W R E N   V I F H   9 4 1 9 1 - 7 6 6 D    IMPRIMIS
NO MORE PRODUCED                                      Native|  Translation
                                                      ------+-----+-----+-----
Form                 5.25"/FH              Cylinders    1632|     |     |
Capacity form/unform   676/  766 MB        Heads          15|     |     |
Seek time   / track  15.5/ 3.0 ms          Sector/track   54|     |     |
Controller           SCSI1 DIFFERENTIAL    Precompensation
Cache/Buffer            32 KB LOOK-AHEAD   Landing Zone
Data transfer rate    1.875 MB/S int       Bytes/Sector      512
                      4.700 MB/S ext SYNC
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 12.210
       idle          23.0 W     Shock        g        10       |     32
       seek               W     Rotation   RPM      3597
       read/write         W     Acoustic   dBA
       spin-up            W     ECC        Bit   48,INTERNAL
                                MTBF         h     150000
                                Warranty Month        12
Lift/Lock/Park     YES          Certificates     CSA,FCC,IEC380,IEC435,UL47...


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SEAGATE  ST4766N (94191-766)  PRODUCT MANUAL 77765353-L, DEC. 1991

  +------------------------------------------------------++-+J4
  |                                                      || |Drive
  |                                                      || |Select/
  |                                                      |+-+Option
  |                                                  +1  |XX
  |                                                  ||  |XX SCSI
  |                                                  ++  |XX Interface
  |                                      Resistor    +1  |XX J3
  |                                      Terminator  ||  |XX
  |                                      Packs       ++  |XX
  |                                                  ++  |XX
  |                                                  ||  |XX
  |                                                  +1  |XX1
  |                                                      |
  |                                                      |XX Power
  |                                                      |XX
  +------------------------------------------------------+  1




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                      J   U   M   P   E   R   S
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SEAGATE  ST4766N (94191-766)  PRODUCT MANUAL 77765353-L, DEC. 1991

 Jumper Setting
 ==============


  J4  SCSI ID/Option Select Header
  --------------------------------
         --+-------------------------+--
           |o  o  o  o  o  o  o  o  o|
           |1  o  o  o  o  o  o  o  o|
           +-------------------------+
           TP TP  4  2  1 (2)(3)(6)(7)
            (4)

      +------------+----------+
      |            | 4  2  1  |
      +------------+----------+  Drive ID is binary coded jumper
      |SCSI ID = 0 | o  o  o  |  position (most significant bit on
      |            | o  o  o  |  left), i.e., jumper in position 1
      +------------+----------+  would be Drive ID 1, no jumpers means
      |SCSI ID = 1 | o  o  x  |  ID 0.
      |            | o  o  X  |
      +------------+----------+
      |SCSI ID = 2 | o  x  o  |
      |            | o  X  o  |
      +------------+----------+
      |SCSI ID = 3 | o  x  x  |
      |            | o  X  X  |
      +------------+----------+
      |SCSI ID = 4 | x  o  o  |
      |            | X  o  o  |
      +------------+----------+
      |SCSI ID = 5 | x  o  x  |
      |            | X  o  X  |
      +------------+----------+
      |SCSI ID = 6 | x  x  o  |
      |            | X  X  o  |
      +------------+----------+
      |SCSI ID = 7 | x  x  x  |
      |            | X  X  X  |
      +------------+----------+

 (2)  CLOSED  Enables the Motor Start Option. In this mode of
              operation the drive will wait for a Start Unit Command
              from the Host before starting the Motor.
      OPEN    see Note (6) below for description of delayed motor
              start feature.

 (3)  CLOSED  Parity checking by the WREN 6 is enabled.
              The use of parity is a system option. The WREN 6 SCSI
              will always generate parity detection.

 (4)  If the unit is not be terminated, remove terminator resistor
      module SIPs (DIPs). TP Jumper in left vertical position means
      terminator power (+5V) is from WREN 6 power connector. Jumper
      in horizontal position means terminator power is taken from
      interface cable. If the drive is not terminated, the TP jumper
      need not be installed.

