After a lot of testing, it looks as though Win98FE beta build 1693 is the last version to play nice with 4 floppy drives and CDROM. Which is promising, since this is a release candidate.

I'm going to see if I can get this to work with Win98FE (Retail), and possibly also Win98SE.

-Brian

I have good news - I think I got this to work Win98SE! Based on my cursory testing, no errors yet.

I'm still having issues getting the Retail version of Win98FE to install successfully on my test machine. But, considering that I heavily-based this patch on build 1693, I'd imagine it will work fine there.

I need to clean-up the patch, before it's ready to share. Once I've done that, I'm going to see if WinME is possible.

-Brian

Great work Brian...
😉

bbuchholtz wrote on 2025-11-30, 07:29:

I have good news - I think I got this to work Win98SE! Based on my cursory testing, no errors yet. […]
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I have good news - I think I got this to work Win98SE! Based on my cursory testing, no errors yet.

I'm still having issues getting the Retail version of Win98FE to install successfully on my test machine. But, considering that I heavily-based this patch on build 1693, I'd imagine it will work fine there.

I need to clean-up the patch, before it's ready to share. Once I've done that, I'm going to see if WinME is possible.

-Brian

Nice work! Please let us know what changes were required once you confirm all is sorted

Here's the patch. It's targeted for Win98SE, but it should also work with Win98FE. When you examine the contents, you will see that I'm overlaying the VMM32 and IOSUBSYS aspects of the OS. Given that this is a low-level system of the OS, IOS.VXD and VMM32.VXD are dependencies for many functions. I basically had to replace much of IOS to keep everything version-level.

Please note, I've done only a limited amount of testing. As such, I welcome any feedback on improving this. There were a few files I was unsure about: BIGMEM.DRV, MRCI2.VXD and QEMMFIX.VXD. For now, the patch will not update these files. But, you will find alternate versions from Win98SE beta build 1693. In particular, I'm leaning towards MRCI2.VXD may need to be patched. I'd be curious to hear your results of testing this.

I've been in the habit of disabling ACPI, when installing Windows 98. It helps free-up resources for lower-end machines. And plays nicer with modern hardware. For those of you not familiar with this switch, you install like this:

1setup.exe /p i

Yes, there is a space between "p" and "i".

I did some poking around in WinME. I think too many changes were made to IOS for this type of approach to be practical. I'll continue to investigate. But, I was never a big user of WinME and am satisfied with having Win98SE. So, it's likely someone else will need to carry the WinME torch...

-Brian

[REMOVED FILE]

I've made another breakthrough. I learned how to decompress VMM32.VXD. This allowed me to greatly optimize the patch for Win98. The patch now needs only four files. It should now play nice with other system updates, including Service Packs.

This new approach is looking to be viable for WinME. As you can see from the screenshot, I'm making good progress! I'll post a patch for WinME, when I have things in a stable state.

I'm going to clean-up file attachments, in other posts, to help prevent confusion. This attachment is the most current patch for Win98.

-Brian

Here's where I'm at with WinME. So far, it looks to be functional.

There is one thing I'm not sure about. When ACPI is not present, the machine goes to a black screen, with blinking cursor, during shutdown. I'm not familiar enough with WinME to determine if this is an expected behavior or a bug. Either way, I'd welcome any testing and suggestions.

-Brian

[REMOVED FILE]

I have another breakthrough. Much like the approach I took for the Win98 patch, I decided to use beta versions of WinME.

What's interesting is that some of the beta builds of WinME support greater than two floppy drives, without any patching! Take for example builds 2380 and 2394. But, four floppy drive support breaks again in build 2452.

I have created a patch that utilizes files from two different beta versions of WinME. I'm using disk-related drivers from build 2394. For PCI and power, I'm using build 2460. I'm still using drivers from Win95 for floppy (they work the best). This version of patch does not contain any files from Win98, unlike my previous WinME patch.

So far, this patch is looking good. Four floppies and CDROM are working properly. Shutdown/reboot is looking good, for both with and without ACPI. Unless anyone finds anything misbehaving with this patch, I'm considering this my final release.

I think this concludes the complete spectrum of Windows 4. I understand that this is a niche use-case. But, I hope you find this useful. I had a lot of fun with this project. I learned more about the underpinnings of Windows 4. And, it was a good excuse to play with beta versions of Windows 😀

-Brian

Thanx for the updates and the patches..
Using the same method as last time..ie my 98se build on CF card was hooked into my main pc.
The old files were mamed just that oldXXX.xxx
...and then your patched versions were copied into the relevant sections in Windows>System
of course as last time only 2 of the files already existed...but all copied in anyway.
The result was the same as last time.
all 4 drives listed in windows explorer....but selecting a floppy drives just hangs the system until the drive is de-selected.Identical results as last time.

Had a look at the attached readme >>
This is a patch for adding greater than two floppy drives support for Windows 98. It's based on files from Windows 95 OSR2 and Windows 98 FE beta build 1693.

Installation:
1.) Disable floppy drives 3 & 4 in the BIOS.
2.) Install Windows 98.
3.) Remove Floppy Controller from within Device Manager.
4.) Boot from an alternate device (i.e.: Floppy or USB).
5.) It is strongly recommeded that you first backup the original files.
6.) Copy the files from this patch to their corresponding locations.
7.) Enable floppy drives 3 & 4 in the BIOS.

