W R E N   I I I   9 4 1 6 6 - 1 4 1    IMPRIMIS
NO MORE PRODUCED                                      Native|  Translation
                                                      ------+-----+-----+-----
Form                 5.25"/FH              Cylinders     969|     |     |
Capacity form/unform   125/  141 MB        Heads           7|     |     |
Seek time   / track  16.5/ 4.0 ms          Sector/track   36|     |     |
Controller           ESDI                  Precompensation
Cache/Buffer               KB              Landing Zone
Data transfer rate    1.250 MB/S int       Bytes/Sector      512
                            MB/S ext
Recording method     RLL 2/7                        operating  | non-operating
                                                  -------------+--------------
Supply voltage     5/12 V       Temperature *C        10 50    |    -40 70
Power: sleep              W     Humidity     %         8 80    |      5 95
       standby            W     Altitude    km    -0.305  3.048| -0.305 12.192
       idle               W     Shock        g         2       |     32
       seek          33.0 W     Rotation   RPM      3597
       read/write         W     Acoustic   dBA
       spin-up            W     ECC        Bit   8
                                MTBF         h     100000
                                Warranty Month
Lift/Lock/Park     YES          Certificates     CSA,FCC,IEC380,UL478,VDE     

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                        L   A   Y   O   U   T
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SEAGATE  ST4182E  PRODUCT MANUAL 77738212-G

  REAR
    +------------------------------------------------------------+
    |                                                            |
    |                                                            |
    |Drive                                                       |
    |Select    Terminator                                        |
    | +----+   +--------+      Control Cable            Power  AC|
    +-+----+---+--------+------XXXXXXXXXXXXXXXXXXXX----XXXXXXX--x+
    |                                                            |
    |        Data Cable                                          |
    +--------XXXXXXXXXXXXXXX----Data-Board-----------x------x----+
    |                                              W3        W4  |
    +------------------------------------------------------------+



  FRONT
    +------------------------------------------------------------+
    |                                                            |
    |                                                            |
    |                                        +-------+SW1        |
    |                                        +-------+           |
    +------SERVO-PWA---------------------------------------------+
    |                                                            |
    |                                                            |
    +------------------------------------------------------------+
    |                                                            |
    +------------------------------------------------------------+



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                      J   U   M   P   E   R   S
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SEAGATE  ST4182E  PRODUCT MANUAL 77738212-G

 Jumper setting
 ==============

 x = Jumpers set at factory


 Drive Select Jumper
 -------------------
           +---+---+---+---+---+---+---+
           | x | o | o | o | o | o | o |
           | X | o | o | o | o | o | o |
           +-+-+-+-+-+-+-+-+-+-+-+-+-+-+
             |   |   |   |   |   |   +-  Drive Select 7
             |   |   |   |   |   +-----  Drive Select 6
             |   |   |   |   +---------  Drive Select 5
             |   |   |   +-------------  Drive Select 4
             |   |   +-----------------  Drive Select 3
             |   +---------------------  Drive Select 2
   x         +-------------------------  Drive Select 1

 Note: Unit select zero (no jumper) is invalid


 Drive Select
 ------------
 The following characteristics apply to the DRIVE SELECT lines:

  1.   Logical unit designation for up to 7 drives is performed during
       installation by installing the jumper on the baseboard
       assembly.

  2.   The controller shall not attempt to select the drive until 1
       second after DC power is applied. The READY output will be
       valid (whether asserted or negated) within 1 us after the
       drive is selected.

  3.   The drive will be selected (and the DRIVE SELECTED Signal
       asserted) within 1 us after the DRIVE SELECT lines contain that
       unit's select address. The drive will be deselected (and the
       DRIVE SELECTED signal negated) within 1 us after the DRIVE
       SELECT lines contain another unit's select address.

  4.   The DRIVE SELECT lines must remain asserted for 1 us after a
       write operation.

  5.   When the DRIVE SELECT lines are asserted, a head change will
       occur, requiring a delay before a read or write operation can
       be initiated.


 DC Power Connector
 ------------------

          +---+---+---+---+
          | 1 | 2 | 3 | 4 |
          +--++--++--++--++
             |   |   |   +---------- + 5V
             |   |   +-------------- + 5V Return
             |   +------------------ +12V Return
             +---------------------- +12V



 Signal/Chassis Ground
 ---------------------
 The WREN 3 Disc Drives are manufactured with the signal and chassis
 grounds common. Zero ohm resistors (designated W3 and W4) on the
 Data board allows modification of this relationship at the customer's
 option. The customer can select any of these grounding options by
 removing W3 and/or W4.