 (6)  Jumper on enables delayed motor start (Motor Start jumper (2)
      must be off). Motor start up is delayed 16 times drive ID number
      in seconds; i.e., Drive 0 starts immediately, Drive 1 starts 16
      seconds later, Drive 2 starts 16 seconds after Drive 1, etc.

 (7)  Reserved Jumper Position


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

 Note: Pins on the drive select and configuration select header are
 provided to facilitate manual drive configuration. No devices other
 than jumpers should be connected to these pins. Improper connection
 to external devices (switches, connectors, etc.) could adversely
 affect drive performance. Exact location of these pins and headers
 may change without notice.



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                      I   N   S   T   A   L   L
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SEAGATE  ST4766N (94191-766)  PRODUCT MANUAL 77765353-L, DEC. 1991

 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


 Drive Orientation
 -----------------
 The balanced rotary arm actuator design of the Wren 6 allows it to
 be mounted in any orientation. All drive performance characterization
 however, has been done with the drive in horizontal (disc level) and
 vertical (drive on its side) orientations, and these are the two
 preferred mounting orientations.

 WREN 6 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 6 into an OEM's
 system, wether in a factory or field environment.


 Mounting Holes
 --------------
 Mounting Holes (6-32 UNC). Four on bottom, two on each side. Max.
 screw length into chassis is 0.14 in. (3.55 mm).


 Cooling
 -------
 Cabinet cooling must be designed by the customer so that the ambient
 temperature immediately surrounding the WREN 6 will not exceed
 temperature conditions. Specific consideration should be given to
 make sure adequate air circulation is present around the PWAs at the
 rear of the drive.


 Service Tools
 -------------
 No special tools are required for site installation or recommended
 site maintenance. The depot repair philiosophy of WREN 6 precludes
 the necessity for special tools. If field repair of items external to
 the HDA is desired, a 6 point Torx T10 driver is required. This may
 be purchased through most commercial tool catalogs.


 Physical Description
 --------------------
 Model 94191 WREN 6 may be daisychained together or with other
 compatible SCSI devices using a common cable. Both ends of the cable
 must be terminated. The WREN 6 implements single ended or
 differential drivers and receivers. Drives having single ended
 interface drivers and receivers allow a maximum cable length of six
 metres (primarily for connection within a cabinet). The Model
 94191-766D WREN 6 implements differential drivers and receivers which
 allow a maximum cable length of 25 metres. All signals are common
 between all SCSI devices. The Model 94191 WREN 6 may be daisychained
 only with SCSI devices having the same type drivers and receivers.
 Devices having single ended interface circuits cannot be on the same
 daisychain with devices having differential interface circuits. A
 maximum of 8 SCSI devices (including the Host) may be daisychained
 together. The SCSI Devices at both ends of the daisychain are to
 terminated. Intermediate SCSI devices shall not be terminated. Remove
 the terminator resistor packs, not the terminator power source
 selector jumper.


 Cable Requirements
 ------------------
 Only nonshielded cable connectors are applicable. A 50 conductor flat
 cable or 25 twisted pair cable shall be used. The maximum total cable
 length shall be 6.0 metres for single ended drivers and receivers,
 and 25.0 metres for differential drivers and receivers. A stub length
 of no more than 0.1 metre for single ended or 2.0 metre for
 differential circuits is allowed off the mainline interconnection
 within any connected equipment. For single ended drivers and
 receivers, an ideal impedance match with cable terminators implies a
 cable characteristic impedance of 132 ohm single ended option and
 122 ohms for the differential option. In general, cables having
 characteristics impedance of those values are not available; however,
 impedances that are somewhat lower are satisfactory. A characteristic
 impedance of 100 ohm   10% is recommended for unshielded flat or
 twisted pair ribbon cable. However, most available cables have a
 somewhat lower characteristic impedance. To minimize discontinuities
 and signal reflections, cables of different impedances should not be
 used in the same bus. Implementations may require trade-offs in
 shielding effectiveness, cable length, the number of loads, transfer
 rates, and cost to achieve satisfactory system operation. If shielded
 and unshielded cables are mixed within the same SCSI bus, the effect
 of impedance mismatch must be carefully considered.

