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Possibility PCI Floppy Drive Controller?

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Shadow Lord

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Okay. So I have no idea how feasible this is or how realistic but in this thread Chuck mentioned that:

So, for example, you could implement a 4-drive controller when all you have is a single drive motherboard by adding a BIOS and implementing the select and motor control logic externally. Since it's a write-only register, that doesn't interfere with a thing. An add-in PCI board could do the trick.
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How realistically possible is this? Could we have a PCI-FDC project that would allow you to add to a "more modern" motherboard that had one drive floppy support: 1. four floppy drives, 2. BIOS support for 360kb-2.88mb drives, 3. 8" drive supports, and 4. external 37pin connector (well the last two should be easily possible if the first two are possible!)?

Again not being an EE I have no idea but this group has created some very awesome projects (XT-IDE) so if anyone has the talent pool to do it it would be found here!
 
sounds like much more of a pain in the ass than its worth

if your board supports a floppy drive the chances are high it will support your usual host of 5.25 and 3.5 inch media. Yes I know some will only support 3.5 inch 1.44 meg media but MOST will support your 4 usual types. So install a 5.25 on there and use a USB 3.5 or a ls120 super disk and problem solved
 
Osgeld said:
sounds like much more of a pain in the ass than its worth
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+1 for what Chuck said plus LS-120 drives have other issues as well. For example on my system even though LS-120 drives are supported in BIOS and are a boot option I can never get a disk to boot.
 
For what it's worth, USB mass storage floppy class supports a lot more than the current 720/1200/1440 and 720/1440 modes that the actual drives do. I don't think it's as flexible as an IBM-style FDC (so, no XDF, DMF, or 2M floppies), but the standard is capable of quite a lot, and could handle any standard IBM format, including the 5.25" ones.
 
any standard IBM format
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System/3 or 3740?

Even among 5.25" IBM non-PC formats could be quite varied.

The problem with USB is that it's modeled on the SCSI command set, which means that it does not use the CHRN-type addressing scheme, so varying data rates and recording modes are not supported. Obviously putting your copy-protected Lotus 1-2-3 program disk on a USB drive is out of the question.

In any case, programs written to the standard PC NEC765-type interface wouldn't know a USB drive from a ham sandwich.
 
Er, standard IBM PC format. (Although I suspect a fair amount of the older 8" formats actually can be represented...)
 
Well, it matters little what could be represented. The fact is that no commodity USB floppy drive does any of this. Some can handle the 8x1024 NEC98 HD format (as can LS120 drives). But USB isn't the solution unless you devise your own protocol and implement it in terms of a legacy PC FDC. For example, Harvard Graphics, a 320KB (IIRC, 8 sector not 9) checks for a signature in the gap between sectors 1 and 2 on a specific track. It uses the "READ TRACK" FDC function with an overlong sector length.
 
With the lack of floppy connector on modern motherboards that would be amazing to have, I'm currently forced to have some older PC available just to write floppies on it.
You may ask why don't you just get a USB floppy drive? Some of them really do many PC formats.
True and I got one, only to find out but they can't do anything else, such as writing .dsk files for an Amstrad CPC. Even for common PC formats (eg DD) you still have to carefully research for a drive to buy since many of them don't write anything else except 1.44MB disks, and I didn't even bring 5 1/4 drives into discussion.
 
The OP is speculating about several different things really.

A PCI FDC is not really possible. While it sort of could be done, it would be impossible to make it 100% hardware compatible as PCI lacks some abilities needed for full compatiblity.

At best, such a controller would be only compatible at a BIOS level. And all the kids these days are snubbing their noses at anything that doesn't exclusively use EUFI and Secure-from-competition Boot.

There has never been standard BIOS support in IBM PCs for 8" floppy drives. Early MS-DOS machines that used 8" drives had to use their own customized "port" of MS-DOS or other special tools to make it work. Of course to a regular PC, 8" drives look mostly like a 1.2MB drive with a few missing tracks.

What chuck was originally proposing was simply using a motherboard that already had a real FDC built in, but was crippled to support only drive. A lot less complicated since the FDC and chipset bus support is already in there. It is just the drive select pin that is missing (cheap Chinese trying to save an entire single pin). Hardware wise all you need is an alternate binary signal from somewhere, but from the software end you would need to modify the BIOS to support that signal or install a device drive like 2M-XBIOS that supports it.

