[Author’s Name]
[Institution’s Name]
Essay on Operating System
Operating system software consists of the operating system and related utility programs. The operating system is the computer program which controls and coordinates the interaction among the various hardware elements and between the hardware and the application programs. The operating system also allocates shared elements among the competing demands of the system. Without some form of operating system, the hardware cannot function.
The operating system was the raft of supporting software that all the mainframe manufacturers were supplying with their computers by the late 1950s. It included all the software, apart from programming languages, that the programmer needed to develop applications programs and run them on the computer. One component of the operating system, for example, was the input/output subroutines, which enabled the user to organize files of data on magnetic tapes and disk drives. The programming of these peripheral devices at the primitive physical level was very complex involving programmer-years of effort but the operating system enabled the user to deal not with physical items, such as the specific location of bits of data on a magnetic disk, but with logical data, such as a file of employee records. Another operating system component was known as a "monitor" or "supervisor," which organized the flow of work through the computer. For IBM's second-generation computers, the operating software consisted of about 30,000 lines of code. By the early 1960s a powerful operating system was a competitive necessity for all computer manufacturers. (David C. Mowery, 1996, pp 90)
Operating systems can be classified as follows:
Multi-user: Allows two or more users to run programs at the same time. Some operating systems permit hundreds or even thousands of concurrent users.
Multiprocessing: Supports running a program on more than one CPU.
Multitasking: Allows more than one program to run concurrently.
Multithreading: Allows different parts of a single program to run concurrently.
Real time: Responds to input instantly. General-purpose operating systems, such as DOS and UNIX, are not real-time.
http://www.webopedia.com/TERM/o/operating_system.html....
