Max users on Linux OS

**vwgtiturbo** · 10-10-2003, 05:55 AM

I am doing a research paper for my English class on the modern infiltration, and take over, of Linux in the home and in business/government, and was just wondering...

How many users can the OS support being logged in at one time? I know you have @64000 UIDs, but are you limited in the number of users that can be locally and remotely logged onto the machine at one time?

Thanks!

**gaxprels** · 10-10-2003, 01:00 PM

I believe there is a limit, but can't remember what the correct number is. The limit has to do with the number of PTY's (pseudo terminal devices) that can be allocated for use at one time. Each login session runs on it's own PTY. Some scripts create their own PTY's to run on as well (for instance, anytime you "spawn" a program in Expect, it opens a PTY for that program.) I know there's a limit to the number of PTY's that can be opened, because you can open all of them very quickly by repeatedly spawning programs in Expect without doing a "wait" for them to close before spawning the next program.

**vwgtiturbo** · 10-10-2003, 04:30 PM

Check this out... Maybe this is it.

http://www.hp-eloquence.com/sdb/html/linux_limits.html

I don't understand... I looked this up last night (under max linux users) and didn't find a thing. Today, I looked it up as 'max linux pty' and this is what google came up with.

**gaxprels** · 10-10-2003, 06:34 PM

Based on that, you can't have more than 256 people logged in at once assuming scripts aren't eating any of those... That doesn't mean you can't have more users than that...