
S T 1 3 8 N - 1    SEAGATE
NO MORE PRODUCED                                      Native|  Translation
                                                      ------+-----+-----+-----
Form                 3.5"/HH               Cylinders     615|     |     |
Capacity form/unform    32/   38 MB        Heads           4|     |     |
Seek time   / track  28.0/ 8.0 ms          Sector/track   26|     |     |
Controller           SCSI1 SINGLE-ENDED    Precompensation
Cache/Buffer               KB              Landing Zone
Data transfer rate    0.938 MB/S int       Bytes/Sector      512
                      1.500 MB/S ext ASYNC
Recording method     RLL 2/7                        operating  | non-operating
                                                  -------------+--------------
Supply voltage     5/12 V       Temperature *C        10 50    |    -40 60
Power: sleep              W     Humidity     %         8 80    |      5 90
       standby            W     Altitude    km    -0.305  3.050| -0.305  9.140
       idle               W     Shock        g        10       |     60
       seek               W     Rotation   RPM      3600
       read/write     9.0 W     Acoustic   dBA        40
       spin-up            W     ECC        Bit   32
                                MTBF         h     150000
                                Warranty Month
Lift/Lock/Park     YES          Certificates     CSA,FCC,IEC435,TUV,UL478,VDE 

**********************************************************************
                        L   A   Y   O   U   T
**********************************************************************
SEAGATE  ST125N/ST138N/ST157N  PRODUCT MANUAL 36045-006, REV.F

  +------------------------------------------------------++-+4
  |                                                      || |2
  |                                                      || |1
  |                                                      || |NC
  |                                                 +-+  |+-+P
  |                                                 | |  |XX SCSI
  |                                                1+-+  |XX Interface
  |                                      Resistor   +-+  |XX Connector
  |                                      Terminator | |  |XX J1
  |                                      Packs     1+-+  |XX
  |                                                 +-+  |XX
  |                                                 | |  |XX
  |                                                1+-+  |X1
  |                                                      |
  |                                                      |XX Power
  |                                                      |XX J3
  +------------------------------------------------------+




**********************************************************************
                      J   U   M   P   E   R   S
**********************************************************************
SEAGATE  ST125N/ST138N/ST157N  PRODUCT MANUAL  36045-002, REV.D

 Jumper setting
 --------------

 J2   SCSI Bus Adress and Parity Check
 -------------------------------------
 Select the desired SCSI ID with Jumpers. Install the optional
 P-Jumper to enable Parity.

      +-------+---------------+
      |SCSI ID| P NC  4  2  1 | Each drive must have a distinct
      +-------+---------------+ adress (SCSI ID) on the bus. SCSI ID 7
      |   0   | o  o  o  o  o | is usually reserved for the SCSI host
      |   1   | o  o  o  o  x | adapter.
      |   2   | o  o  o  x  o |
      |   3   | o  o  o  x  x | The microprocessor only reads the
      |   4   | o  o  x  o  o | SCSI ID during the startup sequence.
      |   5   | o  o  x  o  x | If the adress is changed while system
      |   6   | o  o  x  x  o | power is on, the drive power must be
      |   7   | o  o  x  x  x | removed and then reapplied for the
      +-------+---------------+ changes to take effect.
                |  |
                |  +---- Not used
                |
                +------- Parity Bit Option
                         Some host systems require parity bit checking
                         Install the P-Jumper to enable Parity


 50-Pin SCSI Connector Pin Assignments
 -------------------------------------
    Signal    Pin No.    Signal     Pin No.
    ----------------------------------------
    -DB(0)       2       Ground       28
    -DB(1)       4       Ground       30
    -DB(2)       6       -ATN         32
    -DB(3)       8       Ground       34
    -DB(4)      10       -BSY         36
    -DB(5)      12       -ACK         38
    -DB(6)      14       -RST         40
    -DB(7)      16       -MSG         42
    -DB(P)      18       -SEL         44
    Ground      20       -C/D         46
    Ground      22       -REQ         48
    Ground      24       -I/O         50
    Terminator  26
    Power

  Note: All odd pins, except pin-25 are connected to ground. Pin-25
        is not connected.


 J3   DC Power and pin connector assignments
 -------------------------------------------
      +------------+     1 = + 12 VDC
      | 1  2  3  4 |     2 = + 12 Volts return
      +------------+     3 = +  5 Volts return
                         4 = +  5 VDC



**********************************************************************
                      I   N   S   T   A   L   L
**********************************************************************
SEAGATE  ST125N/ST138N/ST157N  PRODUCT MANUAL  36045-006, REV.F

 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!
      Never install PC board on the Top!

 The drive may be mounted horizontally with the PC board down or on
 either side. Mounting vertically on either end is a prohibited orien-
 tation. The drive should not be tilted front or back, in any posi-
 tion, by more than 5*.

 For optimum performance, the drive should be formatted in the same
 position as it will be mounted in the host system.


 Shock and vibrations
 --------------------
 All shock and vibration specifications assume that the drive is moun-
 ted in an approved orientation with the input levels at the drive
 mounting screws.


 Read/Write Head Auto-Park
 -------------------------
 Upon power-down, the read/write heads automatically move to the ship-
 ping zone. All portions of the Head/slider assembly park inboard of
 the maximum data cylinder.

 When power is applied, the heads will recalibrate to Track 0.


 FCC Verification
 ----------------
 These drives are devices which are intended to be contained solely
 within a personal computer or similar enclosure and not attached to
 an external device. As such, they are considered to be subassemblies
 even when individually marketed to the customer. As a subassembly, no
 Federal Communications Commission authorization, verification or
 certification of the device is required.


 Disc format
 -----------
 The drives disc format is flexible and supports either 256, 512 or
 1024 bytes/sector.
                        ST125N     |     ST138N     |     ST157N
 ----------------------------------+----------------+----------------
 Bytes per Sector:  256  512 1.024 | 256  512 1.024 | 256  512  1.024
 Sectors per Track:  44   26    13 |  44   26    13 |  44   26     13
 Cylinders:              407       |      615       |      615
 Read/Write heads:         4       |        4       |        6
 Capacity (MByte):   18   21    21 |  27   32    32 |  41   49     48


 Record interleave
 -----------------
 User-specific record interleaves are supported from 1:1 (sectors
 occur sequentially on the disk) through the number of sectors per
 track minus 1. This gives the user the ability to configure the drive
 for maximum performance within the individual host operating environ-
 ment.


 Formatting and defect management
 --------------------------------
 Media defects are identified and recorded on the disc during the ma-
 nufacturing process. This defect map is used during formatting and
 enables the drive to bypass these defects. During the formatting
 operation, the controller uses the sector-slip technique to reassign
 defect sectors.


 SCSI Interface
 --------------
 The embedded controller supports the SCSI interface as defined in the
 ANSI X3T9.2/82-2 document. The interface hardware is capable of
 transferring up to 12 Mbits/sec. using asynchronous data transfer.
 Devices on the SCSI Interface are daisy-chained together using a
 common cable. Both ends of the cable are terminated. All signals on
 the interface are common between devices.


 Termination resistor packs
 --------------------------
 The termination resistor packs must be present on devices at both
 ends of the SCSI bus. All other devices should have the termination
 resistors removed.
 Termination resistors prevent signal reflections from the ends of the
 SCSI bus, and assure proper bus timing.


 DC Power specifications
 -----------------------
 Power may be applied or removed in any sequence without loss of data
 or damage to the drive, except during a write operation. Typical
 current and power specifications assume nominal voltages applied,
 25*C ambient temperature, sea level and spindle rotating.
 Voltage tolerance (incl. ripple):  5%


 Input Noise
 -----------
 Maximum permitted input noise ripple: 100 mV (peak-to-peak)
 Maximum permitted input noise: 20 MHz.
 Ripple measured at the host system power supply across an equivalent
 8  resistive load on the +12 V line and an equivalent 3  load on the
 +5 V line.


