So it would seem it hangs only when it detects the emulated HDD(s)? Do you have any mechanical SCSI HDDs to test with? A problem with SCSI bus shouldn't really hang the system, I would guess the issue is with running the SCSI BIOS.

At which point exactly does it freeze? When the HDDs are first detected and BIOS extension is installed? Or past that, when the system tries to boot from one of these emulated devices? Check your BIOS settings, some mobos have simple on/off settings for ROM shadows and some allow shadows with and without write protection. See if switching that makes any difference, some of these ROMs have bugs in them.

It could also be a general issue with VLB. It might seem to work when you enter the Adaptec BIOS during booting because then the mobo usually runs with pretty conservative settings, like cache timings and the like. Once it tries to boot it goes full throttle and that might just cause the VLB card to give up. Try relaxing all cache and RAM timings, see if the mobo has a jumper for wait-states on VLB, and/or try a slower CPU clock.

Yes i will test a real scsi hdd soon.
I check my mainboard manual, both VLB slots can act as master. VLB Waitstate is set to 1. I did no oc so the vlb bus is not overclocked.
System freeze on this screen:

Before that anything looks ok:

and here my bios:

I tryed also the shadow options, lower the timings, or go from WB to WT, nothing helps. So i guess it has to do with the ZuluSCSI..

Not that this is much help, but here is what my ZuluSCSI does on startup. I'm not sure what version i'm running but if there is anything I can check for you let me know.

Edit: Looks like Ive got an RPZuluSCSI, so this is probably different.

OK, so it hangs while trying to read from boot device. Is that card wiped clean? Because if it has some form of bootloader in the first sector then it would most likely be mapped to the first sector of the emulated HDD, and it might be what is crashing the system.

Can you set the system to boot from A: first? Does it also hang if there is a bootable floppy in the drive, or does it load the system from the floppy? You can have both IDE and SCSI on the same system, the problem is getting one of the floppy controllers disabled properly so that the other can work. Why do that? You can have one IDE HDD set in BIOS and one SCSI at ID 0 or 1. This SCSI drive should be then assigned to D: (81h) and the system should boot from IDE. See it that configuration works and if you can access the SCSI drive from DOS once it's loaded.

Note, if the problem is indeed the ZuluSCSI somehow causing the Adaptec to hang on read then you most likely won't be able to boot to DOS at all. It might start to boot (this will be easiest to see on floppy) but hang when DOS tries to detect partition tables. Also make sure the emulated HDD you've set it smaller than 1GB - I'm not sure what AHA-2842VL ROM is capable of but most of the ISA cards required update to support HDD translation for bigger HDDs. You might have old enough ROM that doesn't do that, and the reported C/H/S values are making BIOS/DOS unhappy.

Jackhead,

Can you boot from floppy then run fdisk & format ?

Do you have the ZuluSCSI media setup directly as an HDD or are you using it like I am with files for drives? Does yours create a bootlog?

Here is the bootlog from mine:

