URI: 
  TEXT View Source
       
       # 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
       
   IMG IMG 1
          
       
          +------------------------------------------------------------+
          |                        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 is   |   W27    | closed  |
          |   | IRQ5                              |          |         |
          |---+-----------------------------------+----------+---------|
          |   | Hard drive Interrupt request is   |   W27    |  open   |
          |   | 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.           |
          +------------------------------------------------------------+