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I have this old card, a Future Domain TMC-1680 ISA SCSI card that has a 34-pin floppy disk connector on it. I am trying to research that to see if I can make it work (before anyone asks - just for the hell of it!).

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I don't even know if it's a "standard" floppy interface. It certainly looks like one, and a standard floppy cable fits. But I've heard about SCSI floppies, so am not sure. And without any documentation I've had little success making the card do anything at all.

One thing that I have discovered about this card is that its driver has been removed from the Linux kernel (after 4.16, so it's only recently happened). So I'll have to use a pre-4.17 kernel if I want to use this card.

I have been unable to find any documentation for the card. If there is a source of documentation or other information that would be very welcome.

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    It certainly has PC8477B super floppy controller on the card so I'd expect it to be a perfectly normal floppy interface (although what the dip switch labelled floppy does I'm not sure) . I'd feel happier if I had a manual. – PeterI Jun 27 '18 at 15:27
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    I agree with @PeterI, this should have a standard floppy interface. SCSI floppy drives do exist, but they connect to the 50-pin SCSI bus, not to the 34-pin floppy connector. The driver which was removed from the kernel only takes care of the SCSI side of the adapter, it doesn’t deal with the floppy side. – Stephen Kitt Jun 27 '18 at 15:31
  • The floppy controller can be configured as primary or secondary. The card's BIOS may not support 1.44 floppies, and will require a special floppy= setting in LILO – Stavr00 Jun 27 '18 at 15:36
  • @Stavr00 I would be surprised if 1994 BIOS didn't support 1.44Mb floppies given they were introduced in 1987. – PeterI Jun 27 '18 at 15:38
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    Slots were limited on a lot of older machines. Hence the proliferation of AST & other multi-function cards. So a card with SCSI + Floppy would make sense if you could then take out the original floppy card to make room for the SCSI card. This was especially the case on machines were a card (or two!) were added just to add Expanded Memory. – manassehkatz Jun 27 '18 at 16:46
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It's a normal 8272-style floppy interface that just happens to be on the same card as the SCSI controller. It should work in any motherboard with ISA slots, provided the motherboard doesn't have an integrated floppy controller of its own - or, if it does, that the integrated FDC can be disabled.

The DIP switch is used to enable or disable the floppy controller, as can be seen on this photo of the rear of a TMC-1680, with a label describing the DIP switches:

Read of a TMC-1680

(Source.)

  • I can confirm you're correct. I have booted my test machine from a floppy drive connected to the SCSI card. The system's BIOS appears unable to disable the on-board interface (I did try - deselecting the drives in the BIOS did not help). Every boot I get 611 - Primary Floppy Port Address Assignment Conflict but it works. One interesting point though... I had to seek out a floppy cable without the key in pin 3 because the ISA card's floppy connector has all pins! – starfry Jun 27 '18 at 17:59
  • @starfry it may be worth asking a question about that. Your card may be interfering with some other subsystem somehow. – Wilson Jul 17 '18 at 12:19

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