SUMMARY: I need more pty's

Date: Mon Mar 16 1992 - 17:39:41 CST

In article <>, writes:
> This should be an easy question but I can't find the answer. I have a
> 690 and we have just begun our new acedemic year. Over the summer
> truck loads of xterminals arrived. Now I am getting the 690 running
> out of pty's regularly and I need to make some more. The problem
> is that MAKEDEV only seeme to let me make 56 max. How do I make more?

First thanks to those who replied,

mills@ccu.UManitoba.CA Gary Mills Paul Hoyt Nelson Chris John DiMarco Nick Sayer

I now have enough ptys for the moment.

Below are a few replied which explain what to do to get more ptys.

-------------------------------------------------------- Paul Hoyt Nelson

        There are 2 things to be aware of. First is the creation of the
new ptys. Look in /dev/MAKEDEV. The sections that creates ptys can
take an option. For instance if you wanted to create the 16 ptyu terminals
you would use the command:


5 being the optional argument.
        The second thing to look at is your /etc/ttytab file. It only has
pty entries for some of the possible pseudo terms. You will have to add
entries for any that do not exist and SIGHUP init.
        I am not surprised taht this is not a manual item. Sun has only
recently begun shipping systems that con realisticly support a large
number of network users.

---------------------------------------------------- John DiMarco

You can make up to 256.

MAKEDEV pty0 pty1 pty2 ... ptyN

where (N+1)*16 is the number of pty's you want, up to N=15.

----------------------------- Nick Sayer

1. Have you modified the kernel? You need to find the 'pty' line in
the kernel config file and change the number to reflect how many
ptys you want.

2. MAKEDEV isn't everything. :-). You can use mknod to make the devices
yourself. The standard naming scheme is pqrsPQRS. That means that
minor devices 0-15 are ttyp[0-f]. Minor devices 16-31 are ttyq[0-f].
Minor devices 128-144 are ttyP[0-f]. You get the idea. Remember
that for every ttyxx there is a ptyxx with the SAME minor device
number, but a DIFFERENT major device number. Just make them
in pairs. For example:

% cd /dev ; ls -al ?tys0
crw-rw-rw- 1 root wheel 20, 48 Mar 12 18:12 /dev/ttys0
crw-rw-rw- 1 root wheel 21, 48 Mar 12 18:12 /dev/ptys0

3. You can't have more than 256 ptys. Why you'd want THAT many I'll
never know. :-)


You need to do two things; running MAKEDEV is only one of them. You
also need to make sure you have enough ptys configured into your
kernel. Assuming nothing much has changed in 4.1.2 (we don't have it
yet), your kernel configuration should have a line something like this:

pseudo-device pty256 # pseudo-tty's, also needed for SunView

It might not have a number now; 256 is a good choice for a busy machine.

As for MAKEDEV, you'll want something like this:

        cd /dev
        ./MAKEDEV pty{0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15}

The first few of those will make noise about existing devices. You
can figure out how many to skip with "ls /dev/pty* | wc". Not all
shells accept that syntax; in particular, sh doesn't.


Bill Rea                                                             (o o)
| Bill Rea, Computer Services Centre | E-Mail |
| University of Canterbury           | or |
| Christchurch, New Zealand          | Phone +64 3 642-331 Fax +64 3 642-999 |

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