   W4         W3        Result
   -----------------------------------------------------------
 x X         X         Grounds common, quick connect terminal tied to
                       common ground

   X         O         Grounds separate, quick connect terminal tied
                       to chassis ground

   O         X         Ground separate, quick connect terminal tied to
                       signal ground

   O         O         Grounds separate, quick connect terminal float-
                       ing

 X = Connected
 O = Not Connected



 SW1  Configuration switch setting
 ---------------------------------
 The WREN 3 is configured by turning on/off the switches in SW1 on the
 Servo PWA. SW1 is located behind the fron panel. These switches will
 be set at the factory to be shipped with SW1-1 OFF, SW1-2 ON, SW1-3
 ON and SW1-4 OFF.

                     +--+--+--+--+OFF
                 SW1 |1 |2 |3 |4 |
                     +--+--+--+--+ON

    Switch Purpose     SW1-1                  Option
    --------------     -----                  ------
 x  Motor Option       OFF                    Motor start on power up
                       ON                     Motor start with command

   When the SW1-1 switch is on, a MOTOR ON command is required from
   the controller to start the spindle motor. When power is applied to
   the drive, the drive will generate an Attention signal and assert
   Standard Status Bits 8 and 9 signifying "Power On Reset Conditions
   Exist" and "Spindle Motor Stopped". The controller must then
   respond with a command to Reset the Interace ATTENTION line and
   also the Start Motor Command in order to start the spindle motor.

   Note: This procedure is required anytime that the "Power On Reset
   Condition Exist" status bit is received by the controller if the
   "Motor Control Implemented" switch is on.


                       SW1-2   SW1-3   SW1-4
    Sector Mode        OFF     OFF     OFF    64 Sectors per track
    Select and         ON      OFF     OFF    35 Sectors per track
 x  default sector     OFF     ON      OFF    36 Sectors per track
    size               ON      ON      OFF    34 Sectors per track
    OR
    Address mark
    mode select        ON      ON      ON     Soft Sector operation

   The WREN 3 supports the use of the soft sector format as described
   in the SEAGATE ESDI Specification, 77738076, Section 6.4.4.

   To implement the optional soft sectored format operation, select
   "Address Mark" mode in the WREN 3 by positioning option switches
   SW1-2, SW1-3 and SW1-4 to the ON position.



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                      I   N   S   T   A   L   L
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SEAGATE  ST4182E  PRODUCT MANUAL 77738212-G

 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!



 Drive Orientation
 -----------------
 Only two drive mounting orientations are permitted: discs in the
 horizontal plane and discs in the vertical plane. The uppermost
 surface must be maintained in a level position or drive performance
 may be adversely affected. Mounting with either end down (front or
 rear) is not permissible. The drive may be not mounted inverted
 (upside down) in the horizontal orientation. It is recommended for
 optimum performance that data written in a given orientation be read
 in that same orientation.


 The WREN 3 is designed, manufactured, and tested with a "Plug-in and
 Play" installation philosophy. This philisophy minimizes the
 requirements for highly trained personnel to integrate the WREN 3
 into an OEM's system, wether in a factory or field environment.


 Cooling
 -------
 Cabinet cooling must be designed by the customer so that the ambient
 temperature immediately surrounding the WREN 3 will not exceed
 temperature conditions. Specific consideration should be given to
 make sure adequate air circulation is present around the circuit
 board at the rear of the drive.


 Interface Cabling Options
 -------------------------

 View A
    +---------------------Host-Controller---------------------+
    |                                                         |
    |Data Control   Data Control  Data Control   Data Control |
    +--+-----+--------+-----+--------+-----+--------+-----+---+
       |     |        |     |        |     |        |     |
       |     |        |     |        |     |        |     |
       |     |        |     |        |     |        |     |
       |     |        |     |        |     |        |     |
    +-++-+--++-+-+ +-++-+--++-+-+ +-++-+--++-+-+ +-++-+--++-+-+
    | |T |  |*T| | | |T |  |*T| | | |T |  |*T| | | |T |  |*T| |
    | +--+  +--+ | | +--+  +--+ | | +--+  +--+ | | +--+  +--+ |
    |    WREN    | |    WREN    | |    WREN    | |    WREN    |
    +------------+ +------------+ +------------+ +------------+

    Each cable control length must not exceed 10 feet (3.00m). Each
    data cable length must not exceed 10 feet (3.00m).


