PowerPoint Revision Guide

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					              Year 11 Revision Notes
Communicating            Applications

Handling Information     Operating Systems and

Modelling Spreadsheets   Social Implications

Monitoring and Control

       Revision Notes
      Audience and Purpose
l   All information is communicated for a
    purpose, to an audience;
    – The audience is the group of people that a
      communication is directed at.
    – The purpose is the reason the communication
      takes place.
l   The audience may not always be the same.
l   The purpose may change.
l   A change in purpose may change the
    emphasis in presenting the content of a
l   The extent to which the audience is likely to
    understand what is being communicated
    should be taken into account.
l   Make sure the information is relevant. If
    there is too much divergent information the
    audience may become confused.
             Word Processing
Using a wordprocessor you can:
l   write a letter, an essay, a questionnaire, etc;
l   create, save, open, load and print documents;
l   move around a document by scrolling
l   insert, delete and edit text
l   use different text fonts and sizes, and generate word art
l   move, cut, copy and paste blocks of text
l   import and export text, clip art, database and spreadsheet
l   generate personalized mail using mail merge facility.
            Graphics software
Using graphics software you can:
l   create, save, open or load and print graphics files
l   draw on a screen using a variety of colours
l   use different brushes, sizes and densities of brush strokes
l   draw freehand and regular shapes
l   fill shapes with patterns and colours
l   use different text fonts and sizes
l   zoom in and out to edit text and graphics
l   move, cut, copy and paste blocks of text and graphics
l   import and export scanned images and other graphics
         Desk Top Publishing
Using DTP software you can:
l   lay out the pages of a newsletter, magazine, etc
l   create, save, open or load, and print DTP pages
l   import and export text, scanned images, clipart, database
    reports and spreadsheets
l   resize images
l   view the page in different magnifications, zoom in and out
l   move around a page by scrolling up and down it
l   move, cut, copy and paste blocks of text and graphics
l   use different text fonts and sizes, and generate word art
l   Using multimedia software you can:
    – View encyclopaedias that combine text, graphics,
      sound etc. on a CD-ROM
    – Produce multimedia presentations
l   Using e-mail, you can:
    – Send and receive messages using the internet
    – set up address books and mailing lists
l   Using video conferencing, you can:
    – see people you are talking to on the screen
    – share screens for graphics and other documents
    – take part in meetings and debates with people in
      different places
                Revision Tips
Remember the different ways to generate text
   –   input using a keyboard
   –   scan form a book using OCR
   –   export from one piece of software and import
   –   copy it from a CD-ROM or the WWW
   –   download it using e-mail
Remember the different ways to generate graphics
   – scan line drawings and photos using a scanner
   – take photographs using a digital camera
   – copy an image from a clip-art library
Handling Information
  and Databases

      Revision Notes
A database is an organised collection of information
  consisting of 1 or more files (or tables)
l A database file is a collection of related records.
  For example, a file of information about all the
  pupils in a school
l A record in a database file is a collection of
  related fields. In the records of the same type , the
  fields are in the same order.
l A field is an item of information. For example,
  each pupils surname.
l   A fieldname (reference) is the name given to a
    field. This must be a unique name.
l   A keyfield uniquely identifies a record. This can
    be a record number for instance.
l   Fields can have different data types. Common
    examples are:
    –   alphanumeric (0-9, A-Z & symbols such as £)
    –   Numeric (integer - whole numbers or real)
    –   Date (in standard format e.g. DDMMYY)
    –   Multiple Choice, Ordered Choice etc
    –   Coded (first 2-3 characters only - usually text)
               Data Collection
Data collection can be done using a questionnaire or
  other form.
A Questionnaire should
   –   have a title and introduction explaining its purpose
   –   only collect the information required
   –   be clear and precise about what information is needed
   –   provide sufficient space to write in the information
   –   use character boxes to assist data entry
   –   use tick lists (multiple choice) to show what options are
       Direct Data Capture
Direct data capture and input can be done
l Optical Mark Recognition (OMR)

  e.g.National Lottery or school registers
l Optical Character Recognition (OCR)