I think someone mentioned that the SuperIO chipset was limited to one drive only if it was used to provide a parallel port? If that is true, then is the pin alternately used for drive select routed to the parallel port? Would it then be possible to trick the chip in to 2-drive mode and leach the signal from the parallel port? Obviously the motherboard BIOS would not support that but tools like ImagDisk that bypass BIOS might work, an so might something like 2M-XBIOS.
 
How about using a PCI to ISA bridge, and an ISA floppy controller? You could even add a 98 pin or 62 pin connector to add an external ISA bus.

You might have to have driver or BIOS support for the bridge chipset, but it should work.
 
Shadow Lord said:
Okay. So I have no idea how feasible this is or how realistic but in this thread Chuck mentioned that:



How realistically possible is this? Could we have a PCI-FDC project that would allow you to add to a "more modern" motherboard that had one drive floppy support: 1. four floppy drives, 2. BIOS support for 360kb-2.88mb drives, 3. 8" drive supports, and 4. external 37pin connector (well the last two should be easily possible if the first two are possible!)?

Again not being an EE I have no idea but this group has created some very awesome projects (XT-IDE) so if anyone has the talent pool to do it it would be found here!
Click to expand...

Would not Catweasel or Kyrofux fill the bill for this, or did I miss something which is usually the case these days?

http://webstore.kryoflux.com/catalog/product_info.php?cPath=1&products_id=29

http://www.vesalia.de/e_catweaselmk4plus.htm
 
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Depends on what you'd like to do. If it's run vintage software that uses floppy access, no--such stuff is usually tied into the FDC interface itself.

Both the KF and the CW are relatively old-tech solutions. Truth is, that any remotely new MCU with enough memory can do that job. Emulating a 765-based FDC is much more difficult.
 
Chuck(G) said:
If it's run vintage software that uses floppy access, no--such stuff is usually tied into the FDC interface itself.
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Well, if you are using a PCI based PC what kind vintage software are we talking about? I may be a little off base, but isn't just looking at or copying a floppy about the extent of it, with maybe the ability to format the floppy as a bonus? Beyond that, I don't see much use for a floppy in a modern system beyond USB access.
 
Well, this is the "vintage" forum isn't it? If you're talking about "modern" PCs, I don't see how floppies enter the discussion. :)

Eventually, you're going to run into the case where you need to use legacy hardware; e.g., someone gives you a pile of floppies created with FastBack 1.0...
 
Chuck(G) said:
Well, this is the "vintage" forum isn't it? If you're talking about "modern" PCs, I don't see how floppies enter the discussion. :)

Eventually, you're going to run into the case where you need to use legacy hardware; e.g., someone gives you a pile of floppies created with FastBack 1.0...
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That was my point, I don't consider PCI to be vintage. So, what you do is build a box where the mobo supports you needs. The Swiss Army Knife approach doesn't seem feasible without a large investment on someone's part. There are some fairly recent Gigabyte boards, for example, that support two floppies, 3.5 or 5.25, but you need to reach back to products prior to their 990 chipsets. Just takes a little research. Personally, I don't see where the problem lies. How you can be a computer hobbyist and a one trick pony at the same time so to speak.
 
This is the 8088/8086 subforum, computers which were introduced in 1982 and were the top notch until about 1984 when the IBM AT with 80286 was introduced. These XT class computers don't support PCI, also AT 286 not, also 386 not. You need at least a newer 80486 system from about 1994 to support PCI. So I don't understand the intension of this topic in the 8088/8086 subforum.
 
I could take a stab at that--we're talking mostly about old legacy floppies here from the x86 era and how to accommodate them on later systems that might have a chance of supporting older software.

Really, the best situation is to get an older machine. They're not all gone yet.
 
Stone said:
Once again..... Everyone here should have a capable tweener. :)
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Agreed! However, sometimes it may be easier/necessary to use a more modern system. The topic came up in an OT thread on modern MBs that had floppy support. There were recs for systems w/ Core Duo processor support which still had FDD support built in. Chuck chimed in saying that the limited/crippled floppy support on these boards could easily be expanded to full four floppy support. Now things that seem easy to Chuck can be next to impossible for us mere mortals so I started this thread to see how easily this could be implemented. A real PCI FDC is out of the question but if we can expand these crippled boards we could move on from "tweeners" to "twenty-something" systems as well.

Certain components seem to be in place - we already have a good FDC BIOS because of the FDC-XT project, 8" drive read support is in that card plus D-Bit has a proven tech for writing to 8" drives, and placing external and enough internal connectors are no brainers. The real question would be can we really implement "the select and motor control logic externally"?

To me options are always a good thing.
 
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