problems while you copy
CD's on-the-fly. This means copying a source CD from a CD/DVD-ROM
drive to a blank destination CD in your CD-RW drive without the source CD
being copied to the hard disk first. Copying on-the-fly is less time
consuming than copying the source CD to the hard disk first. However if
you decide to connect your CD-RW drive and another device like a DVD-
ROM on the same IDE cable, it would be fine providing you make an image
of your source CD on a HDD first before copying to your blank CD. You

may have problems such as "buffer under run" errors if you try to copy on-

Place your CD-RW drive into a mounting slot as shown. Position the drive
correctly and screw it onto the case.

Connect the IDE and the power cable to the drive. If you want to use the
CD-RW drive for playing Audio CD's then you also need to connect an
audio cable to the Audio-out socket of the drive. If you have a CD/DVD-
ROM then the audio cable is usually connected that drive instead of the CD-
RW, but there is no reason why you can't have both.

Finally the other end of the IDE cable should be connected to an IDE socket
of the motherboard.

Install TV Card

Installing a TV card is no more difficult than installing any other PCI cards.
Locate an unused PCI slot and place the card on top. Gently push card down
into the slot.

When the card is correctly in position, screw the card securely on to the

Note that a TV card uses two IRQ (Interrupt Request) one for video and one
for audio. It is best to place your TV card into a slot which does not conflict
with an IRQ of another device. Although IRQ sharing is possible, some TV
cards may behave abnormally if you are sharing IRQ's.

Finalizing Stage

Now that you have installed all the necessary hardware there are still few
more things you need to do before switching on your PC for the first time.
Your ATX case has a power switch which turns the PC on, a reset switch for
resetting the system, a power LED which comes on when the PC is switched
on and a hard drive LED which flashes when data is being written or read
from your hard drive. You also have an internal speaker.

                      Figure 1 - Power and Reset switch

The switches and LED's need to be connected to its corresponding
connectors on the motherboard. Please refer to your motherboard manual to
locate where the connectors are. Different motherboards place the
connectors in different locations. The connectors for the switches and LED's
are normally grouped together. They should look similar to the image below.

                   Figure 2 - Switch and LED connectors

Every cable is normally labeled, they are normally named as follows, but
could be slightly different on your system.

                   Power switch    Power / PWR-SW
                   Reset switch    Reset
                                   Power LED / PWR-
                   Power LED
                   Hard drive      HDD-LED / IDE
                   LED             LED
                   Speaker         SPK / Speaker

The connectors on the motherboard are also labeled but may be too small to
see. Instead refer to your motherboard manual which would provide details
on which pins you should connect the cables to. The image below shows
how the pins may be organised on your motherboard.

                         Experiment No. 18
To study monitor, its circuitry and various presents and
           some elementary fault detection

Because we use them daily, many of us have a lot of questions about our
monitors and may not even realize it. What does "aspect ratio" mean? What
is dot pitch? How much power does a display use? What is the difference
between CRT and LCD? What does "refresh rate" mean?

In this article, HowStuffWorks will answer all of these questions and many
more. By the end of the article, you will be able to understand your current
display and also make better decisions when purchasing your next one.

Monitor Display Technology
Often referred to as a monitor when packaged in a separate case, the display
is the most-used output device on a computer. The display provides instant
feedback by showing you text and graphic images as you work or play.
Most desktop displays use liquid crystal display (LCD) or cathode ray tube
(CRT) technology, while nearly all portable computing devices such as
laptops incorporate LCD technology. Because of their slimmer design and
lower energy consumption, monitors using LCD technology (also called flat
panel or flat screen displays) are replacing the venerable CRT on most

Resolution refers to the number of individual dots of color, known as pixels,
contained on a display. Resolution is expressed by identifying the number of
pixels on the horizontal axis (rows) and the number on the vertical axis
(columns), such as 800x600. Resolution is affected by a number of factors,
including the size of the screen.
As monitor sizes have increased over the years, display standards and
resolutions have changed. In addition, some manufacturers offer widescreen
displays designed for viewing DVD movies.

               Common Display Standards and Resolutions

                Standard         Resolution Typical Use
                XGA                       15- and 17-inch
                (Extended                 CRT monitors
                Graphics                  15-inch LCD
                Array)                    monitors
                                      15- and 17-inch
                SXGA (Super           CRT monitors
                XGA)                  17-and 19-inch
                                      LCD monitors
                                      19-, 20-, 21-
                                      inch CRT
                UXGA (Ultra
                            1600x1200 monitors
                                      20-inch LCD
                                     21-inch and
                QXGA (Quad
                           2048x1536 larger CRT
                                    Wide aspect
                WXGA (Wide          15.4-inch
                XGA)                laptops
                                    LCD displays
                WSXGA+               Wide aspect
                (Wide SXGA 1680x1050 20-inch LCD
                plus)                monitors
                                           Wide aspect
                                           22-inch and
                (Wide Ultra      1920x1200
                                           larger LCD

In addition to the screen size, display standards and resolutions are related to
something called the aspect ratio. Next, we'll discuss what an aspect ratio is
and how screen size is measured.

Aspect Ratio and Viewable Area
Two measures describe the size of your display: the aspect ratio and the
screen size. Historically, computer displays, like most televisions, have had
an aspect ratio of 4:3. This means that the ratio of the width of the display
screen to the height is 4 to 3.
For widescreen LCD monitors, the aspect ratio is 16:9 (or sometimes 16:10
or 15:9). Widescreen LCD displays are useful for viewing DVD movies in
widescreen format, playing games and displaying multiple windows side by
side. High definition television (HDTV) also uses a widescreen aspect ratio.
All types of displays include a projection surface, commonly referred to as
the screen. Screen sizes are normally measured in inches from one corner to
the corner diagonally across from it. This diagonal measuring system
actually came about because the early television manufacturers wanted to
make the screen size of their TVs sound more impressive.
Interestingly, the way in which the screen size is measured for CRT and
LCD monitors is different. For CRT monitors, screen size is measured
diagonally from outside edges of the display casing. In other words, the
exterior casing is included in the measurement as seen below.

         For LCD monitors, screen size is measured diagonally
         from the inside of the beveled edge. The measurement
         does not include the casing as indicated in the image

                    LCD screen size

Because of the differences in how CRT and LCD
monitors are measured, a 17-inch LCD display is
comparable to a 19-inch CRT display. For a more
accurate representation of a CRT's size, find out its
viewable screen size. This is the measurement of a CRT
display without its outside casing.
 Popular screen sizes are 15, 17, 19 and 21 inches.
Notebook screen sizes are smaller, typically ranging from
12 to 17 inches. As technologies improve in both desktop
and notebook displays, even larger screen sizes are
becoming available. For professional applications, such
as medical imaging or public information displays, some
LCD monitors are 40 inches or larger!
Obviously, the size of the display directly affects
resolution. The same pixel resolution is sharper on a
smaller monitor and fuzzier on a larger monitor because
the same number of pixels is spread out over a larger
number of inches. An image on a 21-inch monitor with an

800x600 resolution will not appear nearly as sharp as it
would on a 15-inch display at 800x600.