 A minimum conductor size of 28 AWG should be used to minimize noise
 effects.

 Suggested nonshielded flat cable part numbers are:

    Flat cable     3M-3365-50
    Twisted pair   Spectra twist in flat 455-248-50

 Equivalent parts may be used.


 Connector Requirements
 ----------------------
 The nonshielded cable connector shall be a 50 conductor connector
 constisting of to rows of 25 female contacts with adjacent contacts
 100 mils apart.

 Recommended Mating Flat Cable Connector Part Numbers are:

 Closed end   3M-3425-7000      W/O Strain Relief, No Center Key
 (for cable   3M-3425-7050      With Strain Relief, No Center Key
 ends)        Dupont-66900-290  With Strain Relief, With Center Key

 Open end     3M-3425-6000      W/O Strain Relief, No Center Key
 (In Daisy-   3M-3425-6050      With Strain Relief, No Center Key
 chain)       Dupont-66900-250  With Strain Relief, With Center Key

 The Model 94191 WREN 6 device connector is a nonshielded 50
 conductor connector consisting of two row of 25 male pins with
 adjacent pins 100 mils apart. The connector is keyed.

 Drive Connector Part Number: Berg - 65496 - 031 or equivalent.

 Single Ended
 ------------
 All odd pins except pin 25 are connected to ground. Pin 25 is left
 open.

 CAUTION
 Pin 25 must not be connected to ground at the HOST end or the drive
 end of the cable. If the I/O connector should accidentally be
 plugged in upside down, terminator power on Pin 26 will shorted to
 ground.



    +--------------SCSI-DEVICE-----------------+
    |       +--+ HOST ADAPTER/INITIATOR ***    |
    |       |T |                               |
    +-------++-+-------------------------------+
            *|
             |
             |                1 thru 8 SCSI devices
             +--------- -----+--------------+
           **|             **|              |*
    +--------+---+ +---------+--+ +--------++-++
    |WREN        | |WREN        | |WREN    | T||
    |or other    | |or other    | |or other+--+|
    |SCSI device | |SCSI device | |SCSI device |
    +------------+ +------------+ +------------+

 *    Closed end type connector used
 **   Open type (in-line application) Connector used.
 ***  Host need not be on the end of the daisy chain. Another device
      can be on the end with the terminator, the host having no
      terminator.

 T indicates termination required.


 DC Cable and Connector
 ----------------------
 The WREN 6 receives DC power through a 4 pin right angle connector
 mounted on the servo PWA. Recommended part numbers of the mating
 connector are listed below, but equivalent parts may be used.

 Type of cable:      14 AWG
 Connector:          AMP 1-480424-0
 Contacts:           AMP 60619-4 (Loose Piece); AMP 61117-4 (Strip)


 Electrical Description
 ----------------------
 The Model 94191-766 WREN 6 uses single ended interface signals and
 these signals must be terminated with 220 ohm to +5 V and 330 ohm
 to ground at each end of the total cable. All signals use open
 collector or three state drivers. Optional termination is available
 internal to the WREN 6.

 The Model 94191-766D uses differential interface signals and each of
 these must be terminated at each end of the total cable with 330 ohms
 to +5 V and 330 ohms to ground with 150 ohms between each
 differential pair. All signals use open collector, three state
 drivers. Drives are shipped with or without terminators, depending on
 option.


 Single Ended Drivers/Receivers
 ------------------------------
 Single ended drivers and receivers are used by the WREN 6.


 Transmitter Characteristics
 ---------------------------
 The WREN 6 uses an ANSI SCSI compatible open collector single ended
 driver. This driver is capable of sinking a current of 48 mA with a
 low level output voltage of 0.4 volt.


