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Speeding Up the ADP-50L Boot

G

Great Hierophant

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I have an ADP-50L card with 2.18T BIOS. That card displays a splash screen showing the contact information of the maker, Silicon Valley Computer, for several seconds. That is no longer necessary and I assume that the wait time has nothing to do with the card's internal operations. I do not know how to modify the BIOS to remove the wait, I have attached it as a link so someone else may be able to cut that whole screen out. Perhaps this can be a first step to enabling Universal XT-IDE BIOS support.

http://www.mediafire.com/download.php?zrarlb16lshakor
 
I can't help with the bios but just a thought have you tried replacing the bios chip with an XTIDE Bios chip, I have a silicon valey adp-60/70 in my old Zenith and replaced the original bios chip with the XTIDE and it works great, gets rid of the splash screen and it seem's to be a lot faster on boot up too.

Regards
Malc
 
I doubt it would work, the ADP 60/70 has a standard 16-bit IDE port and uses port mapping. The 50L is an 16-bit to 8-bit translating IDE interface and uses memory mapping to speed data transfers. If I had an EPROM programmer I would try it.
 
Patch location 097a in the ROM with C3 (RET) and then recompute the ROM checksum. Recompute the checksum for 0-17FE and put it into location 17FF (only the first 1800h locations of the ROM are used).

If you have trouble figuring this out, I can do it and post the result.
 
Here is what I did :

I deleted the bytes from 17FF to 19FF, including 17FF. I saved the result as a new file, ORIGINAL.ROM. I ran a program called CHECK8.EXE to calculate the resulting checksums. The checksum was FD. Using my hex editor, I changed the value at the location specified and saved it as a different file, MODIFIED.ROM. The checksum was 70.

The original value at 1FFF of the dumped file (ADP50L218T.ROM before any deletions) was 03. So if that was the checksum of the original 0-17FE, I must have done something wrong, but what?
 
Did you truncate the file to 6,144 bytes before generating the checksum?
 
BIOS ROM checksums work by having the lowest 8 bits of the sum work out to 0. So, modified as I mentioned, the sum of the first 17FF bytes is 70H, to make this come out to XX00, you need to add 90H.

Attached is the modified ROM. Let me know how it works.
 

Attachments

  • ADP50A.ZIP
    4.3 KB · Views: 2
Krille said:
You're not happy with XUB running on that? :)
Click to expand...
I still need to test with that. :) I've been unable to get any XUB builds to work with an "XT-IDE Deluxe" card in this persnickety system, so when I was able to get the ADP50L to boot with its standard BIOS (albeit, requiring both master and slave "drives" to be present), I decided to take a pause.
 
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