l Bar codes

l Magnetic stripe card (e.g. visa or access)
Verification is checking that the data captured is accurately
   input into the computer.
Information input from questionnaires or forms should be
The double entry system involves 2 people inputting the
   data. The computer checks that they have both input the
   same information. If it is not a mistake has been made
   which must be corrected.
Double entry verification ensures accuracy but takes longer
   and costs more.
Validation is checking that the data is reasonable,
 for example:
l   a length check checks that a field is not too long or too
l   a type check checks that the information is of the correct
    data type;
l   a range check checks that the information is within the
    expected range;
l   a check digit is recalculated to ensure that, for example, a
    bar code has been read accurately by a bar code reader.
            Database Integrity
The information on a database has to be kept up-to-
  date and secure. To do this, you:
l   edit or amend the information stored in a field if it
l   insert or create a new record to add new information to a
l   delete a record to remove it if is no longer needed;
l   backup the database by making another copy of it;
l   restore the database from the backup copy if you lose the
     What a Database can do
Using a database, you can:
l   Keep records of customers, criminals, books, stock, pupils
l   Select records that match a search condition to find the
    information you want.
l   Sort the information into some order. For example,
    descending alphabetical order (Z to A)
l   Print a report containing the information selected
l   Export the results of a search into another program
l   Import text, images etc. from other software.
Teletext, e.g. Ceefax, is a simple way of handling
  information using a page-based system
l   Teletext pages can be received and displayed on a TV or
    using a computer.
l   Pages are broadcast in cycle. You have to wait for your
    page to be broadcast.
l   Teletext is not interactive
l   Fastext allows several pages next to the selected page to
    be stored in memory. Other pages are not accessed any
                The Internet
The Internet is a worldwide collection of interconnected
There is no one central organisation that owns or
   controls the Internet.
It provides services such as electronic mail (e-mail).
To connect at home you need a modem, a telephone line
   and an Internet Service Provider (ISP).
An ISP provides dial-in lines so that users can connect to
   the Internet. It may also provide other services such
   as News and Weather.
         The World Wide Web
The World Wide Web runs over the Internet. The
  information is stored on information servers (Web
  sites, Web servers) located throughout the world.
You can access the web using a browser.
To find information on the web, you could:
l   Access a page by typing in its Uniform Resource Locater
    (URL). This is its address on the web.
l   Use a search engine to search for particular topics.
l   Surf the web by activating hotspots. There are usually
    hyperlinks on most pages leading to other pages.
   Modelling and

      Revision Notes
A spreadsheet can be used for a wide variety of
  tasks that involve calculations. They are often
  used for financial applications and in mathematics.
l A spreadsheet is divided into vertical columns and
  horizontal rows,
l Cells can contain different types on information:
   –   text, e.g. Mr. Jones
   –   numbers, e.g. 23 or £34.67
   –   formulae, e.g. =SUM(A2:A11)
   –   dates and times, e.g. 20/4/99
               Cell References
l   Cell references can refer to a single cell e.g. D5
l   A cell reference can be a relative cell reference. This will
    adjust automatically when it is moved or copied to a new
l   A cell reference can be an absolute cell reference. This
    will not change when it is moved or copied. For example,
    suppose C3*$A$1 is in D3 and is moved to D4, the
    formula will change to C4*$A$1. $A$1 is an absolute cell
    reference, it does not change.
l   A cell range reference refers to a group of cells. E.g.
    What Spreadsheets can do
l   Formulae may recalculate automatically when the
    numbers in the cells they refer to change.
l   Cells may be moved or copied from one part of a
    spreadsheet to another.
l   Columns and rows can be deleted and inserted.
l   Formats can be applied to cells and ranges of cells
l   It is possible to sort groups of cells
l   You can generate graphs that illustrate the information
    stored in the spreadsheet. For example, bar charts, pie
    charts and line graphs.
l   You can export a range of cells to another piece of
A model is a representation of the real world. It is
  not the real world. It can be used to:
l improve understanding of a well known situation;
l learn about unfamiliar situations;
l increase awareness and understanding of the
  situation modelled;
l help understand problems and try out solutions;
l experiment without danger or expense;
l predict what will happen.
           Modelling using a
Spreadsheets can be used for modelling though they
  are more often used to handle information. A
  spreadsheet model will:

l   allow a range of input variables to be set;
l   use formulae to define the rules on which the
    model is based;
l   output information using the variables, stored
    values and the rules.
      Common spreadsheet
Spreadsheet models commonly used are:
l   Price Forecast
l   Supermarket queue
l   Break-even
l   Predator/Prey
Monitoring and Control

