sgifford at suspectclass.com
Wed Jan 30 12:28:05 GMT 2002
David Lee <t.d.lee at durham.ac.uk> writes:
> > As someone pointed out, pseudo terminals come pretty much in
> > 2 flavors: BSD & System V.
> I suspect we may be using loose terminology. I think the phrase "pseudo
> terminal" was intended to represent a model of doing things, not
> necessarily as an real implementation detail.
I believe that I'm the one that started talking about pseudo
terminals, and I actually did intend it as an implementation detail.
They are widely available, mostly portable, easily understood, and
You can pretty much copy a couple dozen lines out of Stevens' Advanced
Programming in the UNIX Environment and have a quite portable
implementation in an hour or so.
> > As for allocating a pseudo terminal per smb client; again, I'm going
> > to stick to the flavors of Unix that I know, and pick on Solaris. Out
> > of the box, Solaris builds 48 pseudo terminals. Because sometimes
> > users use an X-Windows program (such as exceed) to fire of say "xterm"
> > via "rlogin" or "telnet", etc. (thus "soaking up" 2 pseudo terminals
> > for one user login), this ends up supporting about 30 users. Of
> > course, you can bump this up (to 1024) by editing /etc/systems and
> > doing a reconfiguration reboot ("boot -r" in Sun lingo). As someone
> > mentioned here, they have 800+ smb clients on their system. You
> > could easily run out of psuedo terminals if you allocated one per smb
> > client. If you had enough smb clients, you could allocate all of
> > your pseudo terminals for your smb clients and then not have any
> > left for people to login with.
> Ah! here we get to a misunderstanding. I wasn't anticipating or
> suggesting using real pseudo-ttys (that phrase sounds weird!). Rather
> using some means analogous to pttys, which might be OS-variable.
Why would it be a problem to ask admins to create additional
pseudo-ttys or else not use this feature? On systems with heavy
interactive user, I have seen upwards of 1000 pseudo-ttys with no ill
effects. There's no significant performance penalty for creating many
of them, either
In the traditional UNIX world, each user telnetted into a system and
was allocated a tty; you had to allocate a tty for each user. Now,
users come in via other methods, including filesharing with samba, but
I don't see a reason why it would be a big deal to still allocate them
More information about the samba-technical