8 Dec
2015
8 Dec
'15
5:58 a.m.
I help cleaning out a large repository of DEC parts.
There a quantity of DEC core module assemblies appeared.
According to PDF docs these must be PDP-15 MM15's, but no labels are on
the boards.
I show/offer some of them at
retrocmp.com/flipchipshop ,
under "core memory"
Can somebody confirm they are MM15's?
Are any PDP-15 running at all?
Thanks,
Joerg
8 Dec
8 Dec
7:03 a.m.
I've seen a memory assembly from a PDP-15 and it looks very much like
this. Also, if each connector pair corresponds to one bit it adds up to
18 which matches the word lenght of a PDP-15.
Of course, PDP-1, -4 and -7 used 18 bit word lenght, but they were not
made with flip-chips.
PDP-9 is made with flipchips and is 18 bit. But I seeem to recall it's
memory looks quite different.
/P
On Tue, Dec 08, 2015 at 11:58:07AM +0100, J?rg Hoppe wrote:
I help cleaning out a large repository of DEC parts.
There a quantity of DEC core module assemblies appeared.
According to PDF docs these must be PDP-15 MM15's, but no labels are on the
boards.
I show/offer some of them at
retrocmp.com/flipchipshop ,
under "core memory"
Can somebody confirm they are MM15's?
Are any PDP-15 running at all?
Thanks,
Joerg
7:14 a.m.
Careful. Some PDP-11 memory is also 18 bits wide... 16 bits plus two
parity bits.
Johnny
On 2015-12-08 13:03, Pontus Pihlgren wrote:
I've seen a memory assembly from a PDP-15 and it
looks very much like
this. Also, if each connector pair corresponds to one bit it adds up to
18 which matches the word lenght of a PDP-15.
Of course, PDP-1, -4 and -7 used 18 bit word lenght, but they were not
made with flip-chips.
PDP-9 is made with flipchips and is 18 bit. But I seeem to recall it's
memory looks quite different.
/P
On Tue, Dec 08, 2015 at 11:58:07AM +0100, J?rg Hoppe wrote:
> I help cleaning out a large repository of DEC parts.
> There a quantity of DEC core module assemblies appeared.
> According to PDF docs these must be PDP-15 MM15's, but no labels are on the
> boards.
>
> I show/offer some of them at
> retrocmp.com/flipchipshop ,
> under "core memory"
>
> Can somebody confirm they are MM15's?
> Are any PDP-15 running at all?
>
> Thanks,
> Joerg
9:01 a.m.
But not these - PDP-11's didn't use dual-height connectors on memory.
Anyway, they are indeed PDP-15. (Whether or not they are actually MM15
I don't know). The page on the memory on the provided link indicates:
G100
G613
G614
The modules and options document on
bitsavers.org/dec/modules/modulesAndOptions sez....
G100 Sense Amp & Inhibity Driver, PDP15, 3 Wire, 3D Memory
Where Used: 15
G613 X Diode Matrix, 3 Wire, 4K, 9/I Where Used: 15
G614 X Diode Matrix, 3 Wire, 4K, 9/I Where Used: 15
JRJ
On 12/8/2015 6:14 AM, Johnny Billquist wrote:
Careful. Some PDP-11 memory is also 18 bits wide... 16
bits plus two
parity bits.
Johnny
On 2015-12-08 13:03, Pontus Pihlgren wrote:
I've seen a memory assembly from a PDP-15 and
it looks very much like
this. Also, if each connector pair corresponds to one bit it adds up to
18 which matches the word lenght of a PDP-15.
Of course, PDP-1, -4 and -7 used 18 bit word lenght, but they were not
made with flip-chips.
PDP-9 is made with flipchips and is 18 bit. But I seeem to recall it's
memory looks quite different.
/P
On Tue, Dec 08, 2015 at 11:58:07AM +0100, J?rg Hoppe wrote:
> I help cleaning out a large repository of DEC parts.
> There a quantity of DEC core module assemblies appeared.
> According to PDF docs these must be PDP-15 MM15's, but no labels are
> on the
> boards.
>
> I show/offer some of them at
> retrocmp.com/flipchipshop ,
> under "core memory"
>
> Can somebody confirm they are MM15's?
> Are any PDP-15 running at all?
>
> Thanks,
> Joerg
2:37 p.m.
2015-12-08 15:01 GMT+01:00 Jay Jaeger <cube1 at charter.net>:
But not these - PDP-11's didn't use
dual-height connectors on memory.
Anyway, they are indeed PDP-15. (Whether or not they are actually MM15
I don't know). The page on the memory on the provided link indicates:
G100
G613
G614
The modules and options document on
bitsavers.org/dec/modules/modulesAndOptions sez....
G100 Sense Amp & Inhibity Driver, PDP15, 3 Wire, 3D Memory
Where Used: 15
G613 X Diode Matrix, 3 Wire, 4K, 9/I Where Used: 15
G614 X Diode Matrix, 3 Wire, 4K, 9/I Where Used: 15
I also happen to have a few that need a new home - I have no PDP-15. Trade
for something interesting...
http://i.imgur.com/6xplRge.jpg
JRJ
On 12/8/2015 6:14 AM, Johnny Billquist wrote:
Careful. Some PDP-11 memory is also 18 bits
wide... 16 bits plus two
parity bits.
