
W R E N   I I   9 4 1 5 5 - 5 7    CDC
NO MORE PRODUCED                                      Native|  Translation
                                                      ------+-----+-----+-----
Form                 5.25"/FH              Cylinders     925|     |     |
Capacity form/unform    48/   58 MB        Heads           6|     |     |
Seek time   / track  28.0/ 5.0 ms          Sector/track   17|     |     |
Controller           MFM / ST506           Precompensation   128
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 50    |    -40 70
Power: sleep              W     Humidity     %        20 80    |      5 95
       standby            W     Altitude    km    -0.305  3.048| -0.305 12.192
       idle               W     Shock        g         2       |     32
       seek          28.0 W     Rotation   RPM      3600
       read/write         W     Acoustic   dBA
       spin-up            W     ECC        Bit
                                MTBF         h      40000
                                Warranty Month
Lift/Lock/Park     YES          Certificates     CSA,SDA,FCC,IEC380,IEC435,...


**********************************************************************
                        L   A   Y   O   U   T
**********************************************************************
SEAGATE  ST4086  PRODUCT MANUAL 77715909-H


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


 AC = Quick Connect Terminal




**********************************************************************
                      J   U   M   P   E   R   S
**********************************************************************
SEAGATE  ST4086  PRODUCT MANUAL 77715909-H

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

 x = Jumper setting at factory


 J1   WREN Interface
 -------------------
                  Signal Direction    Signal Direction
   +-----------+                                      +-------------+
   |           |                                      |Signal Ground|
   |           | Head Select  2(3)                    |No.    No.   |
   |           +------------------------------------->|  2     1    |
   |           | Head Select  2(2)                    |             |
   |           +------------------------------------->|  4     3    |
   |           | Write Gate                           |             |
   |           +------------------------------------->|  6     5    |
   |           | Seek Complete                        |             |
   |           |<-------------------------------------+  8     7    |
   |Controller/| Track 0                              |             |
   |Host       |<-------------------------------------+ 10     9    |
   |Interface  | Write Fault                          |             |
   |           |<-------------------------------------+ 12    11    |
   |           | Head Select  2(0)                    |             |
   |           +------------------------------------->| 14    13    |
   |           | Reserved  to J2 pin 7                |             |
   |           +--------------------------------------+ 16    15    |
   |           | Head Select  2(1)                    |             |
   |           +------------------------------------->| 18    17    |
   |           | Index                                |             |
   |           |<-------------------------------------+ 20    19    |
   |           | Ready                                |             |
   |           |<-------------------------------------+ 22    21    |
   |           | Step                                 |             |
   |           +------------------------------------->| 24    23    |
   |           | Drive Select 1                       |             |
   |           +------------------------------------->| 26    25    |
   |           | Drive Select 2                       |             |
   |           +------------------------------------->| 28    27    |
   |           | Drive Select 3                       |             |
   |           +------------------------------------->| 30    29    |
   |           | Drive Select 4                       |             |
   |           +------------------------------------->| 32    31    |
   |           | Direction In                         |             |
   |           +------------------------------------->| 34    33    |
   |           |                                      |             |
   +-----------+                                      +-------------+
                                                       WREN Control
                                                       Cable Connector

   All signals in the control cable are single ended signals.

 Pin 2 in the control cable is defined as Reduced Write Current in the
 Seagate ST412 interface. The WREN 2 controls write current internally
 and thus the line is not needed for this function and is used instead
 for the fourth head select line.

 Note that this is a potential incompatibility with existing drives
 and controllers and applies to the WREN 2 in its full capacity
 versions only: Models 94155-86 (9 Data Heads, 86 MB). Reduced
 capacity WREN 2  models ignore the Reduced Write Current/Head Select
 2(3) signal line, pin 2.



