Types of Unix OS's

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History of UNIX operating system diagram

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3.how unix is organized

The UNIX system is functionally organaized at three levels ::

• The kernal ,which schedules tasks and manages storage
• The Shell, which connects and interprets users commands ,call programes from memory and executes them : and
  
• The tools and applications that offer additional functionality to the operating system

the three levels of unix system ::

• Kernl
• Shell
• Tools & Applications

The Kernel :: The heart of the operating system ,the kernel controls the hardware and turns part of the system on and off at the programmers command .if we ask the computer to list (ls) all the files in a directory,the kernel tells the computerto read all the files from the disk and display them on the screen.

UNIX tools

UNIX comes with hundred of programmes that can divided into classes::

Integral utilities that are absolutely necessary for the operation of the computer such as the command interpreter,and
Tools those are necessary for the operation of the UNIX but provide the user with additional capabilities,such as typesetting capabilities and email.





UNIX communications
E-mail is commonplace today, but it has only come into its own in the business community within the last 10 years.
Not so with the UNIX users ,who have been enjoying e-mail for several decades.
UNIX e-mail at first permitted users on the same computer to communicate with each othervia their teminals

Unix operating system OVERVIEW

1.Overview ::----

The unix operating system designed to let a number of programmers access the computer at the same time and share its resources.
The operating controls all of the commands from all of the keyboards and all of the data being generated ,and permit each user to belicve he or she is the only person working on the computer.
Although UNIX was developed by programmers for programmers ,it provides and environment so powerful and flexible that it is found in business,science,academia,and industry.

2.Uniqueness of Unix:---

The features that made UNIX a hit start are ::-

• Multitasking capability
• Multi-user capability
• Portability
• UNIX programs
• Library if application software

Multitasking ::

Many computer do one thing at a time,as anyone who uses a PC or laptop can attest.try logging onto our company's network while opening the browser while opening a word processing program.chances are the processor will freeze for a few seconds while it sorts out the multiple instructions.

Multi-user::

The same design that permits multitasking permits users to use the computer.the computer can take the commands of a number of users -- determined by the design of the computer -- to run programs,access files,and print documents at the same time.

Portability::

A major contribution of the UNIX system was its portability ,permitting it to move from one brand of one computer to another with a minimum of code changes. At a time when different computer lines of the same vendor didn't talk to each other -- Yet alone machines of multiple vendors that meant a great savings in both hardware and software upgrades Click here to continue ...