   *T  indicates removable terminator resistor pack.
    WREN data ports are permanently terminated.



 Radial Configuration
 --------------------
 View A shows each drive interfaced to its own control cable, which
 allows interfacing an arbitrary number of drives and a variety of
 system operational techniques. Each drive has its data cable and
 control cable connected to the host controller. The length of each
 individual cable must not exceed 10 feet (3.00 meters).
 Terminator resistors must be installed in the host controller for
 each data cable and for each control cable. For this configuration, a
 terminator resistor pack must be installed in each WREN 3 Disc Drive.
 The orientation of Pin 1 of the terminator resistor does not matter.
 Either way is correct.



 View B
    +--------------Host Controller-------------+
    |                                          |
    |Data Control   Data          Data         |
    +-+------+-------+--------------+----------+
      |      |       |              |
      |      |       |              |
      |      |       |              |
      |      +--**---+-------+------+-------+
    +++-+----+---+ +++-+-----+--+ +++-+----++-++
    ||T |        | ||T |        | ||T |    |*T||
    |+--+        | |+--+        | |+--+    +--+|
    |WREN OR ESDI| |WREN OR ESDI| |WREN OR ESDI|
    +------------+ +------------+ +------------+

    Total control cable length must not exceed 10 feet (3.00m). Each
    data cable length must not exceed 10 feet (3.00m).

   *T  indicates removable terminator resistor pack.
   WREN data ports are permanently terminated.
   ** May be up to seven (7) devices in daisychain.


 Daisychain Configuration
 ------------------------
 A daisychain configuration incorporates a maximum of seven drives in
 parallel on a common control cable. Only the drive selected by the
 host system has its control and data signals enabled through this
 common interface. View B illustrates a daisychain of WREN 3 disk
 drives or other ESDI devices. A terminator resistor pack is required
 in the host controller for each data cable. Only the last ESDI device
 in the daisychain requires a terminator resistor pack for the control
 cable. Terminator resistor packs for the control cable or other
 drives must be removed. The total combined control cable length
 (from the controller to the first drive, to the second and subsequent
 drives) must not be more than 10 feet (3.00 meters).


 DC Cable and Connector
 ----------------------
 The WREN 3 receives DC power through a 4 pin right angle connector
 mounted on the servo circuit board. Recommended part number for the
 mating connector are provided, but equivalent parts may be used.

 Type of cable:      18 AWG
 Connector:          AMP 1-480424-0
 Contacts:           AMP 60619-4 (Loose Piece); AMP 61117-4 (Strip)


 Data Cable and Connector
 ------------------------
 The I/O connector for the data interface is a 20 pin board edge
 connector. The odd pins are located on the noncomponent side of the
 printed circuit board. The evne pins are on the component side of the
 printed circuit board. A key slot is provided between pins 3 and 5.
 Seagate recommends keying this connector to prevent installing it
 upside down. However, the WREN will not be damaged if the connector
 is installed upside down. Recommended part numbers for the mating
 connector are included below, but equivalent parts may be used.

 Connector:          20 pin, 3M-3461-0001, AMP 88373-6
 Cable:              Flat Cable (Stranded AWG 28) 3M-3365-20
                     Flat Cable (Stranded AWG 28) 3M-3517-20 (Shielded
                     Cable)
 Key:                AMP 583274-1, 3M-3439-0000


 Control Cable and Connector
 ---------------------------
 The I/O connector for the control interface is a 34 pin board edge
 connector. The odd pins are located on the component side of the
 printed circuit board and are connected to the ground plane. The even
 pins are on the noncomponent side of the printed circuit board. A key
 slot is provided between pin 3 and 5. Seagate recommends keying this
 connector to prevent installing it upside down. However, the WREN
 will not be damaged if the connector is installed upside down.

 Recommended part numbers for the mating connector are provided, but
 equivalent parts may be used.

