21 Jan
2009
21 Jan
'09
9:06 a.m.
On Wednesday 21 January 2009 06:19:57 Pete Turnbull wrote:
Not really -- it's a tabletop CPU/system box sold
for OEM use -- in
other words a standalone unit you'd build a small system, such as a
process controller, into. It has a 2 x 2 backplane, arranged serpentine
style, so you could put up to four dual-height cards in it. It has one
gotcha -- no line-time clock.
http://www.dunnington.u-net.com/public/PDP-11/QBus_chassis
I don't think your monitor unit was ever meant for rack mounting,
either. Apart from having no obvious mounting points for rails, the
power inlet and switch would be inside and facing the side of the rack
if the CRT were facing out the front. I expect it's a tabletop unit, or
was mounted inside something else. Which is not to say it might not
have once sat on a shelf in a rack, of course.
Ahh well no Line time clock is a gotcha. :-) Would have been a little easier
to Divine its true use if the complement of cards were still in it.
Well then what use would this be to a hobbyist other than the obvious hollow
it out and stick a PC MB in it and create some Sim pdp11 thing ??
--
Kindest Regards,
No Problems Only Solutions
Hosting Admins
Baltimore, Maryland
21 Jan
21 Jan
9:44 a.m.
On Wed, 2009-01-21 at 09:06 -0500, Francesca C. Smith wrote:
Ahh well no Line time clock is a gotcha. :-) Would
have been a little easier
to Divine its true use if the complement of cards were still in it.
Doesn't mean you can't add one. You could use a small transformer to
generate it really from the line, or a little crystal oscillator and
divider.
In fact, if I was going to make an add-in LTC I'd use one of the little
8-pin microcontrollers, programmed to generate 50Hz or 60Hz from a GPIO
pin. "Overkill!" I hear some of the list regulars shout (and you know
who you are, too). Not a bit of it - compare a 12C509 with the cost of
even a "common" crystal...
Well then what use would this be to a hobbyist other
than the obvious hollow
it out and stick a PC MB in it and create some Sim pdp11 thing ??
I'd build a little dinky PDP11 in it, with an added-on LTC as described
above so I could run TSX+. I kind of miss my PDP11, and I'd like to get
another (smaller) one.
Gordon
12:02 p.m.
On 21/01/2009 14:06, Francesca C. Smith wrote:
Ahh well no Line time clock is a gotcha. :-) Would
have been a little easier
to Divine its true use if the complement of cards were still in it.
Well then what use would this be to a hobbyist other than the obvious hollow
it out and stick a PC MB in it and create some Sim pdp11 thing ??
Not having the LTC (BEVENT) signal isn't a gotcha if you're running a
system that doesn't need a real time clock (hard realtime systems
wouldn't do timeslicing, for example, and RT-11 can run without an LTC)
or if you use something like a Falcon/Falcon-Plus/SBC-11 processor which
has an on-board clock, or include a KWV11 or KPV11.
--
Pete Peter Turnbull
Network Manager
University of York
1:27 p.m.
On Jan 21, 2009, at 9:06 AM, Francesca C. Smith wrote:
Grrrrr. That is a fairly rare box.
An LTC signal can be generated trivially with a tiny board that
can be buried inside the chassis.
-Dave
--
Dave McGuire
Port Charlotte, FL
Not really --
it's a tabletop CPU/system box sold for OEM use -- in
other words a standalone unit you'd build a small system, such as a
process controller, into. It has a 2 x 2 backplane, arranged
serpentine
style, so you could put up to four dual-height cards in it. It
has one
gotcha -- no line-time clock.
http://www.dunnington.u-net.com/public/PDP-11/QBus_chassis
I don't think your monitor unit was ever meant for rack mounting,
either. Apart from having no obvious mounting points for rails, the
power inlet and switch would be inside and facing the side of the
rack
if the CRT were facing out the front. I expect it's a tabletop
unit, or
was mounted inside something else. Which is not to say it might not
have once sat on a shelf in a rack, of course.
Ahh well no Line time clock is a gotcha. :-) Would have been a
little easier
to Divine its true use if the complement of cards were still in it.
Well then what use would this be to a hobbyist other than the
obvious hollow
it out and stick a PC MB in it and create some Sim pdp11 thing ??
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days inactive
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3 comments
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participants (4)
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fsmith＠ladylinux.com -
gordonjcp＠gjcp.net -
mcguire＠neurotica.com -
pete＠dunnington.plus.com