Unix OS Architecture

User:-  User is nothing but an individual who uses the available hardware & software resources.




Shell:  It is a command line interpreter. The shell access request from user and the checks command existence if the command exist then it converts into kernel understandable language and it send the given request to kernel. The shell access interface between user and kernel.


Types of shells:


nameShell Developed byPromptInterpreter name
Bourne ShellStephen Bourne$Sh
Bash ShellStephen Bourne$bash
Korn ShellDavid Korn$Ksh
Z shellPaul$zsh
C shellBill Joy%csh

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Note:  The advanced version of Bourne shell is Bash shell. Bash means Bourne again shell.


Default Shell nameFlavor name
Bash ShellLinux
Bourne ShellSco-Unix, Solaries, HP-UX
Korn ShellIBM-AIX



   The kernel is the heart of the operating system.

  • The Kernel is responsible for interacting with the hardware and producing output to the screen.
  • It handles the process, memory, file, device and network management for the operating system
  • Linux is truly just the kernel.


Difference between UNIX & WINDOWS:


It is CUIIT is GUI
It is multiuser and Multitasking o/SWINDOWS also multiuser and multitasking o/s
To boot UNIX o/s, 2 MB RAM is Enough12 MB RAM is required.
UNIX is process  based conceptIt is Thread based concept.
In UNIX, any use process is killed it will not effect to others.It effects to all.
Unlimited users working on the server.Limited users working on the server.
UNIX is open systemIt is closed system
It is portable O/S.Not portable.
No down timeDown time is there.

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