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       # WESTERN DIGITAL CORPORATION
       
          WD1002A-WX1 (VER.1)
       
          Data Bus                8-bit                                  
          Card Size               Proprietary                            
          Hard Drives supported   Two ST-506/412(MFM) drives             
          Floppy drives supported None                                   
       
   IMG IMG 1
          
       
          +------------------------------------------------------------+
          |                        CONNECTIONS                         |
          |------------------------------------------------------------|
          |       Function        | Location |   Function   | Location |
          |-----------------------+----------+--------------+----------|
          | 34-pin control cable  |    J1    | 5-pin        |    J4    |
          | connector-hard drive  |          | connector-DC |          |
          |                       |          | power        |          |
          |-----------------------+----------+--------------+----------|
          | 20-pin data cable     |    J2    |              |          |
          | connector-drive 0     |          |              |          |
          +------------------------------------------------------------+
       
          +------------------------------------------------------------+
          |                USER CONFIGURABLE SETTINGS                  |
          |------------------------------------------------------------|
          |               Function                | Label |  Position  |
          |---------------------------------------+-------+------------|
          | » | BIOS enabled                      |  W3   |   Closed   |
          |---+-----------------------------------+-------+------------|
          |   | BIOS disabled                     |  W3   |    Open    |
          |---+-----------------------------------+-------+------------|
          | » | I/O port address 320h             |  W4   | pins 2 & 3 |
          |   |                                   |       |   closed   |
          |---+-----------------------------------+-------+------------|
          |   | I/O port address 324h             |  W4   | pins 1 & 2 |
          |   |                                   |       |   closed   |
          |---+-----------------------------------+-------+------------|
          | » | BIOS ROM size 32K or 64K          |  W5   | pins 1 & 2 |
          |   | (hard-wired)                      |       |   closed   |
          |---+-----------------------------------+-------+------------|
          |   | BIOS ROM size 16K                 |  W5   | pins 2 & 3 |
          |   |                                   |       |   closed   |
          |---+-----------------------------------+-------+------------|
          | » | 8 head hard drive with RWC        |  W6   | pins 2 & 3 |
          |   | supported                         |       |   closed   |
          |---+-----------------------------------+-------+------------|
          |   | 16 head hard drive supported      |  W6   | pins 1 & 2 |
          |   | (head select 3)                   |       |   closed   |
          |---+-----------------------------------+-------+------------|
          | » | Hard drive Interrupt is IRQ5      |  W7   | pins 1 & 2 |
          |   | (hard-wired)                      |       |   closed   |
          |---+-----------------------------------+-------+------------|
          |   | Hard drive Interrupt is IRQ2      |  W7   | pins 2 & 3 |
          |   |                                   |       |   closed   |
          |---+-----------------------------------+-------+------------|
          | » | Single controller setting,        |  W8   | pins 2 & 3 |
          |   | primary controller                |       |   closed   |
          |---+-----------------------------------+-------+------------|
          |   | Dual controller setting,          |  W8   | pins 1 & 2 |
          |   | secondary controller              |       |   closed   |
          |---+-----------------------------------+-------+------------|
          | » | Factory configured - Do not alter | S1/5  |    Open    |
          |---+-----------------------------------+-------+------------|
          | » | Factory configured - Do not alter | S1/6  |    Open    |
          |---+-----------------------------------+-------+------------|
          | » | Factory configured - Do not alter | S1/7  |    Open    |
          |---+-----------------------------------+-------+------------|
          | » | Factory configured - Do not alter | S1/8  |    Open    |
          +------------------------------------------------------------+
       
          +------------------------------------------------------------+
          |              BIOS REVISION DRIVE TYPE TABLE                |
          |------------------------------------------------------------|
          |Drive1 |Drive |      |                                      |
          |       |  0   |      |                                      |
          |-------+------+------+--------------------------------------|
          |   | # | S1/1 | S1/2 | S1/3 | S1/4 |Cap. |Hds |Cyls.|WP |RWC|
          |---+---+------+------+------+------+-----+----+-----+---+---|
          |   | 0 |Closed|Closed|Closed|Closed|20 MB| 4  | 612 |613|613|
          |---+---+------+------+------+------+-----+----+-----+---+---|
          |   | 1 | Open |Closed| Open |Closed|10 MB| 2  | 612 |128|128|
          |---+---+------+------+------+------+-----+----+-----+---+---|
          |   | 2 |Closed| Open |Closed| Open |20 MB| 4  | 612 |128|613|
          |---+---+------+------+------+------+-----+----+-----+---+---|
          |»  | 3 | Open | Open | Open | Open |10 MB| 4  | 306 | 0 |306|
          |------------------------------------------------------------|
          |Note: S1/1 and S1/2 select the setting for drive1 & S1/3 and|
          |S1/4 select the setting for drive 0                         |
          +------------------------------------------------------------+
       
          +------------------------------------------------------------+
          |               MISCELLANEOUS TECHNICAL NOTES                |
          |------------------------------------------------------------|
          |      Note: 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.  |
          |      Two additional jumpers may be present, W1 & W2, and   |
          |      are reserved for factory use and may not be changed.  |
          +------------------------------------------------------------+