2. Systems Software

3. 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.

4. 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.

5. –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

6. Most operating systems are not compatible with one another

7. Tasks that Operating Systems do Booting Managing storage media User interface Managing computer resources Managing files Managing tasks

8. 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

9. 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.

10. 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

11. 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,

12. 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

13. 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.

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

15. 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

16. 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. Types of System Software Cont.

17. 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.

18. 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.

19. 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.

20. 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

21. 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. Types of System Software Cont.