Multi-scanning Monitors
If you have been around computers for more than a
decade, then you probably remember when NEC
announced the MultiSync monitor. Up to that point, most
monitors only understood one frequency, which meant
that the monitor operated at a single fixed resolution and
refresh rate. You had to match your monitor with a
graphics adapter that provided that exact signal or it
wouldn't work.
The introduction of NEC MultiSync technology started a
trend towards multi-scanning monitors. This technology
allows a monitor to understand any frequency sent to it
within a certain bandwidth. The benefit of a multi-
scanning monitor is that you can change resolutions and
refresh rates without having to purchase and install a new
graphics adapter or monitor each time.

Analog and DVI Connections
To display information on a monitor, your computer
sends the monitor a signal. The signal can be in analog or
digital format.

Analog (VGA) Connection
Because most CRT monitors require the signal
information in analog (continuous electrical signals or
waves) form and not digital (pulses equivalent to the
binary digits 0 and 1), they typically use an analog
However, computers work in a digital world. The
computer and video adapter convert digital data into
analog format. A video adapter is an expansion card or
component that provides the ability to convert display
information into a signal that is sent to the monitor. It can
also be called a graphics adapter, video card or graphics

Once the display information is in analog form, it is sent
to the monitor through a VGA cable. The cable connects
at the back of the computer to an analog connector (also
known as a D-Sub connector) that has 15 pins in three
rows. See the diagram below:

       1: Red     6: Red return    11: Monitor ID
       out        (ground)         0 in
                                12: Monitor ID
       2: Green 7: Green return 1 in
       out      (ground)        or data from
       3: Blue    8: Blue return   13: Horizontal
       out        (ground)         Sync out
       4:                          14: Vertical
                  9: Unused
       Unused                      Sync
                                  15: Monitor ID
       5:         10: Sync return
                                  3 in
       Ground     (ground)
                                  or data clock

You can see that a VGA connector like this has three
separate lines for the red, green and blue color signals,
and two lines for horizontal and vertical sync signals. In a
normal television, all of these signals are combined into a
single composite video signal. The separation of the
signals is one reason why a computer monitor can have
so many more pixels than a TV set.
Because a VGA (analog) connector does not support the
use of digital monitors, the Digital Video Interface

(DVI) standard was developed.

DVI Connection
DVI keeps data in digital form from the computer to the
monitor. There's no need to convert data from digital
information to analog information. LCD monitors work
in a digital mode and support the DVI format. (Although,
some also accept analog information, which is then
converted to digital format.) At one time, a digital signal
offered better image quality compared to analog
technology. However, analog signal processing
technology has improved over the years and the
difference in quality is now minimal.
The DVI specification is based on Silicon Image's
Transition Minimized Differential Signaling (TMDS)
and provides a high-speed digital interface. A transmitter
on the video adapter sends the digital information to a
receiver in the monitor. TMDS takes the signal from the
video adapter, determines the resolution and refresh
rate that the monitor is using, and spreads the signal out
over the available bandwidth to optimize the data transfer
from computer to monitor.
DVI cables can be a single link cable that uses one
TMDS transmitter or a dual link cable with two
transmitters. A single link DVI cable and connection
supports a 1920x1080 image, and a dual link
cable/connection supports up to a 2048x1536 image.

    There are two main types of DVI connections:
          DVI-digital (DVI-D) is a digital-only format. It
    requires a video adapter with a DVI-D connection and a
    monitor with a DVI-D input. The connector contains 24
    pins/receptacles in 3 rows of 8 plus a grounding slot for
    dual-link support. For single-link support, the connector
    contains 18 pins/receptacles.
          DVI-integrated (DVI-I) supports both digital and
    analog transmissions. This gives you the option to
    connect a monitor that accepts digital input or analog
    input. In addition to the pins/receptacles found on the
    DVI-D connector for digital support, a DVI-I connector
    has 4 additional pins/receptacles to carry an analog

  DVI-D connectors carry a digital-only signal and
   DVI-I adds four pins for analog capability. Both
    connectors can be used with a single-link or a
  dual-link cable, depending upon the requirements
                     of the display.
If you buy a monitor with only a DVI (digital)
connection, make sure that you have a video adapter with
a DVI-D or DVI-I connection. If your video adapter has
only an analog (VGA) connection, look for a monitor that
supports the analog format.

Color Depth
The combination of the display modes supported by your
graphics adapter and the color capability of your monitor
determine how many colors it displays. For example, a
display that operates in SuperVGA (SVGA) mode can
display up to 16,777,216 (usually rounded to 16.8
million) colors because it can process a 24-bit-long
description of a pixel. The number of bits used to
describe a pixel is known as its bit depth.
With a 24-bit bit depth, eight bits are dedicated to each of
the three additive primary colors -- red, green and blue.
This bit depth is also called true color because it can

produce the 10,000,000 colors discernible to the human
eye, while a 16-bit display is only capable of producing
65,536 colors. Displays jumped from 16-bit color to 24-
bit color because working in eight-bit increments makes
things a whole lot easier for developers and programmers.
Simply put, color bit depth refers to the number of bits
used to describe the color of a single pixel. The bit depth
determines the number of colors that can be displayed at
one time. Take a look at the following chart to see the
number of colors different bit depths can produce:
        Bit-Depth          Number of Colors
                           (High Color, XGA)
                          (True Color, SVGA)
                     (True Color + Alpha Channel)

Notice that the last entry in the chart is for 32 bits. This is
a special graphics mode used by digital video, animation
and video games to achieve certain effects. Essentially,
24 bits are used for color and the other eight bits are used
as a separate layer for representing levels of translucency
in an object or image. Nearly every monitor sold today
can handle 24-bit color using a standard VGA connector.
To create a single colored pixel, an LCD display uses
three subpixels with red, green and blue filters. Through
the careful control and variation of the voltage applied,

the intensity of each subpixel can range over 256 shades.
Combining the subpixels produces a possible palette of
16.8 million colors (256 shades of red x 256 shades of
green x 256 shades of blue).
Now that you have a general idea of the technology
behind computer monitors, let's take a closer look at LCD
monitors, CRT monitors, and the general buying
considerations for both.

