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                            (C)opyright 1993



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

                                        J01Ŀ
                                       (see    1
ͻ                           below) 
 REAR VIEW                                   1Ŀ J4-1Ŀ
ͼ                                  "                 |
                                               "J4 1-6           
                                               "(see below)      |
                                               "J4-6Ŀ         
        (TOP)                    J5            "-J4-7 |         |
          ___________________    1/\     | |         |
        ( 1)ͳ:::::: 0 0 0 0               
          \ĳ/      5GG12               1
       68 pin I/O Cable                         : : : : : : :
       Connection                                      2
                                  Reserved       
Spindle Synch Cable Connector ٳ   (some drives do      
  (pin-11 SSREF, pin-12 ground)      not have this       
Remote LED Connector ٳ    #7 jumper)          
 [pin-9 cathode (neg),              Enable Drive      
  pin-10 anode (pos)]                Terminators           
                                    Reserved     
SCSI ID = 8 ٳ   (default OFF)          
SCSI ID = 4 ٳ  Parity Disable    
SCSI ID = 2 ٳ  Enable Motor Start   
SCSI ID = 1   Delay Motor Start  
SCSI ID = 0 (none)                       (10 sec * ID)             
                                        Write Protect Enable 
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 ____________________________ROTARY VOICE COIL
       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)
       INTERNAL TRANSFER RATE (mbits/sec)________34.3 to 56.5
       EXTERNAL TRANSFER RATE (mbyte/sec) _______20 Sync
       SPINDLE SPEED (RPM) ______________________7,200
       AVERAGE LATENCY (mSEC) ___________________4.17
       BUFFER __W/WD_____________________________1024/512 KByte
         Read Look-Ahead, Adaptive,
         Multi-Segmented Cache
       INTERFACE ________________________________SCSI-2 FAST WIDE
                                                 ASA
       BYTES PER TRACK __________________________50,888 average
       SECTORS PER DRIVE ________________________4,177,781
       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) _______________________17/19
       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
                           IDLE (watts) _________13
       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):     5.97/151.6
                        Weight    (lbs/kg):     2.3/1.04

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. (08/04/94)
