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Thread: Hard disk Driver Card WD1002A-WX1 Without Bios

  1. #11
    Join Date
    May 2006
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    Melbourne, Australia
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    Quote Originally Posted by Malc View Post
    I have the " F300 " version of the WD1002A-WX1, On the printed label it reads " WD1002A-WX1 F300 J " and the Bios ROM is soldered directly onto the PCB.
    That 'F300' is known as a 'WD Feature Number.'

    For example, table 2 within the WDXT-GEN user's guide at [here] reveals that there were (at the time of publication) five different feature numbers available for the WDXT-GEN:

    F300 = Supports a heads=4/cylinders=615/WPC=307/RWC=none/Step=30us drive, AND extra features such as dynamic operation
    F320 = Supports only a heads=4/cylinders=615/WPC=307/RWC=none drive, stepping at 30us
    F335 = Supports only a heads=5/cylinders=733/WPC=367/RWC=none drive, stepping at 18us
    F336 = Supports only a heads=6/cylinders=640/WPC=210/RWC=210 drive, stepping at 18us
    F340 = Supports only a heads=6/cylinders=820/WPC=410/RWC=none drive, stepping at 18us

    (F300 being the more desirable due to its optional dynamic operation.)

    Looking at the differences, they are things done in code, i.e. 'F300' relates to the BIOS ROM.

  2. #12

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    There were a couple things I remember about XT controllers and later AT controllers. I used a XT controller with my NC4000 computer. It is not a x86 processor, it is a stack processor. It would just crash using XT's ROM. So, I wrote my own bios code for the controller.
    I also uses a real ST506 drive ( 5Megs ). 'payed $5 or $1 a Meg.
    Anyway, back to the controller. The XT controller and the AT controller used completely different register to the bus. The AT used a register set like the original WD1000 series ( notice the last number is a 0 ). The XT used a different register set. This means that you can't send the same instructions to a XT controller that a AT class controller can use.
    Both types are easier than the typical floppy controller to write the BIOS for. Both require the typical stuff of the various setups. Things like stepping speed, sector size and such. Both were intended to buffer an entire sector at a time as a minimum. That made writing and reading easy. Fill the buffer and write, empty the buffer on reads.
    One other thing, I believe, starting around the ST255 time, you want to use the auto stepping rather than the fixed stepping. If the drives used the fixed stepping, they when really slow.
    Any way, there are the two different register sets used and the location of the bits are completely different.
    I recall how easy it was to do the hard drive compared to the floppy. The floppy controller did a byte at a time, similar to a serial chip. I couldn't send it to fast or too slow without issues. The NC4000 was so much faster that the controller didn't have time to update the status before it read it after the data write. I needed to add delays.
    The NC4000 had no interrupt or dma. I always thought interrupt control on a single process machine was silly. What were you going to do while waiting for the interrupt, especially on reads. The reason you asked for the data is because, you needed it right now and you had to wait anyway.
    Dwight
    Last edited by Dwight Elvey; September 21st, 2020 at 07:09 AM.

  3. #13
    Join Date
    Apr 2014
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    Dwight,
    Thanks for the insight info about registers.

    As for This XT WD1002 card that originally came with no BIOS I still can not figure out a machine that will understand that card.

    Now I finally have that very old 1987 80286 board running, I thought maybe that will go, but not.
    Ok now with the Bios installed it run's, But without a Bios??
    Then that jumper AT-Mode, as Modem7 recalled this card is not able to int14, so the use of it, the manual does not
    give any clue about running without bios or The AT-mode.

    And why having a Jumper with totally no use, That W3 disabling the Bios so CPU won't recognise any hard drive?
    You have to unscrew and pull the card, replace jumper, put in ,fiddeling with the screw, so it does not see the drive?
    Leave whole card out would be easier.I think.
    There must have been MBoards with BIOS that include MFM, I think.

  4. #14
    Join Date
    Apr 2014
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    Dordrecht , Netherlands
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    At Debug That "10/20/30" Bios is "WX2 Format Revision 6.0"
    See
    WD1002A-WX1_Rev6_1985_Type2732A_Pic.jpg

  5. #15

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    When you have a mother board with a bios, you don't want to install the onboard bios. I can't tell you why your particular system may or may not work with this card. It may be that the card does not work in any system. I do know that if the BIOS you have does not use the right registers it is assured to not work. There are two different register sets typically use in hard drive controllers. The two types of controllers are both MFM on the drive side so MFM or or not it makes no difference. IDE interfaces are completely different. These are not the two controller types I am talking about as the IDE drive actually have the controller on the drive. The card on the buss is just a bus interface.
    Most consider a AT to be a IDE type. I can't see how this board has a AT mode.
    Dwight

    Dwight

  6. #16

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    The card looks strikingly similar to the card I shoehorned into the Kaypro 4-83 (it came from a hardcard with a 20 MB Kalok MFM on it)
    wd_isa_card.jpg

  7. #17

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    Maybe you could dump the bios and the OP could blow an EPROM and attach it to his board.
    Dwight

  8. #18

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    Quote Originally Posted by Dwight Elvey View Post
    Maybe you could dump the bios and the OP could blow an EPROM and attach it to his board.
    Dwight
    With some effort (the ROM seems to be soldered into place) that could be possible.
    I can not read out the rom from the kaypro as I only connected the IO lines needed to access the controller part of the card.

    For the fact why it would ever be necessary to disable the ROM: maybe in a multiple drive setup (more than 2 harddisks) then you would need to add a second card and the roms would conflict?

  9. #19

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    It is in the computer as a specific address. You should be able to read it into a file. The ROM should start at C800:0000. You should be able to able to read it with any descent language.
    Dwight

  10. #20

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    Quote Originally Posted by Dwight Elvey View Post
    It is in the computer as a specific address. You should be able to read it into a file. The ROM should start at C800:0000. You should be able to able to read it with any descent language.
    Dwight
    Alas my Kaypro is not a DOS/80x86 computer

    I needed a MFM controller to drive a nice 10MB Seagate full height drive and found two 8 bit ISA hardcards with defective harddrives.
    The only controller I could find some info on was the WD controller. The controller is mapped into IO space and no memory space is used.

    Wrote a new BIOS for CPM on the Kaypro and finally got it working. It now even boots from the harddisk..

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