DSD-440 and/or drive recommendation for PDP-8
vrs at msn.com
Sun Jun 19 23:45:19 CDT 2005
From: "Allison" <ajp166 at bellatlantic.net>
> From: "vrs" <vrs at msn.com>
> >(It's easily doable, but not trivial.)
> Heres the trick. Don't copy the parts, copy the logic and use
> standard TTL. Most all the functions are easily available or
> or sometimes available in denser (newer relatively) parts.
> Trying to copy verbatim will be hard unless you have a lot of
> DEC junker cards to strip. However most of the logical functions
> are simple so substitutions are not as scary.
Heh, I did that, but I shot myself in the foot by using the denser parts and
not quite getting it right.
Mine is actually a Posibus card (Ethan has the other prototype). There are
other problems with Omnibus cards, too. You can get the bus interface close
to spec., but not dead on, AFAIK with modern parts. Posibus is more
forgiving. (Though you can get close enough for small Omnibus backplanes
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