22 Feb
2018
22 Feb
'18
11:37 p.m.
This is all bringing back when Intel tried to see BM's to me at Tektronix.
Got to go see them being made. Something just told me "dead end".
-pete
On Thu, Feb 22, 2018 at 5:09 PM, dwight via cctalk <cctalk at classiccmp.org>
wrote:
Looking things up, I don't think the Nicolet one
with the scope was the
Intel one.
Dwight
________________________________
From: cctalk <cctalk-bounces at classiccmp.org> on behalf of allison via
cctalk <cctalk at classiccmp.org>
Sent: Thursday, February 22, 2018 3:14:45 PM
To: cctalk at classiccmp.org
Subject: Re: WTB Intel 7110 Bubble Memory Subsystem or Chipset
On 02/22/2018 03:08 PM, Mark J. Blair via cctalk wrote:
I'm about to acquire a couple of
1980s-vintage military surplus
AN/UGC-137A terminals (i.e., glass TTYs with some
local message preparation
and storage capabilities) which have a bubble memory subsystem. They use
plug-in cartridges containing 256 kbytes of storage in the form of two
Intel 7110 1 Mbit bubble memory chips and their 7242 formatter/sense
amplifiers.
One of the cartridges contains the one and only copy of the terminals'
firmware, which I believe they need to load up at each reboot. Naturally,
extracting the contents of that irreplaceable cartridge for archival, and
potential future emulation, is going to be a very high priority for me. I
have a few different approaches in mind for accomplishing that. One
approach would be to remove the two memory devices from the critical
cartridge in order to dump their contents in an independent bubble memory
subsystem.
With that in mind, I'd like to get my hands on a working Intel 7110
bubble
memory subsystem, or the parts to build one myself (i.e., a complete
7110/7220/7230/7242/7250/7254 chipset that I could make a board around).
What you plan is risky. You first need to know how they organize the
data in each of the loops.
The problem is did that interleave the two bubble or are they addressed
seperately. Both possibilities
were the case. Each BM required its own CPG, FSA and drivers but could
share the 7220 BMC.
Might anybody here have what I need available for
sale or trade? I might
be able to use some arbitrary old computer or other device
that has a
subsystem based around the Intel 7110, or a development kit such as the
Intel BPK-72, or a chipset to make my own board.
I got two of them back in the 80s, they are now part of a CP/M Z80
system I built back then.
Not much storage and sorta slow and power hungry.
If I can't acquire or make the hardware to
dump the memory chips outside
of their native system, then I think my next option
would be to passively
snoop the host bus interface of the Intel 7220 controller I expect to find
inside the terminals as they perform their initial firmware load, so that I
can reconstruct the cartridge contents from the trace data.
The best and lowest risk point is to snoop is at the data bus
interface. Logic analyzer or something fast enough to
grab the data. The 7220 chip set gave a nice bus interface with a
fairly simple command set. Its also the side of
the device thats well documented.
I may have a few of the basic bubble memory units 7110 as they were
socketed. No extra CPD, FSA, Driver devices,
or BMC 7220.
Allison
The terminals were made by the Librascope
division of Singer, and
brochures can be found here:
Product_Literature_files/Communications%20Terminal.pdf
Product_Literature_files/SST.pdf
Product_Literature_files/Bubble%20Memory%20Cartridge.pdf
I already have the critical cartridge in hand, and I posted some
pictures of it on
Twitter: