
S T 1 3 8 A - 0    SEAGATE
NO MORE PRODUCED                                      Native|  Translation
                                                      ------+-----+-----+-----
Form                 3.5"/HH               Cylinders     604|  615|     |
Capacity form/unform    32/   38 MB        Heads           4|    6|     |
Seek time   / track  40.0/ 8.0 ms          Sector/track   26|   17|     |
Controller           IDE / AT              Precompensation
Cache/Buffer               KB              Landing Zone
Data transfer rate    0.938 MB/S int       Bytes/Sector      512
                      4.000 MB/S ext
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  3.048| -0.305  9.144
       idle               W     Shock        g        10       |     60
       seek               W     Rotation   RPM      3600
       read/write    11.0 W     Acoustic   dBA        40
       spin-up            W     ECC        Bit
                                MTBF         h     150000
                                Warranty Month
Lift/Lock/Park     YES          Certificates     CSA,FCC,IEC435,TUV,UL478,VDE 

**********************************************************************
                        L   A   Y   O   U   T
**********************************************************************
SEAGATE  ST125A/138A/157A  PRODUCT MANUAL 36045-006, REV.F

  +---------------------------------------------------------+
  |                                  10-pin version  10--+  |
  |                                                   |J2|  |
  |                                   6-pin version   6  |  |
  |                                                   |  |  |XX 40 PIN
  |                                                   +--1  |XX C
  |                                                         |XX O
  |                                                         |XX N
  |                                                         |XX N
  |                                                         |XX E
  |                                                         |XX C
  |                                                         |XX T
  |                                                         |XX O
  |                                                         |XX R
  |                                                         |XX1
  |                                                         |
  |                                                         |XX Power
  |                                                         |XX J3
  +---------------------------------------------------------+  1



**********************************************************************
                      J   U   M   P   E   R   S
**********************************************************************
SEAGATE  ST125A/138A/157A  PRODUCT MANUAL 36045-006, REV.F

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

 J2  Drive configuration 6-pin version
 -------------------------------------
       +-------------------------------------+-------+
       |                                     |2  4  6|
       |                                     +-------+
       |                                     |o  o  o|
       |                                     |*  o  o|
       +-------------------------------------+-------+
       | Single drive                        |X      |
       |                                     |       |
       | Dual-drive master                   |X  X   |
       |                                     |       |
       | Dual-drive slave                    |   X   |
       |                                     |       |
       | (Optional) Drive Activity Indicator |      X|
       +-------------------------------------+-------+

  J2  External LED 6 pin version
  ------------------------------
      pin 5-6  CLOSE  External LED option enabled
               OPEN   External LED option disabled


  J2  Drive configuration 10-pin version
  --------------------------------------
       +-------------------------------------+-------------+
       |                                     |2  4  6  8 10|
       |                                     +-------------+
       |                                     |o  o  o  o  o|
       |                                     |*  o  o  o  o|
       +-------------------------------------+-------------+
       | Single drive                        |   X         |
       |                                     |             |
       | Dual-drive master                   |   X  X      |
       |                                     |             |
       | Dual-drive slave                    |             |
       |                                     |             |
       | (Optional) Drive Activity Indicator |            X|
       |                                     |             |
       | Reserved position                   |X        X   |
       +-------------------------------------+-------------+
           1-2 and 7-8 reserved positions. Do not use !!!


  J2  Master/Slave configuration
  ------------------------------
     Configure up to drives on a single AT bus (table below).

     Drive Type            | Master    |Slave Present
     ----------------------+-----------+-------------
     Only drive in system  | Installed |Removed
     ----------------------+-----------+-------------
     Drive 1 in a two drive| Installed |Installed
     system                |           |
     ----------------------+-----------+-------------
     Drive 2 in a two drive| Removed   |Removed
     system                |           |

     Up to two drives can be daisy-chained (Master/Slave) on the same
     host bus.


 J2  External LED 10 pin version
 -------------------------------
     pin 9-10  CLOSE  External LED option enabled
               OPEN   External LED option disabled

 Remote LED: When pins 9 and 10 on the User Configuration jumper block
 are shorted drive will indicate activity to the system via a connec-
 tor on the host adapter or motherboard.



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



**********************************************************************
                      I   N   S   T   A   L   L
**********************************************************************
SEAGATE  ST125A/138A/157A  PRODUCT MANUAL 36110-001/2, REV.C

 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 position, 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.


 AT Interface Connector Requirements
 -----------------------------------
 The drive connector is a 40-conductor connector with 2-rows of 20
 male pins on 100 mil centers.
 The mating cable connector is a 40-conductor nonshielded connector
 with 2-rows of 20 female contacts on 100 mil centers.