 Cable specification
 -------------------
 A 50-conductor flat cable or 25-conductor twisted pair cable is
 required. The maximum cable length is 6 meters (19.7 ft). Each SCSI
 bus connection may have a 0.1 meter (0.33 ft) maximum stub length.

 The characteristic impedance for unshielded flat or twisted pair
 ribbon cable should be 100    10%. A characteristic impedance greater
 than 90  is preferred for shielded cables.
 To minimize discontinuities and signal reflections it is desirable
 to minimize the use of cables of different impedances in the same
 bus.


 Startup Drive Diagnostics
 -------------------------
 At power-on the drive will execute a series of diagnostic tests. Any
 failure will be indicated by a series of LED (front panel) flashes.
 The first failure will be preserved. The drive is ready to read/write
 if no error codes are received within 22 seconds.

 +-------+---------------------------------------------------------+
 |Flashes|Failures codes                                           |
 +-------+---------------------------------------------------------+
 |   1   |Microprocessor/Internal Memory Test                      |
 +-------+---------------------------------------------------------+
 |   2   |Microprocessor ROM Checksum Test                         |
 +-------+---------------------------------------------------------+
 |   3   |Controller Chip Test                                     |
 +-------+---------------------------------------------------------+
 |   4   |Controller Program RAM Test                              |
 +-------+---------------------------------------------------------+
 |   5   |Data Buffer RAM Test                                     |
 +-------+---------------------------------------------------------+
 |   6   |Spindle Speed Test                                       |
 |       | If the drive is unable to reach and maintaine correct   |
 |       | spindle speed                                           |
 +-------+---------------------------------------------------------+
 |   8   |Read Operating System Microcode From Drive               |
 |       | If the controller is unable to read the operating system|
 |       | from the drive                                          |
 +-------+---------------------------------------------------------+
 |   9   |Read Operating System Microcode From Drive               |
 |       | If the controller reads the operating system records,   |
 |       | but dertermines that they are invalid.                  |
 +-------+---------------------------------------------------------+

 Offline Self-test Routines
 --------------------------
 This product family supports a self-test routine that Seagate recom-
 mends for incoming inspection. This test may be run after the unit
 has successfully passed the power-on diagnostics.

 To enable the test, short the following pins to ground at the SCSI
 connector: 2, 12, 16 and 32.

 The self test has three parts. They will cycle in order until power
 or a ground jumper is removed, or until ten complete passes.

 The LED will remain ON during the test and will turn OFF if an error
 is detected or a jumper is removed. The LED will flash continuously
 if 10 passes are completed without error.


 SCSI Interface Drive Geometry
 -----------------------------
 The SCSI interface handles both drive geometry and defect management
 internally. In AT systems a drive type of zero, or the "no drive in-
 stalled" option is selected for systems with SCSI drvies.


 Set the SCSI Address
 --------------------
 If you are installing one drive, the suggested ID is 0 (no jumper in-
 stalled). A second physical drive may be set at any ID (typically
 Address number 1). These SCSI ID numbers cannot conflict with any
 other devices on the SCSI bus. Each device must have a discrete SCSI
 ID. SCSI ID address 7 is typically used by the SCSI Host Adapter.


 Drive Termination Resistor Packs
 --------------------------------
 If you are installing one drive, leave the resistor packs installed.
 If you are installing multiple drives, remove the resistor packs from
 all drives except the last drive connected to the end of the cable.


 Drive formatting
 ----------------
 All Seagate SCSI interfaces drives are low-level formatted at the
 factory. You may wish to low-level format the drive to optimize its
 performance for your system. Consult the controller documentation for
 information on low-level formatting.

 Partitioning and high-level formatting can be done through DOS.



**********************************************************************
                      F   E   A   T   U   R   E  S
**********************************************************************
SEAGATE  ST125N/ST138N/ST157N  PRODUCT MANUAL 36045-006, REV.F

 Formating and Defect Management
 -------------------------------
 Because Seagate SCSI interface drives have the controller onboard,
 bad sectors are mapped out and become transparent to the user; this
 allows Seagate to specify "guaranteed megabytes" for SCSI drives and
 eliminates the requirement for a media defect specification.


