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Baryonic Being 08-26-2004 06:24 AM

Multi-User Linux Capabilities
 
I read somewhere that Linux and Unix are 'multi-tasking, multi-user' OSs, whereas Windows is a 'multi-tasking, single-user' OS. I definitely exploit the multi-tasking abilities in Linux, but what does it mean to use Linux as a multi-user environment?

And Windows allows the creation of multiple users and the switching of one to the other too, so what's the difference?

Thanks in advance.

amosf 08-26-2004 06:39 AM

Linux allows multiple users to log in at the same time - Imagine a server with several users logged in running apps and such. Newer versions of windows probably allow this as well - server versions at least.

Baryonic Being 08-26-2004 06:51 AM

Thank you. But you say that many users can log in at the same time, but how is that achieved exactly? I'd be interested in knowing, you see.

amosf 08-26-2004 07:17 AM

linux is network oriented. I can get on a pc or terminal in another room and telnet (or ssh) into this pc and run apps if I wish, or many other users can do this. So this one machine would then have several users logged in from terminals in other parts of the house and each might be using several different apps. the linux window environment is also network oriented so these users could be running gui apps with this box as the server and their PC or thin client/terminal being the client. If this machine was very powerful it could run apps for many people and all they need is a thin client to display the apps and run the keyboard and mouse...

Baryonic Being 08-26-2004 07:45 AM

I see. I get it. Thank you for explaining.

Lleb_KCir 08-26-2004 12:30 PM

yes as for windows win2k and 2k3 server both allow for extra licencing for terminal service access. win2k has 2 built in win2k3 has 1 for administrative use. both allow for program (thin client) use but you have to pay for those connections.

under win2k it is possible to have a maximun of 3 ppl loged in via the remote administrative mode for TS, and vertualy unlimited (hardware not withstanding) under the program application mode.

the biggest differance is Linux does this native in all of its OSs, windows only does this if you lease a license to their servers that you already have to buy/lease (win2k = buy, win2k3 = lease) and they work only semi well. there is a large amount of lag when running TS into a win2k box, and same with win2k3 unless the server is one h3ll of a monster server you will lag it out fast.

example. i run win2k in remote administrative mode (no additional licenses needed that way) to access my QuickBooks remotely and keep the database and program running in 1 location. my 2k server is an AMD 800 Athlon with 512M ram. nothing else runs on that box except AD (active directory)... even on a 10/100 LAN i can see the performance degrigation caused via the TS conenction. it is drasticaly reduced when i use rdesktop from a linux box into the win2k server as the overhead in the native TS client for windows is very high.

when i have 1 person touching the server, and 2 ppl TS in, i can see the differance, and that is only 3 users.

now on the other hand i have had 10 ppl loged into my little laptop while it runs a web server, samba server and is being used to play music and browse the web all at the same time and not see any degrigation in performance.

FYI, none of that can be done with any desktop OS from microsoft.

Baryonic Being 08-26-2004 12:37 PM

Thanks. That clears it up for me.

David the H. 08-26-2004 02:16 PM

In addition you also have multiple "virtual" terminals available to you, even on a single PC. Just hit Alt+F1 (Crtl+Alt+F1 in graphics mode), F2, F3, etc. and you can log in as any user you wish on each one and tab between them. So several users can run programs concurrently on the same machine with the same monitor, keyboard, etc. Though obviously you're limited to one person typing at a time, you can run programs in the background, for example, or have one person check his email while a second one is ripping a cd or something. It's quite convenient.

By default you have 6 different virtual terminals (F1-F6). F7 and up are reserved for graphic logins, so Crtl+F7 generally gets you back to your X-session if you've switched out of it.

BTW, I've heard that Linux's multitasking is better than in Windows.

AnanthaP 08-26-2004 07:52 PM

Lleb_KCir, running 10 ppl on a small laptop is a really cool experience. It would be interesting to know the configuration of your little lap top.

This makes another very general point about all Unixes. Servers can really run on older processors and with less RAM as well (and as well!) as on newer processors and RAM.

In fact I am running a desktop with 32MB RAM, IDE hard disk with RedHat 7.1 and it serves quite well on an intranet. Maximum tried 6 - 7 user concurrently running mixture of "vi" thru' telnet and testing "php" programs. That is on an average 2 Unix tasks per user. No problems, no hangs and no looping (Important in a testing environment). It has all services like HTTP (Apache), php and SAMBA with a printer attached to a local W98 PC.

End

michaelk 08-26-2004 09:29 PM

Quote:

Originally posted by amosf
Linux allows multiple users to log in at the same time - Imagine a server with several users logged in running apps and such. Newer versions of windows probably allow this as well - server versions at least.
I guess I'm just an old timer ... anyone remember the pre-personal computer days :) How about main frame computers like IBM 370s, PDP-11s or VAX-780s. Actually the company I work for still has a DEC Alpha server which still interfaces with terminals.

If you ever see a reference to terminal emulation mode VT-100 or VT-52, those were actual peices of equipment i.e. a monitor and keyboard that would connect to a mainframe via RS-232 serial interface ( I actually owned one but alas it died a few years ago). The terminal was also know as a console :)

amosf 08-26-2004 09:42 PM

The early terms I used didn't have a screen. We had to edit code with a line editor on what was essentially a printer with keyboard... :)

Lleb_KCir 08-27-2004 12:18 PM

Quote:

Originally posted by AnanthaP
Lleb_KCir, running 10 ppl on a small laptop is a really cool experience. It would be interesting to know the configuration of your little lap top.

nothing fancy.

P4 1.8m
256M pc100 ram
5400rpm HD

its a toshiba toughbook CF-48X

running RH9

the others that were logged in were only using SSH, or other consouls as mentioned above via atl+crtl+F1-6, but i did have 3 instances of X running at once too.

the CPU took miner hits, but the vid card started to not like that many Xs running at once. i have not tried running X remotly off of that laptop on a LAN, but i did run cgwin 1 time from my school and pulled up gnome with it, and was even able to get gedit running along with a few other little tools. that was real laggy, but then i dont have HUGE upspeeds at the house.


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