 Receiver Characteristics
 ------------------------
 The WREN 6 uses a ANSI SCSI single ended receiver with hysteresis
 gate or equivalent as a line receiver.


 Differential Drivers/Receivers
 ------------------------------
 Differential drivers and receivers are used by the Model 94191-766D
 WREN 6.


 Differential Signals
 --------------------
 All signals consist of two lines denoted +SIGNAL and -SIGNAL. A
 signal is true when +SIGNAL is more positive than -SIGNAL, and a
 signal is false when -SIGNAL is more positive than +SIGNAL. All
 assigned signals ahall be terminated at each end of the cable.


 Output Characteristics
 ----------------------
 Each signal driven by the WREN 6 (Differential Interface) shall have
 the following output characteristics when measured at the WREN 6 SCSI
 connector:

 Low-level output voltage* = 2.0V max. at low-level output current =
 55 milliamps.

 High-level output voltage* = 3.0V min. at high-level output current =
 -55 milliamps.

 Differential voltage = 1.0V min. with common-mode voltages ranges
 from -7V dc to +12V dc.

 *These voltages shall be measured between the output terminal and the
  SCSI device's logic ground reference.

 The output characteristics shall aditionally conform to EIA
 RS-485-1983.


 Input Characteristics
 ---------------------
 Each signal received by the WREN 6 (Differential Interface) shall
 have the following input characteristics when measured at the WREN 6
 SCSI connector:

 Input current on either input = +2.0 milliamps maximum.

 NOTE
 These characteristics include both receivers and passive drivers.

 This requirement shall be met with the input voltage varying between
 -7V dc and +12V dc, with power on or off, and with the hysteresis
 equaling 35 mv, minimum.

 The input characteristics shall additionally conform to EIA
 RS-485-1983.


 Terminator Requirements
 -----------------------
 Internal WREN 6 I/O termination consist of three resistor modules
 which plug into sockets on the Main PWA. The WREN 6 may be ordered
 with or without these termination resistors to facilitate a
 particular application. All single initiator/single target (non-
 daisychain) applications require that the Initiator and WREN 6 be
 terminated. Daisychain applications require that only the unit at
 each end of the daisychain be terminated. All other peripherals on
 the chain should not be terminated.

 Note: Remove terminator resistor packs where terminators are not
 required. Removal of terminator power source selection jumper does
 not disconnect the terminator resistor from the circuit. SIP's for
 Single Ended Interface Drivers/Receivers; SIP's and DIP's for
 Differential Interface Drivers/Receivers Option.


 Terminator Power
 ----------------
 The WREN 6 does not supply Terminator power for the SCSI bus. The
 WREN 6 may be configured to accept terminator power via Pin 26 of the
 SCSI bus or to provide terminator power for optional internal
 termination resistors via the WREN 6 power connector.
 SCSI devices providing termination power (TERMPWR) shall have the
 following characteristics:

     V TERM = 4.0V to 5.25V
     800 mA min source drive capability
     1.0 A maximum



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                      F   E   A   T   U   R   E  S
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SEAGATE  ST4766N (94191-766)  PRODUCT MANUAL 77765353-L, DEC. 1991

 General Description
 -------------------
 The WREN 6 is a member of a family of low cost, high performance,
 highly reliable, random access storage devices designed to meet the
 needs of the OEM marketplace.


 Standards
 ---------
 The WREN 6 has been developed as a system peripherals to the
 highest standards of design and construction. The WREN 6 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 6 is a UL Recognized component per UL 478 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 and EN 60950/1.1.88, DIN
 IEC 435/VDE 0805/11.84 and EN 60950/09.87.

 The WREN 6 as delivered, is designed for system integration before
 use. It is supplied as a sub-assembly, as such, it is not directly
 subject to Subpart J of Part 15 of the FCC Rules and Regulations nor
 the Radio Interference Regulations of the Canadian Department of
 Communications.


