RAM images?

[metertech58761]

I am currently working on reverse engineering a schematic diagram of an early RAM storage device... it uses a Dallas SRAM chip to store programs as well as interfacing with a PC Card-style SRAM card.

I suddenly got the idea of trying to read out the contents of the Dallas chips from both RAM storage devices and a CPU card I had that would work with this device, and I'd like the opinion of the 'brain trust' on the images I read out.

One I'm 99.5% sure is a perfect copy of the factory diagnostic SRAM card - can anyone run it through a disassembler that understands code written for the 8031 MPU and verify?

The other two look like the integrated batteries in the Dallas chips have kicked the bucket. These two would contain program data, but it looks like the pseudo-random data you'd see at initial power-up of a RAM chip...

I also added the dump of the EPROM if it helps in checking the diagnostic cart.

[squadchannel]

To me, it looks like a memory reader/writer for industrial machines, interfaced via a serial connection.
might have been used to replace punched tape.

Of course, if anyone is familiar with MCS-51, can probably to do a memory dump via serial, it would be easy.
if it were me, I would desolder and read it by TL866.

it's 8934, that's 35 years. that's 25 years past his 10 year lifespan. he's a long lived boy.
if he doesn't do something soon, he'll be gone.

I always wonder. How can dallas live so long; CMOS batteries don't even last 10 years.

[metertech58761]

Fortunately, this company had ALL the ICs on its boards socketed, and extracting the Dallas chip was easy.

The CPU card was from 1988, this Program Loader unit was from early 1990.

The second Program Loader that yielded what I think is a good image is young in comparison; it was from 1995 (it also appears to be 'new old stock').

Oh, and this Program Loader replaced an earlier cassette deck that used Dictaphone-type cassettes.

[abyrvalg]

I’ve checked the smaller (8K) image quickly, looks like valid code, found ROM checksum verification under one of the first function calls, computed the same checksum (a simple sum of all bytes) and it is correct (=0).
The bigger image has several gaps, I’ll check it later.

[metertech58761]

Update: Nearly finished the schematic; have ordered fresh sockets and will pull the existing sockets (and read the PAL) once I'm back at work in a few days.