                 MICROPOLIS 1578 DISK DRIVE
                       SPECIFICATIONS

                                  Model Number
Unformatted Capacity:               1578-15

  Total Mbytes        ---------------- 382.3 ---------------------
  Disk Platters       -------------------- 8 ---------------------
  Read/Write Heads    ------------------- 15 ---------------------
  Cylinders           ----------------- 1224 ---------------------
  Bytes per track     --------------- 20,832 ---------------------

Formatted Capacity (typical)

  Total Mbytes        ---------------- 331.7 ---------------------
  Bytes per Sector    ------------------ 512 ---------------------
  Sectors per Track   ------------------- 36 ---------------------

PC Setup

  When using SCSI in a PC, the most common method is to run your
  setup program and define No Drives Present. The SCSI Host Adapter
  will automatically self-configure on power-up. To install the
  drive, follow the manufacturer's instructions to use the on-board
  BIOS routine or software that was supplied with the Host Adapter.

Performance Specifications

  Seek Time (including settling time)     Track-to-Track   4 msec
                                          Average         16 msec
                                          Maximum         35 msec
  Average Rotational Latency                            8.33 msec
  Rotational Speed                              3600 rpm +/- 0.5%
  Data Transfer Rate at Interface
    Synchronous                                    4.0 Mbytes/sec
    Asynchronous                                   1.6 Mbytes/sec
  Internal Data Rate                                 10 Mbits/sec
  MTBF                                              150,000 hours
  Positioner                     Fully balanced rotary voice coil
  Parking                                 Automatic park and lock

General Functional Specifications

  Interface                                                  SCSI
  Supports Full Common Command Set
  Write Precompensation Start Cylinder                       1224
  Reduced Write Current Start Cylinder                       1224
  Landing Zone                                               1224
  Mounting Plane                                  Any orientation

Power Requirements

  +12V +/-5%                                            2.25A avg
                                      (4.25A max during start-up)
  +5V +/-5%                                              2.0A avg
  Power dissipation, typical                             32 Watts

Drive Addressing and Interface Termination

                                                PIN 1
            J2                     J1              |
      ____________   _______________________________      J3
   __|            |_|                               |___________ 
  |  |____________| |_______________________________| |  POWER  |
  |                     RN202     RN203     RN204     |_________|
  |                                                             |
  |                                                             |
  |                             ... W201                        |
  |                             123                             |
  |                                                             |
  |                                                      W5     |
  |                                                      W4     |
  |   (Component Side)                                  W20     |
  |                                                     ID0     |
  |                                                     ID1     |
  |                                                     ID2     |
  |                                                             |


                ____ ID2
               | ___ ID1
               || __ ID0                        PIN 1
          J2   |||                 J1              |
      ____________   _______________________________      J3
   __|            |_|                               |___________
  |  |____________| |_______________________________| |  POWER  |
  |                     RN202     RN203     RN204     |_________|
  |  W4 W5                                                      |
  |                                                         W21 |
  |                             W1 W2                           |
  |                                                             |
  |                             W11                             |
  |                                                             |
  |                                                      W20    |
  |   (Component Side)                                          |
  |                                                             |
  |                                                             |
  |                                                             |
  |                                                             |


ID0, ID1, ID2 SCSI Address Jumpers
  The SCSI ID (drive address) jumpers are identified as ID0, ID1,
  and ID2. ID selection is binary, as shown in the table below.

   SCSI              Jumpers
  Address        ID2   ID1   ID0
  -------        ---   ---   ---
     0           out   out   out
     1           out   out    in
     2           out    in   out
     3           out    in    in
     4            in   out   out
     5            in   out    in
     6            in    in   out
     7            in    in    in

  For  multiple drive installations, on one Host Adapter,each drive
  must unique address. Drives are configured as SCSI ID 0 at the
  factory.

RN202, RN203, RN204 Interface Terminator
  The Interface Terminators factory installed at RN202, RN203, and
  RN204 provide proper termination for the interface lines. When
  daisy-chaining multiple drives, leave the terminators installed
  only in the last physical drive on the daisy chain cable; remove
  all three terminators from each of the other drives. In most 
  PC/AT installations, the C: drive is actually at the end of the
  cable and should retain the terminators.

W201 or W1, W2 Terminator Options
  W201 positions 1-2 and 2-3 (or W1 and W2, respectively, on second
  board shown) select the source of terminator power (+5V) for the
  interface terminators. If a jumper is installed at positions 1-2
  (W1) and no jumper is installed at position 2-3(W2)(the factory
  default configuration), the drive provides terminator power. This
  configuration is used for PC/AT applications. If no jumper is
  installed at W201 position 1-2(W1) but a jumper is installed at
  position 2-3(W2), terminator power must be provided by the host
  computer system via interface connector J1, pin 26.

W11 Bus Option
  W11 (only present on Rev C and higher boards of the second type
  shown) allows the drive to supply interface terminator power to
  the SCSI Bus. If W11 is not installed (the factory default
  configuration), the drive does not supply SCSI bus interface
  terminator power. W11 should not be installed for PC/AT
  applications.

W5 Spindle Option
  W5 selects the spindle control option. If W5 is installed, the
  drive waits for a Start Spindle command (after power is applied)
  to start the spindle motor. If W5 is not installed (the factory
  default configuration), the drive automatically starts the
  spindle motor at power-on. W5 is not installed for PC/AT
  installations.

W4 Bus Parity Check Option
  W4 selects the parity check option. If W4 is installed, the drive
  neither generates nor detects parity. If W4 is not installed (the
  factory default configuration), the drive generates parity and
  enables parity detection. W4 is not installed most PC/AT
  applications. Verify the correct configuration required by your
  Host Adapter.

W21 Ground Options
  W21(only implemented on Rev C and higher boards of the second
  type shown) is used to connect the drive's logic ground to frame
  ground. The factory default configuration, which should be used
  for PC/AT applications, is a jumper installed at W21.

W20 Reserved
  Jumper must be installed
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