OPERATING SYSTEM

Operating System

Operating System

The operating system of a computer is the most basic program in a computer. All computers have an operating system that among other things is used for starting the computer and running other programs (application programs). The operating system performs important tasks like receiving input from the keyboard and mouse, sending information to the screen and keeping track of filesType of Computer operating systems include:• MS Windows 2000 / ME / XP• MS DOS (Microsoft Disk Operating System)• UNIX (originally for mainframes, but now available in versions for mid range and personal computers)• CP /M (the predecessor of MS DOS)The operating system is necessary to be run in the PC, when the computer is switched on, the operating system boots up from the hard disk. This mean that a number of programs are run to prepare the computer for extra use, and part of the operating system software must stay in the random access memory (RAM) of the computer.

Functions of the operating system

Allows the user to select and lunch programs: Loads programs by transferring them from storage into main memory. Manage input and output devices by controlling the data that flows between them and the processor. For example, the operating system deals with data as it is input from other devices, such as floppy disk drives. Data from a disk file must be stored in the current memory (RAM) of the computer until it is ready to be dealt with by the program currently in use. Manage the backing store by creating .opening, moving, deleting files. Allows the user to configure the system.Run programs by transferring instruction one at a time from memory to the processor. Make some space in memory to programs, which mean keeping track of which parts of the memory have already been allocated and the parts that are still free•It manages system security, which involves monitoring and restricting access to programs and data, also preventing unauthorised access to the system.

Utility programs

Utility programs are usually supplied along with an operating system. They are used to carry out routine tasks that are often needed by a user such as:1.Compressing a file to save space on backing storage2.Defragmenting a disk drive3.Recovering data from damaged file4.Checking a disk for faults and repairing them5.Formatting a floppy disk6.Checking the files on a disk for computer virusesMemoryThe most often used part of the operating system must be loaded into memory and stay there while applications are being run. When a computer is first switched on, the Operating system must be transferred from disc to memory. This process is called booting the system.

The operating system must make sure that each task has enough memory to be executed. One task does not need an area of memory allocated to another task. The area of memory is free when the task is completed so that it can be allocated to another task.

File management

Storage space on disc is divided into directories, every disc, when formatted, has a root ...