 Error Recovery
 --------------
 The controller provides error recovery routines which are necessary
 to assure data integrity. These techniques include ECC, seek-retry,
 read-retry, head-offset and defect management. To assure a high de-
 gree of data reliability, the controller utilizesa 32-bit error
 checking and correction polynominal.


 SCSI bus drivers/receivers
 --------------------------
 The drives use open collector drivers. All signals are terminated
 with 220  to +5 VDC (nominal) and 330  to ground. For these
 measurements, SCSI bus termination is assumed to be external to the
 drive. A typical drive is supplied with the resistor termination
 packs installed.

   Signals driven by the drive have the following output
   characteristics, when measured at the drive connector:

   Signal true:               0.0 VDC to 0.4 VDC
   Maximum total input load:  48 mAmps (sinking) @ 0.5 VDC
   Signal false:              2.5 VDC to 5.25 VDC


   Signals received by the drive have the following input
   characteristics, when measured at the drive connector:

   Signal true:               0.0 VDC to 0.8 VDC
   Maximum total input load:  -0.4 mAmps (sinking) @ 0.4 VDC
   Signal false:              0.2 VDC


 DC Power Specifications
 -----------------------
 Power may be applied or removed in any sequence without loss of data
 or damage to the drive.


 Recording Method
 ----------------
 The drives are designed to operate with the SCSI interface
 with Run Length Limited (2,7) encoding at 7.5 Mbits/sec. data
 transfer rate.


 Bit Jitter
 ----------
 Bit jitter reduction determines the relationship between the leading
 edge 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 -40dB of
 bit jitter reduction at 2F with an offset of less than 1.5 nsec.
 shift from the center of the data window.


 UL/CSA Listing
 --------------
 The ST157 drive family is listed in accordance with UL 478 and CSA
 C22.2 (0-M1982), and meets all applicable sections if IEC 380 and
 VDE 0806/08.81, as tested by TUV-Rheinland, North America.



**********************************************************************
                      G   E   N   E   R   A   L
**********************************************************************
SEAGATE   SUPPORT SERVICES

 Seagate Technology
 ------------------
 Technical Support Services
 If you need assistance installing your drive, consult your dealer.
 Dealers are familiar with their unique system configurations and can
 help you with system conflicts and other technical issues. If you
 need additional assistance with your Seagate(r) drive or other
 Seagate products, use one of the Seagate technical support services
 listed below.

 SeaFONE at 1-800-SEAGATE (1-800-732-4283)
 Seagate's 800 number allows toll-free access to automated self-help
 services, providing answers to commonly asked questions,
 troubleshooting tips and specifications for disc drives and tape
 drives. This service is available 24 hours daily and requires a
 touch-tone phone. If you need to speak to a technical support
 engineer, dial this number and listen to the options for technical
 support. (International callers can also reach this automated
 self-help service by dialing 408-456-4496).


 Seagate Technology online services
 Using a modem, you can obtain troubleshooting tips, free utility
 programs, drive specifications and jumper settings for Seagate's
 entire product line. You can also download software for installing
 and analyzing your drive.

 SeaNET
 You can obtain technical information on Seagate drives, Seagate
 software and much more over the Internet from Seagate's World Wide
 Web home page (http://www.seagate.com) or Seagate's ftp server
 (ftp://ftp.seagate.com).

 You may also send E-mail with your questions to DiscSupport@
 Seagate.com or TapeSupport@Seagate.com.


 SeaBOARD
 SeaBOARD is a computer bulletin board system (BBS) that contains
 information about Seagate's disc and tape drive products and is
 available 24 hours daily. Set your communications software to eight
 data bits, no parity and one stop bit (8-N-1). SeaBOARD phone numbers
 are listed in the following table.

