20 Jul
2009
20 Jul
'09
2:54 p.m.
I just happened across a description of the MP8-E memory parity module. It uses another
core stack to maintain parity data for all other memory installed in the machine. All
core was 12-bit. Source: PDP8/e Maintenance Manual, Vol. 2. -- Ian
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-
bounces at classiccmp.org] On Behalf Of Allison
Sent: Friday, July 10, 2009 5:46 PM
To: cctech at classiccmp.org
Subject: Re: DEC H207 Core Memory Boards
There wass never ECC memory as the logic for that likely exceeds
that of the PDP-8. There was 13bit Parity memory (I don't mean the
oddball
13bit rom /ram mix device).
Allison
Subject: Re: DEC H207 Core Memory Boards
From: Ethan Dicks <ethan.dicks at gmail.com>
Date: Fri, 10 Jul 2009 19:43:52 -0400
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at
classiccmp.org>
On 7/10/09, Brent Hilpert <hilpert at cs.ubc.ca> wrote:
> While the use of the H207 has apparently been determined, out of
curiousity
was
> there ever any ECC core memory for the
PDP-8?, it might have have
had a width
>> of 16 or 17 bits.
>
>I have never seen ECC core for any DEC machine (but don't take that as
>the definitive answer). The PDP-8/L, though, was commonly shipped
>with parity (there's space in the CPU chassis that's pre-wired for the
>parity support cards and the slots for the core sense/inhibit wires
>are wired for 13 bits). It might also be supported in the -8/i, but
>I'd have to look that up (I know about the -8/L for certain because
>one of mine arrived with that option populated).
>
>-ethan