                  MICROPOLIS 1684 DISK DRIVE
                        SPECIFICATIONS

                                       Model Number
Unformatted Capacity:                    1684-7

  Total Mbytes            --------------- 389.3 -----------------
  Disk Platters           ------------------- 4 -----------------
  Read/Write Heads        ------------------  7 -----------------
  Cylinders               ---------------  1780 -----------------
  Bytes per track         -------------- 31,248 -----------------

Formatted Capacity

  Total Mbytes            --------------- 339.6 -----------------
  Bytes per Sector        ----------------- 512 -----------------
  Sectors per Track       -----------------  54 -----------------

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         14 msec
                                          Maximum         30 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                                 15 Mbits/sec
  MTBF                                              150,000 hours
  Positioner                     Fully balanced rotary voice coil
  Parking                                 Automatic park and lock

General Functional Specifications

  Interface                                                  SCSI
  Supports Common Command Set
  Write Precompensation Start Cylinder                       1780
  Reduced Write Current Start Cylinder                       1780
  Landing Zone                                               1780
  Mounting Plane                                  Any orientation

Power Requirements

  +12V +/-5%                                             0.9A Avg
                                       (2.0A max during start-up)
  +5V +/-5%                                              0.8A avg
  Power dissipation, typical                           14.8 Watts

7. Drive Addressing and Interface Termination


              _ID2
             |  _ID1
             | |  _ID0
             | | |                        Pin 1
         J2  | | |              J1            |       J3 (Power
      ___________    __________________________     ________under 
    _|           |  |                          |   |W14  W9 | board
   | |___________|_ |__________________________|___|   W3   |
   |                                                        |
   |                   W31 W2 W1                            |
   |                                                        |
   |                            RN9                         |
   |                                                        |
   |                                                        |
   |                                                        |
   |                                                        |
   |                                                        |
   |                                                        |
   |                                 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 have a unique address. Drives are configured as SCSI ID 0
  at the factory.

RN9 Interface Terminator
  The Interface Terminators factory installed at RN9 provides   
  proper termination for the interface lines. When daisy-chaining 
  multiple drives, leave the terminator installed only in the last 
  physical drive (or drives) on the daisy chain cable; remove the 
  terminator from each of the other drives (or the host computer).

W1, W2 Terminator Option
  W1 and W2 selects the source of terminator power (+5V) for the 
  interface terminators. When a jumper is installed at W1(the  
  factory default configuration) and no jumper is installed at W2 
  the drive provides terminator power. This configuration is used 
  for PC/AT applications. If a jumper is installed at W2,    
  terminator power is provided by the host system via interface  
  cable J1, pin 26. If a jumper is installed at W2 and W31, the
  drive provides terminator power to its on-board terminators and
  also to the SCSI bus via interface cable J1.

W31 Bus Option
  W31 allows the drive to supply interface terminator power to the
  SCSI Bus. If W31 is not installed (the factory default  
  configuration), the drive does not supply SCSI bus interface   
  terminator power. W31 should not be installed for PC/AT      
  applications.

W3, Spindle Option
  W3 selects the spindle control option. If W3 is installed, the
  drive waits for a Start Spindle command (after power is applied)
  to start the spindle motor. If W3 is not installed (the factory
  default configuration), the drive automatically starts the    
  spindle motor at power-on. W3 is not installed for PC/AT      
  installations.

W9 Bus Parity Option
  W9 selects the parity check option. If W9 is installed, the drive
  neither generates nor detects parity. If W9 is not installed (the
  factory default configuration), the drive generates parity and
  enables parity detection. W9 is usually not installed for PC/AT
  applications. Verify the correct configuration required by your
  Host Adapter.