 BBS Location           Modem number
 United States      Disc: 408-434-1080; Tape: 408-456-4415
 England            44-1628-478011
 France                         33 1-48 25 35 95
 Germany            49-89-140-9331
 Singapore          65-292-6973
 Thailand           662-531-8111
 Australia          61-2-9756-2359
 Taiwan             886-2-719-6075

 Seagate CompuServe forum
 Online technical support for Seagate products is available on
 CompuServe. To access our technical support forum, type go seagate.
 This forum provides information similar to that found on SeaBOARD.
 In addition, you can type questions or browse through previous
 questions and answers on the forum messages.

 Seagate Technology FAX services
 SeaFAX
 You can use a touch-tone telephone to access Seagate's automated FAX
 system to receive technical support information by return FAX. This
 service is available 24 hours daily.
 Location               Telephone number
 United States          1-800-SEAGATE or 408-456-4496
 England                44-1628-894084
 Australia              61-2-9756-5170

 Seagate technical support FAX
 You can FAX questions or comments to technical support specialists 24
 hours daily. Responses are sent during business hours.
 Location               FAX number
 United States          408-944-9120
 England                        44-1628-890660
 France                 33 1-46 04 42 50
 Germany                        49-89-1430-5100
 Australia              61-2-9725-4052
 Singapore              65-293-4722
 Hong Kong              852-2368 7173
 Taiwan                 886-2-715-2923
 Korea                          82-2-556-7294/4251


 Seagate technical support
 You can talk to a technical support specialist during business hours
 Monday through Friday for one-on-one technical help.  Before calling,
 note your system configuration and drive model number (STxxxx). There
 are several technical support phone numbers available for various
 Seagate products.

 Location          Telephone  number
 United States Please dial 1-800-SEAGATE for the specific product
               telephone number.
               (6:00 A.M. to 11:15 A.M., 12:30 P.M. to 5:00 P.M.,
               Pacific time, M-F)
 England       44-1628-894083 (10:00 A.M. to 1:00 P.M., 2:00 P.M. to
               5:00 P.M., M-F)
 France        33 1-41 86 10 86 (9:30 A.M. to 12:30 P.M., 2:00
               P.M. to 5:00 P.M., M-F)
 Germany       Disc: 49-89-140-9332; (9:30 A.M. to 12:30 P.M., 2:00
               P.M. to 4:00 P.M., M-F)
               Tape: 49-89-140-9333
 Australia     61-2-9725-3366 (9:00 A.M. to 5:00 P.M., M-F)
 Singapore     65-290-3998 (9:00 A.M. to 12:00 P.M., 2:00
               P.M. to 5:00 P.M., M-F)
 Hong Kong     852-2368 9918
 Taiwan        886-2-514-2237
 Korea         82-2-556-8241


 SeaTDD 408-944-9121
 Using a telecommunications device for the deaf (TDD), you can send
 questions or comments 24 hours daily and exchange messages with a
 technical support specialist between 6:00 A.M. to 11:15 A.M. and
 12:30 P.M. to 5:00 P.M. (Pacific time) Monday through Friday.


 Customer Service Centers
 Seagate direct OEM, Distribution, System Integrator and Retail
 customers should contact your Seagate Service Representative for
 warranty information.  Other customers contact your place of
 purchase.  Seagate offers comprehensive customer support for all
 Seagate drives.  Seagate customer service centers are the only
 facilities authorized to service Seagate drives. These services are
 available worldwide.

 Location                       Telephone number                FAX number
 United States          1-800-468-3472;                 405-949-6740
 Other Americas
 (Canada & Brazil)      405-949-6706;               405-949-6738
 Mexico                         525-546-6965;                   525-546-4888
 Europe, Middle
 East & Africa          31-2065-43300;              31-2065-34320
 Asia Pacific &
 Australia              65-485-3595;                    65-485-4980
 Japan                          81-3-5462-2904;                 81-3-3462-2979


 Seagate, Seagate Technology and the Seagate logo are registered
 trademarks of Seagate Technology, Inc. SeaFAX, SeaFONE, SeaBOARD,
 SeaTDD, SeaNET, Medalist and DiscWizard are either trademarks or
 registered trademarks of Seagate Technology, Inc. or one of its
 subsidiaries. All other trademarks or registered trademarks are the
 property of their respective owners.


