9 May
2012
9 May
'12
3:16 p.m.
There was some debate at VCF East whether this "IBM 256KB Memory
Card" P/N 6407740 is a bubble memory card (pic below). The card was
on display with my IBM PC 5150 exhibit. I originally pulled it from
an IBM 5155 portable.
http://www.vintagecomputer.net/ibm/5155/ibm_256KB_memory_card_6407740.jpg
Typically you don't see 32-pin 64K RAM chips on a ISA card. That
does not make it bubble memory though, so I put this out to the
esteemed CCTECH community for answers/ideas.
I do not have a technical reference manual, but I do have the IBM
64/256KB Memory Expansion Option manual. That ain't it.
Date codes on some of the chips are from 1984.
The memory chips are marked 6119927 IBM-14 PQ ESD 1 H28 708016
I found this from a web search for IBM 6407740:
IBM-14 PQ ESD 64KB 32-PIN MEMORY MODULE 5150/5175
...so, whadda we gots ?
Thanks
Bill
9 May
9 May
4:02 p.m.
On 9 May 2012 at 18:16, B Degnan wrote:
There was some debate at VCF East whether this
"IBM 256KB Memory
Card" P/N 6407740 is a bubble memory card (pic below). The card was
on display with my IBM PC 5150 exhibit. I originally pulled it from
an IBM 5155 portable.
http://www.vintagecomputer.net/ibm/5155/ibm_256KB_memory_card_6407740.
jpg
Typically you don't see 32-pin 64K RAM chips on a ISA card. That does
not make it bubble memory though, so I put this out to the esteemed
CCTECH community for answers/ideas.
Nope, they're IBM 64KB memory modules. Google on '6119927 IBM" for
more clues.
I think it's in my O&A. I can check if you'd like.
--Chuck
6:09 p.m.
On 5/9/2012 4:02 PM, Chuck Guzis wrote:
Nope, they're IBM 64KB memory modules. Google on
'6119927 IBM" for
more clues. I think it's in my O&A. I can check if you'd like. --Chuck
Also, those square packages, and the circuit boards with all the dot
patterns on the same centers as these packages come out of an IBM cad
system, which pretty much is used on everything. They can put them in
industry standard packages. However if they had a project where these
chips were packaged in sufficient quantities for say an RT or other mini
system, it would not be surprising to see these sorts of packages.
Also if you had any of the full length 3270 cards for the ISA bus, they
had some logic in the same packaging, so were probably in there for the
same reason.
I know that the air cooled mainframes I had had most of their logic
implemented with the IC's in these metal type packages.
The bubble memory I have most resembles some sort of an odd transformer
on the card, rather than metal packages such as these. I think mine are
from both TI and Intel, but I'd have to find them
to check (bubble
memories).
Jim
8:51 p.m.
On 9 May 2012 at 18:09, Jim Stephens wrote:
Also, those square packages, and the circuit boards
with all the dot
patterns on the same centers as these packages come out of an IBM cad
system, which pretty much is used on everything. They can put them in
industry standard packages. However if they had a project where these
chips were packaged in sufficient quantities for say an RT or other
mini system, it would not be surprising to see these sorts of
packages.
You could also find a couple on the first 5150 floppy controller used
for the data separator. One big, one small, if memory serves.
--Chuck
8:28 p.m.
Easy to spot bubble memory modules: They get HOT :o)
---
Enviado do meu Motorola PT550
Meu site: http://www.tabalabs.com.br
----- Original Message -----
From: "Chuck Guzis" <cclist at sydex.com>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Sent: Wednesday, May 09, 2012 8:02 PM
Subject: Re: Bubble Memory "IBM 256KB Memory Card" P/N 6407740 ?
On 9 May 2012 at 18:16, B Degnan wrote:
There was some debate at VCF East whether this
"IBM 256KB Memory
Card" P/N 6407740 is a bubble memory card (pic below). The card was
on display with my IBM PC 5150 exhibit. I originally pulled it from
an IBM 5155 portable.
http://www.vintagecomputer.net/ibm/5155/ibm_256KB_memory_card_6407740.
jpg
Typically you don't see 32-pin 64K RAM chips on a ISA card. That does
not make it bubble memory though, so I put this out to the esteemed
CCTECH community for answers/ideas.
Nope, they're IBM 64KB memory modules. Google on '6119927 IBM" for
more clues.
I think it's in my O&A. I can check if you'd like.
--Chuck
9 May
9 May
9:39 p.m.
