IDE hard disks do work with that card. It is a non PnP card so the IDE is enabled with jumpers and not by software. That is a good thing.

But the problem is that BIOS needs to support the IDE address and since you have 486DX-33 it is very likely limited to only support primary IDE (at address 1F0h). That sound card, however, does only support secondary (170h), tertiary (1E8h) and quaternary (168h) IDE ports but not the primary. That is very typical since multi-I/O-cards have the primary IDE so having it also on sound card would only create conflict.

What you need is a BIOS that supports those other IDE addresses. XTIDE Universal BIOS does support all of them but you need a network card or some other card where to install the ROM. Another alternative is some ontrack solution that is installed to hard disk boot sector (bootable hard disk on primary IDE) and it replaces motherboard IDE bios when loaded. It should also provide support for at least the secondary IDE. No other driver is needed, just BIOS support.

Thanks for the insight -- it all makes sense now. XTIDE and/or replacing BIOS at run-time sounds like an interesting project for the future. In the meanwhile, I decided to test it with the CD drive, and with that it worked with the first try (merely had to add the /P parameter for the existing mtmcdai.sys to point it to correct IO/IRQ). With CD ROM no longer occupying a slot on the primary, on-board IDE, I can in fact now have two hard drives plugged in.

Anyway, thanks for confirming it all -- saved me probably hours of troubleshooting something which is not even intended to work as such.

Hi, getting back to this after some experiments. I have spent some time with XTIDE, flashing ROMs for it, learning to configure it, write the EEPROMs, etc. I can now reliably boot with XTIDE (using my 3Com network adapter boot rom to host it). In addition, XTIDE detects IDE devices on both the primary on-board ide, and on the secondary IDE which is hosted by the SoundBlaster CT2800.

However, my problem is that immediately after detecting the drives during boot process, the system completely freezes. It happens whenever I have any kind of IDE devices attached to the CT2800. If I unplug the devices, the system boots just fine, so XTIDE is fine. I have tried with all kinds of XTIDE configuration: with and without IRQ set for secondary IDE, with 8k and 32k versions of the ROM and so on. I have used 170h as the IO port and ensured it matches with the jumper settings on the card. But nothing seems to help. Somehow I think it fails immediately it tries to do any real I/O with the device, which makes me think it could have something to do with the Control block address defined in XTIDE config. By default, it suggests base address +200h -> 370h. However, on some articles out there I have found some indication what Sound Blaster could actually use 376h or 377h. I tested also with 376h, but no difference.:

Sometimes I have got a little bit of variance: once it reported there is no bootable disk in the system, and once I got all sorts of beeps from the PC speaker together with a blank screen -> probably an indication of some sort of HW conflict.

Otherwise I would have given up with this already, but I have a strong feeling that during my first experiments with XTIDE it actually did work at some point with devices attached to both primary (onboard) and secondary (Sound Blaster) IDE. Makes it very difficult to give up anymore 😀 But maybe it's easier to just find a generic ISA IDE adapter and go with that...

So HDD detection works for the drive connected to CT2800 but after that it fails? Could be interrupt related since IRQ is not used for drive detection. When you disabled IRQ did you disable it from XTIDE Universal BIOS and from CT2800. Both needs to be disabled. And if you enable it, both needs to be configured to use the same IRQ.

Control block address is indeed another thing to suspect since there is Device Control Register at control block base + 6h. It is used for controller reset and enabling/disabling IRQ so it could also explain IRQ related issues. If, for some reason, control block is not at IDE base + 200h on this card you could try IDE base +8h or +10h. But I'm pretty sure it was at +200h on the Sound Blasters I've tested.

Well -- it works now! What I did, based on your thoughts:

- Just for the heck of it, changed the SB IDE IRQ jumper setting from 10 -> 11. And configured the same for XUB.
- Changed the IO base address from 170h -> 1E8h (from secondary to tertiary) in SB jumper settings. And configured the same for XUB.
- Set Control Block Address to 1E8h + 200h = 3e8h in XUB config.

I have no idea why this fixed it, because there is nothing on IRQ10 to my knowledge (the only other card in addition to the Sound Blaster is 3Com, and it's using IRQ7). In addition, I'm 100% sure I have tested the combination of 170h & 370h for IO Base address and Control Block address. Weird stuff, but thanks again for your ideas, those helped me to search from the right direction!