 Connector:          34 pin, 3M-3463-0001, AMP 88373-3
 Key:                AMP 583274-1, 3M-3439-0000
 Cable:              Flat cable (Stranded AWG 28) 3M-3365-34
                     Flat cable (Stranded AWG 28) 3M-3517-34 (Shielded
                     Cable)
                     Spectra Strip Twist'n Flat 455-248-34 (Stranded
                     AWG 28 Twisted Pair)



 Interface Drivers/Receivers
 ---------------------------
 The WREN 3 uses two types of signals; single ended and balanced
 differential. The data and clock signals use balanced differential
 drivers and receivers. All other signals use single ended drivers and
 receivers.


 Single Ended Drivers/Receivers
 -------------------------------
 Transmitter Characteristics
 The WREN 3 uses the 7406 open collectorhex inverter buffer/driver to
 transmit status to the host. This driver is capable of sinking a
 current of 40 mA with a low-level output voltage of 0.7 V.

 Receiver Characteristics
 The WREN 3 uses the 74LS14 Hex Inverter with hysteresis gate as a
 line receiver. The input of each receiver is terminated in a 150 ohm
 pullup resistor.


 Terminator Characteristics
 The terminator is a resistor module that plugs into a socket in the
 last drive in a daisychain. Each drive is furnished with a
 terminator. Terminators must be removed from all except the last
 drive on the cable prior to daisychain operation. An equivalent
 terminator must be provided in the controller on each input signal
 line from the drive to the controller. Only the control cable
 resistor module is removable.


 Balanced Differential Drivers/Receivers
 ---------------------------------------
 Transmitter Characteristics
 The WREN 3 uses 26LS31 type balanced differential driver. An
 assertion on the interface is defined when "+" output is more
 positive than the "-" output.

 Receiver Characteristics
 ------------------------
 The WREN 3 uses 26LS32 type balanced differential receivers. An
 assertion one on the interface is defined when the "+" input is more
 positive than the "-" input.

 Terminator Requirements
 -----------------------
 Each differential receiver in the drive is terminated with a 100 ohm
 resistor. An equivalent terminator must be provided in the controller
 on each input signal line from the drive to the controller.



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                      F   E   A   T   U   R   E  S
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SEAGATE  ST4182E  PRODUCT MANUAL 77738212-G

 Standards
 ---------
 The WREN 3 has been developed as a system peripherals to the highest
 standards of design and construction. The WREN 3 depends upon its
 host equipment to provide adequate power and environment in order to
 achieve optimum performance and compliance with applicable industry
 and governmental regualations. Special attention must be given in the
 areas of safety, power distribution, shielding, audible noise
 control, and temperature regulation.

 The WREN 3 complies with Seagate standards.

 The WREN 3 is a UL Recognized component per UL478 and a CSA Certified
 Component per CSA C22.2, No. 154-M1983. It also meets the
 requirements of DIN IEC 380/VDE 0806/8.81.

 The WREN 3, as delivered, is designed for system integration before
 use. It is supplied as a Class A Computing Device per the FCC
 Rules and Regulations, Part 15, Subpart J governing EMI of computing
 devices.


 Media Description
 -----------------
 The media used in the WREN 3 has a diameter of approximately 5
 inches (130 mm). The aluminum substrate is coated with a thin film
 magnetic material, and lubricated to permit the heads to contact the
 surface when starting and stopping.

 Each data surface has a total of 969 tracks and is capable of
 recording 20,232,720 bytes of unformatted data.


 Media defects are characterized as correctable or uncorrectable de-
 pending on the type and magnitude of the media flaw. Various error
 correction codes may be implemented. The code chosen should be
 consistent with Seagate media testing and certification methods.
 WREN 3 media certification is performed using the following
 standards:

           An error burst of 11 bits or less is a correctable error.

           An error burst greater than 11 bits in length is an un-
           correctable error.

 Host systems using the WREN 3 should have, as a minimum, resident
 capabilities to recognize and map defective tracks and perform track
 reallocation routines.

 At the time of shipment from the point of manufacture, the WREN 3
 recording surfaces will meet the following requirements.

       1. 969 total tracks per surface.

       2. Track 0 to be error free on each data surface.

       3. 30 defects per surface maximum.

       4. Cumulative defects not to exceed 1 per megabyte, based on
          total available unformatted drive capacity.


 Defect and Error Management
 ---------------------------
 The WREN 3, as delivered, complies with this specification. The read
 error rate and specified storage capacity are not dependent upon use
 of defect management routines. However, a carefully chosen defect
 management plan can significantly enhance overall system performance.

