From: Theodore Ts'o <tytso@athena.mit.edu> Subject: Re: The great serial device naming controversy.... Date: 30 May 1993 23:02:59 -0400
From: almesber@nessie.cs.id.ethz.ch (Werner Almesberger)
Date: Sun, 30 May 1993 14:08:10 GMT
In article <1u1bfuINN41l@senator-bedfellow.MIT.EDU> tytso@athena.mit.edu writes:
> [...] and I can't imagine EVER needing more than 48 pty's)
However, considering the respective computing power of modern PCs, it
doesn't seem too far-fetched to me that more than hundred users might log
on over TCP and do some light-weighted work (e.g. BBS access). If they
are allowed to use screen, one could quickly end up with peak loads of
200-300 processes and about the same number of allocated pty pairs.
Considering the cost of modern PC's, it seems to me that the concept of
the overloaded time-sharing system is a dinosaur, a thing of the past.
Computers are getting cheap enough that each person will be able to have
their own on their desk. The Linux OS itself is one of these driving
forces which is making the concept of a "personal Unix machine" more and
more possible.
So if there should be ever yet another tty renaming, I think it would be
worthwile to address this issue too.
Using the current convention /dev/tty[p-z][0-9a-f], there is room for
176 PTY pairs, which is more than enough for any sane use of a PC. And
if this convention is changed, it would require modifying and compiling
every single program which attempts to allocate a pty, since it would
mean deviating from the standard which nearly all Unix systems which
have PTY's use. Given how difficult it would be, it's not worth it.
If people want to have a completely academic argument of how to name the
177th PTY pair, that's fine. It will absolutely useless until you start
modifying programs to use that new convention. And in any case, it is
completely pointless until the kernel tty code is rewritten so you can
have more than 64 PTY's. That will be a lot of work, and I for one will
leave for someone who really needs more than 64 PTY's (if such a person
exists).
- Ted