UNIX OPERATING SYSTEM:
The UNIX operating system is a set of programs that act as a link between the computer and the user
Structure:
Kernel: The kernel is the heart of the operating system.It interacts with the hardware and most of the tasks.
Shell: The shell is the utility that processes your request.When you type a in a command at your terminal,the shell interprets the command and call the programme you want.
Commands and Utilities: There are various commands and utilities which you whould use in your day to day activities.
Features:
Multi-user system: Multi-user capability of UNIX allow different users to use the same computers to performs several tasks.
Multi-tasking: Multi-tasking is the capability of operating system to perform various tasks simultaneously,i.e a user can run various tasks concurrently.
Programming Facility: Unix is highly programmable,the unix shell has all necessary ingredients like conditional and control structure etc.
Security: Unix allows sharing of data;every user must have single login name and password.So,accessing another user’s data is impossible without his permission.
Portable: Unix is portable because it is written in high level language.So,UNIX can be run on different computers.
Process management:
Unix is multitasking system.
Multiple programs can execute at same time.
If there is one CPU,multiple programs can execute by Time Sharing.That is all programs are claimed to be executing, In fact most of them are waiting for the CPU.
Memory management in UNIX:
Swapping
It is easy to implement and less system overhead.
Demand overhead:
It is greater flexible.
File management in UNIX:
In unix there are three basic types of files:
Ordinary file:An ordinary file is a file on the system that contains data,text and programs instructions.
Directories:Directories stores both ordianary and special files.
Special files:Some special files provide access to hardware such as hard drives,CD ROM drives,modems and Ethernet adapters.
File access modes in file management:
Read:Grant the capability to read,i.e view the contents of the file.
Write:Grant the capability to modify,or remove the contents of the file.
Execute:User with execute permission canrun a file as a program
I am founder of javaHint.com and a Computer Scientist. I have studied Computer Science and currently enrolled research student .I am providing information about computer, s web Programming Languages, Architecture and All other basic information Such as Information Technology and Computer Science. For Any Query and suggestion you are always welcome to contact me.
0 comments:
Post a Comment