1) has me confused since floppy drives 3 & 4 dont appear in my PCs bios...
do you mean the quadflop bios rather than the PCs bios ?
Perhaps I need to actually re build win98se with no floppy support and the quad flops second pair of drive controllers disabled ?
then apply the patches..the reboot with the quadflops second controller enabled. ?

a bit like applying the FIX95CPU_V3_FINAL patch which has to be done at a specific point in the install ...and isn't applied retrospectively after the build is complete.

I have a feeling I'm not understanding the process correctly.
..in that I'm trying to change/patch a prebuilt 98se system and not building it fresh as you have done Brian.
in short I'm mighty confused.

Vipersan wrote on 2025-12-06, 20:16:

1) has me confused since floppy drives 3 & 4 dont appear in my PCs bios...
do you mean the quadflop bios rather than the PCs bios ?

Did you try the MRBIOS motherboard BIOS update I had recommended? This is how the floppy drive setup looks in my motherboard's BIOS...

-Brian

Still waiting for the chips I ordered from poland ...they are on route but will have to be patient.
Hopefully I'll then be able to try the MrBios you recommended.
I dont want to risk re flashing the existing chip and bricking the mobo.
cheers

The chips arrived this morning...so this afternoon I pulled the original bios chip.
Flashed one the 3 x 28F1000PPC-12C4 with MR BIOS....replaced and booted.
It does look like this bios will play nice with my motherboard...though I cannot get it to allow the 2mb CF card DOS 6.22/WFW 3.11 to complete boot and run.
I suspect this is because it was built with the CD expected @D: and not as it now is F I think.
I did try and edit the config.sys and autoexec.bat ...but that didn't help.
The intoduction of 2 more floppy drives being the reason for the CD shift.
I have all the drivers so will start over and build a new CF which will hopefully play nice with the MR bios.
I did try a very basic build of just DOS on a 512mb CF ...and that booted and ran fine and all 4 floppy drives could be addressed.
I want to establish it working with a very basic win 3.11/DOS build before I tackle Win98se again....which most likely will also require a re-build.
So far ...so good...though.

It's much more likely that it's presumed the hdd is drive C, than that the CDRom drive letter changed.

A fresh install might well be needed/easier than fixing.

wierd_w wrote on Yesterday, 18:44:

It's much more likely that it's presumed the hdd is drive C, than that the CDRom drive letter changed.

A fresh install might well be needed/easier than fixing.

You are likely correct..
It is wierd to see 4 floppy drives in my bios...
wierd...but cool.
😉

Good to hear the BIOS looks to be compatible with your board! Hopefully you'll now have better luck getting four floppies to work under Win9x.

-Brian

Got excited too soon methinks..
Some wierdness going on ???
I haven't even got DOS installed yet.
Sometimes the PC hangs at checking extended ram...
The keyboard was there all the way through the install of Dos 6.22...but following the completion and reboot..
..sometimes it makes it through to the > prompt but no key strokes input..?
just hangs...at the prompt.
I even flashed the CF card to an early pre installed build of DOS...and the same odd behaviours.
Some sort of instability and or incompatibility here.
I do have a pre built DOS 512mb CF card which has windows on it > mouse and CD installed ..and that at least lets me get to the dos prompt with a working keyboad..
This build doesn't allow "win" at the prompt.....so CD\Windows then WIN...does work and I can view the contents of a disk in drive A:
The CD doesn't show up in win 3xx of course cos there aint enough drive letters available due to the 4 floppies ...
Definately strange behaviour...
It's going to take some serious thinking about.

A few strategies to try:

Start with a minimal amount of hardware, and gradually add devices.

Experiment with how devices are attached. Onboard FDC vs card.

Try legacy hard drive vs CF.

If you're running out of drives in DOS, try the LASTDRIVE command.

-Brian

I've looked at this topic as it went by, of a bit of interest because I do know floppy drives on the PC quite well, but I've not posted here because I do not know this board at all (in fact I didn't know this existed)

The original PC design only wired the FDC for 2 drives, and in fact used the other drive select lines for other things (like drive-dependant motor-on)

As a result of this, I've never seem a BIOS supportine more than four drives.

-- I do switch drives quite a bit... As the developer of ImageDisk, naturally I tend to work a lot of different and non-standard(to PC) drives (anyone else have an 8" drive on your PC)

My usuall approach is to use a long FDC cable, and move the A: connector to the middle, so B: can be at the end (two twists around the middle connector). With the original ImageDisk system used a 37-Pin 'D' connector in a slot to make the external cable easily accessible from outside the case - after I sold that system and build a new IMD system on a block of wood, I just have the end of the floppy cable come out the side:

Re: Windows 95 on a Breadboard

This cable has the standard 5.25" and 3.5" drive connectors, and I have made adapters to allow connection of other drive types.

-- I have in some cases made up special cables (for others) with connectors for more than 2 drives - and front (or back) panel switches to select different drives to show up as A: (or B:)

-- I am curious, how does this type of board make all 4 drives accessible? Does it contain a BIOS extension?

How do you get it to work with operating systems which load their own drivers and don't use BIOS for floppy access? Do many of the OS companies/groups provide drivers for it?