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Operating System Operating System Utility Programs Raja Owais Ali Overview •

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Operating System Operating System Utility Programs Raja Owais Ali Overview • Powered By Docstoc
					Operating System & Utility
               Programs




   Raja Owais Ali
Overview
• OS
  – Definition
  – Current and popular OS
• Utility programs
  – Definition
  – Types of utility programs
  – Current and popular utility programs


                     Raja Owais Ali
Operating System (OS)
• OS is a set of programs that lies between
  applications software and the hardware
• The fundamental software that controls
  access to all other hardware and software
  resources
• Program that controls other programs
• Acts as the interface between program
  and hardware
• Manages application programs
                  Raja Owais Ali
Operating System (OS)




            Raja Owais Ali
Operating System (OS)
• Systems software
  – Often interchangeably with operating system
  – All programs related to coordinating computer
    operations.
  – Includes operating system but also includes
    other elements such as programming
    language translators and a variety of utility
    programs.


                    Raja Owais Ali
Operating System (OS)
• Systems software
       End
       User

                             Programmers


     Application
                                           Operating System
      Programs
                                               Designer
      Utility Programs


          Operating system

              Computer Hardware
                         Raja Owais Ali
Operating System (OS)
• Objectives of OS
  – Convenience
     • Easy for the users to use the computer
  – Efficiency
     • Allows resources to be used in an efficient manner
  – Ability to evolve




                        Raja Owais Ali
Operating System (OS)
• Services offered
  –   Program development
  –   Program execution
  –   Access to i/o devices
  –   Controlled access to files
  –   System access
  –   Error detection & responds
  –   Accounting
       • Statistics
       • Monitor performance
       • For billing purposes

                            Raja Owais Ali
Operating System (OS)
• Three main functions:
  – Managing the computer’s resources
    • E.g. CPU, memory, disk drives and printers
  – Establish an user interface
  – Execute and provide services for application
    software




                      Raja Owais Ali
Kernel
•   A.k.a. nucleus/resident
•   Portion of OS
•   Resides in the main memory
•   Contains all the most frequently used functions
•   Controls the entire operating system and loads
    in memory nonresident operating system
    programs from disk to storage as needed.
    – This process is called booting.


                          Raja Owais Ali
Evolution of OS
• Serial processing -> simple batch system
• Serial processing
  – No OS
  – Machine runs from console
  – Scheduled
    • Time to run is scheduled




                      Raja Owais Ali
Evolution of OS
• Simple batch system
   – Batch jobs together
   – The program will branches back when finished
   – Uses monitors
      • Software that controls the sequence of events
   – Requires:
      • JCL (Job Control Language)
          – To give instruction to monitor
      • Memory protection
          – User mode
          – Kernel mode
      • Timer
      • Privileged Instruction
      • Interrupts

                                 Raja Owais Ali
Characteristics of Modern OS
•   Microkernel architecture
•   Multithreading
•   Symmetric multiprocessing
•   Distributed operating system
•   Object-oriented design




                    Raja Owais Ali
Multithreading
• Ability to support multiple threads of
  execution
  – Threads: an execution unit that is codeless
    that keeps track of the running code within its
    memory area




                     Raja Owais Ali
Uniprogramming
• Run one program at a time
• Cons:
  – Time-consuming (due to the waiting)
  – Low CPU utilization




                    Raja Owais Ali
Multiprogramming
• Run multiple programs simultaneously
• Ability to run multiple programs in one time
• Multiple programs are being loaded into
  the memory and they are being processed
  in batch
• Pros:
  – Higher CPU utilization
  – Shorter waiting time
                     Raja Owais Ali
Multiprocessing
• A computer with more that one CPU can
  run multiple programs simultaneously,
  each using its own processor.




                 Raja Owais Ali
Current and popular OS




            Raja Owais Ali
Current and Popular OS




            Raja Owais Ali
Utility Programs
• Programs that perform many common
  tasks for users
• Help manage, maintain and control
  computer resources
• To help the user with day-to-day chores
  associated with personal computing and to
  keep your system running at peak
  performance.
                  Raja Owais Ali
Types of Utility Programs
•   File managers
•   Backup and restore
•   File compression
•   Scandisk
•   Disk defragmenter




                   Raja Owais Ali
File Managers
• Enables you to store files in a hierarchical
  directory structure that is organized in a
  way that make sense to you
  – Directory: a named area in storage that can
    contain files and other directories.




                    Raja Owais Ali
File Compression
• Reduces the amount of space required by
  a file
  – To take up less space and also take less time
    to transmit across communication lines




                    Raja Owais Ali
Backup and Restore
• Backing up
  – Involves making duplicate copies and storing them in
    a safe place, just in case something happen to the
    originals
• Backup and restore programs enable you to
  make backups of entire hard drives or of
  selected directories
• Rudimentary backup and restore programs
  accompany most operating systems, but more
  capable utilities are provided with tape and CD
  and can be purchased separately.
                       Raja Owais Ali
Scandisk
• A utility program provided with Windows
  computers.
• Scans disks to see if there are any
  potential problem on the disk
  – E.g. bad disk areas.




                     Raja Owais Ali
Disk defragmenter
• A software that assists you in keep
  reorganizing your disk drive.
     • After files are saved, deleted and resaved again,
       the disk can become fragmented - available space
       is in small blocks located throughout the disk.
• Disk defragmenters gather those free
  spots and put them together to enable you
  to continue to save your data in the most
  efficient manner.
                       Raja Owais Ali
Virus scanning software
• A utility program designed to protect the
  computer from computer viruses
  – Virus: small computer programs created to
    disrupt and destroy computer file and/or
    operating system




                    Raja Owais Ali
Device Drivers
• Allow the operating system to
  communicate with peripheral equipments.




                  Raja Owais Ali
Current and Popular Utility
Programs
•   winRAR
•   winZIP
•   Kaspersky Anti-Virus
•   AVG
•   Bit Defender




                    Raja Owais Ali

				
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