i dont have the answer to this, but maybe You could advise - how much could one map this way?

Depends on how much can you use 😀 Typically, the safe bet is 128KB in segments D and E, but depending on the graphics card you have and other cards that may or may not have their option ROMs, you can map RAM to other segments that are not used.
http://www.vcfed.org/forum/showthread.php?626 … d-Portable-5155

OK, I found it - it's called U44V2M.ZIP

Kubik wrote:

OK, I found it - it's called U44V2M.ZIP

Yes. You can down load it from the following linked thread at VCFED.ORG
http://www.vcfed.org/forum/showthread.php?281 … 2433#post202433

Yep, I got it from there. Now I need to fix those 5160 boards I found and I'll give it a try 😀

If you like, I could burn a GAL for you and add the requisite ground leg jumper. I would only charge cost of shipping. I bought a bunch of 16v8 GALs a while back for a steal, so I've been giving them away for the 1megXT project. Just PM me if interested.

PS
This offer is good for anyone interested in this mod for the 5160 Motherboard.

Greg

Thanks a lot, but I am fine. I have my (t)rusty ALL-11 that can burn pretty much everything, and I've got a handful of 16V8s salvaged from various boards.

Hello Greg,

Does your shipping offer for a GAL still stand?

I would be very interested to fill my IBM 5155 motherboard with 1 MB of RAM for having access to UMB. That would also allow me to save ISA slots (1/4 of them are currently occupied by RAM expansions to get to 640 KB).

Thanks in advance!

xmamat wrote on 2020-04-16, 13:48:

Hello Greg, […]
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Hello Greg,

Does your shipping offer for a GAL still stand?

I would be very interested to fill my IBM 5155 motherboard with 1 MB of RAM for having access to UMB. That would also allow me to save ISA slots (1/4 of them are currently occupied by RAM expansions to get to 640 KB).

Thanks in advance!

I see you're looking for a GAL. I'll have a look this weekend and see if I have any left in my stash. I also need to get my programmer set up and test the GAL before I can commit. If it all comes together, yes the deal still stands. One GAL programmed for 1 MB Ram on XT MOBO for the price of shipping. Let me know by PM where it's shipping to and I'll give you a quote.

Greg

That is very generous of you!
I'll be more than happy to pay you the shipping fees to my place (Paris, France).

Also, I have one more question that I'd like to share on the public thread before I order the 256K x 1 bit chips:
Is the 74LS158 chip in socket U84 required as for the 640KB modification described in http://minuszerodegrees.net/5160/motherboard/ … ard_to_640k.pdf? Or will the newly programmed GAL in socket U44 with all banks filled with 256K x 1 bit chips be enough to get to 1MB?

Uh-oh, looks like I cannot PM yet as I subscribed recently and need to participate more in the general discussions...
I guess I'll just do that!

xmamat wrote on 2020-04-18, 16:07:

That is very generous of you! I'll be more than happy to pay you the shipping fees to my place (Paris, France). […]
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That is very generous of you!
I'll be more than happy to pay you the shipping fees to my place (Paris, France).

Also, I have one more question that I'd like to share on the public thread before I order the 256K x 1 bit chips:
Is the 74LS158 chip in socket U84 required as for the 640KB modification described in http://minuszerodegrees.net/5160/motherboard/ … ard_to_640k.pdf? Or will the newly programmed GAL in socket U44 with all banks filled with 256K x 1 bit chips be enough to get to 1MB?

Yes, you will need the 74LS158 if you have not yet performed the 640k mod. It can be purchased at https://www.futurlec.com/74LS/74LS158pr.shtml

Also, since your Private messaging isn't yet active, you can send me an Email at gregsaling"at"comcast.net
Of course, you'll need to replace "at" with @

OK, thank you very much for the info. I'm sending you an email right now.