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Possible to add 3 floppy drives to my 486 DOS PC Build?

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First post, by machonacho

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Hello everyone! New member here and new to the retro PC scene in general. I just did a recent build of a 486 machine that can be seen here: https://youtu.be/Xu3In9C1GiM?si=p0uI911YbOgG5uOL

As of right now I'm using a Monster FDC to control my 3 floppy drives, a 5.25, 3.5 and a Gotek. I feel as though it is a bit clunky but it is working. I was curious if there was a period correct card that I could use that would allow me to use these 3 drives for a more seamless and "authentic" experience? It seems most of the ISA Floppy controllers can support only 2 drives. Also my BIOS seems to only support 2 as well.

Any insight would be very much appreciated!

Thank you!

Reply 1 of 6, by konc

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I'd say you have pretty good solution already, let me explain.

Floppy controller cards with connectors for 2 cables are rare indeed. A realistic "authentic" scenario would be two cards, with the second one allowing to configure it as the secondary floppy controller at 0x370. And even then you'd face the BIOS problem. Now you have everything, it's ISA, tested and working on XTs, and no BIOS problems. For me it's the opposite of clunky.

Reply 2 of 6, by Errius

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Yes I didn't know this existed. It greatly simplifies things.

The traditional way to get 3 floppy drives working was to replace the 3.5" drive with an LS-120 connected to the IDE controller. This requires a DOS driver though I understand, which is not ideal.

Is this too much voodoo?

Reply 3 of 6, by machonacho

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Thanks for the input! I'll definitely stick with the FDC Monster as is since all 3 drives are working currently

Reply 4 of 6, by Cbb

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Errius wrote on 2025-04-10, 15:32:

Yes I didn't know this existed. It greatly simplifies things.

The traditional way to get 3 floppy drives working was to replace the 3.5" drive with an LS-120 connected to the IDE controller. This requires a DOS driver though I understand, which is not ideal.

no drivers are needed for ATAPI LS-120 to function under DOS/Windows. it works out-of-the-box.
drivers are needed for SCSI/LPT/USB models only (not sure if DOS for USB ever exists)

Reply 5 of 6, by Disruptor

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I'm uncertain what your BIOS (= DOS driver) does when drive letters A and B already are occupied.

Reply 6 of 6, by Jo22

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Hi, there were rare floppy controller cards with two headers (2x 2 floppies).
I think some were on RAID or SCSI cards, too.

Another alternative is to use the controller card of an internal 3,5" streamer drive.
They're essentially high-speed floppy controllers that use an alternate port address.

Such controllers might be accessible with a custom DRIVER.SYS file, that uses that port address.
(Driver.sys and DRIVPARM were often used to configure unsupported floppy formats.)

Another idea is using an alternative floppy BIOS.
Something like 2M-XBIOS, but for ATs and the alternative floppy controller.

https://www.minuszerodegrees.net/2M-XBIOS/2M- … 4M%20as%20B.htm

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