 J2   DC 506 Interface
 ---------------------
                  Signal Direction    Signal Direction
   +-----------+                                      +-------------+
   |           |                                      |Pin No. Type*|
   |           | Drive Selected                       |             |
   |           |<-------------------------------------+  1      SE  |
   |           | Ground                               |             |
   |           +--------------------------------------+  2          |
   |           | Reserved                             |             |
   |           +--------------------------------------+  3      SE  |
   |           | Ground                               |             |
   |           +--------------------------------------+  4          |
   |Controller/| Reserved                             |             |
   |Host       +--------------------------------------+  5      SE  |
   |Interface  | Ground                               |             |
   |           +--------------------------------------+  6          |
   |           | Reserved  to J1 Pin 16               |             |
   |           +--------------------------------------+  7          |
   |           | Ground                               |             |
   |           +--------------------------------------+  8          |
   |           | Reserved                             |             |
   |           +--------------------------------------+  9          |
   |           | Reserved                             |             |
   |           +--------------------------------------+ 10          |
   |           | Ground                               |             |
   |           +--------------------------------------+ 11          |
   |           | Ground                               |             |
   |           +--------------------------------------+ 12          |
   |           | +MFM Write Data                      |             |
   |           +------------------------------------->| 13      DIFF|
   |           | -MFM Write Data                      |             |
   |           +------------------------------------->| 14      DIFF|
   |           | Ground                               |             |
   |           +--------------------------------------+ 15          |
   |           | Ground                               |             |
   |           +--------------------------------------+ 16          |
   |           | +MFM Read Data                       |             |
   |           |<-------------------------------------+ 17      DIFF|
   |           | -MFM Read Data                       |             |
   |           |<-------------------------------------+ 18      DIFF|
   |           | Ground                               |             |
   |           +--------------------------------------+ 19          |
   |           | Ground                               |             |
   |           +--------------------------------------+ 20          |
   |           |                                      |             |
   +-----------+                                      +-------------+
                                                       Data Cable
                                                       Connector

 * SE   = Single Ended Signal
   DIFF = Differential Signal


 Drive Select Jumper
 -------------------

           +---+---+---+---+---+
           | o | o | o | o | o |
           | o | o | o | o | o |
           +-+-+-+-+-+-+-+-+-+-+
             |   |   |   |   +------  Radial Select Option
             |   |   |   +----------  Drive Select 4
             |   |   +--------------  Drive Select 3
             |   +------------------  Drive Select 2
             +----------------------  Drive Select 1


 Drive Select 1-2-3-4
 --------------------
 The following characteristics apply to the Drive Select lines:

  1.   Logical unit designation is established at the time of
       installation by setting the jumper plug located on the Servo
       PWA.

  2.   All control cable lines are gated with Drive Select. No data
       cable signal lines are gated with Drive Select.

  3.   Drive Select must remain active during any communication with
       the host controller.

  4.   When the radial select jumper is installed, the drive will be
       selected all the time.

  5.   The drive should not be selected until 1 second after DC power
       is applied. The Drive Ready input will be valid within 500 ns
       after the drive is selected (Drive Selected true) and after the
       35 seconds power on delay.

  6.   The drive will be selected within 1 us after the activation of
       Drive Select, if the power on sequence is complete. The drive
       will be the deselected within 1-us after the deactivation of
       Drive Select.

  7.   The drive will activate the Drive Selected signal within 1 us
       after receipt of Drive Select if the drive is selected. The
       drive will deactivate Drive Selected within 1 us after the
       Drive Select signal is deactivated.

  8.   Drive Select must be valid 100 ns minimum before the first step
       pulse is received and 100 ns minimum after the last step pulse
       is received.

  9.   At the completion of a write operation, Drive select must
       remain active for 1 us.

 10.   When the Drive Select line is activated, a ead change will
       occur, thus 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 2 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

 (W4/W3 are located on the upperside of the printed circuit board)

 W3 and W4 zero ohm resistors are on the Data Boards of drives which
 are Series Code Five and above. The series code of the drive is
 indicated by the first two digits of the serial number, ie, 05000001.