 The Head, Disc and Actuator Assembly chamber (HDA) is environmentally
 sealed at the factory. Air is recirculated within the HDA through a
 nonreplaceable filter to maintain a contamination free disc/actuator
 environment.

 The WREN 6 uses a dedicated landing zone at the innermost radius of
 the media thus eliminating the possibility of destroying or degrading
 data by landing in the data zone.

 The WREN 6 incorporates an automatic shipping look which prevents
 potential damage to the heads and disks caused by movements during
 shipping and handling. The shipping lock is automatically disengaged
 when power is applied to the drive.

 The WREN 6 decodes Track 0 location from the dedicated servo
 surface thereby eliminating mechanical transducer adjustments and
 related reliability concerns.

 The WREN 6 uses a high performance actuator assembly consisting of
 a low inertia, balanced, patented, straight arm design which provides
 excellent performance with minimum power dissipation.


 Media Description
 -----------------
 The media used on the WREN 6 has a diameter of approximately 5
 inches (130 mm). The aluminum substrate is coated with a thin film
 magnetic material, overcoated with a proprietary protective layer for
 improved durability and environmental protection.


 Defect and Error Management
 ---------------------------
 WREN 6, as delivered, complies with this specification. The read
 error rate and specified storage capacity are not dependent upon use
 of defect management routines by the host (initiator).

 Defect and error management in the SCSI system involves WREN 6
 internal defect/error management and SCSI systems error considera-
 tions (errors in communications between Initiator and WREN 6). Tools
 for use in designing a defect/error management plan are briefly
 outlined in this section, with references to other sections where
 further details are given.


 WREN 6 Internal Defects/Errors
 ------------------------------
 Identified defects are recorded on the WREN 6 defects list tracks
 (referred to as the primary or ETF defect list). It is recommended
 that these known defects be reallocated during the initial WREN 6
 format operation. The WREN 6 internal retries and data correction
 by ECC should be enabled to recover data from additional flaws if
 they occur. If data correction by ECC is required to recover data,
 the host should immediately reallocate this sector by use of the
 Reassign Blocks command. If the WREN 6 automatic retries and data
 correction by ECC features are not used, defects are usually un-
 recoverable and need to be reallocated as they are diacovered. For
 reallocation of bad sectors, the number of spare sectors per track or
 cylinder and the number of spare tracks per volume is programmable.
 After formatting, defects can be automatically reallocated by the
 WREN 6, or can be reallocated when the host sends the Reassign
 Blocks Command.


 Seek Time
 ---------

                                          |  94191  |
        ----------------------------------+---------+
        Track-to-Track         msec. typ. |    3    |
                               msec. max. |    4    |
                       Average msec. typ. |   15.5  |
                       Average msec. max. |   17.5  |
        Full Stroke            msec. typ. |   35    |
                               msec. max. |   40    |
        Latency                msec. avg. |    8.33 |
        ----------------------------------+---------+
 Seek times does not include drive controller overhead.


 Read Look-Ahead/Cache Control
 -----------------------------
 The WREN 6 Model 94191 provides a Read Look-ahead buffering algorithm
 which can in may cases enhance system performance. This feature may
 be selected by issuing a Mode Select Command with the Enable/Disable
 Cache bit set in the Cache Control page.


 Power Sequencing
 ----------------
 Power sequencing is not required for the WREN 6. The WREN 6 protects
 against inadvertent writing during power up and down. Daisychain
 operation requires that power be maintained on the terminated WREN 6
 to ensure proper termination of the peripheral I/O cables.


 Start/Stop Time
 ---------------
 After DC power has been applied, the WREN 6 will become ready within
 39 seconds if the Motor Start Option is disabled. During this time,
 the drive will respond to the SCSI interface. Stop time will be less
 than 30 seconds from removal of DC power.

