                 MICROPOLIS 1660 DISK DRIVE
                       SPECIFICATIONS

                                       Model Number
Unformatted Capacity:                    1664-7

  Total Mbytes            --------------- 389.3 -----------------
  Disk Platters           ------------------- 4 -----------------
  Read/Write Heads        ------------------- 7 -----------------
  Cylinders               ---------------- 1780 -----------------
  Bytes per track         -------------- 31,832 -----------------


Formatted Capacity

  Total Mbytes            --------------- 344.4 -----------------
  Bytes per Sector        ----------------- 512 -----------------
  Sectors per Track       -----------------  54 -----------------

PC Drive Types.


  If you are using third-party installation software or an board 
  BIOS on the controller, follow the instructions included with
  the software or controller. Otherwise, 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.

Performance Specifications

  Seek Time (including settling time)      Track-to-Track  4 msec
                                           Average        14 msec
                                           Maximum        30 msec
  Avg Rotational Latency                                8.33 msec
  Rotational Speed                              3600 rpm +/- 0.5%
  Data Transfer Rate                                 15 Mbits/sec
  MTBF                                              150,000 hours
  Positioner                     Fully balanced rotary voice coil
  Parking                                 Automatic park and lock

General Functional Specifications

  Interface                                                  ESDI
  Sectoring (see W1 description, below)              Hard or Soft
  Write Precompensation Start Cylinder                     1780 *
  Reduced Write Current Start Cylinder                     1780 *
  Landing Zone                                               1780
  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%                                             0.9A Avg
                                      (2.0A max. during start-up)
  +5V +/-5%                                              0.7A avg
  Power dissipation, typical                             14 Watts

Drive Addressing and Interface Termination

   NOT                                         
   USED       J2                   J1             J3            
   ____   ___________       _________________   ________  Power
  |    | |         |1|     |               |1| || Power | (under
  |    |_|           |_____|                 |_| -------| board)
  |                                                     |
  |                                                     |
  |                 Terminator                          |
  |                                                     |
  |                                                     |
  |                                                     |
  |                                                     |
  |                                                     |
  |                                                     |
  |    DA1                                              |
  |    DA2                                              |
  |    DA3                    (Component side)          |
  |     W5                                              |
  |     W4                                              |
  |     W3                                              |
  |     W2                                              |
  |     W1                                              |

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

DA1, DA2, DA3 Drive Address Jumpers
  The drive address jumpers are identified as DA1, DA2 and DA3.
  Address selection is binary, as shown in the table below. The
  ESDI controllers's documentation will specify the drive address
  to use.

   Drive            Select Jumpers
  Address        DA3     DA2     DA1
  -------        ---     ---     ---
     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

  "Drive address 0" (no jumper at DA1, DA2, or DA3) is a "deselect"
  (i.e., no drive selected). Drives are factory configured as Drive
  Address 1. For many multiple drive installations, each drive must
  have a unique address. An exception is that for every drive in
  a PC/AT installation, verify that the only Drive Address is at
  DA2; move  the jumper if necessary(the special twisted interface
  cable  that is generally used takes care  of assigning a unique
  address to each drive). PC/AT controller can typically support
  a maximum of two drives.

W5 Selects the Spindle Control Option.
  W5 selects the spindle a 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 applications.

W1 Selects  the Sectoring Mode.
  If W1 is installed, the drive operates in the soft-sectored mode.
  If W1 is not installed(the factory default configuration), the
  drive operates in the hard-sector mode. W1 is not installed for 
  most PC/AT in applications.

W2, W3, W4 Sector Size and Number Options
  The number of bytes per sector may be specified using the Set
  Bytes Per Sector command or by selecting a default sector 
  configuration with jumpers W2, W3, and W4 as follows:

       Jumpers            Sectors            Bytes/Sector
    W4    W3    W2       Per Track       Formatted  Unformatted
    ---   ---   ---      ---------       ---------  -----------
    out   out   out         53              512          588
 -------------------------------------------------------------
| * out   out    in         54              512          576  |
 -------------------------------------------------------------
    out    in   out         28             1024         1116
    out    in    in         14             2048         2232
     in   out   out          7             4096         4464
 ----------------------- RESERVED ----------------------------
     in    in   out         97              256          321
     in    in    in          1           31,248       31,248

  * This is the default (factory installed) configuration and is
  recommended for PC/AT applications
         