**********************************************************************
                      I   N   S   T   A   L   L
**********************************************************************
SEAGATE  ST4086  PRODUCT MANUAL 77715909-H

 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!



 Maximum screw length into chassis bottom not more than 0.24 in.
 Maximum screw length into chassis side not more than 0.31 in.


 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. In the vertical plane, the drive may be
 mounted on either side, but not on either end. 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.


 WREN 2 is designed, manufactured, and tested with a "Plug-in and
 Play" installation philosophy. This minimizes the requirements for
 highly trained personnel to integrate the WREN 2 into an OEM's
 system, wether in a factory or field environment.


 WREN 2 CDC 506 interface
 ------------------------
 The WREN 2 CDC 506 interface consists of a 34 pin command interface
 cable and a 20-pin data interface cable. This interface is compatible
 with the recognited industry standard ST506 interface. The 34 pin
 command interface is designed to allow daisychain or radial
 connections between the Host and WREN 2 Disc Drives.


 Cooling
 -------
 Cabinet cooling must be designed by the customer so that the ambient
 temperature immediately surrounding the WREN 2 will not exceed
 temperature limits. Specific consideration should be given to ensure
 adequate air circulation around the heat sinks on the circuit board
 on 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 control cable length must not exceed 20 feet (6.10m). Each
    data cable length must not exceed 20 feet (6.10m).


   *T  indicates removable terminator resistor pack.
    T  indicates terminator resistor pack.
    WREN data cables 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 radially connected to the host controller. The length
 of each individual cable must not exceed 20 feet (6.10 meters).
 Terminator resistors must be installed in the host controller for
 each data cable and for each control cable.



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

    Total control cable length must not exceed 20 feet (6.10m). Each
    data cable length must not exceed 20 feet (6.10m).

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

 Daisychain Configuration
 ------------------------
 A daisychain configuration incorporates a maximum of four 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 shouws four WREN Disc Drives only. A
 terminator resistor pack is required in the host controller for each
 data cable. Only the last WREN 2 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 20
 feet (6.1 meters).


 DC Cable and connector
 ----------------------
 The WREN 2 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 even 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.

 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.

 Recommended part numbers for the mating connector are included below,
 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 2 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 2 uses the 74F38 open collector quad-2-input driver to
 transmit status to the host. This driver is capable of sinking a
 current of 48 mA with a low-level output voltage of 0.4V.

 Receiver Characteristics
 The WREN 2 uses the 74LS14 Hex Inverter with hysteresis gate as a
 line receiver. The input of each receiver is terminated in a 220ohm/
 330 ohm resistor network.

 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 2 uses 26LS31 type balanced differential driver. Logic 1 on
 the interface is defined when "+" output is more positive than the
 "-" output.

 Receiver Characteristics
 ------------------------
 The WREN 2 uses 26LS32 type balanced differential receivers. A logic
 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.



**********************************************************************
                      F   E   A   T   U   R   E  S
**********************************************************************
SEAGATE  ST4086  PRODUCT MANUAL 77715909-H

 Standards
 ---------
 The 94155-YY WREN 2 has been developed as a system peripherals to the
 highest standards of design and construction. The WREN depends upon
 its 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 2 complies with Seagate standards.

 The WREN 2 is a UL Recognized component per UL478 and a CSA Certified
 product per CSA C22.2, No. 220-M1986. It also meets the requirements
 of DIN IEC380/VDE0806/8.81, DIN IEC 435/VDE 0805/11.84 and EN
 60950/09.87.

 The WREN 2, 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 and the Radio Interference Regulations of the Canadian
 Department of Communications. However, the WREN 2 has been tested and
 found to comply with the Class B requirements of the referenced FCC
 Rules and Regulations when installed in a typical commercial
 computing system.


 Media Description
 -----------------
 The media used in the WREN has a diameter of approximately 5
 inches (130 mm). The aluminum substrate is coated with lubricated
 ferrous oxide to permit the heads to contact the surface when start-
 ing and stopping.

