S T 4 0 5 1   ( 1 9 8 7 )    SEAGATE
NO MORE PRODUCED                                      Native|  Translation
                                                      ------+-----+-----+-----
Form                 5.25"/FH              Cylinders     977|     |     |
Capacity form/unform    42/   50 MB        Heads           5|     |     |
Seek time   / track  40.0/ 8.0 ms          Sector/track   17|     |     |
Controller           MFM / ST412           Precompensation 65535
Cache/Buffer               KB              Landing Zone
Data transfer rate    0.625 MB/S int       Bytes/Sector      512
                      0.625 MB/S ext
Recording method     MFM                            operating  | non-operating
                                                  -------------+--------------
Supply voltage     5/12 V       Temperature *C        10 45    |    -40 60
Power: sleep              W     Humidity     %         8 80    |      5 90
       standby            W     Altitude    km    -0.305  3.048| -0.305  9.144
       idle          25.5 W     Shock        g         6       |     25
       seek          37.5 W     Rotation   RPM      3600
       read/write         W     Acoustic   dBA
       spin-up            W     ECC        Bit
                                MTBF         h      12000
                                Warranty Month
Lift/Lock/Park     YES          Certificates     CSA,FCC,IEC380,TUV,UL478,VDE 

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                        L   A   Y   O   U   T
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SEAGATE  ST4038/4051  PRODUCT MANUAL 36038-001, REV. A, 2/5/87

  +---------------------------------------------------------+
  |                                                         |XX
  |                                *JP1                     |XX J2
  |                                                         |XX
  |                                                         |XX
  |                                                         1-+ J10
  |                                                         | |xx/
  |                                                         |J9 Frame
  |                                                         +-+
  |                                                         |XX
  |                                                         |XX J1
  |                                      JP2++  +---------+ |XX
  |                                         1+  +---------1 |XX
  |                                             Terminator  |XX
  |                                                         |XX
  |                                                         |  1
  |                                                         |XX J3
  |                                                         |XX Power
  +---------------------------------------------------------+  1



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                      J   U   M   P   E   R   S
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SEAGATE  ST4026/4038/4051  PRODUCT MANUAL 36038-001, REV. A, 2/5/87

 Jumper Setting
 ==============

 The ST4038/4051 may be configured for specific system requirements.

 Drive Configuration Shunt: J9
 -----------------------------
 J9 is a right-angle shunt located midway between the J1 and J2
 connectors. The ST4026 has an eight-pin shunt. The ST4038/4051 have
 a sixteen-pin shunt. Use the provided shorting block(s) to enable the
 Drive Select line and any options.


 Drive Select
 ------------
 The Drive Select line enables the controller to select and address
 the drive. Control cable interface options may use either a Daisy-
 Chain or Radial configuration.

 Pins 1-2 shorted enables DRIVE SELECT 1
 Pins 3-4 shorted enables DRIVE SELECT 2
 Pins 5-6 shorted enables DRIVE SELECT 3
 Pins 7-8 shorted enables DRIVE SELECT 4


      ST4026 J9                 ST4038/4051 J9
      ---------                 --------------

      +-------- DS4                 +-------- DS4
      | +------ DS3                 | +------ DS3
      | | +---- DS2                 | | +---- DS2
      | | | +-- DS1                 | | | +-- DS1
     +-+-+-+1+            15-+-+-+-+-+-+-+-+
     +-+-+-+-+             +-+-+-+-+-+-+-+-+
     +8+-+-+-+             +-+-+-+-+-+-+-+-2
                            | | | +---------- NOT CONNECTED
                            | | +------------ WRITE FAULT
                            | +-------------- RECOVERY MODE
                            +---------------- RADIAL


 Daisy-Chain/Radial Drive Configurations
 ---------------------------------------
 The ST4038/4051 can be configured in either a Daisy-Chain or Radial
 mode. The ST4026 can be configured in a Daisy-Chain mode only.

 In a Daisy-Chain configuration, the last drive in a chain must have
 the resistor termination pack installed.

 The radial option on the ST4038/4051 is enabled by shorting pins 15
 and 16 at J9. The resistor termination packs must remain installed on
 any radially configured drive.


 Write Fault Latch options: JP2 and J9
 -------------------------------------
 The ST4038/4051 allow the user to configure the Write Fault reset to
 specific system requirements. These drives have provisions for pins
 to be installed at JP2 to enable the desired options.

 NOTE
 As shipped, there may be a trace between pins 2 and 3 on JP2. This
 trace must be cut to allow use of the options requiring pins 1 and 2.

 JP2 Unlatched: Write Fault will be cleared when write gate is false.
 A Write Fault will only occur when write gate is True.

 JP2 Latched: This option will maintain Write Fault True after write
 gate goes false and is recommended for controllers that do not edge-
 detect Write Fault.

 The latched operation has two configurations which are provided at
 the J9 shunt, pins 11-12.

 1. No jumper at J9: The Write Fault signal can only be cleared by a
    power-on/off cycle. Use of this option in conjunction with the DC-
    Unsafe option is not recommended.

 2. Pins 11-12 shorted at J9: The Write Fault signal can be cleared by
    de-selecting the drive. When the drive is deselected, and the
    fault condition is corrected, the Write Fault signal will be
    false.


 DC-Unsafe Option: JP1
 ---------------------
 There are provisions on the ST4038/4051 for pins to be installed to
 enable this option. When shorted, a DC-Unsafe condition will cause a
 Write Fault to be sent to the interface.