 Translation/Native Mode Selection
 ---------------------------------
 The drive(s) will always power-up in their respective default
 Translation modes.


 Virtual Emulation
 -----------------
 The drive will support any 17-sector-based disc geometry as long as
 the number of logical heads is   16, the number of logical cylinders
 is   1,024 and the resulting number of sectors does not exceed the
 drive's total guaranteed sector count.


 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
 20  resistive load on the +12 V line and an equivalent 8  load on the
 +5 V line.


 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.


 Shipping Zone
 -------------
 When the read/write heads are positioned in the shipping zone, all
 portions of the head/slider assembly park inboard of the maximum data
 cylinder.

 The read/write heads automatically move to the shipping zone at
 power-down.

 The read/write heads may be parked by issuing a seek command to any
 cylinder between 614 and 666.

 When power is applied, the heads will recalibrate to Track 0. If the
 heads are parked while power is applied, any step pulse will cause
 the unit to 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 drive is required.
 Seagate Technology, Inc. has tested these devices in an enclosure as
 described above to ensure that the total assembly (enclosure, disk
 drive, motherboard, power supply, etc.) does comply with the limits
 for a Class B computing device. Operation with non-certified assem-
 blies is likely to result in interference to radio and television
 reception.


 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%


 Handling and Static-Discharge Precautions
 -----------------------------------------
 After unpacking, and prior to system integration, the drive may be
 exposed to potential handling and ESD hazards. It is mandatory that
 you observe standard static-discharge precautions. A grounded wrist-
 strap is preferred. Handle the drive by the frame only and always
 rest the drive on a padded surface until it is mounted in the host
 system.


 Shipping
 --------
 When transporting or shipping a drive, a Seagate-approved container
 MUST BE USED. SHIPPING A DRIVE IN A NON-APPROVED CONTAINER WILL VOID
 THE DRIVE WARRANTY!


 Supported System BIOS revisions
 -------------------------------
 The system will report the BIOS type and version number on a cold
 boot. The ST125A, ST138A and ST157A are AT interface compatible
 drives. The BIOS manufacturers listed below have indicated that the
 referenced BIOS revisions are fully compatible with the IBM AT Task
 File Interface specifications.

 Earlier BIOS revisions may provide only partial AT support. Compati-
 bility problems may include repeated drive access errors or system
 timeout errors.

     +-------------+-----------------------------------+
     | AMI         | Dated 4/9/90 or later             |
     +-------------+-----------------------------------+
     | Award       | Version 3.04 or higher            |
     +-------------+-----------------------------------+
     | Quadtel     | Single Drive System: Any Version  |
     |             | Dual Drive System: 3.04 or higher |
     +-------------+-----------------------------------+
     | Phoenix     | BIOS Plus 286: 3.10 or higher     |
     |             | BIOS Plus 386: 1.10 or higher     |
     +-------------+-----------------------------------+
     | PhoenixBIOS | Version 1.00 or higher            |
     +-------------+-----------------------------------+


 CMOS Configuration
 ------------------
 Seagate AT interface drives mimic (translate) other drive geometries.
 If none of the drive types offered by the CMOS supports the numbers
 of heads, cylinders and sectors shown by the table, and your system
 does not support a "user defined" drive type, then select a drive
 type in your systems CMOS with a capacity which is less than or equal
 to the capacity of the drive.

 When specifying drive geometry to the system CMOS, different values
 may be used for the cylinders, read/write heads and sectors/track
 than those given below. However, the final drive capacity shown by
 the CMOS cannot exceed the capacity of the drive.

 After the drive has been properly configured for the system, and the
 correct drive type has been specified to the system CMOS, the drive
 should be low-level formatted.


 Low Level Formatting
 --------------------
 Seagate AT Interface drives are low-level formatted at the factory
 and do not require low-level formatting!


 Partitioning
 ------------
 A drive can be subdivided into "partitions", which behave as indivi-
 dual drives within the system. Earlier versions of DOS have a limi-
 tation on maximum drive capacity and consequently require high capa-
 city drives to be divided into smaller partitions. For DOS users,
 each partition will be assigned a different letter, i.e., C: and D:
 for a drive with two partitions.

 Drive partitioning in DOS is done by using the FDISK utility. After
 the drive has been configured, defined in CMOS and low-level format-
 ted (if necessary), the user must boot the system to the floppy drive
 with a bootable DOS diskette. The user must then run the FDSIK util-
 ity to partition the drive. Refer to your DOS manual for instruction
 on using FDISK.