 Each data surface has total of 925 tracks and is capable of record-
 ing 9,634,800 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, but the code chosen should be
 consistent with Seagate media testing and certification methods. In
 the WREN 2 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 2 should have, as a minimum, resident
 capabilities to recognize and map defective tracks and perform track
 reallocation routines.

       1. 925 total tracks per surface.

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

       3. 15 defects per surface maximum.

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



 Driver/Receiver Characteristics
 -------------------------------
 Logic Level                   Drive Output         Receiver Input
 --------------------------------------------------------------------
 High (false/deactivated) (0)     2.5 V;   5.25 V      2.0 V;   5.25 V
 Low (true/activated)     (1)     0.4 V;   0.0 V       0.5 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 2 |
        ----------------------------------+--------+
        Track-to-Track         msec. typ. |   5    |
                               msec. max. |   7    |
                       Average msec. typ. |  28    |
                       Average msec. max. |  32    |
        Maximum Seek Time      msec. typ. |  65    |
                               msec. max. |  70    |
        Latency                msec. avg. |   8.33 |
        ----------------------------------+--------+

 Seek time is defined as the elapsed time from the receipt of a seek
 command by the WREN 2 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 3600   0.5% r/min. The speed tolerance includes
 motor performance and motor control circuit tolerances.

 The average latency time is 8.33 milliseconds, based on a nominal
 disc speed of 3600 r/min. The maximum latency time is 16.74 milli-
 seconds based on a maximum disc speed of 3582 r/min.


 Read Data Transfer Rate
 -----------------------
 The nominal read serial data transfer rate is 5.0 Mbits per second.


 Start/Stop Time
 ---------------
 The WREN 2 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.

 There is no power control switch on the WREN 2.


 Heat/Power Dissipation
 ----------------------
 Each WREN 2 will dissipate no more than 33.5 watts (116 BTU's per
 hour) of DC power average. Typical power dissipation under nominal
 conditions is less than 28 watts.


 Air Cleanliness
 ---------------
 The WREN 2 is designed to operate in a typical office environment
 with minimum environmental control.

 Power Sequencing
 ----------------
 Power sequencing is not required for the WREN 2. It protects against
 inadvertent writing during power up and down. Daisychain operation
 requires that power be maintained on the terminated unit to insure
 proper termination of the peripheral I/O cables.


 Temperature
 -----------
 50* to 122* F (10* to 50* C) Operating Ambient with a maximum
 gradient of 18* F (10* C) per hour. Above 1000 feet (305 meters)
 altitude the maximum temperature is derated linearly to 95* F (35* C)
 at 10,000 feet (3048 meters). Cabinet packaging designs must provide
 ample air circulation around the WREN 2 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 2. The
 temperature of the base casting should not be allowed to exceed 135*F
 (57* C) at the hottest point. The hottest point may vary between
 different applications.


 Write Precompensation
 ---------------------
 MFM Write Data must conform to the conventional MFM encoding rules
 and must be write precompensation by   12 ns per the industry
 standard MFM data write precompensation rules. Write precompensation
 is recommended on all tracks, however, write precompensation MUST be
 performed on tracks greater than Track 128. An optional configuration
 which does not require write data precompensation may be specified
 for delivery.


 Nonprecompensation Operation
 ----------------------------
 The Standard 94155 Wren require that the write data be
 precompensated   12 ns. Precompensation must start at or before
 cylinder 128 and address all cylinders beyond that point. An optional
 94155 configuration is available at the users request which does not
 require write precompensation. This configuration must be specified
 at the time of order.


 Reliability
 -----------
 The following reliability specifications assume correct host/drive
 operational interface implementation, including all interface
 timings, power supply voltages, environmental conditions, and
 appropriate data handling circuits in the host system.

 MTBF                       40,000 hours
 Service Life             5 years
 Preventive Maintenance   None required


