So after reading various unrelated threads, I came across the idea that some PCI cards don't handle systems with > 64MB of RAM. I temporarily removed 64MB of my 128MB but no joy. I'm primarily focusing on using the 3COM 3C905-TX PCI card using a 3C905B-TX driver diskette which allegedly is backward compatible with the 3C905-TX card. OS is still NT 3.51. Every time I try to install the driver I get an error message that the service was unable to start, which still points back to either a driver issue, or the BIOS on this motherboard isn't fully plug-n-play compatible. I certainly don't see anything about PnP BIOS extensions loading after startup like I do on other systems. Still, I've been unable to find an appropriate BIOS update for this system and I don't really know what would be comparable from another system. It's a Socket 4 motherboard using an Intel 430LX chipset.

After more digging and research, I noticed there's an option in the BIOS to either allocate no IRQ to PCI, or allocate IRQ 9, 11, or 15 to the first PCI card, and subsequent PCI cards will receive the next available IRQ. I've tried all three IRQ options and none worked.

I then booted off a Win98SE boot desk (DOS 7.1) and ran the 3C90XCFG.EXE diagnostics off the EtherCD 5.4 / floppy disk 2 and it sees the 3C905-TX card. I ran all tests 10 times and they all passed. I made sure to save the configuration to the card and rebooted into NT 3.51 but still it refuses to see the NIC nor load the driver. I am using Service Pack 5 just in case the driver(s) require a fully-patched OS.

I suspect this card will work fine if I switch the OS to Windows 95B or newer (> 2GB EIDE drive requiring FAT32), but I wanted this to be an old-school DOS & Windows 3.1 (& Windows NT) coding box with an interface resembling the platform I'm coding for. (I've tried the coding tools under Windows 3.11 but after a few compiles, resources are exhausted and a restart is needed.)

The saga continues....

I had similar fun with a PCI SCSI card in an early motherboard today. In my case it wasn't IRQ but interrupt line that did the trick. I could select INT# A, B, C, D or AUTO. Default allocation was A to slot 1, B to slot 2 and C to slot 3. On my board, only INT A worked, regardless of PCI slot it was allocated to and regardless which IRQ as allocated to it. AUTO also did the trick. If you have similar settings you could try the same.

Hi dionb, thanks for posting! Glad I'm not the only one that's had these weird issues. I've seen the settings you're talking about in other motherboards, but this BIOS seems incredibly limited; I don't see the PCI INT assignments on the two whole pages of configuration item the BIOS provides. In fact, this BIOS doesn't even display messages at boot time about the plug-n-play BIOS extensions I'm used to seeing, hence why I kind of think if I could find a BIOS update it may work better.

I may have to try Windows 95 just to see if my suspicion is correct. Annoying because I already have most of my software loaded on the hdd and don't really want to have to re-load it again.

I decided to test my hypothesis and I went ahead and installed Windows 95C on this system. Sure enough, after installing the 3COM drivers from the driver disk, the network card works. Interestingly though, Windows 95 only sees 16MB out of the 128MB installed. I know DOS/Win9x OSes query the BIOS for the total installed memory (though INT 88h I believe?), whereas NT OSes query the hardware differently (can't remember if it's through the chipset directly or simply a different interrupt), which would explain why NT can see all the memory and Win9x can't.

So back to the drawing board with this system. I may just give up and choose a different PC for my coding projects. I have a Packard Bell Legend 5200 Socket 4 system with a Pentium 60 that seemed to work well with Windows NT and networking. I'll figure something out.

Huzzah! Success!

Upon re-installing NT 3.51 (which, by the way, didn't like an unpartitioned hdd and unformatted partitions! I had to create a partition and format it before the NT boot disk would load properly even though this is a full version of NT), I decided to install the NIC drivers during NT setup, and lo and behold it works! Normally I prefer to just install the OS then setup any device drivers afterward - unless it's required during boot time such as storage drivers. I'm still not entirely clear as to what the exact problem was, but I think it was an IRQ issue. The ESS SoundScape sound card defaults the MPU401 to IRQ9, which is the first IRQ you can assign to PCI in this BIOS - though during NT Setup I had PCI set to IRQ 11.

I still think a BIOS update would have prevented this. I think this BIOS is still operating off pre-Plug-n-Play concepts. Normally the BIOS will assign INTA - INTD to PCI devices then route them to legacy IRQs as needed (not all PCI devices require IRQs). This BIOS looks to assign PCI devices directly to IRQs instead of virtualized ones. Given the age of this platform (Socket 4) and it looks like it's still using an early BIOS, I think my hypothesis is likely correct though I have no way to tell.

So meh. Whatever. At least I got it working. Now I've installed VB 4.0 (16 & 32bit), MS Visual C++ 1.52, and Symantec C++ 7.21 under a stable Windows NT OS and I can return to trying to learn programming for older systems. 😀