
S T 4 7 6 9 E S   W R E N   R U N N E R    SEAGATE
NO MORE PRODUCED                                      Native|  Translation
                                                      ------+-----+-----+-----
Form                 5.25"/FH              Cylinders    1552|     |     |
Capacity form/unform   691/  802 MB        Heads          15|     |     |
Seek time   / track  14.4/ 2.9 ms          Sector/track   58|     |     |
Controller           ESDI                  Precompensation 65535
Cache/Buffer               KB              Landing Zone
Data transfer rate    2.750 MB/S int       Bytes/Sector      512
                            MB/S ext
Recording method     RLL 1/7                        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 12.210
       idle               W     Shock        g         2       |     32
       seek          27.0 W     Rotation   RPM      4800
       read/write         W     Acoustic   dBA
       spin-up            W     ECC        Bit
                                MTBF         h     100000
                                Warranty Month
Lift/Lock/Park     YES          Certificates     CSA,IEC380,IEC435,UL478,VDE



**********************************************************************
                        L   A   Y   O   U   T
**********************************************************************
SEAGATE  ST4767ES/ST4769ES  PRODUCT MANUAL 77765457

  +--------------------------------------------------------+
  |                                                        |XX J4
  |                                                  J9+-+ |XX Data
  |                                                    | | |XX Cable
  |                                                    +-+ |XX
  |                                                J11+-+  |X1
  |                                                   +-1  |
  |                                        Terminator  +1  |XX
  |                                        Resistor    ||  |XX J3
  |                                        Pack        ||  |XX Control
  |                                                    ||  |XX Cable
  |                                                    ++  |XX
  |                                                    +-+ |XX
  |                                                  J8| | |XX
  |                                                    +-+ |X1
  |                                                        |
  |                                                        |XX Power
  |                                                        |XX J1
  +--------------------------------------------------------+  1



**********************************************************************
                      J   U   M   P   E   R   S
**********************************************************************
SEAGATE  ST4767ES/ST4769ES  PRODUCT MANUAL 77765457

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

 x = Jumpers are set at factory



 J1  Power Connector
 -------------------

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



 J8 Drive Select/Write Protect
 -----------------------------

          ---+---+---+---+---+--- PWA
             | o | o | o | o |
             +-+-+-+-+-+-+-+-+Pin 1
               |   |   |   +-----------  Drive Select 1 --+
               |   |   +---------------  Drive Select 2 --+ Binary
               |   +-------------------  Drive Select 4 --+ Coded
               +-----------------------  Write Protect



 J8 Drive Select
 ---------------

  x           x
   +-x-----x-+                             +---------+
   | O  x  O |  Drive Select 0             | O  O  X | Drive Select 1
   | x  O  x |  Unit select zero (no       | O  O  X |
  x+---------+x jumper) is invalid         +---------+


   +---------+                             +---------+
   | O  X  O |  Drive Select 2             | O  X  X | Drive Select 3
   | O  X  O |                             | O  X  X |
   +---------+                             +---------+


   +---------+                             +---------+
   | X  O  O |  Drive Select 4             | X  O  X | Drive Select 5
   | X  O  O |                             | X  O  X |
   +---------+                             +---------+


   +---------+                             +---------+
   | X  X  O |  Drive Select 6             | X  X  X | Drive Select 7
   | X  X  O |                             | X  X  X |
   +---------+                             +---------+


 Pins on the drive ID select and configuration select header are
 provided to facilitate manual drive configuration. No devices other
 than jumpers should be connected to these pins. Connection to
 external devices (Switches, Connectors, etc.) could result in adverse
 drive performance. Exact location of these pins and header may be
 changed without notice.


 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 jumpers on pins on a connector
       header on the main PWA. The jumpers are installed in a 1
       through 7 position configuration to select device addresses 1
       through 7. Zero is not a valid address.

  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.


 J8  Write Protect
 -----------------
 Entire Write Protected when jumper ON.
 The WREN RUNNER-2 can be write protected by installing a jumper plug
 on the leftmost jumper position of the ID select header, J8. The
 host can detect if the drive is write protected by checking bit 12
 of the Standard Status returned by the drive. If bit 12 is "1", the
 drive is write protected. If bit 12 is "0" the drive is not write
 protected.



