Getting Unix V7 to work with the DZ11 terminal multiplexer

Unix V7 contains a driver for the DZ11 8-port terminal multiplexer, but the driver is not included in the mkconf program, which is used to configure a new kernel. This page provides a patch for mkconf.c and describes how to make V7 work with the DZ11.

The short story

  1. Check that the time is set appropriately.
  2. Clear out the .o files in /usr/sys/conf.
  3. Download this patch and apply it to /usr/sys/conf/mkconf.c
  4. Rebuild mkconf.
  5. Write a configuration file that includes the line dz.
  6. Run mkconf, then build a new kernel with make.
  7. Look in /usr/sys/conf/c.c to find out which major number to use for the tty devices.
  8. Use mknod to create character device files tty00, tty01, ..., tty15 in /dev. You determined the major number in the previous step, and the minor number should be 0, 1, ..., 15.
  9. Edit /etc/ttys. Change 00tty00 to 12tty00 and so on for all the tty devices you created in the previous step.
  10. Reboot with your new kernel.

Some details

I installed Unix V7 on version 3.1-0 of the Simh PDP-11 simulator using the Keith_Bostic_v7 tape. If you got your V7 installation from some other source, run sum /usr/sys/conf/mkconf.c and see if it gives you something different than 04000 29. If so, you may want to compare your version of mkconf.c to that in the Henry_Spencer_v7 tarball.

V7 was released in 1979, nine years before Larry Wall wrote patch, so I also prepared an ed script with my changes to mkconf.c. Feed it to ed in order to patch mkconf.c.

If you transfer the patch to your PDP-11 using cut and paste in an xterm or some similar method, verify that tab characters have not been translated into spaces. Mkconf generates the assembly file l.s, and the assembler distinguises between tabs and spaces.

In installing V7, I found Hellwig Geisse's instructions and mktape utility helpful.

Tim Newsham notes that he had to set the DZ11 in Simh to 16 lines to avoid a panic. Second, he had to attach the device with the -m flag to make it use modem control lines.

Last updated: 2014-12-08