Re: Short question: No Available PTYs
On Tue, Jun 08, 1999 at 11:04:13AM -0500, Jesse Jacobsen wrote:
> I've got a slink and a potato machine on a network. The potato machine
> will often complain of "No Available PTYs" and refuse a telnet
> connection or to start an xterm (though it will start an rxvt -- dunno
> why). I don't know what PTY's -- pseudo terminals I guess -- are all
> about, so I don't really know how to go about diagnosing this problem.
> Any clues or hints would be appreciated.
I had (I think) the same problem, but it is not specific to potato (mine was
a slink system). Also, I do not believe it would occur if you used Unix98
pty's (I guess that you, too, were not).
The source of the problem was that the system used up all of the /dev/pty*
files. Debian by default has 64 of them (/dev/pty[p-s][0-9a-f], major
number 2, minor numbers 0-63), which wasn't enough for the several
programmers each running many xterms! The solution was "MAKEDEV
/dev/pty[tuvw]" , which creates 64 more.
My understanding is that you can create up to 256 pty/tty pairs this way,
though Linux 1.2 was limited to 64. Perhaps this is the reason that Debian
only came with 64. I do think this is a Debian bug (I am biased by the
couple hours I spent debugging this, though), but I won't file it since I
assume that potato will default to Linux 2.2 and Unix98 ptys. (Please
correct me if I'm wrong.)
Andrew
--
Don't forget that Linux became only possible because 20 years of OS
research was carefully studied, analyzed, discussed and thrown away.
- kernel hacker Ingo Molnar
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