I found this card on ebay. It's been robbed of all the ram ICs. Can't find anything on it at all. Surely it was OEM'd by the usual Taiwan suspects?
Places I looked:
Wayback machine
google books (magazines)
scrolled through ALL the ram cards on retroweb, none match layout
This card looks like it has three banks of 9 memory chips providing one bit each (including parity). Memory chips that fit the card could be 64K x 1 (4164 / 4264) or 256k x 1 (41256). You can find out whether the card supports 256K x 1 chips by checking whether pin 1 on the RAM sockets is connected anywhere. Possibly 41256 chips are only supported in one bank: A standard configuration for XTs was a main board that could have 256K, and then adding one bank of 256K and two banks of 64K to get to the full 640K on the ISA bus.
The DIP switches set the starting address (how much memory you have on the mainboard or possibly other RAM cards) and possibly the RAM type and number of populated banks. If you manage to obtain 27 64K x 1 chip and you have a mainboard that can be configured down to 64K onboard RAM, you can likely find out the interpretation of the DIP switches by experimentation. If a combination is meant for 256K chips, you will get the same 64K repeated four times if you install 64K chips instead. That's why I recommend the small chips for easiest experimentation.
mkarcher wrote on 2025-08-12, 20:14:This card looks like it has three banks of 9 memory chips providing one bit each (including parity). Memory chips that fit the card could be 64K x 1 (4164 / 4264) or 256k x 1 (41256). You can find out whether the card supports 256K x 1 chips by checking whether pin 1 on the RAM sockets is connected anywhere. Possibly 41256 chips are only supported in one bank: A standard configuration for XTs was a main board that could have 256K, and then adding one bank of 256K and two banks of 64K to get to the full 640K on the ISA bus.
The DIP switches set the starting address (how much memory you have on the mainboard or possibly other RAM cards) and possibly the RAM type and number of populated banks. If you manage to obtain 27 64K x 1 chip and you have a mainboard that can be configured down to 64K onboard RAM, you can likely find out the interpretation of the DIP switches by experimentation. If a combination is meant for 256K chips, you will get the same 64K repeated four times if you install 64K chips instead. That's why I recommend the small chips for easiest experimentation.
Good info.
So if I write 0xFF to a location in the first 64K with debug I'd see it repeated 3 more times at 64K boundaries, right?
January 1987 device, so very likely a cost reduced replacement for an ast six pack
Interesting history for a local to me pc maker
kingcake wrote on 2025-08-12, 22:13:So if I write 0xFF to a location in the first 64K with debug I'd see it repeated 3 more times at 64K boundaries, right?
Yeah. This is the first 64K of a bank, no the first 64K of the system of course. Furthermore, this is true for any 64K block of a bank, not just the first one. So assuming the card supports and you found the configuration for 256K + 64K + 64K with a start address of 256K (20000 hex), and further assuming that the 256K bank is first:
rmay635703 wrote on 2025-08-13, 03:29:January 1987 device, so very likely a cost reduced replacement for an ast six pack
The AST Six Pak series of cards are multi-function cards (although I have trouble counting six functions). The main selling point of the Six Pak series of cards was that these cards conserve slots (remember the 5150 only had 5 slots, and the original mainboard only had 64KB of RAM onboard). This card on the other hand is a memory card only, which there also were plenty of back in the 80's. Nevertheless, you are correct that this card is cost reduced, and the memory expansion function (not expanded memory!) of this card works the same way as the memory expansion portion of the AST Six Pak cards. Due to their age, cards like the Six Pak Plus support 64K x 1 chips only, and thus require 6 banks for the 384K memory size required to bring a 256K mainboard to 640K. Being able to use 256K chips (which is just an educated guess) is a key point to make the card smaller, because with those chips 3 banks suffice.
The AST 6 pack was so named after the 6 banks of ram, the onboard features weren’t part of the naming convention
rmay635703 wrote on 2025-08-13, 19:49:The AST 6 pack was so named after the 6 banks of ram, the onboard features weren’t part of the naming convention
bullshit
maxtherabbit wrote on 2025-08-14, 12:02:rmay635703 wrote on 2025-08-13, 19:49:The AST 6 pack was so named after the 6 banks of ram, the onboard features weren’t part of the naming convention
bullshit
Wierd, the 6th pack of the 6 pack are utilities and software, never knew that. (AKA there never were 6 features)
https://dosdays.co.uk/media/ast/SixPak%20Plus … -05-29_0084.jpg
It does say we would like to think the 6 pack is named for the 6 banks of memory in the add though.
Considering the game port was optional they just liked the name and miscounted.
Hey now!
I before E, but only for Me!
E before I, when describing the guy!
😁
