A flash ROM + Dallas IC combo... perhaps a CMOS (BIOS) backup.

Could it be one of those Y2K-compliance cards? A workaround for machines that had the Y2K rollover bug.
Not the same card but there's an example of one on this page.
http://web.archive.org/web/19991004024054/htt … ons/plug-in.htm

I think its an Real Time Clock ADD-on card.. The eprom have extended bios adresses to extended the normal XT system bios.. And the realtime clock is a new model without hassle with battery..

Who would use an XT back in 1997?

I'm going to assume I will not be needing this card in the system to get it up and running fine, because if so I am sure that Dallas RTC's internal battery is long dead... Would I be correct in this assumption? I'm working on restoring the thing right now, washed out the motherboard , case, psu etc, heat dried in oven to get majority of the moisture out, and sanded down rusty spots on the case.

It probably does replace the RTC but its not aimed at XT's which were well obsolete in 1997 (further evidenced by the fact that it was removed from a Pentium 75...)

I'd say that its definitely a Y2K compliance card. I started working in a hospital in about 2003 and I was involved in a project to roll out XP to over a thousand machines. Some of the old ones we replaced were nearly 7-8 years old at this point and a couple of machines had these types of cards in them.

A lot of people say that Y2K was a scam but that's a very ignorant way of looking at it. For the average home or office PC there was nothing to worry about and cards like this were a waste of money. If your PC was turned on at midnight december 31 1999 and it rolled over to 1900 then I think the worst that would happen is you wouldn't be able to log on to the domain because your clock didn't match the servers, or maybe some app you were running would crash. If you just turned it off, and set the date manually to 2000 you wouldn't have a problem. (at least every PC I've ever seen does this).

Where the problem really lay was big corporate servers - not windows machines but big-iron Unix machines running character based systems like PICK databases, these are usually running 24/7 and often the software they are using was originally built in the 70's and had just been added to since then.

In our case we were using such a system but it had been modified to be Y2K compliant well in advance. I heard that a hospital on the other side of the country using a different system ran into Y2K problems though, and they tried very hard to cover it up - and why wouldn't they? There had been so much hype about it and plenty of forewarning, you would look pretty stupid in the public eye to have Y2K issues.

To give an example of a potential issue, during my time there someone from the Finance department ran the end-of-month billing cycle a day early (they got confused and though the 30th was the end of the month but it was really the 31st). This basically locked every record in the patient management system for the next day, so NO patients could be admitted or discharged in the system. Everything had to be done manually, and new patients couldn't have their medical records retrieved through the system because they weren't admitted. Basically the fix was one of the PICK programmers had to go through and manually unlock all records because it was impractical and potentially dangerous to wait until the next day. Although not Y2K related this shows the sorts of issues that incorrect dates can cause in these systems.

Professor: in answer to your question I'd say your PC will work perfectly fine without that card.