 Identified defects are recorded on the defects list tracks per
 Seagate ESDI specification. It is recommended that these known
 defects be reallocated during the initial format operation. Sector
 reallocation is suggested because, in general, it is more efficient
 and may offer significant performance improvement. Error Correction
 Code (ECC) should be used to correct additional flaws as they occur.
 ECC is recommended since most of the defects are recoverable with
 ECC. If ECC is not used, defects are usually unrecoverable and need
 to be reallocated as they are discovered.


 Custom Formatting
 -----------------
 The WREN 3 is formatted during production. Seagate maintains custom
 formatting capability which can incorporate many of the unique
 formats used in the Winchester marketplace. A majority of special
 format requirements can be implemented as specified.


 Drive/Receiver Characteristics
 ------------------------------
 Logic Level            Drive Output         Receiver Input
 -------------------------------------------------------------
 High (negated)  (0)      2.5 V;   5.25 V      2.0 V;   5.25 V
 Low  (asserted) (1)      0.7 V;   0.0 V       0.8 V;   0.0 V

 The difference in the voltages between input and output signals is
 due to the losses in the cable.


 Seek Time
 ---------

                                          | WREN 3 |
        ----------------------------------+--------+
        Track-to-Track         msec. typ. |   4    |
                               msec. max. |   5    |
                       Average msec. typ. |  16.5  |
                       Average msec. max. |  18    |
        Latency                msec. avg. |   8.34 |
        ----------------------------------+--------+

 Seek time is defined as the elapsed time from the receipt of a seek
 command until the drive signals the controller that it is ready to
 perform another seek or a read/write function on the new cylinder.
 Average seek time is determined by dividing the sum of the time for
 all possible movements by the total number of movements.


 Spindle Speed and Latency
 -------------------------
 The spindle speed is 3597   0.5% r/min. The speed tolerance includes
 motor performance and motor control circuit tolerances.

 The average latency time is 8.34 milliseconds, based on a nominal
 disc speed of 3597 r/min. The maximum latency time is 16.76 milli-
 seconds based on a minimum disc speed of 3579 r/min.


 Read Data Transfer Rate
 -----------------------
 The read serial data transfer rate is 10.0 Mbits per second, 1.25
 Megabytes per second.


 Start/Stop Time
 ---------------
 The WREN 3 will become ready less than 35 seconds after application
 of DC power. Stop time will be less than 30 seconds after removal of
 DC power.


 Power Sequencing
 ----------------
 Power sequencing is not required for the WREN 3. The drive protects
 against inadvertent writing during power up and down. Daisychain
 operation requires that power be maintained on the terminated unit
 to ensure proper termination of the peripherals I/O cables.


 Temperature
 -----------
 50*F to 122*F (10*C to 50*C) operating ambient with a maximum
 gradient of 18* F (10* C) per hour. Above 1000 feet (305 metres)
 altidude the maximum temperature is derated linearly to 112* F
 (44.4*C) at 10,000 feet (3048 metres). Cabinet packaging designs must
 provide ample air circulation around the WREN 3 to ensure
 environmental limits are not exceeded as a result of heat transfer
 from other system components. Operating ambient for specification
 purposes is defined as the environment immediately surrounding the
 WREN 3. The temperature of the base deck must not  exceed 135* F when
 measured at the isolation mount adjacent to the front panel LED.


 Heat/Power Dissipation
 ----------------------
 Each WREN 3 will dissipate no more than 33.0 watts (113 BTUs per
 hour) of DC power average. Typical power dissipation under idle
 operating conditions is less than 21 watts.

 Air Cleanliness
 ---------------
 The WREN 3 is designed to operate in a typical office environment
 with minimum environmental control.


 Options
 -------
 All options are either incorporated or packaged at the manufacturing
 facility.


 Front Panel
 -----------
 The WREN 3 is available with a black front panel. The panel has a
 single red rectangular LED which indicates the drive is selected when
 glowing. A flashing LED indicates the presence of a nonrecoverable
 fault. A fault indication is displayed irrespective of DRIVE SELECT
 status.


 Reliability
 -----------
 The following reliability specifications assume correct host/drive
 operational interface has been implementated, including all interface
 timings, power supply voltages, and environmental conditions.

 MTBF                     100,000 hours
 Service Life             5 years
 Preventive Maintenance   None required