Реферат: DOS And Unix Essay Research Paper Compare

DOS And Unix Essay, Research Paper

Compare and Contrast Microsoft DOS with UNIX

As

is suggestive of its name, an operating system (OS) is a collection of programs

that operate the personal computer (PC). Its primary purpose is to support

programs that actually do the work one is interested in, and to allow competing

programs to share the resources of the computer. However, the OS also controls

the inner workings of the computer, acting as a traffic manager which controls

the flow of data through the system and initiates the starting and stopping

processes, and as a means through which software can access the hardware and

system software. In addition, it provides routines for device control, provides

for the management, scheduling and interaction of tasks, and maintains system

integrity. It also provides a facility called the user interface which issues

commands to the system software. Utilities are provided for managing files and

documents created by users, development of programs and software, communicating

between users with other computer systems and managing user requirements for

programs, storage space and priority. There are a number of different types of

operating systems with varying degrees of complexity. A system such as DOS can

be relatively simple and minimalistic, while others, like UNIX, can be somewhat

more complicated. Some systems run only a single process at a time (DOS), while

other systems run multiple processes at once (UNIX). In reality, it is not

possible for a single processor to run multiple processes simultaneously. The

processor of the computer runs one process for a short period of time, then is

switched to the next process and so on. As the processor executes millions of

instructions per second, this gives the appearance of many processes running at

once. User programs are usually stored on a hard disk and need to be loaded into

memory before being executed. This presents the need for memory management, as

the memory of the computer would need to be searched for a free area in which to

load a users program. When the user was finished running the program, the memory

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