I am using this emulator for UNIX V7: http://www.jbox.dk/sanos/pdp11.htm

When I type ps to get a list of processes, I get the following error:

Screenshot indicating "No Namelist"


1 Answer 1


ps in V7 expects to find the unstripped kernel binary in /unix, or named as the second parameter. In the Sanos simulator, you should run

cd /
ln rl2unix unix

to set the /unix link up correctly.

That won’t fix ps completely though, it fails looking for /dev/swap... I don’t know what the node should be for that, none of the values in /dev/makefile work.

  • So the problem is from the Sanos simulator?
    – user4916
    Apr 19, 2017 at 16:29
  • 1
    Not with Sanos, with the V7 image I think. Apr 19, 2017 at 16:32
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    @Muzer, in V7, ps reads the kernel’s data structures in memory directly, there isn’t a nice interface between the kernel and userspace. ps needs the namelist from the kernel to determine where the process map is located. See nlist(3) and a.out(5) for details (this is where I notice that GitHub now formats troff... nice...). Apr 20, 2017 at 9:32
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    Yep, before procfs and equivalents were introduced, that's how ps did it :) Apr 20, 2017 at 13:29
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    ...and far more modern systems still had these kind of mechanics: groups.google.com/forum/#!topic/muc.lists.netbsd.tech.kern/… Apr 21, 2017 at 9:46

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