September 11, 2009 at 4:37 PM
The UNIX operating system was developed at AT&T Bell Laboratories in Murray Hill, New Jersey in the late 1960's.Its major version is AT&T's UNIX System V.
It is having four basic components:
1) The kernel constitutes the nucleus of the operating system and
coordinates the internals such as allocating system resources.
2) The file system, which is part of the kernel, controls the storage and
access of data. It is similar to the VMS file system in that the structure is hierarchical.
3) Commands are programs that you request the computer to execute.
4) Programs (commands) called shells serve as command interpreters. They
act as links between the user and the computer, interpreting and executing
commands. They are also high-level interpretive programming languages.
Advantages of Unix:
1) Full multitasking with protected memory. Multiple users can run multiple
programs at the same time without interfering each other.
2) It is having Very efficient virtual memory, so many programs can run with a modest amount of physical memory.
3) It is secure and can access controls.All users must be authenticated by a valid account and password to use the system at all. All files are owned by particular accounts. The owner can decide whether others have read or write access to his files.
4) It provides the ability to string commands and utilities together in
unlimited ways to accomplish more complicated tasks.
5) It is portable.
6) It is optimized for program development, and thus for the unusual
circumstances that are the rule in research.
7) Unix is extremely powerful. User can customize their own shell easily, and can do pipes, shell scipts etc.
Disadvantages of Unix:
1) The traditional command line shell interface is user hostile designed
for the programmer, not the casual user.
2) Commands often have cryptic names and give very little response to tell
the user what they are doing.
3) There is a need to understand some of the main designs to use Unix well.
4) It makes the beginner confuse.