Transcript Systems Software

Systems Software
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.
Types of System Software
1. 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.
– 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
• Most operating systems are not compatible
with one another
Tasks that Operating Systems do
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Booting
Managing storage media
User interface
Managing computer resources
Managing files
Managing tasks
Booting
• Refers to the process of loading an
operating system into a computer’s main
memory from disk.
• The process is accomplished by a program
called the boot strap loader or boot routine
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.
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
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,
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
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 user’s programs at the
same time.
• Time-sharing - for more than one user executing different user’s programs in roundrobin fashion.
• Multiprocessing - for single or multiple userssimultaneous processing by more than one
computer
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 7
• Novell’s Netware
• UNIX
• LINUX
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.
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.
• 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.
• Data Compression - these utilities remove
redundant elements, gaps and unnecessary data
from a computer’s storage space so less space
is needed to store or transmit data.
• Files are made more compact for storage on
the hard disk drive.
• 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
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.