I heard that unix,linux are multi-user,multi-tasking.... OS..

Many users can log into same linux box and run programs in the same time.

I am wondering how can it be possible,there is only one keyboard,one hd....

it will be too busy switching position in the computer room.


please forgive me,i am such a newbie . if my question is very stupid.......

Multitasking. Well, suppose you want to print something out, but you didn't want to wait before you went on surfing the internet. With linux, no problem. Just click print, wait a few seconds while it dumps to the print spooler, and on with surfing. Linux (and any other multitask) will use spare cpu cycles to print out the job in the background.

Multiuser. Linux has virtual consoles. You can switch between them with alt-Fn (or control-alt-Fn if in X). You can log in as different users in each or as multiple instances of the same user. You could for example have a man page open in one, a vi editor in another, a cat of a README in another, and a compile in progress in another, all as the same user. Then quickly jump from one to the other with alt-Fn (Fn being a key F1,F2 etc.) It's also possible to log in remotely from another computer in a local network or even over the internet.

To expand on what kevin said at the end there:

You can have one server running linux and a whole load of dumb terminals (computers without hard disks or even processors of their own - basically just a keyboard, mouse and network connection to the server) for people to use - all the processing/file access is done on the one linux server. Hence the multi user / tasking capabilities come into play as all users on the dumb terminals are actually logged into the one linux server.

Search for articles on Linux Terminal Server Projects if you want more information.
http://www.ltsp.org/ as a starter!

Multiuser:
Linux/Unix thrives on networks :) ... imagine you had a
very powerful workstation with a incredible performance
for CAD/CAM ... it would be bored out of its tree with
only one user. So you attach it to a network, and have
several people open a session remotely.



Cheers,
Tink

my-unix-dream:multitasking systems can split up the CPU cycles so that one programs can run for this many cycles, while another gets that... and so on..... its the job scheduler in the kernel that handles this (just in case those "..." marks meant 1 processor to)

Thank you so much .......