SEAGATE TECHNOLOGY, INC.
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                            (C)opyright 1993



ST-12550N SCSI-2 Fast (Barracuda 2)

 ╔═══════════╗               J01─────┐  1─┐ ───────J4-1──────────────┐
 ║ REAR VIEW ║              (see    1│┐ │"│                          │
 ╚═══════════╝               below) └─┘ │"│                          │
                                        │"│J4 1-11                   │
 Terminating Resistors─┐                │"│(see detail below)        │
         ┌──────┐ ┌────│─┐              │"│                          │
(TOP)    └──────1 └──────1              └"┘─J4-11┐                   │
      ╒═════════════════════════╤/═════════\     │                   │
     ═╡::::::::::::::::::::::::1╞│ 0 0 0 0 ╞═    │                   │
      ╘══════════════════════│══╧└─5─G─G─12┘     │               5   1
 50 pin I/O Cable Connection─┘                   : : : : : : : : : : :
                                                 │ │ │ │ │ │ │ │ 6 │ 2
                              SCSI ID = 0 (none) │ │ │ │ │ │ │ │ │ │ │
                              SCSI ID = 4 ───────┘ │ │ │ │ │ │ │ │ │ │
                              SCSI ID = 2 ─────────┘ │ │ │ │ │ │ │ │ │
                              SCSI ID = 1 ───────────┘ │ │ │ │ │ │ │ │
                        Reserved (default OFF) ────────┘ │ │ │ │ │ │ │
                        Parity Disable ──────────────────┘ │ │ │ │ │ │
                        Enable Motor Start ────────────────┘ │ │ │ │ │
                        Delay Motor Start (10 sec * ID) ─────┘ │ │ │ │
                        Write Protect Enable ──────────────────┘ │ │ │
                        Remote LED Connector ────────────────────┘ │ │
                         [pin-5 cathode (neg), pin-6 anode (pos)]  │ │
                        Reserved (default OFF) ────────────────────┘ │
                        Spindle Synch Cable Connector ───────────────┘
                          (pin-1 SSREF, pin-2 ground)

┌────────────────────────────────┐
│ J01 - Terminator Power Jumpers ├──────────────────┐
└────────────────────────────────┘                  │
            Terminator power from the drive.       ╓1─2╖
              (default)                            ╙°─°╜
                                                    ° °
            Terminator power from pin 26 on the      ╓─╖
              SCSI bus.                             °║°║
                                                    °╙°╜

            Terminator to the SCSI bus on pin 26.   ╓─╖
                                                    ║°║°
                                                    ╙°╜°

            Terminator power to the SCSI bus and    ╓─╥─╖
              drive.                                ║°║°║
                                                    ╙°╜°╨
    Note: ST-12550ND (differential model) does not come with any
          provision to use Termination resistors.  Therefore, SCSI bus
          needs to be externally terminated.


                            ST-12550N


       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) _______4 Async
       EXTERNAL TRANSFER RATE (mbyte/sec) _______10 Sync
       SPINDLE SPEED (RPM) ______________________7,200
       AVERAGE LATENCY (mSEC) ___________________4.17
       BUFFER ___________________________________1024 KByte
         Read Look-Ahead, Adaptive,
         Multi-Segmented Cache
       INTERFACE ________________________________SCSI-2 FAST
                                                 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. (08/08/94)