2 Aug
1998
2 Aug
'98
12:21 p.m.
I finally took a good look at that new PDP-11/23 I purchased some time
ago. It seems to have some normal looking DEC cards in it (LSI-11/2,
others). It does, however, have an interesting looking card set from
Associated Computer Consultants, called "MDMA" (as far as I can tell). It
appears to be from the mid-1980s. One card contains some sort of engine,
with ROMs and (4) 2901s. The other card contains a bunch of glue and
interface stuff, and has a connection to a big round military type
connector (the modern versions of the Cannon connector) on the back panel
of the chassis marked "IMP".
Being that this computer came from a certain spooky branch of the
U.S., that "IMP" looks awfully suspicious. Could this little DEC box have
been slated for the ARPAnet, but came just a little too late?
All I have is the processor - no drives or OS, so I can not tell much if I
power it up.
William Donzelli
william(a)ans.net
2 Aug
2 Aug
12:30 p.m.
Being that this computer came from a certain spooky
branch of the
U.S., that "IMP" looks awfully suspicious. Could this little DEC box have
been slated for the ARPAnet, but came just a little too late?
All I had to do was look...
<http://lwp.ualg.pt/docs/htbin/ien/ien-96.html>
William Donzelli
william(a)ans.net
12:53 p.m.
Here is a snippet I recently posted on comp.sys.dec.micro and a few
other newsgroups asking for identification:
1) 2 dual-height boards, connected by 40-conductor cable
a) board 1: labelled ACC MDMA 6800043
contains 4 AM2901PC bit-sliced processors
11 PROMs (20-pin DIPs)
1 bank of wire-wrap jumpers
b) board 2: labelled ACC X0/1822 6800044
4 PROMs (20-pin DIPs)
5 LEDs
1 26-pin external connector
3 banks of wire-wrap jumpers
Nobody responed. Thanks for answering my question! Want some more
cards?
Dave
P.S. I suspect that these were also a part of the same system:
2) dual-height board
Corvus Systems 1981
LSI-11 Interface
P/N 40020019 Rev 02
contains 28-pin external connector
3) dual-height board
Corvus Systems 1981
LSI-11 Transporter Omninet
P/N 8169
contains 3-pin external connector
LED
8-position DIP switch
4) dual-height board (2 each)
Corvus Systems 1981
LSI-11 Transporter Omninet
P/N 8010-08032
contains 3-pin external connector
LED
8-position DIP switch
William Donzelli wrote:
I finally took a good look at that new PDP-11/23 I purchased some time
ago. It seems to have some normal looking DEC cards in it (LSI-11/2,
others). It does, however, have an interesting looking card set from
Associated Computer Consultants, called "MDMA" (as far as I can tell). It
appears to be from the mid-1980s. One card contains some sort of engine,
with ROMs and (4) 2901s. The other card contains a bunch of glue and
interface stuff, and has a connection to a big round military type
connector (the modern versions of the Cannon connector) on the back panel
of the chassis marked "IMP".
Being that this computer came from a certain spooky branch of the
U.S., that "IMP" looks awfully suspicious. Could this little DEC box have
been slated for the ARPAnet, but came just a little too late?
All I have is the processor - no drives or OS, so I can not tell much if I
power it up.
William Donzelli
william(a)ans.net
2:50 p.m.
1) 2 dual-height boards, connected by 40-conductor
cable
a) board 1: labelled ACC MDMA 6800043
contains 4 AM2901PC bit-sliced processors
11 PROMs (20-pin DIPs)
1 bank of wire-wrap jumpers
b) board 2: labelled ACC X0/1822 6800044
4 PROMs (20-pin DIPs)
5 LEDs
1 26-pin external connector
3 banks of wire-wrap jumpers
Exactly!
Nobody responed. Thanks for answering my question!
Want some more
cards?
Donate them to RCS/RI!
P.S. I suspect that these were also a part of the
same system:
3 Aug
3 Aug
8:03 a.m.
[IMP?]
That means Interface Messaging Prcessor.
For connecting things to the ARPAnet.
Not sure what it did, but it's mentioned in the ITS arcana...
-------
8:19 a.m.
On Mon, 3 Aug 1998, Daniel A. Seagraves wrote:
[IMP?]
That means Interface Messaging Prcessor.
For connecting things to the ARPAnet.
Not sure what it did, but it's mentioned in the ITS arcana...
Back in the day before standards (late 60s) the designers of the Arpanet
decided they needed a uniform network interface that all the different
computer systems of the time could connect to. The IMP was that
interface. It was actually a computer itself that acted as a gateway,
passing data to and from the host computer from the nascent Internet. It
handled the protocol conversion, etc.
It was the equivalent of a NIC today.
Sam Alternate e-mail: dastar(a)siconic.com
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