WESTERN DIGITAL CORPORATION

WD1004A-WX1

Data bus: 8-bit, PC/AT, PC/AT

Size: Half-length, full-height card

Hard drives supported: Two MFM ST506/412 drives

Floppy drives supported: None

Maximum heads/cyl.: 16 heads and 1024 cylinders

[Image]

                        USERS CONFIGURABLE SETTINGS

               Function                    Location           Setting

  »   Hard drive Interrupt request           W27              closed
      is IRQ5

      Hard drive Interrupt request           W27               open
      is IRQ2

                           CONNECTIONS

                  Function                        Location

  34-pin control cable connector-hard drive          J1

  20-pin data cable connector-drive 0                J2

  20-pin data cable connector-drive 1                J3

  5-pin connector-DC power                           J4

  4-pin connector-drive active LED                   J5

                 BIOS DRIVE TYPE TABLE - (WD1004-27X ONLY)

  Table     W17       W18       W19       W20     Cap.    Hds.     Cyls.
    #

      0    closed    closed    closed   closed    21MB      4       612

      1     open     closed     open    closed    10MB      4       306

      2    closed     open     closed    open     10MB      2       615

  »   3     open      open      open     open     21MB      4       615

                          I/O PORT & BIOS ADDRESS

   I/O Port Address       BIOS Address           W21             W22

  »      320-323h         C8000-C9FFFh           open           open

         324-327h         CA000-CBFFFh          closed          open

         328-32Bh         CC000-CDFFFh           open          closed

         32C-32Fh         CE000-CFFFFh          closed         closed

                       MISCELLANEOUS TECHNICAL NOTES

   This controller has a built-in low-level format program. To enter the
     program run the DEBUG utility supplied with DOS and at the prompt
                             enter: G=C800:5.

      If the system is not compatible with the Western Digital BIOS, a
         resistor must be installed at R23 to disable the WD BIOS