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2 More 8 bit ISA cards I need help Identifying

VERAULT

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I have two more RAM cards I need help identifying. I think I got these from Member Radracer203.

Photos here: https://photos.app.goo.gl/KVdHf4tU7P43xd1e7

One is labeled Digigraphic Systems Extend 384MA PN 30000022 It has a large pin header above the ISA connector and it has a large VARTA MEMpak which I removed before it could do any damage. It has a dipswitch package of 5. It has 6 banks of 9 X 3764-15 Ram chips. All OKI brand

The second is by 4SR INC. And besides a Rev 2 1983 and a SN# there is nothing on it giving any info. It has a dipswitch package of 4. It has four banks of 9 X 4264-15 Ram chips. All MT ram brand

Would love to test these out but need info and software first. I remember a site years back that had all these old 8 bit cards in black line diagrams you can go through to quickly find your card. I forgot where that was or if its still up.
 

Chuck(G)

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The 4SR card is an oddball one. Has 256KB of memory and an 8085 CPU. Probably a co-processor board.

The Digigraphics one looks like a straightforward memory expansion board.
 

VERAULT

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The 4SR card is an oddball one. Has 256KB of memory and an 8085 CPU. Probably a co-processor board.

The Digigraphics one looks like a straightforward memory expansion board.
I didnt even notice the 8085! What could that even be used for ? The ROM didnt have a sticker over it I am not sure if its damaged, there isnt much on it. Here is a rom dum attached.

Sure 384KB but Its not registering anyting in the machine. Why does it have that large pin header?
 

Attachments

  • 4sr inc.zip
    190 bytes · Views: 5

Chuck(G)

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The header is probably for a "piggyback" board. Unknown function, however.
The 4SR prom has very little in it:

STA 1ff3h
LXI SP, 8020
JMP 6

and a couple more jumps a bit later in the code. Must be some software to load into the RAM missing.
 

Chuck(G)

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Impossible to say. Were it a CP/M card, I'd have thought that basic I/O support routines would be in the PROM for use by the CP/M CBIOS. I can find next to nothing about the vendor.
 

twolazy

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I'm going to guess that 4SR card is some sort of ramdrive.... Have you dumped the eprom yet?

EDIT: Doh didnt see the zip file... grabbing it now

Wow , talk about a strange dump. Its 95% just blank with only a handful of instructions. Weird.
 
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twolazy

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So did an EDGAR search as well as histortical search... Cant find any computer related company named 4SR. There was a mention of a 4SR in canada in a small newspaper but alas can't find anything else...

Nothing is showing up on the OCR'd Byte archive either...
 

twolazy

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I had a 16 bit ramdrive card that utilized a 186...And the Bocaram AT Plus I have now has way less on it... I dunno just a guess.
 

VERAULT

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I have a BocaRAM AT Plus in the box complete, but it is the 0Kb model where you need to populate the whole board yourself.
 

rmay635703

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4sr INC points to a low volume lab equipment company.

If that’s the case the card would definitely need more hardware / software to perform its intended purpose.

Unfortunate you don’t have the system it came from.
 
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VERAULT

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4sr INC points to a low volume lab equipment company.

If that’s the case the card would definitely need more hardware / software to perform its intended purpose.

Unfortunate you don’t have the system it came from.
thats interesting. if i can confirm that ill tkse the ram chips out for other boards.
 

Chuck(G)

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The 4SR card is interesting to my EE's eye. Note the 74LS283 near the DIP switch--that's a 4-bit adder. Or the 74LS670 near the CPU chip--a 4 by 4 bit register file. Note also, near the bottom, the TBP28L22N bipolar PROM. And the 74LS279 R-S latch.

Given that, the 256KB of DRAM doesn't seem so odd--it's being bankswitched in 4x64KB segments. Given that there are no other external headers on this thing, my guess is that it's purpose was to emulate an older 8085-based system with bankswitching. There's no other good reason to use an 8085 in 1983, rather than, say a Z80. Personally, I'd keep the board intact, complete with DRAM. It's an odd duck and very much sui generis.
 

VERAULT

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The 4SR card is interesting to my EE's eye. Note the 74LS283 near the DIP switch--that's a 4-bit adder. Or the 74LS670 near the CPU chip--a 4 by 4 bit register file. Note also, near the bottom, the TBP28L22N bipolar PROM. And the 74LS279 R-S latch.

Given that, the 256KB of DRAM doesn't seem so odd--it's being bankswitched in 4x64KB segments. Given that there are no other external headers on this thing, my guess is that it's purpose was to emulate an older 8085-based system with bankswitching. There's no other good reason to use an 8085 in 1983, rather than, say a Z80. Personally, I'd keep the board intact, complete with DRAM. It's an odd duck and very much sui generis.
Chuck, its yours for the cost of shipping (all chips intact of course). If it is such a board, than it is extemely interesting. Without proper software its just going to sit in a box indefinitely.
 

Chuck(G)

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I'll PM you later--I'm curious to see if it might emulate a more common 8 bit system.

Reverse-engineering is something that I find to be entertaining... :)
 
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