LCD Monitors
Liquid crystal display technology works by blocking
light. Specifically, an LCD is made of two pieces of
polarized glass (also called substrate) that contain a liquid
crystal material between them. A backlight creates light
that passes through the first substrate. At the same time,
electrical currents cause the liquid crystal molecules to
align to allow varying levels of light to pass through to
the second substrate and create the colors and images that
you see.

Active and Passive Matrix Displays
Most LCD displays use active matrix technology. A
thin film transistor (TFT) arranges tiny transistors and
capacitors in a matrix on the glass of the display. To
address a particular pixel, the proper row is switched on,
and then a charge is sent down the correct column. Since
all of the other rows that the column intersects are turned
off, only the capacitor at the designated pixel receives a
charge. The capacitor is able to hold the charge until the
next refresh cycle.

    The other type of LCD technology is passive matrix.
    This type of LCD display uses a grid of conductive metal
    to charge each pixel. Although they are less expensive to
    produce, passive matrix monitors are rarely used today
    due to the technology's slow response time and imprecise
    voltage control compared to active matrix technology.
    Now that you have an understanding of how LCD
    technology works, let's look at some specific features
    unique to LCD monitors.

    CRT Monitors
    A CRT monitor contains millions of tiny red, green, and
    blue phosphor dots that glow when struck by an electron
    beam that travels across the screen to create a visible
    image. The illustration below shows how this works
    inside a CRT.

    The terms anode and cathode are used in electronics as
    synonyms for positive and negative terminals. For
    example, you could refer to the positive terminal of a
    battery as the anode and the negative terminal as the

    In a cathode ray tube, the "cathode" is a heated filament.
    The heated filament is in a vacuum created inside a glass
    "tube." The "ray" is a stream of electrons generated by an
    electron gun that naturally pour off a heated cathode into
    the vacuum. Electrons are negative. The anode is
    positive, so it attracts the electrons pouring off the
    cathode. This screen is coated with phosphor, an organic
    material that glows when struck by the electron beam.
    There are three ways to filter the electron beam in order
    to obtain the correct image on the monitor screen: shadow
    mask, aperture grill and slot mask. These technologies
    also impact the sharpness of the monitor's display. Let's
    take a closer look at these now

    Display History 101
    Displays have come a long way since the blinking green
    monitors in text-based computer systems of the 1970s.
    Just look at the advances made by IBM over the course of
    a decade:
           In 1981, IBM introduced the Color Graphics
    Adapter (CGA), which was capable of rendering four
    colors, and had a maximum resolution of 320 pixels
    horizontally by 200 pixels vertically.
           IBM introduced the Enhanced Graphics Adapter
    (EGA) display in 1984. EGA allowed up to 16 different
    colors and increased the resolution to 640x350 pixels,
    improving the appearance of the display and making it
    easier to read text.
           In 1987, IBM introduced the Video Graphics Array
    (VGA) display system. The VGA standard has a
    resolution of 640x480 pixels and some VGA monitors are
    still in use.
    IBM introduced the Extended Graphics Array (XGA)
    display in 1990, offering 800x600 pixel resolution in true
    color (16.8 million colors) and 1,024x768 resolution in
    65,536 colors.

    CRT Features and Attributes
    To evaluate the specifications of CRT monitors, here are

    a few more things you need to know:

    A shadow mask is a thin metal screen filled with very
    small holes. Three electron beams pass through the holes
    to focus on a single point on a CRT displays' phosphor
    surface. The shadow mask helps to control the electron
    beams so that the beams strike the correct phosphor at
    just the right intensity to create the desired colors and
    image on the display. The unwanted beams are blocked
    or "shadowed."
    Monitors based on the Trinitron technology, which was
    pioneered by Sony, use an aperture-grill instead of a
    shadow-mask type of tube. The aperture grill consists of
    tiny vertical wires. Electron beams pass through the
    aperture grill to illuminate the phosphor on the faceplate.
    Most aperture-grill monitors have a flat faceplate and
    tend to represent a less distorted image over the entire
    surface of the display than the curved faceplate of a
    shadow-mask CRT. However, aperture-grill displays are
    normally more expensive.
    A less-common type of CRT display, a slot-mask tube
    uses a combination of the shadow-mask and aperture-grill
    technologies. Rather than the round perforations found in
    shadow-mask CRT displays, a slot-mask display uses
    vertically aligned slots. The design creates more
    brightness through increased electron transmissions
    combined with the arrangement of the phosphor dots.
    Dot pitch
    Dot pitch is an indicator of the sharpness of the displayed
    image. It is measured in millimeters (mm), and a smaller
    number means a sharper image. How you measure the dot
    pitch depends on the technology used:
          In a shadow-mask CRT monitor, you measure dot
    pitch as the diagonal distance between two like-colored
    phosphors. Some manufacturers may also cite a

    horizontal dot pitch, which is the distance between two-
    like colored phosphors horizontally.
          The dot pitch of an aperture-grill monitor is
    measured by the horizontal distance between two like-
    colored phosphors. It is also sometimes are called stripe

    The smaller and closer the dots are to one another, the
    more realistic and detailed the picture appears. When the
    dots are farther apart, they become noticeable and make
    the image look grainier. Unfortunately, manufacturers are
    not always upfront about dot pitch measurements, and
    you cannot necessarily compare shadow-mask and
    aperture-grill CRT types, due to the difference in
    horizontal and vertical measurements.
    The dot pitch translates directly to the resolution on the
    screen. If you were to put a ruler up to the glass and
    measure an inch, you would see a certain number of dots,
    depending on the dot pitch. Here is a table that shows the
    number of dots per square centimeter and per square inch
    in each of these common dot pitches:
    Dot Pitch Approx. number of Approx. number of

                  pixels/cm2               pixels/in2
  .25 mm             1,600                  10,000
  .26 mm             1,444                   9,025
  .27 mm             1,369                   8,556
  .28 mm             1,225                   7,656
  .31 mm             1,024                   6,400
  .51 mm              361                    2,256
   1 mm               100                     625

Refresh Rate
In monitors based on CRT technology, the refresh rate is
the number of times that the image on the display is
drawn each second. If your CRT monitor has a refresh
rate of 72 Hertz (Hz), then it cycles through all the pixels
from top to bottom 72 times a second. Refresh rates are
very important because they control flicker, and you want
the refresh rate as high as possible. Too few cycles per
second and you will notice a flickering, which can lead
to headaches and eye strain.

