Welcome to the computer world. Practice materials for 1st year students. Еранина Т.И - 32 стр.

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                     Operating systems

           When computers were first introduced in the 1940's and 50's,
every program written had to provide instructions that told the
computer how to use devices such as the printer, how to store
information on a disk, as well as how to perform several other tasks not
necessarily related to the program. The additional program instructions
for working with hardware devices were very complex, and time-
consuming. Programmers soon realized it-would be smarter to develop
one program that could control the computer's hardware, which others
programs could have used when they needed it. With that, the first
operating system was born.
           Today, operating systems control and manage the use of
hardware devices such as the printer or mouse. They also provide disk
management by letting you store information in files. The operating
system also lets you run programs such as the basic word processor.
Lastly, the operating system provides several of its own commands that
help you to use the computer.
           DOS is the most commonly used PC operating system. DOS
is an abbreviation for disk operating system. DOS was developed by a
company named Microsoft. MS-DOS is an abbreviation for « Microsoft
DOS ». When IBM first released the IBM PC in 1981, IBM licensed
DOS from Microsoft for use on the PC and called it PC-DOS. From the
users perspective, PC-DOS and MS-DOS are the same, each providing
the same capabilities and commands.
           The version of DOS release in 1981 was 1.0. Over the past
decade, DOS has undergone several changes. Each time the DOS
developers release a new version, they increase the version number.
           Windows NT (new technology) is an operating system
developed by Microsoft. NT is an enhanced version of the popular
Microsoft Windows 3.0, 3.1 programs. NT requires a 386 or greater and
8 Mb of RAM. For the best NT performance, you have to use a 486
with about 16 Mb or higher. Unlike the Windows, which runs on top of
DOS, Windows NT is an operating system itself. However, NT is DOS
compatible. The advantage of using NT over Windows is that NT
makes better use of the PC's memory management capabilities.
           OS/2 is a PC operating system created by IBM. Like NT,
OS/2 is DOS compatible and provides a graphical user interface that
lets you run programs with a click of a mouse. Also like NT, OS/2
performs best when you are using a powerful system.
           Many IBM-based PCs are shipped with OS/2 preinstalled.
           UNIX is a multi-user operating system that allows multiple
users to access the system. Traditionally, UNIX was run on a larger