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Thread: FDC controller chip diagnostics?

  1. #1

    Default FDC controller chip diagnostics?

    Is there any such software or diagnostic tools that check what kind of Floppy support was programmed on a Floppy Disk Controller chip? 360k 720k 1.44MB 2.88MB etc.....Or am I going to completely bonkers?

    I have a Gotek floppy drive emulator with FlashFloppy and I have mixed (hit or miss) results when trying to access 2.88MB floppy images on some computers I have. ie. 386,486 pentium...and others. I'm thinking its an issue where the BIOS maybe programmed to support a 2.88B Floppy drive but the FDC chip may only be programmed up to a 1.44MB drive?

  2. #2
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    That is a good question. Not a lot of people actually included tested 2.88mb support as the drives were very uncommon. A clone 386/486 was not likely to have BIOS support, but many ISA cards had 2.88mb hardware support - primarily to accommodate FDC based tape drives that made use of the extra speed, not actual 2.88mb drives.

    To use a 2.88mb floppy disk (real or emulated) you would need both BIOS support and FDC chip support.

    I don't know of a good utility to test hardware. I'd suggest something like ImageDisk's TestFDC, but that does not support 2.88mb.

    Not sure how to test the BIOS, but if you do not need the disk to be bootable, I think the "2m-abios.exe" TSR (the AT version of the popular 2m-xbios.exe) driver may add 2.88mb BIOS support in the same way it adds 1.44mb support to BIOSes that only support 1.2mb.

  3. #3
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    Check your BIOS setup. Three questions:

    1) Does your system have floppy support integrated on the motherboard, or is it provided through an expansion card?
    2) Does it have a setup option for 2.88M HD drives?
    3) If the answer to the above questions is "I don't know", what chip does your system use for an FDC?

  4. #4

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    Quote Originally Posted by Chuck(G) View Post
    Check your BIOS setup. Three questions:

    1) Does your system have floppy support integrated on the motherboard, or is it provided through an expansion card?
    2) Does it have a setup option for 2.88M HD drives?
    3) If the answer to the above questions is "I don't know", what chip does your system use for an FDC?

    1) Floppy support is integrated
    2) 2.88MB is supported in BIOS
    3) VIA 8237

    I'm just wondering if there is a possibility of the BIOS being programmed to support 2.88MB drives but the FDC chip not being programmed to support the 2.88MB structure/drive. I only ponder that because I have motherboards where the opposite is true. There is hardware ie a header on the motherboard for a ps/2 connector but no option in the BIOS to enable/disable ps/2 mouse capability

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    3) VIA 8237

    IIRC, that's just the southbridge chip. What floppy controller is it attached to? The LPC VT1211 is pretty common, but isn't the only choice. If so, it does support 2.88M.

  6. #6
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    The 8237 isn't 2.88MB capable. You'd need an 82077AA or 82077SL, AFAIK . Probably there isn't the 1Mbps data rate support either.

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    You lost me--what VT8237 are you looking at?

    My reference shows that the VT8237 provides an LPC interface for a "super i/o" chip. usually a VT1211, which does support 2.88M 1Mbps transfer rate.

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    My bad, an egregious assumption that any Intel 8237-alike would have the same features/limitations.

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    No, the 8237 is a very quirky southbridge-with-ATA/SATA support. Linux gave up supporting it a few years back, because the driver was a mess and nobody wanted to re-write it. OpenBSD still, as far as I know, still works with it, as well as some of the older Linux distros. Used in thin clients quite a bit with the VIA CPUs (Eden, C3, C7). They're interesting in that many support an alternate instruction set (i.e. non-x86) in addition to the regular x86 one.

    As I said, "quirky".

    FWIW, the Intel 8237, IIRC, is a DMAC.

  10. #10

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    Quote Originally Posted by Chuck(G) View Post
    3) VIA 8237

    IIRC, that's just the southbridge chip. What floppy controller is it attached to? The LPC VT1211 is pretty common, but isn't the only choice. If so, it does support 2.88M.

    Im just seeing the southbridge...no other chip looks or amounts to a FDC controller....u sure its not part of the southbridge itself and i can agree the 8237 is a finicky southbridge

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