It looks like a BIOS/ROM card to me.

Yep. HY6264LP-10 is an SRAM just like the ones used in old console cartridges, the "LP" stands for low power to avoid running the battery down quickly.

I have similar feeling - something like that... What I have found - contains just memory and bus controller... But the original computer is working without this card and there is a battery on the mainboard as well. It is Philips 5107-200-36154 386sx-20 motherboard. But... It still beeps an error (FDD) during setup. I suppose that the integrated controller is gone and want to connect fdd to some ISA controller (not yet tested...).

I have no idea about its purpose...

You'd better dump and post here the BIOS extension from DOS and then it can be told with more certainty. For now it looks to me like a BIOS extension that saves its setup in the SRAM, most likely could be a BIOS extension for larger hard drives.

Any possibility it's a licensing dongle but as an entire card?

jakethompson1 wrote on 2025-09-05, 22:42:

Any possibility it's a licensing dongle but as an entire card?

Anything is possible with licensing dongles, but I would hope most licensing dongles used serial EEPROM instead of battery-backed SRAM for license information, if that information needs to be modified after the dongle is deployed. Furthermore, if the licensing information is in the SRAM, there would be no need to have a ROM on the card as well. And if the licensing information is in the ROM, why would you deal with the hassle of implementing a battery-backup solution (with a leaky NiCd battery, leakage damage is clearly visible on the photo).

It's definitely possible, there were arcade machines that were purposefully designed to store their graphics data on battery-powered SRAM. When the battery went flat, no more sprites...

(Did I mention the battery was epoxied to the chip, enclosing/hiding its existence?)

georgel wrote on 2025-09-05, 21:44:

You'd better dump and post here the BIOS extension from DOS and then it can be told with more certainty. For now it looks to me like a BIOS extension that saves its setup in the SRAM, most likely could be a BIOS extension for larger hard drives.

thanks. can you give an advice, what sw to use? i dont have experince with this...