Nope, they're IBM 64KB memory modules. Google on
'6119927 IBM" for
more clues.
I have one of these cards, given to me by an IBMer that had a hand in its
design. Yes, the memory modules are just as you say. I think they contain
two individual chip dies. The card was made for use with the 5155 portable.
--
Will
10 May
10 May
12:53 p.m.
There was some debate at VCF East whether this "IBM 256KB Memory
Card" P/N 6407740 is a bubble memory card (pic below). The card was
on display with my IBM PC 5150 exhibit. I originally pulled it from
an IBM 5155 portable.
http://www.vintagecomputer.net/ibm/5155/ibm_256KB_memory_card_6407740.jpg
Typically you don't see 32-pin 64K RAM chips on a ISA card. That
does not make it bubble memory though, so I put this out to the
esteemed CCTECH community for answers/ideas.
I doubt very much if it's bubble memory, for sevrral reasons.
1) What would eb the point of having part of the sytem RAM non-volatile?
2) Buble memory is slow, and sequential access at the device level. It is
not really suitable for use as main memoty. My experience of it is
limited to the HP bubble memroy card used in HP9000/200 machines where
it's addressed in the I/O space and is used by the system as a fast 'disk
drive' .
3) Unless those metal cans are bubble memory devices with built-in
cotnroller circuitry, thwre is nothing apporximatign to a buble memeory
controlelr on that board. You can't do it with a handful of TTL parts. A
'bare' bubble memroy device has not that many conenctions either.
I am pretty sure there's a photo and schematic for the HP bubble memory
board I mentioned over on http://www.hpmuesum.net/
I do not have a technical reference manual, but I do have the IBM
64/256KB Memory Expansion Option manual. That ain't it.
That board is not min my Techref either. But I think it's just plain DRAM.
I do wonder why it existed. It is trivial to put 640K on the motherboard
of a 5155, jsut as in a 5160 (XT). It's a matter of putting the right
TAMs in (41256s in banks 0 and 1, 4164s in banks 2 and 3), adding a
74S158 (or 74F158) in the enpty socket towards the front and jumpering E1
to E2.
-tony
2:19 p.m.
There was some debate at VCF East whether this
"IBM 256KB Memory
Card" P/N 6407740 is a bubble memory card (pic below). The card was
on display with my IBM PC 5150 exhibit. I originally pulled it from
an IBM 5155 portable.
http://www.vintagecomputer.net/ibm/5155/ibm_256KB_memory_card_6407740.
jpg
I am certain those are 64 KB CMOS DRAM chips, not bubble memory. I've seen
them on 30-pin SIMMs too.
Camiel.
2:58 p.m.
> There was some debate at VCF East whether this
"IBM 256KB Memory
> Card" P/N 6407740 is a bubble memory card (pic below).
Apparently my original post was trashed, so:
I have one of these cards, given to me by one of the IBM old timers I see
from time to time. He is one of the original engineers
for it. So, second
hand from the horses mouth - no, not bubble memory. The card was
designed
specifically for use in the 5155, for some reason.
--
Will
11 May
11 May
11:53 a.m.
I have one of these cards, given to me by one of the
IBM old timers I see
from time to time. He is one of the original engineers for it. So, second
hand from the horses mouth - no, not bubble memory. The card was designed
specifically for use in the 5155, for some reason.
I suspoect it was designed for the 5155, but it can be used in the 5150
and 5160 too.
The point being that the 5155 layout is differnet to the otehr machines.
Since the CRT monitor and PSU take up the entire elft side of the case,
the motherboard is mounted towards the right side (not the left side as
in the desktop machines) and thus most of the expansion slots are right
behind the floppy drives. So only 'short' cards will fit. Making a
'short' memory card that would go in one of these slots was obviosly
useful for such a machine.
Why they didn't just put the memory on the motherboard, which they ahd
designed to take it, is mystery, though.
-tony
10 May
10 May
2:26 p.m.
On 10 May 2012 at 20:53, Tony Duell wrote:
That board is not min my Techref either. But I think
it's just plain
DRAM.
As I mentioned, it's in the O&A under "IBM 256KB Memory Expansion
Option". To quote:
"The IBM 256KB Memory Expansion Option has four pluggable sockets.
Each socket will accept a 64KB Memory Module, consisting of one (64K
by 9) 32-pin D RAM Module. The 256KB expansion option comes with all
four modules installed providing 256KB of memory."
For what it's worth, this is a three-supply card; +5, -5 and +12 VDC.
The section includes a pinout of a 64KB module.
--Chuck
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