 Many UNIX based operating systems allow partitioning of the drive for
 use by DOS applications. In UNIX, drive formatting and partitioning
 are both done by a single operating system utility. Refer to your
 system documentation for instructions.


 High level formatting
 ---------------------
 High-level formatting verifies the information written by the low-
 level format and establishes drive access information used by the
 operating system.
 High-level formatting in DOS creates the File Allocation Table used
 by DOS for all drive access. The high-level format is initiated in
 DOS by the FORMAT command.
 High-level formatting in UNIX creates the I-NODE used by the system
 for file access information. In UNIX, drive formatting and partitio-
 ning are both done by a single operating system utility.



**********************************************************************
                      F   E   A   T   U   R   E  S
**********************************************************************
SEAGATE  ST125A/138A/157A  PRODUCT MANUAL 36045-006, REV.F

 Media Defects
 -------------
 A media defect is a read error when the data, which has been
 correctly written, cannot be recovered within 16 retries.
 A label is fixed to the drive listing the location of any media
 defects by cylinder, head and bytes from index. For MFM encoding,
 this is based on 1.6  sec./byte. AT interfaces drives have the
 controller onboard. This allows bad sectors to mapped out; thereby
 transparent to the user. Seagate specifies gurabteed megabytes for
 ST157 family AT interface drives.

 AT Interface
 ------------
 This drive family uses the industry-standard IBM AT task file
 interface. It support both 8 and 16-bit data transfer and has no DMA
 capability.
 All data transfers are done via programmed I/O.

 AT Interface Connecter Pin Assignments
 --------------------------------------
      pin     signal        I/O  | pin     signal        I/O
      ---------------------------+--------------------------
      01      /Host Reset    O   | 21      Reserved      O
      02      Ground             | 22      Ground
      03      Host Data  7   I/O | 23      /HIOW         O
      04      Host Data  8   I/O | 24      Ground
      05      Host Data  6   I/O | 25      /HIOR         O
      06      Host Data  9   I/O | 26      Ground
      07      Host Data  5   I/O | 27      Reserved
      08      Host Data 10   I/O | 28      Host ALE      O
      09      Host Data  4   I/O | 29      Reserved
      10      Host Data 11   I/O | 30      Ground
      11      Host Data  3   I/O | 31      IRQ14         I
      12      Host Data 12   I/O | 32      Host IO16     I
      13      Host Data  2   I/O | 33      Host ADDR 1   O
      14      Host Data 13   I/O | 34      /PDIAG         Notes
      15      Host Data  1   I/O | 35      Host ADDR 0   O
      16      Host Data 14   I/O | 36      Host ADDR 2   O
      17      Host Data  0   I/O | 37      /Host CSO     O
      18      Host Data 15   I/O | 38      /Host CS1     O
      19      Ground             | 39      /Host SLV/ACT Notes
      20      Key                | 40      Ground

 Notes:
       * /Indicates active low signal
       * Direction is with respect to the host
       * I indicates to the host, O indicates from the host
       * Reserved pins/ground do not have direction
       * /PDIAG and HOST/SLAVE are used for communication between
         Master and Slave drive
       * Pin-1 is referenced in LAYOUT. It may also be located by the
         square solder pad on the PC board.

 AT Bus Signal Levels
 --------------------
 Signal driven by the drive must have the following output character-
 istics at the drive connector:
                                Logic Low:      0 to 0.4  VDC
                                Logic High:   2.5 to 5.25 VDC


 Signal received by the drive must have the following input character-
 istics, measured at the drive connector:
                                Logic Low:      0 to 0.8  VDC
                                Logic High:   2.0 to 5.25 VDC


 Seek Time Definition and Timing
 -------------------------------
 Seek time is a true statistical average (at least 5,000 measure-
 ments) of the time to execute the seek, less overhead.
 All measurements assume a block size of 512 bytes, nominal voltages,
 25*C ambient temperature and sea level.
 Track-to-track seek time is the average of all possible single-
 track seeks in both directions. Average seek time is measured by
 executing seek in both directions between random cylinders or Logi-
 cal Block Addresses (LBA). Full-stroke seek time is one-half the
 time needed to seek from LBA zero to the maximum LBA and back to LBA
 zero.

                                          | ST1**A |
        ----------------------------------+--------+
        Track-to-Track         msec. typ. |   8    |
                               msec. max  |  10    |
                       Average msec. typ. |  28    |
                       Average msec. max. |  30    |
        Full-Stroke            msec. typ. |  70    |
                               msec. max. |  75    |
        Latency                msec. avg. |   8.33 |
        ----------------------------------+--------+


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


 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.