[10ms] Platform: ZuluSCSI RP2040
[10ms] FW Version: 1.2.1-release Feb 16 2023 20:07:25
[11ms] DIP switch settings: debug log 0, termination 0
[11ms] NOTE: SCSI termination is disabled
[12ms] Flash chip size: 4096 kB
[14ms] SCSI target/disk mode selected by DIP switch, acting as a SCSI disk
[128ms] SD card detected, FAT64 volume size: 60874 MB
[129ms] SD MID: 0x03, OID: 0x53 0x44
[129ms] SD Name: SD64G
[129ms] SD Date: 1/2023
[130ms] SD Serial: 0xB9298860
[132ms] Config file zuluscsi.ini not found, using defaults
[132ms] Active configuration:
[134ms] -- SelectionDelay: 255
[136ms] -- EnableSCSI2 is on
[287ms] Finding HDD images in directory /:
[288ms] -- Opening /HD0.hda for id:0 lun:0
[288ms] ---- Image file is contiguous, SD card sectors 67072 to 16844287
[289ms] ---- Read prefetch enabled: 8192 bytes
[290ms] -- Opening /HD1.hda for id:1 lun:0
[290ms] ---- Image file is contiguous, SD card sectors 16844288 to 33621503
[291ms] ---- Read prefetch enabled: 8192 bytes
[292ms] -- Opening /HD3.hda for id:3 lun:0
[292ms] ---- Image file is contiguous, SD card sectors 33621504 to 50398719
[293ms] ---- Read prefetch enabled: 8192 bytes
[294ms] -- Opening /HD4.HDA for id:4 lun:0
[296ms] ---- Image file is contiguous, SD card sectors 50398720 to 67175935
[296ms] ---- Read prefetch enabled: 8192 bytes
[297ms] -- Opening /HD5.hda for id:5 lun:0
[299ms] ---- Image file is contiguous, SD card sectors 67175936 to 83953151
[300ms] ---- Read prefetch enabled: 8192 bytes
[300ms] -- Opening /HD6.hda for id:6 lun:0
[302ms] ---- Image file is contiguous, SD card sectors 83953152 to 100730367
[303ms] ---- Read prefetch enabled: 8192 bytes
[311ms] -- Platform supports ROM drive up to 3740 kB
[311ms] ---- ROM drive image not detected
[312ms] SCSI ID:0 BlockSize:512 Type:0 Quirks:0 ImageSize:8388608kB
[312ms] SCSI ID:1 BlockSize:512 Type:0 Quirks:0 ImageSize:8388608kB
[313ms] SCSI ID:3 BlockSize:512 Type:0 Quirks:0 ImageSize:8388608kB
[314ms] SCSI ID:4 BlockSize:512 Type:0 Quirks:0 ImageSize:8388608kB
[314ms] SCSI ID:5 BlockSize:512 Type:0 Quirks:0 ImageSize:8388608kB
[315ms] SCSI ID:6 BlockSize:512 Type:0 Quirks:0 ImageSize:8388608kB
[816ms] Initialization complete!
[21261ms] SCSI ID 0 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[21265ms] SCSI ID 1 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[21268ms] SCSI ID 3 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[21269ms] SCSI ID 4 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[21271ms] SCSI ID 5 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[21272ms] SCSI ID 6 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[110238ms] SCSI ID 0 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[110243ms] SCSI ID 1 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[110245ms] SCSI ID 3 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[110247ms] SCSI ID 4 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[110248ms] SCSI ID 5 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[110250ms] SCSI ID 6 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[199666ms] SCSI ID 0 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[199671ms] SCSI ID 1 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[199673ms] SCSI ID 3 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[199675ms] SCSI ID 4 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[199676ms] SCSI ID 5 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[199678ms] SCSI ID 6 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[263243ms] SCSI ID 0 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[263248ms] SCSI ID 1 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[263250ms] SCSI ID 3 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[263252ms] SCSI ID 4 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[263253ms] SCSI ID 5 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[263255ms] SCSI ID 6 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[336331ms] SCSI ID 0 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[336335ms] SCSI ID 1 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[336337ms] SCSI ID 3 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[336339ms] SCSI ID 4 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[336340ms] SCSI ID 5 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)
[336342ms] SCSI ID 6 negotiated synchronous mode 10 MB/s (period 4x25 ns, offset 15 bytes)

My bios Bootoptions are A-C or C-A so i cant boot A only.
I format the SD first fat32 and than in the Adaptec Bios again.
When i tryed switching the bootoption than i got a error message that the cylinders are wrong for a 2GB+ drive

So you guys maybe right, its the partition of the SD card.

The ZuluSCSI V6.4 act like the SCSI2SD. So i cant put files or a image on the SD to boot from like the RP2040.

Jackhead wrote on 2025-02-20, 18:14:

My bios Bootoptions are A-C or C-A so i cant boot A only.

So, does A->C setting work? With bootable floppy in the drive? Or does it also hang? And if it hangs, is it right away or does it read a bit first (this would be loading IO.SYS into memory, it should get at least this far).

Jackhead wrote on 2025-02-20, 18:14:

When i tryed switching the bootoption than i got a error message that the cylinders are wrong for a 2GB+ drive

Do try with smaller drive configuration. Preferably even below 1G, like 400MB or so. This is a safe value that should always map correctly to CHS within limits. And if that works then look for ROM update for your SCSI VLB card.

If i use A-C than the floppy is start booting, after 2-3 sec there is a short access on the zulu and than it freeze up.
C-A result the same without come to the floppy. Without SCSI Cable connected i can boot from floppy without problems.
I found a firmware in the archive here. Will try that bios, but i think it comes from the zulu.

I read out my bios, its the same as the source here. V1.01. Anyone have a newer 2842vl bios file?

Jackhead wrote on 2025-02-21, 15:46:

I read out my bios, its the same as the source here. V1.01. Anyone have a newer 2842vl bios file?

The link on Adaptec site is broken now, but perhaps the file can be found by its name in other places.

Did you try smaller emulated HDD? Set up just one HDD on the card, with 400MB size, try that. At least you'll know if the ZuluSCSI works at all on this system or not.

I installed for testing a real SCSI HDD (4,3GB IBM). And it still freeze..

So it can be a conflict or the controller has a hardware problem i would say.

Perhaps you try a modded BIOS:
INT13 Extensions to Adaptec 274x EISA & 284x VLB
See the full project here:
Showing some love for Adaptec's ugly ducklings: Adding big drive support to EISA and VL controllers

Thanks for the link!
I order a AHA-2842A. Will see how the other Adaptec work..

As result:
I switched to the AHA-2842A and all problems gone, ZuluSCSI V6.4 works. WB jumper 5 is set.
Im not sure my other controller has a fault or just Problems with a WB system board.
Need to check in another setup..