    Because your monitor's refresh rate depends on the
    number of rows it has to scan, it limits the maximum
    possible resolution. Most monitors support multiple
    refresh rates. Keep in mind that there is a tradeoff
    between flicker and resolution, and then pick what works
    best for you. This is especially important with larger
    monitors where flicker is more noticeable.
    Recommendations for refresh rate and resolution include
    1280x1024 at 85 Hertz or 1600x1200 at 75 Hertz.
    Multiple Resolutions
    Because a CRT uses electron beams to create images on a
    phosphor screen, it supports the resolution that matches
    its physical dot (pixel) size as well as several lesser
    resolutions. For example, a display with a physical grid of
    1280 rows by 1024 columns can obviously support a
    maximum resolution of 1280x1024 pixels. It also
    supports lower resolutions such as 1024x768, 800x600,
    and 640x480. As noted previously, an LCD monitor
    works well only at its native resolution.

    LCDs vs. CRTs
    If you are looking for a new display, you should consider
    the differences between CRT and LCD monitors. Choose
    the type of monitor that best serves your specific needs,
    the typical applications you use, and your budget.

    Advantages of LCD Monitors
          Require less power - Power consumption varies
    greatly with different technologies. CRT displays are
    somewhat power-hungry, at about 100 watts for a typical
    19-inch display. The average is about 45 watts for a 19-
    inch LCD display. LCDs also produce less heat.
          Smaller and weigh less - An LCD monitor is
    significantly thinner and lighter than a CRT monitor,
    typically weighing less than half as much. In addition,
    you can mount an LCD on an arm or a wall, which also
    takes up less desktop space.

           More adjustable - LCD displays are much more
    adjustable than CRT displays. With LCDs, you can adjust
    the tilt, height, swivel, and orientation from horizontal to
    vertical mode. As noted previously, you can also mount
    them on the wall or on an arm.
           Less eye strain - Because LCD displays turn each
    pixel off individually, they do not produce a flicker like
    CRT displays do. In addition, LCD displays do a better
    job of displaying text compared with CRT displays.
    Advantages of CRT Monitors
           Less expensive - Although LCD monitor prices
    have decreased, comparable CRT displays still cost less.
           Better color representation - CRT displays have
    historically represented colors and different gradations of
    color more accurately than LCD displays. However, LCD
    displays are gaining ground in this area, especially with
    higher-end models that include color-calibration
           More responsive - Historically, CRT monitors
    have had fewer problems with ghosting and blurring
    because they redrew the screen image faster than LCD
    monitors. Again, LCD manufacturers are improving on
    this with displays that have faster response times than
    they did in the past.
           Multiple resolutions - If you need to change your
    display's resolution for different applications, you are
    better off with a CRT monitor because LCD monitors
    don't handle multiple resolutions as well.
           More rugged - Although they are bigger and
    heavier than LCD displays, CRT displays are also less
    fragile and harder to damage.
    So now that you know about LCD and CRT monitors,
    let's talk about how you can use two monitors at once.
    They say, "Two heads are better than one." Maybe the
    same is true of monitors!

    Other Technologies
    Touch-screen Monitors
    Displays with touch-screen technology let you input

information or navigate applications by touching the
surface of the display. The technology can be
implemented through a variety of methods, including
infrared sensors, pressure-sensitive resistors or electronic
Wireless Monitors
Similar in looks to a tablet PC, wireless monitors use
technology such as 802.11b/g to connect to your
computer without a cable. Most include buttons and
controls for mousing and web surfing, and some also
include keyboards. The displays are battery-powered and
relatively lightweight. Most also include touch-screen
Television and HDTV Integration
Some displays have built-in television tuners that you can
use for viewing cable TV on your computer. You can also
find displays that accept S-video input directly from a
video device. Additional features include picture-in-
picture or picture-on-picture capability, a remote control
and support for high-definition television (HDTV).
               VESA Brings Standardization
  The Video Electronics Standards Association
  (VESA) is an organization that supports and sets
  industry-wide interface standards for the PC,
  workstation and consumer electronics industries.
  VESA promotes and develops timely, relevant,
  open standards for the display and display interface
  industry, ensuring interoperability and encouraging
  innovation and market growth.
  In August of 1992, VESA passed the VESA Local
  Bus (VL-Bus) Standard 1.0. This standard had a
  significant impact on the industry, because it was
  the first local bus standard to be developed, which
  provided a uniform hardware interface for local bus
  peripherals. The creation of this standard ensured
  compatibility among a wide variety of graphics
  boards, monitors, and systems software.
  Today, VESA is a worldwide organization that

  promotes and develops open display and display
  interface standards for interoperability. VESA is a
  formative influence in the PC industry and a
  contributor to the enhancement of flat panel display,
  monitor, graphics, software and systems
  technologies including home networking and PC
Monitor Trends
DisplayPort Standard
The Video Electronics Standards Association (VESA) is
working on a new digital display interface for LCD,
plasma, CRT and projection displays. The new
technology, which is called DisplayPort, supports
protected digital outputs for high definition and other
content along with improved display performance.
According to VESA, the DisplayPort standard will
provide a high-quality digital interface for video and
audio content with optional secure content protection.
The goal is to enable support for a wide range of source
and display devices, while combining technologies. For
example, the audio and video signals will be available
over the same cable -- a smaller video connector will
allow for smaller devices such as notebook computers,
and the standard will enable streaming high definition
(HD) video and audio content.
Organic Light-Emitting Diode
Organic Light-Emitting Diodes (OLEDs) are thin-film
LED (Light-Emitting Diode) displays that don't require a
backlight to function. The material emits light when
stimulated by an electrical current, which is known as
electroluminescence. OLEDs consist of red, green and
blue elements, which combine to create the desired
colors. Advantages of OLEDs include lower power
requirements, a less-expensive manufacturing process,
improvements in contrast and color, and the ability to
Surface-Conduction Electron Emitter Displays
A Surface-Conduction Electron Emitter Display (SED) is

a new technology developed jointly by Canon and
Toshiba. Similar to a CRT, an SED display utilizes
electrons and a phosphor-coated screen to create images.
The difference is that instead of a deep tube with an
electron gun, an SED uses tiny electron emitters and a
flat-panel display.

                          Experiment No. 19
      To study printer assembly and elementary fault
            detection of DMP and laser printer.

The Basics: Static Electricity

The primary principle at work in a laser printer is static electricity, the same
energy that makes clothes in the dryer stick together or a lightning bolt travel
from a thundercloud to the ground. Static electricity is simply an electrical
charge built up on an insulated object, such as a balloon or your body.
Since oppositely charged atoms are attracted to each other, objects with
opposite static electricity fields cling together.

