9 Jul
2019
9 Jul
'19
2:11 p.m.
Hi there.
I just acquired a board with the number M7609. It was advertised as an M630-CA which my
research tells me is supposed to be 16MB. How do I tell on the board if this is 8MB or
16MB? There does not seem to be a suffix on the board that I can see.
What to look for?
73 Eugene W2HX
9 Jul
9 Jul
2:52 p.m.
M7608 == 4MB
M7609 == 8MB
AFAIK the only DEC 16MB Q-bus board is the MS650 M7622 for the KA640,
KA650, KA655, KA660
On Tue, Jul 9, 2019, 2:36 PM W2HX via cctech <cctech at classiccmp.org> wrote:
Hi there.
I just acquired a board with the number M7609. It was advertised as an
M630-CA which my research tells me is supposed to be 16MB. How do I tell on
the board if this is 8MB or 16MB? There does not seem to be a suffix on the
board that I can see.
What to look for?
73 Eugene W2HX
3:08 p.m.
On Tue, 9 Jul 2019 21:11:39 +0000
W2HX via cctech <cctech at classiccmp.org> wrote:
Hi there.
I just acquired a board with the number M7609. It was advertised as an
M630-CA which my research tells me is supposed to be 16MB. How do I tell on
the board if this is 8MB or 16MB? There does not seem to be a suffix on the
board that I can see.
What to look for?
M7609-AA MS630-CA Q 8-Mbyte parity 36-bit RAM for KA630 (MicroVAX II)
Lyle
--
73 NM6Y
Bickley Consulting West Inc.
https://bickleywest.com
"Black holes are where God is dividing by zero"
4:43 p.m.
Thanks, Lyle. I was reading this. I guess its wrong?
https://en.wikipedia.org/wiki/MicroVAX
The MS630 memory expansion module was used for expanding memory capacity. Four variants of
the MS630 existed: the 1 MB MS630-AA, 2 MB MS630-BA, 4 MB MS630-BB and the 16MB MS630-CA.
Wouldn't be the first time wikipedia was wrong...
Eugene
________________________________________
From: Lyle Bickley <lbickley at bickleywest.com>
Sent: Tuesday, July 9, 2019 6:08 PM
To: cctech at classiccmp.org
Cc: W2HX
Subject: Re: DEC MS630/M7609 Question
On Tue, 9 Jul 2019 21:11:39 +0000
W2HX via cctech <cctech at classiccmp.org> wrote:
Hi there.
I just acquired a board with the number M7609. It was advertised as an
M630-CA which my research tells me is supposed to be 16MB. How do I tell on
the board if this is 8MB or 16MB? There does not seem to be a suffix on the
board that I can see.
What to look for?
M7609-AA MS630-CA Q 8-Mbyte parity 36-bit RAM for KA630 (MicroVAX II)
Lyle
--
73 NM6Y
Bickley Consulting West Inc.
https://bickleywest.com
"Black holes are where God is dividing by zero"
10 Jul
10 Jul
7:32 a.m.
On Tue, 9 Jul 2019 23:43:17 +0000
W2HX <w2hx at w2hx.com> wrote:
Thanks, Lyle. I was reading this. I guess its wrong?
https://en.wikipedia.org/wiki/MicroVAX
The MS630 memory expansion module was used for expanding memory capacity.
Four variants of the MS630 existed: the 1 MB MS630-AA, 2 MB MS630-BA, 4 MB
MS630-BB and the 16MB MS630-CA.
The use of suffix's to identify the amount of memory was common with DEC - and
the line I copied only referenced the "AA" version of the MS630.
Wouldn't be the first time wikipedia was wrong...
Their probably right (in this case ;)
Lyle
______________________________________
From: Lyle Bickley <lbickley at
bickleywest.com>
Sent: Tuesday, July 9, 2019 6:08 PM
To: cctech at classiccmp.org
Cc: W2HX
Subject: Re: DEC MS630/M7609 Question
On Tue, 9 Jul 2019 21:11:39 +0000
W2HX via cctech <cctech at classiccmp.org> wrote:
--
73 NM6Y
Bickley Consulting West Inc.
https://bickleywest.com
"Black holes are where God is dividing by zero"
Hi there.
I just acquired a board with the number M7609. It was advertised as an
M630-CA which my research tells me is supposed to be 16MB. How do I tell on
the board if this is 8MB or 16MB? There does not seem to be a suffix on the
board that I can see.
What to look for?
M7609-AA MS630-CA Q 8-Mbyte parity 36-bit RAM for KA630 (MicroVAX II)
Lyle
--
73 NM6Y
Bickley Consulting West Inc.
https://bickleywest.com
"Black holes are where God is dividing by zero" 
9 Jul
9 Jul
4:57 p.m.
On 09/07/2019 22:11, W2HX via cctech wrote:
Hi there.
I just acquired a board with the number M7609. It was advertised as an M630-CA which my
research tells me is supposed to be 16MB. How do I tell on the board if this is 8MB or
16MB? There does not seem to be a suffix on the board that I can see.
What to look for?
The simple answer is to install it in a uVAX2 system and see what it
says :-)
IIRC the M7608 comes in (at least) two variants, the MS630-BA, which is
2MB, and the MS630-BB, which is 4MB. I think that if you hold them side
by side, it's obvious one has half the memory positions not filled.
But the M7609 is an MS630-CA, which is always 8MB. There are various
suffixes to the MS7609 board, but they (I think) just tell you the
manufacturer of the RAM chips; the board is always 8MB.
Antonio
--
Antonio Carlini
antonio at acarlini.com
10 Jul
10 Jul
10:08 a.m.
The simple answer is to install it in a uVAX2 system
and see what it
says :-)
Or look up the part number on one of the DRAM chips, count the number
of DRAM chips, and then work out the total.
If the M7609 uses 256Kbit DRAM chips (as all MS630 boards do), then 9
of them are 256KB with parity, 36 of them are 1MB, and the total of
288 256Kbit DRAM chips on the M7609 is a total of 8MB.
9:13 p.m.
DEC used to use the first letter of the suffix for density, and the second
letter for the chip manufacturer.
On Wed, Jul 10, 2019 at 12:08 PM Glen Slick via cctalk <
cctalk at classiccmp.org> wrote:
The simple
answer is to install it in a uVAX2 system and see what it
says :-)
Or look up the part number on one of the DRAM chips, count the number
of DRAM chips, and then work out the total.
If the M7609 uses 256Kbit DRAM chips (as all MS630 boards do), then 9
of them are 256KB with parity, 36 of them are 1MB, and the total of
288 256Kbit DRAM chips on the M7609 is a total of 8MB.
1775
days inactive
1777
days old
7 comments
5 participants
participants (5)
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a.carlini＠ntlworld.com -
glen.slick＠gmail.com -
lbickley＠bickleywest.com -
useddec＠gmail.com -
w2hx＠w2hx.com