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 by||Prompt||Interpreter name|
|Bourne Shell||Stephen Bourne||$||Sh|
|Bash Shell||Stephen Bourne||$||bash|
|Korn Shell||David Korn||$||Ksh|
|C shell||Bill Joy||%||csh|
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Note: The advanced version of Bourne shell is Bash shell. Bash means Bourne again shell.
|Default Shell name||Flavor name|
|Bourne Shell||Sco-Unix, Solaries, HP-UX|
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 CUI||IT is GUI|
|It is multiuser and Multitasking o/S||WINDOWS also multiuser and multitasking o/s|
|To boot UNIX o/s, 2 MB RAM is Enough||12 MB RAM is required.|
|UNIX is process based concept||It 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 system||It is closed system|
|It is portable O/S.||Not portable.|
|No down time||Down time is there.|
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