               The path of a piece of paper through a laser

A laser printer uses this phenomenon as a sort of "temporary glue." The core
component of this system is the photoreceptor, typically a revolving drum
or cylinder. This drum assembly is made out of highly photoconductive
material that is discharged by light photons.

The basic components of a laser printer

                          Experiment No.20
    To observe various cables and connectors used in
What is Network Cabling?

Cable is the medium through which information usually moves from one
network device to another. There are several types of cable which are
commonly used with LANs. In some cases, a network will utilize only one
type of cable, other networks will use a variety of cable types. The type of
cable chosen for a network is related to the network's topology, protocol, and
size. Understanding the characteristics of different types of cable and how
they relate to other aspects of a network is necessary for the development of
a successful network.

The following sections discuss the types of cables used in networks and
other related topics.

            Unshielded Twisted Pair (UTP) Cable
            Shielded Twisted Pair (STP) Cable
            Coaxial Cable
            Fiber Optic Cable
            Cable Installation Guides
            Wireless LANs

Unshielded Twisted Pair (UTP) Cable

Twisted pair cabling comes in two varieties: shielded and unshielded.
Unshielded twisted pair (UTP) is the most popular and is generally the best
option for school networks (See fig. 1).

                            Fig.1. Unshielded twisted pair

     The quality of UTP may vary from telephone-grade wire to extremely high-
     speed cable. The cable has four pairs of wires inside the jacket. Each pair is
     twisted with a different number of twists per inch to help eliminate
     interference from adjacent pairs and other electrical devices. The tighter the
     twisting, the higher the supported transmission rate and the greater the cost
     per foot. The EIA/TIA (Electronic Industry Association/Telecommunication
     Industry Association) has established standards of UTP and rated six
     categories of wire (additional categories are emerging).

                       Categories of Unshielded Twisted Pair

Category                  Speed                                      Use

1          1 Mbps                                 Voice Only (Telephone Wire)

2          4 Mbps                                 LocalTalk & Telephone (Rarely used)

3          16 Mbps                                10BaseT Ethernet

4          20 Mbps                                Token Ring (Rarely used)

           100 Mbps (2 pair)                      100BaseT Ethernet
           1000 Mbps (4 pair)                     Gigabit Ethernet

5e         1,000 Mbps                             Gigabit Ethernet

6          10,000 Mbps                            Gigabit Ethernet

Unshielded Twisted Pair Connector

The standard connector for unshielded twisted pair cabling is an RJ-45
connector. This is a plastic connector that looks like a large telephone-style
connector (See fig. 2). A slot allows the RJ-45 to be inserted only one way.
RJ stands for Registered Jack, implying that the connector follows a
standard borrowed from the telephone industry. This standard designates
which wire goes with each pin inside the connector.

                           Fig. 2. RJ-45 connector

Shielded Twisted Pair (STP) Cable

Although UTP cable is the least expensive cable, it may be susceptible to
radio and electrical frequency interference (it should not be too close to
electric motors, fluorescent lights, etc.). If you must place cable in
environments with lots of potential interference, or if you must place cable
in extremely sensitive environments that may be susceptible to the electrical
current in the UTP, shielded twisted pair may be the solution. Shielded
cables can also help to extend the maximum distance of the cables.

Shielded twisted pair cable is available in three different configurations:

          1. Each pair of wires is individually shielded with foil.
          2. There is a foil or braid shield inside the jacket covering all
             wires (as a group).
          3. There is a shield around each individual pair, as well as around
             the entire group of wires (referred to as double shield twisted

Coaxial Cable

Coaxial cabling has a single copper conductor at its center. A plastic layer
provides insulation between the center conductor and a braided metal shield
(See fig. 3). The metal shield helps to block any outside interference from

                              Fig. 3. Coaxial cable

Although coaxial cabling is difficult to install, it is highly resistant to signal
interference. In addition, it can support greater cable lengths between
network devices than twisted pair cable. The two types of coaxial

Thin coaxial cable is also referred to as thinnet. 10Base2 refers to the
specifications for thin coaxial cable carrying Ethernet signals. The 2 refers to
the approximate maximum segment length being 200 meters. In actual fact
the maximum segment length is 185 meters. Thin coaxial cable has been
popular in

Thick coaxial cable is also referred to as thicknet. 10Base5 refers to the
specifications for thick coaxial cable carrying Ethernet signals. The 5 refers
to the maximum segment length being 500 meters. Thick coaxial cable has
an extra protective plastic cover that helps keep moisture away from the
center conductor. This makes thick coaxial a great choice when running
longer lengths in a linear bus network. One disadvantage of thick coaxial is
that it does

Coaxial Cable Connectors

The most common type of connector used with coaxial cables is the Bayone-
Neill-Concelman (BNC) connector (See fig. 4). Different types of adapters
are available for BNC connectors, including a T-connector, barrel connector,
and terminator. Connectors on the cable are the weakest points in any
network. To help avoid problems with your network, always use the BNC
connectors that crimp, rather

                            Fig. 4. BNC connector

Fiber Optic Cable

Fiber optic cabling consists of a center glass core surrounded by several
layers of protective materials (See fig. 5). It transmits light rather than
electronic signals eliminating the problem of electrical interference. This
makes it ideal for certain environments that contain a large amount of
electrical interference. It has also made it the standard for connecting
networks between

Fiber optic cable has the ability to transmit signals over much longer
distances than coaxial and twisted pair. It also has the capability to carry
information at vastly greater speeds. This capacity broadens communication
possibilities to include services such as video conferencing and interactive
services. The cost of fiber optic cabling is comparable to copper cabling;
however, it is

The center core of fiber cables is made from glass or plastic fibers (see fig
5). A plastic coating then cushions the fiber center, and kevlar fibers help to
strengthen the cables and prevent breakage. The outer insulating jacket made
of teflon or PVC.

                           Fig. 5. Fiber optic cable

There are two common types of fiber cables -- single mode and multimode.
Multimode cable has a larger diameter; however, both cables provide high
bandwidth at high speeds. Single mode can provide more distance, but it is
more expensive.

                         Ethernet Cable Summary

                  Specification           Cable Type

                  10BaseT          Unshielded Twisted Pair

                  10Base2          Thin Coaxial

                  10Base5          Thick Coaxial

                  100BaseT         Unshielded Twisted Pair

                  100BaseFX        Fiber Optic

                  100BaseBX        Single mode Fiber

                  100BaseSX        Multimode Fiber

                  1000BaseT        Unshielded Twisted Pair

                  1000BaseFX       Fiber Optic

                  1000BaseBX       Single mode Fiber

                  1000BaseSX       Multimode Fiber

Installing Cable - Some Guidelines

When running cable, it is best to follow a few simple rules:

            Always use more cable than you need. Leave plenty of slack.
            Test every part of a network as you install it. Even if it is brand
             new, it may have problems that will be difficult to isolate later.
            Stay at least 3 feet away from fluorescent light boxes and other
             sources of electrical interference.