 If the Motor Start Option is enabled, the internal controller will
 accept a Motor Start, Inquiry or Request Sense Command via the SCSI
 interface 3 seconds after DC power has been applied. After the Motor
 Start Command has been received the WREN 6 will become ready for
 normal operations within 36 seconds. During this time the drive will
 respond to the SCSI interface in accorance with the rules for Command
 Queing.

 There is no power control switch on the drive.


 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 temperatures at the locations are not exceeded. Air flow may
 be needed to achieve these temperature values.


 Air Cleanliness
 ---------------
 The WREN 6 is designed to operate in a typical office environment
 with minimal environmental control.


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

 MTBF                     150,000 hours
 Service Life             5 years
 Preventive Maintenance   None required


 Sectors per track
 -----------------
 54 @ 512 bytes per sector
 28 @ 1024 bytes per sector


 Formatted Capacity
 ------------------
 Formatted capacity achieved depends on the number of spare
 reallocation sectors reserved and the number of bytes per sector. The
 following table shows some typical formatted capacities achievable.

 +--------------------------+-----------------------------------+
 |Spare Sectors or Cylinders|           Sector Size*            |
 |Reserved for reallocation |512 Bytes/Sector| 1024 Bytes/Sector|
 +--------------------------+----------------+------------------+
 |No Spares                 |     676 MB     |      701 MB      |
 +--------------------------+----------------+------------------+
 |One Spare Sector per track|                |                  |
 |and two spare Cyl/Unit**  |     663 MB     |      675 MB      |
 +--------------------------+----------------+------------------+
 |Two Spare Cylinders/Unit**|     675 MB     |      701 MB      |
 +--------------------------+----------------+------------------+

 The standard OEM Model is as follows:

                             Formatted Data Block Size*  Unformatted
 Model 94191-766 (15 Heads)  1024 Byte   512 Byte
                              675 MB     663 MB             766 MB

 * User selectable at format time. The user may  modify the data block
   size before issuing a format command and obtain different formatted
   capacities than those listed. User available capacity will depend
   on spare reallocation scheme selected.

 ** Spare cylinders are on the inner tracks


 Heat/Power Dissipation
 ----------------------
 Each single ended interface WREN 6 will dissipate no more than 27
 watts (92 BTUs per hour) of DC power average under worst case operat-
 ing conditions. Typical power dissipation under idle operating con-
 ditions is less than 21 watts.

 WREN 5 drives having the differential interface circuits will
 dissipate no more than 30 watts (102.2 BTU's per hour) of DC power
 average under worst case operating conditions. Typical power
 dissipation under idle operating conditions is less than 23.1 watts.


 Electromagnetic Susceptibility
 ------------------------------
 As a component assembly, the WREN 6 is not required to meet any
 susceptibility performance requirements. It is the responsibility of
 the system integrator to perform those tests required to assure that
 equipment operating in the same system as the WREN 6 does not
 adversely affect the performance of the WREN 6.


 Logical Unit Number (LUN)
 -------------------------
 The logical unit number (LUN) addresses one of up to eight physical
 devices or virtual devices attached to a target. The only valid LUN
 number for WREN 6 is Zero.

 The LUN in the CDB is provided for systems that do not implement the
 Identify Message. If an Identify message is sent to the WREN 6, the
 WREN 6 will use the LUN number specified in this message. In this
 case, the WREN 6 shall ignore the LUN specified within the command
 descriptor block.

 The WREN 6 will reject commands which select an invalid LUN (except
 Request Sense and Inquiry) by requesting and accepting the command
 bytes, then going to Status phase and sending Check Condition status.
 Note that the LUN is sent in the LUN field of a CDB (if no Identify
 message has been received for this selection) or by the LUN field
 of an Identify message.

 Request Sense commands selecting an invalid LUN will receive a Sense
 Data block with the Illegal Request Sense Key and an Invalid LUN
 Error Code. Inquiry commands will return Inquiry Data with the
 Peripheral Device Type field set to Logical Unit Not Present (7FH).
 Request Sense and Inquiry commands will not send Check Condition
 status in response to an invalid LUN selection.