Large disk support for Adaptec 1520B / 1522B \ VOGONS

Large disk support for Adaptec 1520B / 1522B

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First post, by mkarcher

Posted on 2023-07-16, 17:59

mkarcher Offline

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Continuing the effort started in these threads

INT13 Extensions to SDMS 3.0 & 4.0 - SCSI by NCR / Symbios Logic / LSI Logic , resulting in https://github.com/karcherm/sdms_8g
Showing some love for Adaptec's ugly ducklings: Adding big drive support to EISA and VL controllers , resulting in https://github.com/karcherm/scsi_edd

I now added BIOS patches for the Adaptec 1520B / 1522B to add BIOS support for disk drives above 8GB to the newer "scsi_edd" repository. The enables LBA-capable versions of Windows 9x to access big drives on these controllers.

In this case, I wrote the source code in a kind of literate programming approach: You can read the assembler source code file for the BIOS patch as a complete explanation, how that patch works and why it is written that way. A deep link directly into that file: https://github.com/karcherm/scsi_edd/blob/v1.3/152xB115.asm

The BIOS for the 1522B will most likely not work on the 1520 or 1520A, as those chips use older Adaptec interface chips.

Reply 1 of 5, by Horun

Posted on 2023-07-16, 20:14

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Nice work ! yeah the AIC 6260 is not same as newer 6360

Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor. Stuff: https://archive.org/details/@horun

Reply 2 of 5, by Disruptor

Posted on 2023-07-16, 20:20

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We have tested it on an Adaptec 1520B with AIC-6370Q.
Please note that the corresponding ASPI2DOS.SYS may not need to be patched.

Reply 3 of 5, by weedeewee

Posted on 2023-07-16, 21:02

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Can this work with a AHA-1535A ?

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Reply 4 of 5, by mkarcher

Posted on 2023-07-16, 21:03

mkarcher Offline

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Horun wrote on 2023-07-16, 20:14:

Nice work ! yeah the AIC 6260 is not same as newer 6360

It seems like

AHA-1510/1520/1522 uses the AIC-6260, the most recent BIOS image I have is 1.4, copyright 1990
AHA-1510A/1520A/1522A uses the AIC-6360, the most recent BIOS image I have is 1.20L, copyright 1993
AHA-1510S100/1520S100/1522S100 (also S105) seem to be very similar to the A series
AHA-1510B/1520B/1522B uses the AIC-6370, the most recent BIOS image I have is 1.15, copyright 1996

The AHA-1510 controllers do not have a BIOS and do not have the support logic for the BIOS, like the ISA address decoder. So there won't be any BIOS patches for the 1510 series.

Reply 5 of 5, by mkarcher

Posted on 2023-07-16, 21:11

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weedeewee wrote on 2023-07-16, 21:02:

Can this work with a AHA-1535A ?

No. The 1535A seems to be a cost-reduced version of the 1540CF or 1540CP. Their architecutre is completely different from the 1520 architecture. The latest 154xCF BIOS already includes large disk support, so possibly the AHA-1535A does so, too.

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