            If it is necessary to run cable across the floor, cover the cable
             with cable protectors.
            Label both ends of each cable.
            Use cable ties (not tape) to keep cables in the same location

Wireless LANs

More and more networks are operating without cables, in the wireless mode.
Wireless LANs use high frequency radio signals, infrared light beams, or
lasers to communicate between the workstations and the file server or hubs.
Each workstation and file server on a wireless network has some sort of
transceiver/antenna to send and receive the data. Information is relayed
between transceivers as if they were physically connected. For longer
distance, wireless communications can also take place through cellular
telephone technology, microwave transmission, or by satellite.

Wireless networks are great for allowing laptop computers or remote
computers to connect to the LAN. Wireless networks are also beneficial in
older buildings where it may be difficult or impossible to install cables.

The two most common types of infrared communications used in schools are
line-of-sight and scattered broadcast. Line-of-sight communication means
that there must be an unblocked direct line between the workstation and the
transceiver. If a person walks within the line-of-sight while there is a
transmission, the information would need to be sent again. This kind of
obstruction can slow down the wireless network. Scattered infrared
communication is a broadcast of infrared transmissions sent out in multiple
directions that bounces off walls and ceilings until it eventually hits the
receiver. Networking communications with laser are virtually the same as
line-of-sight infrared networks.

Wireless standards and speeds

The Wi-Fi Alliance is a global, non-profit organization that helps to ensure
standards and interoperability for wireless networks, and wireless networks
are often referred to as WiFi (Wireless Fidelity). The original Wi-Fi standard
(IEEE 802.11) was adopted in 1997. Since then many variations have
emerged (and will continue to emerge). Wi-Fi networks use the Ethernet

                 Standard     Max Speed     Typical Range

                 802.11a      54 Mbps       150 feet

                 802.11b      11 Mbps       300 feet

                 802.11g      54 Mbps       300 feet

Advantages of wireless networks:

            Mobility - With a laptop computer or mobile device, access can
             be available throughout a school, at the mall, on an airplane,
             etc. More an more businesses are also offering free WiFi
            Fast setup - If your computer has a wireless adapter, locating a
             wireless network can be as simple as clicking "Connect to a
             Network" -- in some cases, you will connect automatically to
             networks within range.
            Cost - Setting up a wireless network can be much more cost
             effective than buying and installing cables.
            Expandability - Adding new computers to a wireless network is
             as easy as turning the computer on (as long as you do not
             exceed the maximum number of devices).

Disadvantages of wireless networks:

            Security - Wireless networks are much more susceptible to
             unauthorized use. If you set up a wireless network, be sure to
             include maximum security. You should always enable WEP
             (Wired Equivalent Privacy) or WPA (Wi-Fi Protected Access),

    which will improve security and help to prevent virtual
    intruders and freeloaders.
   Interference - Because wireless networks use radio signals and
    similar techniques for transmission, they are susceptible to
    interference from lights and electronic devices.
   Inconsistent connections - How many times have you hears
    "Wait a minute, I just lost my connection?" Because of the
    interference caused by electrical devices and/or items blocking
    the path of transmission, wireless connections are not nearly as
    stable as those through a dedicated cable.
   Power consumption - The wireless transmitter in a laptop
    requires a significant amount of power; therefore, the battery
    life of laptops can be adversely impacted. If you are planning a
    laptop project in your classroom, be sure to have power plugs
    and/or additional batteries available.
   Speed - The transmission speed of wireless networks is
    improving; however, faster options (such as gigabit Ethernet)
    are available via cables. In addition, if set up a wireless network
    at home, and you are connecting to the Internet via a DSL
    modem (at perhaps 3 Mbps), your wireless access to the
    Internet will have a maximum of 3 Mbps connection speed.

                           Experiment No.21
         Trouble-shooting exercises related to various
                  components of Monitor?
   1.   Monitor Troubleshooting
   2.   Monitor out of adjustment
   3.   Cleaning your flat screen monitor
   4.   Cut down on screen glare
   5.   Low Volume, High Pitch Whining Sound
   6.   What do I need to run a dual monitor setup?
   7.   Fixing stuck pixels on your LCD monitor

If you are experiencing the following problems with your monitor:

Monitor is blank after restarting system
After connecting a monitor, the picture looks bad
The monitor has started making a strange noise
Monitors display settings are not correct
Display is rotated

<>Monitor is blank after restarting system:

   1. Check to be sure that the Monitor has power and that the light is on.
   2. Disconnect all devices except for the mouse, keyboard and monitor.
      Reboot your computer to see if the issue is resolved. If it is, then it is
      one of the devices that you have disconnected that is causing the
      problem. try connecting them one at a time and rebooting each time
      until the original problem occurs. Once identified, try reinstalling the
      device and updating the driver to resolve the issue.
   3. Try connecting the monitor to a different PC using the problem
      monitor's power cable. If it still doesn't work, try the known good
      monitors power cable.
   4. Try unplugging the monitors power cable, then wait about 20 or 30
      seconds and plug it back in.
   5. If none of the above troubleshooting steps does not solve the issue,
      then it is likely that the monitor is bad.

<>After connecting a monitor, the picture looks bad:

   1. Start the system in Safe Mode by rebooting the system and pressing
      the F8 key once per second while it is rebooting. Once you see the
      Windows Startup menu, select Safe Mode from the listed options.
      press Enter.
   2. Go to Start>> Right click My Computer>> Properties>> Hardware
      tab>> Device Manager button.
   3. Click the plus (+) symbol next to the Monitors entry to expand it.
   4. Once expanded, right click on the installed monitor(s) and select
   5. Exit the Device Manager and restart your system.

Windows will reinstall your hardware automatically.

<>The monitor has started making a strange noise:

It is usually a glass display type monitor that will create some unusual noise.
Such noise could be:

   1. A high pitched tone or high pitched squealing sound:
      Usually, these sounds will be of such a high frequency that they are
      our of the human ears range. But it is possible for these frequencies to
      radiate off of internal components making the sound audible. Most of
      the time, moving or adjusting the height of the monitor cures this
      problem. Also, try simply turning the monitor off and then back on. If
      the sound continues or worsens, then either have a qualified
      technician take a look at your monitor or replace the monitor.

   2. Monitor is making a clicking sound:
      This type of noise is usually caused by the monitors relays opening
      and closing. You could hear this type of sound when the computer
      starts up or when you are playing a game and a display setting is
      changed. This sound is considered normal.

