MICROPOLIS 2112A DISK DRIVE
                        SPECIFICATIONS

                                       Model Number
Unformatted Capacity:                    2112A-15

Total Mbytes            --------------  1220 -----------------
Disk Platters           -----------------  8 -----------------
Read/Write Heads        ----------------- 15 -----------------
Cylinders               --------------- 1760 -----------------
Bytes per track         ----------- VARIABLE -----------------

Formatted Capacity

Total Mbytes            --------------- 1050 -----------------
Bytes per Sector        ---------------- 512 -----------------
Sectors per Track       ----------- VARIABLE -----------------

Performance Specifications

  Seek Time                       Adjacent Track         1.5 msec
    (including settling time)     Average               10.0 msec
                                  Maximum                 25 msec

  Average Rotational Latency                            5.56 msec
  Rotational Speed                              5400 rpm +/- 0.5%

  Data Transfer Rate at Interface            Up to 5.6 Mbytes/sec

  Internal Data Rate                                 24 to 40 MHz

  MTBF                                              300,000 hours
  Positioner                     Fully balanced rotary voice coil
  Parking                                 Automatic park and lock

 General Functional Specifications

  Interface                                                AT/IDE
  Supports Full Common Command Set                            YES
  Mounting Plane                                  Any orientation

Power Requirements

  +12V +/-5%                                           0.75A  Avg
                                        (2.0 max during start-up)
  +5V +/-5%                                              1.0A avg

  Power dissipation, typical                           11.5 Watts


















7. Drive Options

      ____   _______________________   ________
     | J2 | |         J1            | |   J3   |
     |    |_|_______________________|_|________|
     |                                         |
     |               RESERVED                  |
     |               | | |                     |
     |           : : : : :                     |
     |           | |                           |
     |          W1 |                           |
     |            W2                           |
     |                                         |
     \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/

      /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
     |           LED                           |
     |________||_______________________________|


W1, W2 Jumpers (Master / Slave Selection)
    The interface allows up to two drives (a Master and one Slave) to be
    attached to the AT/IDE bus. The following table shows the configurations.

       W1     W2    Description
    +------+------+-------------------------------------------------------+
    |  IN  |  IN  | Drive emulates *both* Master and Slave (DEFAULT)      |
    +------+------+-------------------------------------------------------+
    | OUT  |  IN  | Drive is Master, Slave is present                     |
    +------+------+-------------------------------------------------------+
    |  IN  | OUT  | Drive Slave                                           |
    +------+------+-------------------------------------------------------+
    | OUT  | OUT  | Drive is Master                                       |
    +------+------+-------------------------------------------------------+

DRIVE EMULATES BOTH MASTER AND SLAVE
    Specifies that one 2112A drive can emulate both the Master drive (Drive 0)
    and the Slave drive (Drive 1). This option allows for existing host systems
    to utilize the full capacity of the drive.

    When the drive is configured as both the Master and the Slave, the Master's
    (Drive 0) capacity is set to:

          1024 logical cylinders,
            16 logical heads, and
            63 logical sectors.
       This setting yields 528,482,304 bytes.

    The Slave's (Drive 1) capacity is set to the remaining storage on the
    disk drive.

    For this configuration, the recommended drive type setting in your
    computer's CMOS memory is as follows:

                             Drive 0    Drive 1
    Logical Cylinders:          1024       1010
        Logical Heads:            16         16
      Logical Sectors:            63         63

    NOTE:  The capacity of the 2112A drive may exceed the capacity that the
    host can access. This limitation stems from the communication link between
    the DOS and the BIOS. A typical limit is:

              1024 cylinders
                16 heads
                63 sectors

    For optimum use of the following options, the BIOS may need to be modified.

DRIVE IS MASTER, SLAVE IS PRESENT
     Specifies the Master drive (Drive 0) when two 2112A drives are used in the
     system. The other drive is the Slave.

DRIVE IS SLAVE
     Specifies the Slave drive (Drive 1) when two 2112A drives are used in the
     system. The other drive is the Master.

     NOTE: If you have a machine with a BIOS that supports over 16 heads, you
           can get the drive to work as one full partition. To do this, set
           the drive for:

               991 cylinders
                64 heads
                32 sectors

DRIVE IS MASTER
     Specifies the Master drive (DRIVE 0) when one 2112A drive is used in a
     system.

     NOTE: If you have a machine with a BIOS that supports over 16 heads, you
           can get the drive to work as one full partition. To do this, set
           the drive for:

               991 cylinders
                64 heads
                32 sectors