WESTERN DIGITAL CORPORATION

WD1004-27X, WD1004A-27X

Replaces the WD1002-27X and WD1002A-27X respectively

Data bus: 8-bit, PC/AT

Size: Half-length, full-height card

Hard drives supported: 2 RLL ST506/412 drives

Floppy drives supported: None

Maximum heads/cyl.: 16 heads and 1024 cylinders

[Image]

                           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

                        USERS CONFIGURABLE SETTINGS

               Function                    Location           Setting

  »   Hard drive Interrupt request           W27              closed
      is IRQ5

      Hard drive Interrupt request           W27               open
      is IRQ2

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

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

      0    closed    closed    closed   closed    65MB      6       820

      1     open     closed     open    closed    42MB      4       782

      2    closed     open     closed    open     21MB      2       782

  »   3     open      open      open     open     32MB      4       615

            I/O PORT & BIOS ADDRESS JUMPERS - (WD1004-27X ONLY)

   I/O Port Address       BIOS Address          W21             W22

  »      320-323h          C800-C9FFh           open            open

         324-327h          CA00-CBFFh          closed           open

         328-32Bh          CC00-CDFFh           open           closed

         32C-32Fh          CE00-CFFFh          closed          closed

                     SECTORS AND CONFIGURATION OPTION

    Table      Sectors     Translate    Dynamic        W25         W26

     RLL          17          yes          no         closed       open

     RLL          26          no          yes          open       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.