
                      1670/1680 MAC SERIES
                         Specifications

The Micropolis Macintosh-Compatible disk drives are designed
especially for Value-Added Distributors and Resellers of Macintosh
storage systems and sub systems.

Compatible with Mac Plus, Mac SE, Mac II, and Mac IIx computers.
  Half-height form factor adapts easily to Mac II and Mac IIx    
  systems.
  Half-Height form factor adapts for low profile external        
  package integration.
  The drives employ a closed-looped digital servo which ensures  
  accurate tracking under all environmental conditions.
  Macintosh-compatible SCSI interface permit easy integration,   
  eliminating the need for cable modification.
  SCSI features include:
    A full 64 Kbytes buffer with read-ahead capability for faster 
    data access
    Less than 600 microseconds command overhead to improve       
    overall throughput numbers
    Cylinder oriented defect management, offering the most       
    reliable data integrity system available

1670 Mac Series
                                Formatted Capacity

  Model                 1673-5                   1674-7 
  Total Mbytes             112                      158
  Bytes Per Sector  ------------------- 512 ---------------------
  Sector Per Track  -------------------- 36 ---------------------
  Cylinders         ------------------ 1245 ---------------------
  Data Heads                 5                        7

1680 Mac Series
                                Formatted Capacity

  Model                 1683-4                   1684-7 
  Total Mbytes             193                      340
  Bytes Per Sector  ------------------- 512 ---------------------
  Sector Per Track  -------------------- 54 ---------------------
  Cylinders         ------------------ 1776 ---------------------
  Data Heads                 4                        7

1670 Performance
  Seek Time (includes settling)            Track to Track  4 msec
                                           Average        16 msec
                                           Maximum        37 msec
  Latency Time(average)                                 8.33 msec
  Rotational Speed                                      3600 msec
  Media Transfer Rate                                      10 MHz

1680 Performance

  Seek Time (includes settling)            Track to Track  4 msec
                                           Average        14 msec
                                           Maximum        30 msec
  Latency Time(average)                                 8.33 msec
  Rotational Speed                                      3600 msec
  Media Transfer Rate                                      15 MHz

Interface

  Compatibility                                          Mac SCSI
  Command Overhead                     Less than 600 Microseconds
  Buffer                                     64 KByte with parity
Defect Management                               Cylinder oriented

Physical

Form Factor             (Industry standard for 5 1/4 half-height)
  Height                                   1.625 inches (41.3 mm)
  Width                                   5.75  inches (146.1 mm)
  Depth                                   8.00  inches (203.2 mm)
  Weight                               5 pounds (2.27 kg) maximum

Other Specifications

Power Requirements-typical
  + 12V +/- 5%                                   1.0 Avg. Seeking
                                     2.0A Maximum during start-up
  + 5V +/- 5%,                                  1.9A Avg. Seeking
Power Dissipation, typical                               15 Watts
Acoustic Noise
  Idling                                                   40 dBA
  Seeking                                                  45 dBA
Mounting       Half-height 5 1/4 inch disk drive, any orientation

Reliability
  MTBF                                       150,000 power-on hrs
  MTTR                                                 15 minutes
Preventive Maintenance                                       none
Electronic Adjustments                                       none
Data Integrity 
  Automatic Retry with early/late strobe, track offset
  48 bit ECC polynomial
  Parity through buffer
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