Yes I have one that I used extensively. It is pretty much plug and play. Plug the ribbon cable and it will operate both drives. You have a jumper to decide which would be A and B.. that's about it. For the BIOS just set A as 1.2MB and B as 1.44MB. If POST complains about bad floppy drive settings, flip them and you're good to go.

The ribbon cable doesn't even need to have a twist. It is just going to flip the drive assignments one more time.

Ah! Interesting. In the bios it only showed up as a single drive, so I assumed it's not recognizing the dual setup, but once I set drives A and B to 5.25" and 3.5" it just worked in spite of saying drive B isn't installed.
I know these drives are pretty desirable/expensive, but are they reliable?

Does your BIOS actually detect a second drive (B:) if it's not set up.
I know some BIOSs didn't.

Presumably this thing show up the same as two drives - I don't see how BIOS could tell the difference.

You could try my ImageDisk and do floppy operations/test on both drives and see if it has any problems, this might help detect if there are any actual differences from two distinct drives.

ImageDisk accesses the floppy drives/controller directly and does not go through BIOS (in fact I keep the drives set to "None" on my ImageDisk system to keep anything else from messing with them). If it does detect "problems" that might help figure out what exactly is different from two separate drives.

darkfalzx wrote on 2025-12-22, 16:51:

I know these drives are pretty desirable/expensive, but are they reliable?

It worked great for me. The only downside is the difficult maintenance. It is much harder to clean the heads should they get dirty.. so if you plan to use the drive with disks from bad storage, you'll hate it. Otherwise it served me really well. No complaints.

I used it in my Lego PC build because I was aiming for a fully featured yet-compact form factor.
Lego PC - Traditional Damascus Theme

I've been kepeing my eye out for a combo floppy for a while but the prices are somewhat eye watering

DaveDDS wrote on 2025-12-22, 19:28:

Does your BIOS actually detect a second drive (B:) if it's not set up.
I know some BIOSs didn't.

Initially, BIOS only shown drive A: installed, but allowed me to configure both A: and B:. Once I set them up and rebooted, the second drive just showed up like it was always there. No additional software needed in either DOS or Windows 95!

NeoG_ wrote on 2025-12-22, 22:28:

I've been kepeing my eye out for a combo floppy for a while but the prices are somewhat eye watering

It's basically two completely independent drives sandwiched together, presenting a really neat and compact front, but looking really awkward on the inside. I didn't even know such things existed until literally pulling one out of a dumpster.

NeoG_ wrote on 2025-12-22, 22:28:

I've been kepeing my eye out for a combo floppy for a while but the prices are somewhat eye watering

Although it might be nice to have both drive types in one slot, I'm not sure I'd be comfortable in relying on a drive that is irreplacable (or at least would be very expensive to replace - if you could find one).

As you might guess, over the years I've used a LOT of floppy drives, and have seen enough of them fail that I still have a good stack of replacements.

And... since this has been mostly ImageDisk related, I usually had to switch between many different drive types:

5.25" 40-Track DD (360k)
5.25" 80-track HD (1.2m)
5.25" 80-track DD (720k)
3.5" 80-track DD (720k) *1
3.5" 80-track HD (1.4m) *1
8" 77-track

*1: Yes, there were some disk types I had to use an actual DD drive, to reliably read on some controllers.

And there were sometimes cases where I needed to use actual single-sided drives.

So... I have come up with ways to more easily add/change a second drive on a system without having to have "slots" for them all:

Re: TexElec Quad-Flop (FDC) and Windows 95

Re: TexElec Quad-Flop (FDC) and Windows 95

darkfalzx wrote on 2025-12-23, 02:44:

Initially, BIOS only shown drive A: installed, but allowed me to configure both A: and B:. Once I set them up and rebooted, the second drive just showed up like it was always there. No additional software needed in either DOS or Windows 95!

I did get that - I was just wondering if there is "something enough different" about this drive that BIOS didn't detect it when I would have detected a "normal" B: drive.

To test this, you need to connect an actual second drive as B:, clear/reset BIOS and see if the system finds it.

Probably not worth doing now as you've figured out a workable solution.

DaveDDS wrote on 2025-12-23, 11:40:

I did get that - I was just wondering if there is "something enough different" about this drive that BIOS didn't detect it when […]
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darkfalzx wrote on 2025-12-23, 02:44:

Initially, BIOS only shown drive A: installed, but allowed me to configure both A: and B:. Once I set them up and rebooted, the second drive just showed up like it was always there. No additional software needed in either DOS or Windows 95!

