HD support > 512MB depends on the driver that you use. I’d review this thread : 32 Bit Disk Access drivers on a 2 GB Windows 3.1 Hard disk. The Microhouse fast FastDisk driver is recommended. Here is the last Microhouse driver. It supports LBA for drives > 8.4GB http://vogonsdrivers.com/getfile.php?fileid=2070

As for CL 5424 vs CL 5429, the 5429 has hardware for block transfers, so it should be much nicer if you have a driver that uses that feature. Try doing “dir c:\windows” in a windowed DOS session. You should see a big difference as the text scrolls. The scrolling text will be noticeablely slow and stuttering if there’s no “bitBLT” going on.

My 1995 era Omnitec 486dx2-66 with a Micronics vlb motherboard actually detected an 8gb aftermarket HD partitioned in 4x 2.1gb without any special software which was extremely surprising . Just used dos 6.22 and fdisk.

To go larger takes the unofficial Dos 7.x or special utilities

As douglar mentioned, overlay software from this era tended to come bundled along with a 32-Bit Disk Access driver for Windows 3.x, too.

The WDCTRL that comes bundled is so bare-bones it doesn't even assume IDE, it would work with an old WD1003 card in a real AT.

Many thanks for the links and info. I think I'll play with this Microhouse driver sometime but not now. It turned out that one of the older HDDs I had considered for this project might be developing sticky surface, it has serious trouble spinning up (it auto retries and starts on the 2nd try though). I think I'll just use this one for the project, before it expires and becomes junk. It was a trash bin rescue anyway.

WfW 3.11 here on a 1GB 2-partition HDD: 256MB and 744MB. Works great and accesses both C and D without issues. I'm using 32-bit disk and file access (using WD driver).

I seem to recall that the Microhouse driver didn't play nice with the XUB when I tried it. Western Digital themselves released an updated WDCTRL (called WDCDRV) which supports big drives and *does* play nice with XUB, but it only loads with WD branded drives.

maxtherabbit wrote on 2024-07-08, 23:54:

I seem to recall that the Microhouse driver didn't play nice with the XUB when I tried it. Western Digital themselves released an updated WDCTRL (called WDCDRV) which supports big drives and *does* play nice with XUB, but it only loads with WD branded drives.

I'm not surprised, XUB is a mess (code wise).
I once tried (failed) to compile an V20 version for my XT and it was a nightmare.
I've never seen such an amount of encapsulated code before. 🙁

In it's function, though, XUB is very good I do admit.

XT-IDE hardware is also a bit slower than my 20MB MFM/RLL HDD with its 1984 HDD controller card.
Which is a good thing, actually, because it gives authentic loading times. No kidding.
That's good for retro software development. If you write something like a video player, it's important that XTIDE isn't faster than the real thing.

That being said, I remember that my copy of XUB had issues with both OS/2 Warp and Windows 95, too.
Maybe these 32-Bit systems do expect certain things that MS-DOS doesn't need.

And to be fair, that's what XUB had been designed for in first place, to get things things working on an PC/XT.

And here it does work very well.
It also supports MS-DOS 5 and 6.x, which are the reference I think.
It's MS-DOS 6.22 compatibility that matters most. It was the last MS-DOS sold, after all.

Anyway, I think there's one more alternative to try. Or two alternatives, actually.
a) get a more modern BIOS or a patched BIOS that supports modern CF cards/HDDs
b) try one of these BIOSes found EIDE Enhancer Cards. They're similar to XUB.

Edit: I do admit that the MicroHouse driver isn't the final answer, maybe.
It's simply the most universal, maybe.
I liked the fact that the supplied Windows help file had some information about the limits of the driver.

Other drivers maybe can be patched to not check for manufacturer ID, not sure.
If they can be patched, maybe an IPS file can be made, so that other users can patch the driver without legal worries.
I'm merely thibking out loud here, it's not meant as an actual suggestion.

Jo22 wrote on 2024-07-09, 01:38:

That being said, I remember that my copy of XUB had issues with both OS/2 Warp and Windows 95, too.
Maybe these 32-Bit systems do expect certain things that MS-DOS doesn't need.

When a protected mode driver starts up, like the Win 3.11 WDCTRL, it has to take control of the storage subsystem from the real mode INT13h handler without corrupting the users data. There are lots of ways that things can get corrupt, and one that challenged the developers was when the drive geometry in use by the INT13h handler didn't match what was in the BIOS drive table. So when the protected mode drivers start, they tried to do some tests to make sure they had things under control. In the Win 3.11 days, those tests look a little arbitrary in hindsight: https://www.os2museum.com/wp/how-to-please-wdctrl/

Anyway, it is a rare thing to find protected mode drivers that understand LBA geometry before 1996. XUB can and frequently does use LBA geometry. In cases when INT13h is doing LBA, it's best if the protected mode drivers realize that they will fail and refuse to load.