Johnny
On 2015-12-08 13:03, Pontus Pihlgren wrote:
I've seen a memory assembly from a PDP-15 and
it looks very much like
this. Also, if each connector pair corresponds to one bit it adds up to
18 which matches the word lenght of a PDP-15.
Of course, PDP-1, -4 and -7 used 18 bit word lenght, but they were not
made with flip-chips.
PDP-9 is made with flipchips and is 18 bit. But I seeem to recall it's
memory looks quite different.
/P
On Tue, Dec 08, 2015 at 11:58:07AM +0100, J?rg Hoppe wrote:
> I help cleaning out a large repository of DEC parts.
> There a quantity of DEC core module assemblies appeared.
> According to PDF docs these must be PDP-15 MM15's, but no labels are
> on the
> boards.
>
> I show/offer some of them at
> retrocmp.com/flipchipshop ,
> under "core memory"
>
> Can somebody confirm they are MM15's?
> Are any PDP-15 running at all?
>
> Thanks,
> Joerg
4:42 p.m.
From: Pontus Pihlgren
Sent: Tuesday, December 08, 2015 4:03 AM
I've seen a memory assembly from a PDP-15 and it
looks very much like
this. Also, if each connector pair corresponds to one bit it adds up to
18 which matches the word lenght of a PDP-15.
Of course, PDP-1, -4 and -7 used 18 bit word lenght,
but they were not
made with flip-chips.
Flip Chip technology was invented for the PDP-7, after the failure of the
large System Modules used in the PDP-6. The only part of the PDP-7 which
uses System Modules(TM) is the DECtape controller for the 555 DECtape
drives.
If you'd like to visit the museum, I'll happily show you the internals of
a running PDP-7. :-)
Rich
Rich Alderson
Vintage Computing Sr. Systems Engineer
Living Computer Museum
2245 1st Avenue S
Seattle, WA 98134
mailto:RichA at LivingComputerMuseum.org
http://www.LivingComputerMuseum.org/
9 Dec
9 Dec
2:52 a.m.
On Tue, Dec 08, 2015 at 09:42:27PM +0000, Rich Alderson wrote:
Flip Chip technology was invented for the PDP-7, after the failure of the
large System Modules used in the PDP-6. The only part of the PDP-7 which
uses System Modules(TM) is the DECtape controller for the 555 DECtape
drives.
After posting I had a nagging feeling I was wrong. I recall seeing both
System Modules and flip chips(light blue?) in relation to PDP-7. Thank
you for clearing that up.
What where the failure(s) with System Modules in the PDP-6? cost?
reliabilty?
If you'd like to visit the museum, I'll
happily show you the internals of
a running PDP-7. :-)
Oh yes! If/when I cross the atlantic you will have to show me internals
of _everything_. Can you buy a five-day pass? :-)
Thanks,
Pontus.
9:57 a.m.
On 12/8/15 11:52 PM, Pontus Pihlgren wrote:
What where the failure(s) with System Modules in the
PDP-6? cost?
reliabilty?
Connectors. They had over the top and backplane connectors. They also
had problems with solder joints on rivets used for connecting traces
on the front and back side of the pcb.
I think Steve Russell talked about having to resolder all of the rivets
in SAIL's PDP-6 over time in his CHM oral history.
3:32 p.m.
From: Pontus Pihlgren
Sent: Tuesday, December 08, 2015 11:52 PM
On Tue, Dec 08, 2015 at 09:42:27PM +0000, Rich
Alderson wrote:
> Flip Chip technology was invented for the PDP-7,
after the failure of
> the large System Modules used in the PDP-6.
What where the failure(s) with System Modules in the
PDP-6? cost?
reliabilty?
Soldered edge connectors on 2 sides of the board. In order to remove or
repair a board in the middle of a module (say, a bit in an accumulator),
you had to carefully unsolder all the connections to boards next to it and
move the wiring out of the way.
Seriously fragile.
> If you'd like to visit the museum, I'll
happily show you the internals of
> a running PDP-7. :-)
Oh yes! If/when I cross the atlantic you will have to
show me internals
of _everything_. Can you buy a five-day pass? :-)
Annual memberships are available. I'll send you costs of 1 day vs.
membership privately, or you can look them up on our site under the
"Visit Us" and "Get Involved" tabs on the home page.
Rich
Rich Alderson
Vintage Computing Sr. Systems Engineer
Living Computer Museum
2245 1st Avenue S
Seattle, WA 98134
mailto:RichA at LivingComputerMuseum.org
http://www.LivingComputerMuseum.org/
3149
days inactive
3150
days old
8 comments
7 participants
participants (7)
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aek＠bitsavers.org -
bqt＠update.uu.se -
cube1＠charter.net -
j_hoppe＠t-online.de -
mattislind＠gmail.com -
pontus＠Update.UU.SE -
RichA＠LivingComputerMuseum.org