                         SEAGATE TECHNOLOGY, INC.
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                            (C)opyright 1993



ST-12550W SCSI-2 Fast Wide (Barracuda 2) (aka ST-12551N)

                                         J01Ŀ
ͻ                           (see    1
 REAR VIEW                             below) 
ͼ                                   1Ŀ J4-1Ŀ
                                                "                |
                                                "J4 1-6          
                                                "(see below)     |
        (TOP)                    J5             "J4-6Ŀ         
          34________________1    1/\       |         |
        (  )ͳ:::::: 0 0 0 0                
          \ĳ/      5GG12                1
       68 pin I/O Cable                           : : : : : :
       Connection                                       2
                                                        
Spindle Synch Cable Connector ٳ  Enable Drive      
  (pin-11 SSREF, pin-12 ground)     Terminators *         
Remote LED Connector ٳ  Reserved     
 [pin-9 cathode (neg),               (default OFF)          
  pin-10 anode (pos)]               Parity Disable    
                                    Enable Motor Start   
SCSI ID = 8 ٳ  Delay Motor Start  
SCSI ID = 4 ٳ   (10 sec * ID)             
SCSI ID = 2 ٳ  Write Protect Enable 
SCSI ID = 1 
SCSI ID = 0 (none)

Ŀ
 J01 - Terminator Power Jumpers Ŀ
                  
            Terminator power from the drive.       1ķ *
              (default)                            
                                                     
            Terminator power from pin 26 on the      ķ
              SCSI bus.                             
                                                    

            Terminator to the SCSI bus on pin 26.   ķ  *
                                                    
                                                    

            Terminator power to the SCSI bus and    ķ*
              drive.                                
                                                    
            * Valid for single ended drives only.


    Note: ST-12550WD (differential model) does not come with any
          provision to use Termination resistors.  Therefore, SCSI bus
          needs to be externally terminated.


                            ST-12550W


       UNFORMATTED CAPACITY (MB) ________________2572
       FORMATTED CAPACITY (xx SECTORS) (MB) _____2139
       AVERAGE SECTORS PER TRACK ________________81 rounded down
       ACTUATOR TYPE ____________________________STRAIGHT ARM
       TRACKS ___________________________________51,433
       CYLINDERS ________________________________2,707 user
       HEADS ______PHYSICAL______________________19
       DISCS (3.5 in) ___________________________10
       MEDIA TYPE _______________________________THIN FILM
       RECORDING METHOD _________________________ZBR RLL (1,7)
       TRANSFER RATE INTERNAL (mbits/sec)________34.3 to 56.5
       SPINDLE SPEED (RPM) ______________________7,200
       AVERAGE LATENCY (mSEC) ___________________4.17
       BUFFER ___________________________________1024 KByte
         Read Look-Ahead, Adaptive,
         Multi-Segmented Cache
       INTERFACE ________________________________SCSI-2 FAST WIDE
       BYTES PER TRACK __________________________50,888 average
       SECTORS PER DRIVE ________________________
       TPI (TRACKS PER INCH) ____________________3,047
       BPI (BITS PER INCH) ______________________52,187
       AVERAGE ACCESS (ms) (read/write)__________8.0/9.0
         Drive level without controller overhead
       SINGLE TRACK SEEK (ms) ___________________0.6/0.9
       MAX FULL SEEK (ms) _______________________20.0/21.0
       MTBF (power-on hours) ____________________500,000
       POWER REQUIREMENTS: +12V START-UP (amps) _2.18
                           +12V TYPICAL (amps) __0.83 idle
                           +5V START-UP (amps) __1.0
                           +5V TYPICAL (amps) ___0.76 idle
                           TYPICAL (watts) ______10.7
                           MAXIMUM (watts) ______
       WRITE PRECOMP (cyl) ______________________N/A
       REDUCED WRITE CURRENT (cyl) ______________N/A
       LANDING ZONE (cyl) _______________________AUTO PARK
       IBM AT DRIVE TYPE ________________________0 or NONE

       Physical:
                        Height (inches/mm):     1.63/41.4
                        Width  (inches/mm):     4.00/101.6
                        Depth  (inches/mm):     5.97/146.1
                        Weight    (lbs/kg):     1.8/0.80

Already low-level formatted at the factory with 9 spare sectors
per cylinder and 1 spare cylinder per unit.

ZBR = Zone Bit Recording = Variable sectors per track

Seagate reserves the right to change, without notice, product
offerings or specifications. (10/11/93)
