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Operating System Functions (Part 5)Operating System Functions (Part 5)10. Task Management A computer can perform many tasks at a time. For example, in word processing it accepts input data, stores data on the disk and prints out a document simultaneously. Some operating systems can handle more than one program at the same time. For example, you are downloading information from the Internet through browser, listening speech, printing a document through word processing program, entering data into a worksheet etc. Each program is displayed in a separate window on the screen. The operating system manages all these tasks. A task is an operation such as storing, printing or calculating etc. Some operating systems have single user functionality and can support only one user at a time. The operating systems can perform the following tasks. i) Multi Tasking In multitasking, more than one program can be executed at a time on a single computer. Some operating systems allow multitasking. In multitasking, you can run multiple programs concurrently, When multiple programs are running in different application windows, one is in the foreground called the active window and others are in the background. You can easily switch between different application programs running on the computer. ii) Multi Programming In multiprogramming, different users can simultaneously run two or more programs. This type of tasking is controlled by the multi-user operating systems on mainframe or supercomputer where thousands of users can perform different tasks at same time.
iii) Multiprocessing In multiprocessing, multiple programs (more than one programs) are executed on different processors at same time. This type of processing is very fast. Some operating systems have. features of multiprocessing and to control these types of tasks. iv) Time Sharing In Time Sharing, a single computer processes the tasks of multiple users at the same time. Time-sharing is used when multiple users are connected to a single computer in a communication network.
v) Multithreading In multithreading operating systems a running program can start the execution of another program before the completion of its own execution. The started program (called child program) in turn can trigger the execution of other programs and so on. These child programs are called threads and the top most program is called parent program. Parent program’s execution proceeds on the completion of execution of all its child programs or threads. vi) Virtual Memory Some operating systems use virtual memory to manage multiple programs simultaneously. Virtual memory is actually a portion of secondary storage like hard disk, which is linked with actual memory (i.e. RAM). Thus a greater memory space becomes available to running programs. This increases the speed of computer and user can run programs, which are larger than actual RAM space. vii) Spooling Spooling is a technique in which an operating system uses buffers (a segment of memory) to place data before transferring it from or to input/output devices. This is done because sometime earlier data is being processed while the new data arrives. For example, a computer sends some data to a printer. In the meanwhile new data arrives for printing while the previous data is still being printed. This new data can now be placed in a buffer, which will be fed to the printer later on whenever the printer completes its previous job. See Also or Related Articles:
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