29 Jul
2016
29 Jul
'16
5:05 a.m.
Sven Mascheck <mascheck(a)in-ulm.de> wrote:
Sequent Dynix "universes" (idea picked up by
Siemens Sinix) puts several
targets in one symlink. Example:
ln -c ucb=.bin att=/usr/att/bin /bin
and the actual resolving (and usage of different default PATHs)
is controlled by an environment variable, as far as I know
(s.a. http://www.in-ulm.de/~mascheck/various/universes/)
Pyramid did something similar, also called universes, in the mid-80s.
I think they used a system call and corresponding command to set
the visible universe either to BSD or System V. I don't remember the
details as to how exactly it worked.
I *think* this was before Dynix, but I'm not sure.
We had a Pyramid when I was working at Georgia Tech. DMR visited one time
and spoke; I remember him saying that he thought what Pyramid had done
was an awful idea... :-) (They were interesting machines. It was RISC,
with loadable microcode... About the same speed as a Vax 780 but half
the price.)
Arnold