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                      I   N   S   T   A   L   L
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SEAGATE  ST4026/4038/4051  PRODUCT MANUAL 36038-001, REV. A, 2/5/87

 Notes on installation
 =====================

 Drive mounting
 --------------

     horizontally             vertically
   +-----------------+   +--+             +--+ +------------------+
   |                 |   |  +-----+ +-----+  | |                  | x
   |                 |   |  |     | |     |  | x+----------------+x
 +-+-----------------+-+ |  |     | |     |  | ||x              x||
 +---------------------+ |  |     | |     |  | ||  x          x  ||
                         |  |     | |     |  | ||    x      x    ||
      x           x      |  |     | |     |  | ||      x  x      ||
 +------x------x-------+ |  +-----+ +-----+  | ||       xx       ||
 +-+------x--x-------+-+ +--+             +--+ ||     x    x     ||
   |       xx        |                         ||   x        x   ||
   |     x    x      |                         || x            x ||
   +---x--------x----+                         |x                x|
     x            x                           x++----------------++x
      UNACCEPTABLE!                                UNACCEPTABLE!

 The ST4026/4038/4051 may be mounted horizontally with the Main
 Control PC Board with the J1 and J2 connectors down or on either
 side. Mounting vertically on either end is a prohibited orientation.

 The drive should not b etilted front or back, in any position, by
 more than 5*. For optimum performance the drive should be formatted
 in the same orientation as it will be mounted in the host system.


 Shock Mounting Recommendations
 ------------------------------
 It is recommended that any external shock mounts between the drive
 and the host frame b edesigned so that the composite system has a
 vertical resonant frequency of 25 Hz or lower. A minimum clearance of
 0.050 inches should be allowed around the entire perimeter of the
 drive to allow for cooling airflow and moton during mechanical shock
 or vibration.


 Mounting Holes
 --------------
 4 on bottom, 2 on each side: 6-32 UNC-2B x .31 deep min.



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                      F   E   A   T   U   R   E  S
**********************************************************************
SEAGATE  ST4026/4038/4051  PRODUCT MANUAL 36038-001, REV. A, 2/5/87

 Introduction
 ------------
 This manual supports the ST4026/4038/4051 disk drives. It is a
 consolidation of the ST4026, ST4038 and ST4051 Product Manuals, part
 number 36011-001, 36012-001 and 36013-001, which are now out of
 print.


 Shipping Zone
 -------------
 Upon power-down, the actuator will automatically position the read/
 write heads over the shipping zone and carriage lock will engage. All
 portions of the head/slider assembly will park inboard of the maximum
 data cylinder. When power is applied the lock will automatically
 disengage and the heads will recalibrate to Track 0.


 Seek-Retry
 ----------
 Seek-Retry is an internally generated command implemented by the
 drive to enhance seek performance.

 If the drive detects an off-track condition, or the seek was not
 completed, th edrive will recalibrate the heads to Track 0 and retry
 the seek. All writing is inhibited during retry.

 If the target is still not achieved, or the seek was not completed,
 the drive will set Write Fault true, and Ready and Seek Complete
 false. Write Fault will remain active until the condition that
 caused the fault is corrected and the reset is completed.


 Auto-Truncation
 ---------------
 The drive will enter the auto-truncation mode if the controller
 issues an excessive number of step pulses, which would place the
 read/wrie heads outward beyond Track 0 or inward beyond the maximum
 data cylinder.

 With auto-truncation active, the drive will ignore additional pulses,
 take control of the actuator, and recalibrate the heads to Track 0.

 CAUTION
 If the controller is still issuing Slow-Step pulses after the drive
 issues Seek Complete from auto-truncation mode with Direction In
 false, or step the remaining cylinders with Direction In true.


 Precompensation
 ---------------
 The ST4051 does not require precompensation.

 Precompensation is required for the ST4026/4038 on cylinders 300
 through the maximum data cylinder in order to achieve optimum
 performance. The optimum amount of precompensation is 12 nsec. for
 both early and late bits. The table below indicates the bit patterns
 and the direction to be compensated.
  +---------+-------+----+-----------------+
  |Previous |Sending|Next|Timing           |
  +----+----+-------+----+-----------------+
  | X  |  0 |   1   |  1 |Write Data Late  |
  | X  |  1 |   1   |  0 |Write Data Early |
  | 1  |  0 |   0   |  0 |Write Clock Late |
  | 0  |  0 |   0   |  1 |Write Clock Early|
  +----+----+-------+----+-----------------+
 An X denotes a don't care state


 Bit Jitter
 ----------
 Bit jitter reduction determines the relationship between the leading
 esge of read data and the center of the data window.

 The specified read error rates are based on the following bit jitter
 specifications: the data separator must provide at least -40 dB of
 bit jitter reduction at 2F with an offset error of less than 1.5
 nsec. shift from the center of the data window.


 Media Defects
 -------------
 A media defect is a read error when the data, which has been
 correctly written, cannot be recovered within 16 retries. A printout
 will be provided with each drive shipped listing the locations of any
 defect by head, cylinder, sector and byte. It will also specify the
 number of bytes from index.

 ST4026
 There will be no more than thirty-two (32) defects total per drive.
 Cylinder 0 will be free of defects.

 ST4038
 There will be no more than thirty-six (36) defects total per drive.
 Cylinder 0 will be free of defects.

 ST4051
 There will be no more than forty (40) defects total per drive.
 Cylinder 0 will be free of defects.