      Revision Notes
      Sensors and Actuators
l   A sensor is an input device used to measure
    environmental conditions. Different sensors can
    monitor temperature, humidity, light, sound,
    pressure, wind speed, wind direction, tilt, etc.
l   An actuator is an output device used to adjust
    environmental conditions. Actuators are heaters,
    motors, valves, pumps, boilers, etc. Their source
    of power could be electricity, hydraulics,
    compressed air, etc.
                 Data logging
Data logging is the automatic recording and storage of the
  information provided by sensors. For example, weather
  stations automatically record and store the temperature
  once every hour.
The stored information can then be downloaded to a
  computer perhaps over a network.
The frequency of sampling or time interval gives the time
  between measurements.
The period of logging is the length of time the logging takes
             Control Systems
l   Control systems monitor and control environmental
    conditions using sensors to determine what is
    happening and actuators to change what is happening
l   Feedback is a cycle of sensing, processing and
l   Computer control systems use a control interface.
    This is the hardware that converts the signals from the
    sensors so that the computer can understand them and
    the signals from the computer so that the actuators can
    understand them.
         Computer Programs
Computers themselves are controlled by programs. A
  computer program is a list of instructions to a computer
  written in a computer language.
l A computer language may be designed to initiate a very
  restricted range of actions.
l General purpose computer languages are harder to
  understand but can do a wider range of tasks, for example,
l Different program structures can be used in computer
  programs. Examples are:
   – Conditional statements: IF INPUT = “YES” THEN [action]
     ELSE [action]
   – A loop is a series of instructions that is to be repeated.
   – A procedure is a self-contained sequence of instructions that can
     be run from elsewhere in the program.
 Switched on?          END          A flowchart
                                    can be used
                                    to describe
Measure the                         how a task is
                                    done or a
      Too hot?          Turn off    program is
                       the heater
                        Turn on
  Too cold?            the heater


      Revision Notes
An application is using IT to do a useful task.
 IT is used throughout commerce and
 industry for a wide variety of applications.
Common commercial applications include: payroll,
  stock control, orders and deliveries, banking,
  shopping, booking tickets, lottery tickets etc.
l   An IT system is the whole system of hardware, software
    and human activities that is used in an application.
l   A legacy system is an old IT system that is still in use.
l   A manual system is a system that does not use IT.
      Processing Information
l   Interactive processing takes place when the user and the
    computer have a ‘conversation’. It is a cycle of input,
    processing, output, and user reaction. Interactive IT
    systems react to the information input as they are being
l   In batch processing, all the data to be processed is
    available before processing starts. Data is processed in
    batches. For example, a payroll system.
l    In real time processing, data is processed as it is input.
    Real time systems are very fast and interactive. They are
    usually run on dedicated computers.
         The system life cycle
l   System investigation
l   Feasibility study
l   System analysis and design
l   Program design, coding and testing
l   Implementation
l   System documentation
l   Evaluation
l   Maintenance
    – A parallel run tests the new system by running the old system at
      the same time.
 Operating Systems
   and Networks