 J9  Sector Configuration
 -------------------------

 |ST4767ES  |  ST4769ES |                Jumper Plug          (1) |
 +----------+-----------+-----+-----+-----+-----+-----+-----+-----+
 |Sectors   |  Sectors  |  1  |  2  |  3  |  4  |  5  |  6  |  7  |
 +----------+-----------+-----+-----+-----+-----+-----+-----+-----+
 |  (6)     |    (6)    | (3) | (5) | OFF | OFF | OFF | (5) | (7) |
 |  60      |    50     | (3) | (5) | OFF | OFF | ON  | (5) | (7) |(2)
 |  61      |    51     | (3) | (5) | OFF | ON  | OFF | (5) | (7) |
 |  62      |    52     | (3) | (5) | OFF | ON  | ON  | (5) | (7) |(7)
 |  63      |    53     | (3) | (5) | ON  | OFF | OFF | (5) | (7) |
 |  33      |    29     | (3) | (5) | ON  | OFF | ON  | (5) | (7) |
 | Reserved | Reserved  | (3) | (5) | ON  | ON  | OFF | (5) | (7) |
 | Address  | Address   | (3) | (5) | ON  | ON  | ON  | (5) | (7) |
 | Mark (9) | Mark (9)  |     |     |     |     |     |     |     |
 +----------+-----------+-----+-----+-----+-----+-----+-----+-----+

 (1)  ON - Plug installed;  OFF - Plug not installed

 (2)  The configuration of the installed jumper plugs on the Option
      Select Header is specified by a customer configurator document.

 (3)  Motor Start Option Jumper. If #1 installed, the drive requires
      a Motor Start command to spin up.

 (4)  All of these configurations are for head sector operation.

 (5)  Factory use only.

 (6)  Special sector switch setting that can be factory configured to
      customer requirements.

 (7)  Synchronized spindle terminator connected. Install jumper only
      on last drive of daisy chain when operating in synchronized
      spindle mode.

 (8)  Input header for Reference Signal for synchronous spindle
      operation.

 (9)  Soft Sector Option
      The WREN RUNNER-2 ESDI supports the use of the soft sector
      format as described in the ESDI Specification, 77738076,
      Section 5.4.4.

      To implement the optional soft sectored format operation, select
      "Address Mark" mode in the WREN RUNNER-2 ESDI by installing
      option jumper plugs 2, 3, and 4.



 J11  Synchronous Spindle Operation
 ----------------------------------
 The Synchronous Spindles Interface (SSI) allows several drives
 operating from the same host to operate their spindles at a
 synchronous rotational rate. Drives operating in a system in
 synchronous mode increase the system capacity and transfer rate in a
 cost effective manner.

 There is no requirement by the ESDI standard that drives from
 multiple vendors operate together in the synchronous spindle mode. A
 mix of drives from different manufacturers is not likely to work to-
 gether in the synchronous mode, because spindle rotation rate, sync
 fields, sync bytes, etc. need to be virtually identical.



**********************************************************************
                      I   N   S   T   A   L   L
**********************************************************************
SEAGATE  ST4767ES/ST4769ES  PRODUCT MANUAL 77765457

 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 RUNNER-2 ESDI 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 RUNNER-2 ESDI into an OEM's system, wether in a factory or
 field environment.


 Mounting Holes
 --------------
 Mounting Holes four on bottom. Two on each side. 6-32-UNC. max. screw
 length into side of chassis 3.19 mm (0.125 in.) max. Srew length
 into bottom of chassis is 3.19 mm (0.125 in).


 Cooling
 -------
 Cabinet cooling must be designed by the customer so that the ambient
 temperature immediately surrounding the WREN RUNNER-2 ESDI 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 OR ESDI| |WREN OR ESDI| |WREN OR ESDI| |WREN OR ESDI|
    +------------+ +------------+ +------------+ +------------+

    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 (3.0 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 RUNNER-2 ESDI
 Disc Drive. The orientation of Pin 1 of the terminator resistor
 matters.



 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.
   ** A maximum of 7 devices may be interconnected.


 Daisychain Configuration
 ------------------------
 A daisychain configuration connects a maximum of seven drives in
 parallel on a common control cable. Only the drive selected by the
 host system has its control signals enabled through this
 common interface. View B illustrates a daisychain of WREN RUNNER-2
 ESDI 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 RUNNER-2 ESDI receives DC power through a 4 pin right angle
 connector mounted on the main circuit board. Recommended part number
 of 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 back (up) side of the
 printed circuit board. The even pins are on the front (down) 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 back (up) side of the
 printed circuit board and are connected to the ground plane. The even
 pins are on the front (down) 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 RUNNER-2 ESDI 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 RUNNER-2 ESDI uses the 74F38 open collector 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 RUNNER-2 ESDI 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. Note orientation of pin 1. 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 RUNNER-2 ESDI uses 8923 type balanced differential drivers.
 An assertion on the interface is defined when "+" output is more
 positive than the "-" output.