I did get that - I was just wondering if there is "something enough different" about this drive that BIOS didn't detect it when I would have detected a "normal" B: drive.

To test this, you need to connect an actual second drive as B:, clear/reset BIOS and see if the system finds it.

Probably not worth doing now as you've figured out a workable solution.

the guy just didn't have his second floppy drive defined in the bios. there is nothing more to wonder about.

DaveDDS wrote on 2025-12-23, 11:40:

I did get that - I was just wondering if there is "something enough different" about this drive that BIOS didn't detect it when I would have detected a "normal" B: drive.

It sounds like darkfalzx was saying the BIOS was not "detecting" the B drive, but it was just the previous configuration unchanged with a single drive A: set and drive B: unset. I guess they thought the BIOS would detect the floppy drive type automatically.

NeoG_ wrote on 2025-12-23, 12:24:

It sounds like darkfalzx was saying the BIOS was not "detecting" the B drive, but it was just the previous configuration unchanged with a single drive A: set and drive B: unset. I guess they thought the BIOS would detect the floppy drive type automatically.

Yeah, I'd guess thats what happened. From the initial posts I though that this mainboard was expected to auto-detect drive B:

Most BIOS detect drive A: - many don't detect drive B: (but some do).

The big problem with BIOS auto-detect is that it can't tell some drives apart without "stressing" the drive.

You *can* tell a 360k from a 1.2m by stepping out past track 39 then counting steps back till track0 detect comes on, but most 40track drives will go a few tracks past 39 - so you have to step far enough to insure it hits the stop, and not knowing the drive you have to go 10 or more tracks past 39 - which "hits the stop" every time to try to step past the stop - and there is indicator to tell the PC it's hit the stop...

And even if you detect 80 tracks, is it a 5.25" or 3.5"? If the latter is it HD or DD?

Most BIOS will try to detect drive A: and make a "guess" as to the most common drive type at the time it was made... Basically trying to reduce the number of "my new PC doesn't boot" tech support calls.

weedeewee wrote on 2025-12-23, 11:54:

the guy just didn't have his second floppy drive defined in the bios. there is nothing more to wonder about.

Well... you could "wonder" why the "the drive I just installed doesn't work"? ... As I tried to explain, this gave the impression that it was either configured or expected to be auto-detected.

We didn't learn till later that it wasn't configured, leaving "expected to be auto-detected" as the thing that didn't work.

I couldn't think of a reason a dual-drive would be functionally different ... but I've not personally had one, and I like to know as much about the various drives available as I can.

DaveDDS wrote on 2025-12-23, 15:33:

Well... you could "wonder" why the "the drive I just installed doesn't work"? ... As I tried to explain, this gave the impressio […]
Show full quote

weedeewee wrote on 2025-12-23, 11:54:

the guy just didn't have his second floppy drive defined in the bios. there is nothing more to wonder about.

Well... you could "wonder" why the "the drive I just installed doesn't work"? ... As I tried to explain, this gave the impression that it was either configured or expected to be auto-detected.

We didn't learn till later that it wasn't configured, leaving "expected to be auto-detected" as the thing that didn't work.

I couldn't think of a reason a dual-drive would be functionally different ... but I've not personally had one, and I like to know as much about the various drives available as I can.

There's nothing different about it aside from the 5"1/4 drive is thinner, and the 3"1/2 drive is like a laptop drive.
Squish those together, add an interface board so you only need to hook up one connector and you get one of these "dual" drives.
I've never known any consumer ibm-pc bios to autodetect the floppy drive,
and I do not want to go off on a tangent here.

weedeewee wrote on 2025-12-23, 16:01:

There's nothing different about it aside from the 5"1/4 drive is thinner, and the 3"1/2 drive is like a laptop drive.
Squish those together, add an interface board so you only need to hook up one connector and you get one of these "dual" drives.

Exactly as I suspected - good to have confirmation!

I've never known any consumer ibm-pc bios to autodetect the floppy drive,
and I do not want to go off on a tangent here.

I have seen a few - more common before HD and 3.5" drives were a thing (all PC drives were the same back then) - and agreed, no need to go on a tangent.