      Revision Notes
      Hardware and Software
l   Information Technology is the use of computers and
    other equipment to store, process and transmit information.
l   Hardware is the physical equipment, e.g. monitor.
l   Software are the programs that control the computer.
l   Mainframes are large computers
l   Microcomputers are Personal Computers (PC’s). These
    can be desktop PC’s, portables or laptops. Desktops
    typically consist of a monitor, a processor case, a hard
    disk, a floppy disk drive, a keyboard and a mouse.
    Multimedia PC’s also have a CD-ROM drive and stereo
         Memory and Storage
l   Random Access Memory (RAM) is usually installed in
    the processor case. Programs and data is stored in RAM
    while they are being used. RAM is volatile, the
    information stored on it is lost when the computer is
    switched off.
l   Backing storage is on a hard disk, floppy disk or CD-
    ROM. Backing storage is non-volatile, it is not lost when
    the computer is switched off.
    – The size of memory and backing storage is measured in bytes. 1
      byte is the memory required to store 1 character.
        • 1 Kilobyte (Kb) = 1024 bytes
        • 1 Megabyte (Mb) = 1024 Kb
        • 1 Gigabyte (Gb) = 1024 Mb
               File Operations
Software and data are saved on disk as files. A
  directory is a list of all the files on a disk.
File operations are:
l   Saving a file.
l   Loading a file.
l   Merging two files to form 1 file.
l   Updating a file by editing or amending it.
l   Deleting a file by removing it.
l   Renaming a file.
l   Copying a file.
Information can be input to a PC using a mouse and
  a keyboard. Other input methods are:
l   Optical Mark Recognition (OMR) and Optical
    Character Recognition (OCR) using a scanner. Bar
    codes using a light pen or laser scanner.
l   Magnetic Ink Character Recognition (MICR), to read
    bank cheques. Magnetic Stripe Cards. e.g. Credit cards
l   Microphone. Voice recognition is spoken input.
l   Midi technology allows sound and music to be input.
l   Touch screens using a pen or your finger.
l   Video digitiser and digital cameras.
l   Printers can be:
    – Impact dot matrix. Cheap to buy and run, slow with poor quality.
    – Ink jet. Cheap to buy but expensive to run. Slow but good
    – Laser. Expensive to buy and run. Quick with excellent quality.
l   A printer buffer is RAM memory built into the printer. It
    is used to store print jobs, releasing the computer to
    continue with other jobs.
l   Spooling is the queuing of files waiting to be printed on a
    hard disk.
l   Other output methods include:
    – Graph plotters, draws using pens. Very high quality.
    – Speech synthesis which is the output of human speech.
           Operating Systems
An Operating System (OS) is software that runs
 between the hardware and the applications
 software. An OS will:
l   Carry out OS commands. Either through the GUI or at
    the command line, e.g. COPY C:\ACCESS\AGENTS A:.
l   Supervise programs. The OS will try to keep programs
    running, giving the user messages when there are
l   Make the hardware easier to use, so that you do not have
    to know the internal complexities of the hardware.
l   Continued . . . .
           Operating Systems
l   Help users decide what to do. For example, if the printer
    is unavailable, it will tell you and ask you what you want
    to do.
l   Providing utilities to manage the computer system. For
    example, to format floppy disks.
l   Optimize the use of the computer’s resources. For
    example, printing in the background.
l   Support multitasking, running more than 1 piece of
    software at the same time.
l   Make programs portable, so that they can be run on
    different computers with the same OS.
A network allows users to share software and
  hardware, and communicate with other networks.
A Local Area Network (LAN) is a small network,
  in one building. Computers are probably
  connected by cables.
A Wide Area Network (WAN) is a widespread
  network, probably national or international.
  Computers are probably connected to a WAN
  using a modem and the telephone network.
    Network Operating Systems
A Network Operating Systems (NOS) can:
l   Allow networked computers to communicate, e.g. e-mail
l   Support multiaccess, allow more than 1 user to access a
    computer at the same time.
l   Share software and Data. Store data on the server etc.
l   Share hardware. For example, networked printers.
l   Manage printer queues and spooling.
l   Organize user identification and passwords.
l   Keep a log of who uses the network.
The security of IT systems is important to protect
  users’ data and software. To help keep your
  system secure you should:
l   backup files regularly, using the ancestral system;
l   limit access using User Identification and Passwords;
l   use locks, ID cards and guards to control access to room;
l   put grills and security laminates on the windows of rooms;
l   attach computers to desks using clamps;
l   use firewalls to prevent access from external networks;
l   use automatic virus checks.
 Social Implications

      Revision Notes
Lifestyle and leisure are affected by developments in IT.
l   Domestic work has been made easier, this has made it
    easier for people to take part in education, employment and
    social activities outside the home.
l   Home entertainment has been enriched by the use of TV,
    teletext, PC’s with games and CD-ROM’s, the Internet etc.
l   Personal communications has been extended through the
    use of mobile phones, WWW and e-mail etc.
l   On-Line shopping and banking are both possible from
    home. Users can buy and sell shares, transfer money etc.
l   Cash-less society: magnetic stripe cards have led to a
    dramatic reduction in the use of cash.
As IT is introduced into the workplace an number of
  changes take place.
l   Some jobs disappear and some skills are no longer needed.
l   Some jobs are done in new ways. For example, typists
    have been replaced by wordprocessor operators.
l   New jobs are created. For example, manufacturing
    computer hardware and writing software.
l   New ways of organizing work arise. For example,
    teleworking. Teleworking helps the housebound to work,
    reduces traffic congestion, and cuts employers’ expenses
    by reducing the costs of running a central workplace.
IT systems can store large amounts of information.
  Personal information may be stored by doctors,
  local authorities, schools, the police, banks,
  employers etc. These systems can improve the
  quality of services but your privacy may suffer.
The Data Protection Act (1984) regulates the use of
  personal information. Users of personal
  information must register with the Data Protection
  registrar, and they must comply with the
  principles of good practice.
IT can help track individuals which could affect their
  freedom of movement and association.
l   Entry control systems using stripe cards to regulate
    access to many places, buildings and rooms.
l   Electronic tagging of criminals, used to limit their
l   Transport control. IT systems can identify cars that are
    speeding and fine their owners automatically.
l   Closed Circuit Television (CCTV) cameras record much
    of what happens in town centres.
l   Telecommunications by fax, e-mail and telephone can be
    automatically monitored.
IT systems that track individuals’ movements and
  monitor their activities have many beneficial uses.
l   They help prevent unauthorized access to buildings.
l   Criminals are constrained and more easily caught.
l   They can help prevent antisocial behaviour.

However, the same IT systems that can protect
    individuals’ freedom of movement and association
    could also be used to enforce unreasonable levels
    of social control.

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