 Synchronous Spindles Interface
 ------------------------------
 The synchronous Spindles Interface (SSI) allows several drives
 operating from the same host to operate their spindles at a
 synchronous rotational rate.


 Termination
 -----------
 The Reference Index Signal is termined with a 150 Ohm resistor. The
 Termination resistor is located in the last drive in the reference
 signal daisy chain, which is the drive farthest from the master drive
 (or host). A jumper on jumper position 7 of the Configuration Select-
 ion Header connects the terminator resistor into the circuit.


 Physical Interface
 ------------------
 The connector mounted on the PWA to interconnect the drives, is a
 2-pin gold header type connector, Seagate part number 51860845 (Du
 Pont Electronics part number 78978-202 or equivalent). A recommended
 mating connector is a Mini-Latch Housing, DuPont Electronics part
 number 65039-035 or equivalent.



**********************************************************************
                      F   E   A   T   U   R   E  S
**********************************************************************
SEAGATE  ST4767ES/ST4769ES  PRODUCT MANUAL 77765457

 Standards
 ---------
 The WREN RUNNER-2 ESDI has been developed as a system peripherals to
 the highest standards of design and construction. The WREN RUNNER-2
 ESDI 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 RUNNER-2 ESDI complies with Seagate standards.

 The WREN RUNNER-2 ESDI is a UL Recognized component per UL478 and a
 CSA Certified  Component per CSA C22.2, No. 220-M1986. It also meets
 the requirements of DIN IEC 380/VDE 0806/8.81, EN60 950/1.8.8, and
 DIN IEC 435/VDE 805/11.84.

 The WREN RUNNER-2 ESDI, as delivered, is designed for system
 integration and installation into a suitable enclosure prior to use.
 As such the WREN RUNNER-2 ESDI is supplied as a sub-assembly and is
 not subject to Subpart J or Part 15 of the FCC Rules and Regulations
 or the Radio Interference Regulations of the Canadian Department of
 Communications. However, the unit has been tested using proper
 shielding and grounding and found to be compliant with Class A limits
 of the FCC Rules and the Regulations of the Canadian Department of
 Communications.


 Media Description
 -----------------
 The media used in the WREN RUNNER-2 ESDI 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 1399 tracks (Model ST4767ES) and
 is capable of recording 53,469,504 bytes of unformatted data. The
 Model ST4769ES has 1552 tracks and 52,580,016 data bytes per surface.

 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 RUNNER-2 ESDI 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 RUNNER-2 ESDI 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
 RUNNER-2 ESDI recording surfaces will meet the following
 requirements.

       1. 1399 (Model ST4767ES) or 1552 (Model ST4769ES) total
          tracks per surface.

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

       3. 50 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 RUNNER-2 ESDI, as delivered, complies with this specifica-
 tion. The read error rate and specified storage capacity are not
 dependent upon use of defect management routines. The error rate
 specification does assume that the sectors with defect in the defect
 log are deallocated. However, a carefully chosen defect management
 plan can significantly enhance overall system performance. Identified
 defects are recorded on the defects list tracks per 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.


 The WREN RUNNER-2 ESDI defect list is written on maximum track,
 maximum track minus eigth and a special track 4095 on each surface in
 the format given in the ESDI Specification, with the write splice
 byte omitted from the format. To successfully read the drive defect
 list on the standard drive the Read Gate must be asserted only at the
 first bit of the first byte of the PLO sync field that follows the
 drive ISG field immediately following Index. Read gate should not be
 toggled and reasserted after the address field and before the data
 field. The ISG field can be determined by using the Request
 Configuration Command (code 3700H). An option is available upon
 customer request to have the defect list formatted with a write
 splice byte between the address and data fields. This would then
 allow for the reassertion of Read Gate after the address field and
 prior to the data field.


 Custom Formatting
 -----------------
 The WREN RUNNER-2 ESDI is formatted during production. Seagate
 maintains custom formatting capability which can incorporate many of
 the unique formats used in Winchester marketplace. A majority of
 special format requirements can be implemented as specified.


 Electrical Description
 ----------------------
 The electrical interface consists of one digital TTL reference index
 signal and ground. The Reference Index Signal (REFINF-) is an output
 if the drive is configured as a master and is an input otherwise. The
 Reference Index Signal is connected from drive to drive in a daisy
 chain fashion.


 Drivers and Receivers
 ---------------------
 The driver circuits have the following electrical specifications.

 ASSERTED  (TRUE):     0.0 V to + 0.4 V @ I = - 48 mA (max).
 NEGATED  (FALSE):   +22.4 V to +5.25 V @ I = +250 uA.