<>Monitors display settings are not correct:

This problem usually occurs when a new monitor is installed. It can happen
if the automatic detection installs the wrong driver for your hardware
resulting in incorrect display settings for your application.

You can try reinstalling the monitor by using the above troubleshooting step;
"After connecting a monitor, the picture looks bad". It is possible that
Windows will find the correct drivers this time.

Or, visit the manufactures web site and manually install the correct driver for
your hardware and operating system .

<>Display is rotated:

This is usually caused from a game that has changed the Rotation setting
within the Graphics Controller. To change this back:

   1. Go to Start>> Control Panel>> Intel Extreme Graphics Applet>>
      Rotation tab.
   2. Uncheck the Enable Rotation check box.
   3. Click Apply, then OK.
   4. Exit Control Panel.

Note: The above steps may vary depending on the graphics card you have
installed. You are looking for the Graphics Controller properties window to
change the Rotation setting.

An alternate method of finding your Rotation setting is:

   1.   Right click an empty area of your desktop.
   2.   Select Properties.
   3.   Click the Settings tab.
   4.   Select the Advanced button.
   5.   Click the Graphics card tab.
   6.   Select the Graphics Properties button.
   7.   Click the Rotation tab.
   8.   Uncheck the Enable Rotation checkbox.
   9.   Select Apply and exit all windows.
                           10.Monitor out of adjustment

It may be that your Monitor is simply out of adjustment if you are
experiencing any of the following symptoms:

      Excessive black areas around the picture
      Parts of the picture are missing around the edges
      Picture scrolls up and down
      Incorrect colors
      Image is too dark or too bright.

Your adjustment would depend on the monitor you are using. Please visit the
manufactures web site for details on how to make the proper adjustments to
clear up the above symptom(s).

                     Cleaning your flat screen monitor

Over time, your flat screen monitor can developed smudges or scratches.
Many manufactures have there own method of cleaning these LCD (Liquid
Crystal Display) monitors, so I would always want to steer you in that
direction, especially when still under warranty. There are some general
guidelines I will share though:

It is usually best to turn off your monitor so that you can see the smudges
better. Always use a soft cotton cloth dampened with warm water and wipe
either from top to bottom or side to side. Avoid using a swirling motion. If a
stronger cleaning solution is required, then you can use a solution of vinegar
and water. Your cleaning solution should be applied to your cloth rather than
directly to your screen. Avoid using Windex or any ammonia-based cleaners
as they will yellow your screen over time.

                         Cut down on screen glare

Is the glare on your computer giving you headaches or straining your eyes?
From experience, I know how painful a screen glare headache can be. There
are a few steps you can take that may help you cut down on the amount of
screen glare that you are getting. here's how:

   1. Position your computer so that the computer screen is facing away
      from the window. Also, be sure that you are not facing the window as
      well. A proper screen to window angle should be around 90 degrees.

   2. It is fine to have sunlight from outside shining in to your office. But, it
      is best if this light is defused by using shades or blinds. Even the use
      of flat paints will help reduce glare in an office.

   3. Avoid having a bright light directly above your work station. If you
      have such a light, try (if possible) turning that light off and use a desk
      lamp instead.

   4. If you are not able to avoid the glare from outside or a bright light
      above you (or both), you can purchase an anti-glare screen to put on
      your monitor screen.

                    Low Volume, High Pitch Whining Sound


The recommended resolution for my 17" CRT monitor is 1024x768. But I
prefer to use the resolution 1152x864 at max supported 75 Hz. But recently
since a few months from using the latter resolution, my monitor gives a
audible low-volume, high-pitched continuous whining sound, which
disappears if I change the resolution to 1024x 768 at 85Hz. But reverting
back to 1186x864 at 75 Hz doesn't produces any whine at all.


Most of the time a monitor will whine because the sealant on the flyback,
which is a high voltage transformer, is coming off or apart. The reason you
hear it is because of the cycle it's going in. You will have to take it to a shop
for them to put sealant on there. DO NOT try to do this yourself due to an
extremely high voltage shock hazard, even when unplugged. It doesn't hurt
the monitor to run this way, but it sure does get annoying!

                 Fixing stuck pixels on your LCD monitor

 A dead pixel is defined as: A pixel in a LCD display that is not functioning
   correctly. Incorrect function can either be that the pixel is stuck in the
lighted position or does not light up at all. To identify a stuck pixel, you can
                          use a small utility such as:

                              Dead Pixel Locator:

 Dead Pixel Locator displays the faulty pixel in a color that will stand out
                     against the background color.

               To repair the stuck pixel, try this handy tool:


JScreenFix will help fix stuck pixels on LCD screens. Most stuck pixels are
 repaired within 20 minutes. Some users have reported that JScreenFix can
even fix dead pixels! For more information, visit JScreenFix' web site (link

                              Experiment No.22
             To remove, study and replace USB Drive
A USB flash drive consists of flash memory data storage device integrated with a USB
(Universal Serial Bus) 1.1 or 2.0 interface. USB flash drives are typically removable and
rewritable, much smaller than a floppy disk, and most weigh less than 1 ounce (30 g).[1]
Storage capacities can range from a few megabytes to 256 GB[2] with steady
improvements in size and price per capacity. Some allow 1 million write or erase
cycles[3][4] and have 10-year data retention,[5].

USB flash drives are often used for the same purposes as floppy disks were. They are
smaller, faster, have thousands of times more capacity, and are more durable and reliable
due to their lack of moving parts. Until approximately 2005, most PC and laptop
computers were supplied with floppy disc drives, but most recent equipment has
abandoned floppy disk drives in favor of USB ports.

Flash drives use the USB mass storage standard, supported natively by modern operating
systems such as Windows, Mac OS X, Linux, and other Unix-like systems. USB drives
with USB 2.0 support can store more data and transfer faster than a much larger optical
disc drive and can be read by most other systems such as the Microsoft Xbox 360.

Nothing moves mechanically in a flash drive; the term drive persists because computers
read and write flash-drive data using the same system commands as for a mechanical disk
drive, with the storage appearing to the computer operating system and user interface as
just another drive.[4] Flash drives are very robust mechanically, and can withstand
anything that does not actually break the circuit board or connector.

A flash drive consists of a small printed circuit board carrying the circuit elements and a
USB connector, insulated electrically and protected inside a plastic, metal, or rubberized
case which can be carried in a pocket or on a key chain, for example. The USB connector
may be protected by a removable cap or by retracting into the body of the drive, although
it is not likely to be damaged if unprotected. Most flash drives use a standard type-A
USB connection allowing plugging into a port on a personal computer, but drives for
other interfaces also exist.

