Systems Software

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Systems Software
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System Software

• Enables the applications software to interact
  with the computer and
• Helps the computer manage its internal and
  external resources.
• Is required to run applications software.

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Types of System Software

• Operating systems
• Is the principal component of system software in
  any computer system.
• Consists of the master system of programs that
  manage the basic operations of the computer.

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• These programs provide resource management
  services of many kinds such as the control and
  use of hardware resources including
• disk space
• memory
• CPU time allocation and
• peripheral devices.
• An operating system written for one kind of
  computer eg IBM will not be able to run on
  another kind of computer eg MacIntosh

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• Most operating systems are not compatible with
  one another

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Tasks that Operating Systems do

• Booting
• Managing storage media
• User interface
• Managing computer resources
• Managing files
• Managing tasks

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Booting

• Refers to the process of loading an operating
  system into a computers main memory from disk.
• The process is accomplished by a program called
  the boot strap loader or boot routine

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Managing storage media

• An example of managing storage media is the task
  of formatting blank disks - electronically
  preparing a disk so it can store data or programs.

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Providing a user interface

• The user interface is the user-controllable part
  of the operating system that allows you to
  communicate, or interact, with it.
• The types of user interfaces are
• Command-driven
• Menu-driven
• Graphical
• Network

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Managing computer resources

• The operating system directs traffic through the
  system. This is achieved by the supervisor, or
  kernel, the central component of the operating
  system.
• The supervisor manages the CPU and resides in
  main memory while the computer is on and directs
  other programs to perform tasks to support
  applications programs,

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Managing Files

• The operating system manages changes to files and
  helps you locate and gain access to them.
• Some management commands are
• Copy
• Back up
• Erase
• Rename

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Managing Tasks

• Tasks that are managed by operating systems are
• Multitasking - for one user -executing more than
  one program at the same time
• Multiprogramming - for more than one user -
  executing different users programs at the same
  time.

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• Time-sharing - for more than one user - executing
  different users programs in round-robin fashion.
• Multiprocessing - for single or multiple users-
  simultaneous processing by more than one computer
  

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Types of Operating Systems

• Some common types of operating systems used
• DOS - disk operating system
• MacIntosh OS9, OSX, Panther, Snow Leopard (OS
  10.6.2)
• Windows 95, 98, NT, ME, 2000, XP, Vista, Windows
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• Novells Netware
• UNIX
• LINUX

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Types of System Software Cont.

• 2. Utility programs
• Special programs used to support, enhance or
  expand existing programs in a computer system.
• Provide services not provided by othe system
  software programs.

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Specific Utility Tasks

• Back Up - makes a duplicate of every file on your
  hard disk onto other storage media eg CD RW, Zip
  disk, etc
• Data Recovery - utilities used to resurrect, or
  undelete, a file or information that has been
  accidentally deleted.
• File Defragmentation - will find all the
  scattered files on your hard disk and recognise
  them as contiguous files.

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• Disk Repair - will check you hard disk drive for
  defects and make repairs on the spot or mark the
  bad areas.
• Virus Protection - a virus consists of hidden
  programming instructions that are buried within
  an applications or systems program. They copy
  themselves to other programs causing damage to
  the computer system. Antivirus software is a
  utility program that scans hard disks, diskettes
  and memory to detect viruses and to eradicate
  them.

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• Data Compression - these utilities remove
  redundant elements, gaps and unnecessary data
  from a computers storage space so less space is
  needed to store or transmit data.
• Files are made more compact for storage on the
  hard disk drive.

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• Memory Management - different computers have
  different types of memory and different
  applications programs have different memory
  requirements.
• Memory management utilities are programs that
  determine how to efficiently control and allocate
  memory resources. These utilities may be
  activated by software drivers - small software
  programs that allow the operating system to
  communicate with hardware devices eg mouse,
  printer, etc

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Types of System Software Cont.

• 3. Language Translators
• Software that translates a program written by a
  programmer in a language such as Word 2008 into
  machine language (0s and 1s) which the computer
  can understand.