 Seek Time
 ---------

                                          |ST4767ES|ST4769ES
        ----------------------------------+--------+--------
        Track-to-Track         msec. typ. |   2.9  |   2.9
                               msec. max. |   4    |   4
                       Average msec. typ. |  12.9  |  14.4
                       Average msec. max. |  14    |  15.5
        Latency                msec. avg. |   6.25 |   6.25
        ----------------------------------+--------+--------

 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 times for
 all possible movements by the total number of movements.


 Spindle Speed and Latency
 -------------------------
 The spindle speed is 4800   1% r/min. The speed tolerance includes
 motor performance and motor control circuit tolerances.

 The average latency time is 6.25 milliseconds, based on a nominal
 disc speed of 4800 r/min. The maximum latency time is 12.50 milli-
 seconds based on a minimum disc speed of 4752 r/min.



 Synchronous Spindle Operation
 ----------------------------------
 The Synchronous Spindles Interface (SSI) allows several drives
 operating from the same host to operate their spindles at a
 synchronous rotational rate. Drives operating in a system in
 synchronous mode increase the system capacity and transfer rate in a
 cost effective manner.

 There is no requirement by the ESDI standard that drives from
 multiple vendors operate together in the synchronous spindle mode. A
 mix of drives from different manufacturers is not likely to work to-
 gether in the synchronous mode, because spindle rotation rate, sync
 fields, sync bytes, etc. need to be virtually identical.

 Standard WREN RUNNER-2 drives do not operate in the synchronous
 spindle mode. Drives that operate in the synchronous spindle mode
 have a special Main Circuit Board and a special Power circuit board.
 The interface consists of a twisted pair cable that connects the
 drives in the synchronous system in a daisy chain configuration. Each
 drive in the system can be configured to operate in either the
 master or slave mode. Drives are configured by use of the Set
 Configuration command. The host can test the enabled/disabled status
 of the drive using the request configuration command. The master
 provides the reference signal to which all other drives phase lock,
 including the master. There is only one master per system, and that
 can be a drive or the host computer. All drives may be configured as
 slaves allowing the host to provide the reference signal. All drives
 default to the synchronous mode when powered up. Each drive can be
 configured for the non-synchronous mode in which it ignores any
 reference signal that migth be present. The connection of the
 synchronous reference signal to the host is required only if the host
 is to provide the reference signal. If the host does not provide the
 reference signal, the host should not be connected and the master
 should be drive #1. The drive with the terminator connected to the
 reference signal line (via jumper) should always be the drive at the
 greatest distance from the master.


 Read Data Transfer Rate
 -----------------------
 The read serial data transfer rate is:

    Model              Megabits/Sec          Megabytes/Sec
    ------------------------------------------------------
    ST4767ES               24.0                  3.0
    ST4769ES               22.0                  2.75


 Start/Stop Time
 ---------------
 The WREN RUNNER-2 ESDI will become ready less than 39 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 RUNNER-2 ESDI.


 Power Sequencing
 ----------------
 Power sequencing is not required for the WREN RUNNER-2 ESDI. 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
 -----------
 The drive will meet all specifications over a 50* F to 122* F (10* C
 to 50* C) ambient temperature range with a maximum gradient of 36* F
 (20* C) per hour. The enclosure for the drive should be designed such
 that the temperature at the locations are not exceeded. A small
 amount of wir flow may be needed to chieve these temperatures values.


 Electromagnetic Susceptibility
 ------------------------------
 As a component assembly, the wREN RUNNER-2 EDSI is not required to
 meet any susceptibility performance requirements. It is the
 responsibility of the system integrator to perform those tests re-
 quired to assure that equipment operating in the same system as the
 WREN RUNNER-2 ESDI does not adversely affect the performance of the
 WREN RUNNER-2 ESDI.


 Heat/Power Dissipation
 ----------------------
 Each WREN RUNNER-2 ESDI will dissipate no more than 32.0 watts (125
 BTUs per hour) of DC power average. Typical power dissipation under
 idle operating conditions is less than 27 watts.

 Air Cleanliness
 ---------------
 The WREN RUNNER-2 ESDI 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 RUNNER-2 ESDI is available with a black front panel. The
 panel has a window through wich a single red* LED shows from its
 mounting on the Main PWA. The LED, when glowing, indicates the
 presense of a nonrecoverable fault. A fault indication is displayed
 irrespective of Drive Select status.

 *Green for Amber LED indicator will be available, but must be
  specified when ordering units.


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

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