Most USB flash drives derive their power from the USB connection, and do not require a
battery. Some devices which combine the functionality of a digital audio player with
flash-drive-type storage require a battery for the player function.

Main articles: Flash memory and USB

Flash memory combines a number of older technologies, with lower cost, lower power
consumption and small size made possible by recent advances in microprocessor
technology. The memory storage was based on earlier EPROM and EEPROM
technologies. These had very limited capacity, were very slow for both reading and
writing, required complex high-voltage drive circuitry, and could only be re-written after
erasing the entire contents of the chip.

Hardware designers later developed EEPROMs with the erasure region broken up into
smaller "fields" that could be erased individually without affecting the others. Altering
the contents of a particular memory location involved copying the entire field into an off-
chip buffer memory, erasing the field, modifying the data as required in the buffer, and
re-writing it into the same field. This required considerable computer support, and PC-
based EEPROM flash memory systems often carried their own dedicated microprocessor
system. Flash drives are more or less a miniaturized version of this.

The development of high-speed serial data interfaces such as USB made semiconductor
memory systems with serially accessed storage viable, and the simultaneous development
of small, high-speed, low-power microprocessor systems allowed this to be incorporated
into extremely compact systems. Serial access requires far fewer electrical connections
for the memory chips than does parallel access, which has simplified the manufacture of
multi-gigabyte drives.

Computers access modern flash memory systems very much like hard disk drives, where
the controller system has full control over where information is actually stored. The
actual EEPROM writing and erasure processes are, however, still very similar to the
earlier systems described above.

Many low-cost MP3 players simply add extra software and a battery to a standard flash
memory control microprocessor so it can also serve as a music playback decoder. Most of
these players can also be used as a conventional flash drive, for storing files of any type.

[edit] History
[edit] First commercial product

Trek Technology and IBM began selling the first USB flash drives commercially in 2000.
Singaporean company Trek Technology sold a model dubbed the "ThumbDrive," and
IBM marketed the first such drives in North America, with its product the "DiskOnKey"
(which was manufactured by the Israeli company M-Systems). IBM's USB flash drive
became available on December 15, 2000,[6] and had a storage capacity of 8 MB, more
than five times the capacity of the commonly used floppy disks (floppy disks having a
capacity of 1.44MB).

In 2000 Lexar introduced a Compact Flash (CF) card with a USB connection, and a
companion card read/writer and USB cable that eliminated the need for a USB hub.

On July 24, 2002 Netac Technology was granted a highly-contested Chinese patent for
the USB flash drive.[7]

In 2004 Trek Technology brought several lawsuits against other USB flash drive
manufacturers and distributors in an attempt to assert its patent rights to the USB flash
drive. A court in Singapore ordered competitors to cease selling similar products[8] that
would be covered by Trek's patent, but a court in the United Kingdom revoked[9] one of
Trek's patents in that country.

[edit] Second generation

Modern flash drives have USB 2.0 connectivity. However, they do not currently use the
full 480 Mbit/s (60MB/s) the USB 2.0 Hi-Speed specification supports due to technical
limitations inherent in NAND flash. The fastest drives currently available use a dual
channel controller, although they still fall considerably short of the transfer rate possible
from a current generation hard disk, or the maximum high speed USB throughput.

Typical overall file transfer speeds vary considerably, and should be checked before
purchase. Speeds may be given in Mbyte per second, Mbit per second, or optical drive
multipliers such as "180X" (180 times 150 KiB per second). Typical fast drives claim to
read at up to 30 megabytes/s (MB/s) and write at about half that. Older "USB full speed"
12 Mbit/s devices are limited to a maximum of about 1 MB/s.

[edit] Design and implementation
One end of the device is fitted with a single male type-A USB connector. Inside the
plastic casing is a small printed circuit board. Mounted on this board is some power
circuitry and a small number of surface-mounted integrated circuits (ICs). Typically, one
of these ICs provides an interface to the USB port, another drives the onboard memory,
and the other is the flash memory.

Drives typically use the USB mass storage device class to communicate with the host.

[edit] Essential

There are typically four parts
to a flash drive:

      Male type-A USB
       connector – provides an
       interface to the host
      USB mass storage
       controller – implements
       the USB host
       controller. The
       controller contains a
       small microcontroller
       with a small amount of              Internals of a typical USB flash drive
       on-chip ROM and
       RAM.                         1   USB connector
      NAND flash memory            2   USB mass storage controller device
       chip – stores data.
       NAND flash is                3   Test points
       typically also used in       4   Flash memory chip
       digital cameras.
      Crystal oscillator –         5   Crystal oscillator
       produces the device's        6   LED
       main 12 MHz clock
       signal and controls the      7   Write-protect switch (Optional)
       device's data output         8   Space for second flash memory chip
       through a phase-locked

[edit] Additional components

The typical device may also include:

      Jumpers and test pins – for testing during the flash drive's manufacturing or
       loading code into the microprocessor.
      LEDs – indicate data transfers or data reads and writes.
      Write-protect switches – indicate whether the device should be in "write-
       protection" mode.
      Unpopulated space – provides space to include a second memory chip. Having
       this second space allows the manufacturer to use a single printed circuit board for
       more than one storage size device.

      USB connector cover or cap – reduces the risk of damage and prevents the ingress
       of fluff or other contaminants, and improves overall device appearance. Some
       flash drives use retractable USB connectors instead. Others have a swivel
       arrangement so that the connector can be protected without removing anything.
      Transport aid – the cap or the body often contains a hole suitable for connection
       to a key chain or lanyard. Connecting the cap, rather than the body, can allow the
       drive itself to be lost.
      Some drives offer expandable storage via an internal memory card slot, much like
       a memory card reader.[10][11]

[edit] Size and style of packaging

Flash drives come in various, sometimes bulky or novelty, shapes and sizes, in this case
ikura sushi

Some manufacturers differentiate their products by using elaborate housings, which are
often bulky and make the drive difficult to connect to the USB port. Because the USB
port connectors on a computer housing are often closely spaced, plugging a flash drive
into a USB port may block an adjacent port. Such devices may only carry the USB logo if
sold with a separate extension cable.

USB flash drives have been integrated into other commonly-carried items such as
watches, pens, and even the Swiss Army Knife; others have been fitted with novelty
cases such as toy cars or LEGO bricks. The small size, robustness and cheapness of USB
flash drives make them an increasingly popular peripheral for case modding.

Heavy or bulky flash drive packaging can make for unreliable operation when plugged
directly into a USB port; this can be relieved by a USB extension cable. Such cables are
USB-compatible, but do not conform to the USB standard

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