                 MICROPOLIS 1320 SERIES DISK DRIVE
                          SPECIFICATIONS

                                      Model Number
Unformatted Capacity:   1323     1323A     1324    1324A     1325

  Total Mbytes          42.7      53.3     64.0     74.7     85.3
  Disk Platters            3         3        4        4        5
  Read/Write Heads         4         5        6        7        8
  Cylinders             ------------------ 1024 -----------------
  Bytes per track       ---------------- 10,416 -----------------

Formatted Capacity:

  Total Mbytes          35.6     44.5      53.4     62.3     71.3
  Bytes per Sector      ------------------- 512 -----------------
  Sectors per Track     -------------------- 17 -----------------

PC Drive Types

  Examine the entries in your drive table and find the type that
  most resembles the head and cylinder parameters of the drive 
  without exceeding these parameters. If you are using third-party 
  installation/partitioning software, follow the instructions 
  included with the software as it may perform this step 
  automatically.

Performance Specifications

  Seek Time (including settling time)     Track-to-Track   6 msec
                                          Average         28 msec
                                          Maximum         62 msec
  Average Rotational Latency                            8.33 msec
  Rotational Speed                              3600 rpm +/- 0.5%
  Data Transfer Rate                                  5 Mbits/sec
  Optimum Step Rate             20 usec or faster (buffered seek)
  MTBF                                               35,000 hours
  Positioner                     Fully balanced rotary voice coil
  Parking                                 Automatic park and lock

General Functional Specifications

  Interface                                            ST-506/412
  Encoding Method             MFM (Modified Frequency Modulation)
        (Although these drives may be capable of functioning in
        an RLL environment, Micropolis does not certify or
        warrant them for this application.)
  Sectoring                                                  Soft
  Write Precompensation Start Cylinder                      1024*
  Reduced Write Current Start Cylinder                      1024*
  Landing Zone                                               1024
  Type of Media                                             Oxide
  Mounting Plane                                  Any orientation

  * These are effectively turned off by specifying a non-existent
  cylinder. Some systems accomplish this by using a value of "-1"

Power Requirements

  +12V +/-5%                                             2.0A avg
                                       (3.9A max during start-up)
  +5V +/-5%                                              0.9A avg
  Power dissipation, typical                             29 Watts

Drive Addressing and Interface Termination

                   J1                  J2
   ____   __________________     ____________   ________
  |    | |1|                |   |1|          | | W W    |
  |    |_|                  |___|            |_| 7 8    |
  |                    D D D D                          |
  |   TERMINATOR   W W S S S S                          |
  |                1 2 1 2 3 4                          |
  |                                                     |
  |                                                     |
  |                 (COMPONENT SIDE)                    |

DS1, DS2, DS3, DS4 Drive Select Jumpers
  The Drive Select jumper locations are identified as DS1, DS2, 
  DS3, and DS4. Only one Drive Select jumper is installed on a 
  drive. The drives are shipped with the jumper installed at DS1.
  For every drive in a PC/AT installation, move the jumper from DS1
  to DS2 (the special twisted interface cable that is generally
  used takes care of assigning a unique address to each drive).
  Some other systems may require that each drive be jumpered to a
  unique address (i.e., different DS numbers).

RN1 Interface Terminator
  The Interface Terminator factory installed at RN1 provides proper
  termination for the interface lines. When daisy-chaining multiple
  1320 drives, leave the terminator in the last physical drive on
  the daisy chain cable; remove the terminator 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
  terminator.

W1 Write Fault Latch
  W1 is the Write Fault Latch. If W1 is present and the drive
  encounters a write fault, all writing to the drive is inhibited
  until after the drive has been de-selected. If W1 is absent,
  fault conditions are not latched. Drives are shipped with a
  jumper installed at W1; remove it for PC/AT installations.

W2 is always installed.

W7 is never installed.

W8 is always installed.


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