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Hard Drive: IMPRIMIS: WREN IIIHH 94211-91 83MB 5.25"/HH SCSI1 SE

W R E N   I I I H H   9 4 2 1 1 - 9 1    IMPRIMIS
NO MORE PRODUCED                                      Native|  Translation
Form                 5.25"/HH              Cylinders     992|     |     |
Capacity form/unform    83/   91 MB        Heads           5|     |     |
Seek time   / track  18.0/ 4.0 ms          Sector/track     |     |     |
Controller           SCSI1 SINGLE-ENDED    Precompensation
Cache/Buffer               KB              Landing Zone
Data transfer rate    1.250 MB/S int       Bytes/Sector      512
                            MB/S ext
Recording method     RLL 2/7                        operating  | non-operating
Supply voltage     5/12 V       Temperature *C        10 50    |    -40 70
Power: sleep              W     Humidity     %         8 80    |      5 95
       standby            W     Altitude    km    -0.305  3.048| -0.305 12.210
       idle          18.0 W     Shock        g         2       |     32
       seek               W     Rotation   RPM      3600
       read/write         W     Acoustic   dBA
       spin-up            W     ECC        Bit
                                MTBF         h      40000
                                Warranty Month
Lift/Lock/Park     YES          Certificates                                  



  |                                   Terminator +--------+ |XX J1
  |                                   Connector  |  (3)   | |XX Power
  |                                   Mount PWA  +--------+ |xx
  |                                   (Visable from bottom) |+-+
  |                                                         || |J2
  |                                                         |+-+
  |                                                         |++
  |                                                         |||J3
  |                                                         |||
  |                                                         |++
  |                                                         |1X Inter-
  |                                                         |XX face
  |                                                         |XX J4
  |                                                         |XX
  |                                                         |XX
  |                                                         |XX



Jumper setting

  J2 SCSI ID/Parity Check
           | o  o  o  o |
           | o  o  o  o |
             4  2  1  P(2)

      |            | 4  2  1  |
      +------------+----------+  Drive ID in 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 Parity checking by the WREN 3HH is enabled.

J3 Terminator Power/Test Seek

     Position A
 (3)| o    o    xxxxxxx   o    o    o    o |
        J4-26   TP  +5V        TST  GRD  M

     Position B
 (3)| o    xxxxxxx   o    o    o    o    o |
        J4-26   TP  +5V        TST  GRD  M

     Position C (DO NOT USE)
 (3)| xxxxxxx   o    o    o    o    o    o |
        J4-26   TP  +5V        TST  GRD  M

 (3) Jumper in position A means terminator power (+5V) for the
     internal terminators is from the WREN 3HH power connector.

     Jumper in position B means terminator power is taken from the
     interface cable, pin 26. If the I/O cable is removed with
     jumper in position B and with terminators in, drive will not
     power up.

     Do not use position C.

If unit is not to be terminated, remove the terminator resistor
packs. Removal of terminator power source select jumper does not
disconnect the terminator resistor from the circuit.

     Motor Start Option
 (4)| o    o    o    o    o    o    xxxxxx |
        J4-26   TP  +5V        TST  GRD  M

 (4) CLOSED   Enable 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     The Motor will starts as soon as DC power is applied to
              the unit.

     Test Seek Jumper
 (5)| o    o    o    o    o    xxxxxxx   o |
        J4-26   TP  +5V        TST  GRD  M

 (5) With the jumper in this position the unit will continuously
     perform test seeks to random cylinders. Motor starts as soon as
     DC power is applied.

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

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. Connection
to external devices (switches, connectors, etc.) could adversely
affect drive performance. Exact location of these pins and headers
may change without notice.



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!

Drive Orientation
Only two WREN 3HH mounting orientations are permitted: discs in the
horizontal plane and discs in the vertical plane. Horizontal
mounting with the front (non I/O cable end) raised as much as 15*
above the horizontal is acceptable. Mounting with either end down
(front or rear) or upside down is not permissible. It is recommended
that data written in a given orientation be read in that same

WREN 3HH 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 3HH into an OEM's
system, whetherin a factory or field environment.

Mounting Holes
Mounting Holes (6-32 UNC-28). Four on bottom, four on each side. Max.
screw length into chassis 0.125 in. (3.17 mm).

Cabinet cooling must be designed by the customer so that the ambient
temperature immediately surrounding the WREN 3HH 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 3HH precludes
the necessity for special tools. If field repair of items external to
the HDA is desired, two sizes of 6 point Torx drivers are required
(T10 and T15). They may be purchased through most commercial tool

Physical Description
Model 94211 WREN may be daisychained together or with other
compatible SCSI devices using a common cable. Both ends of the cable
must be terminated. The WREN 3HH implements single ended drivers and
receivers, which allow a maximum cable length of six metres
(primarily for connection within a cabinet). All signals are common
between all SCSI devices. The Model 94211 WREN 3HH may be
daisychained only with SCSI devices with single ended drivers and
recovers. 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

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. A stub length of no more than 0.1 metre
is allowed off the mainline interconnection within any connected

An ideal impedance match with cable terminators implies a cable
characteristic impedance of 132 ohm (single ended option). In
general, cables with this high of a characteristics impedance are not
available; however, impedances that are somewhat lower are satis-
factory. 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 discontionuities 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

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

Suggested non-shielded 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-3425-7600 W/O Strain Relief, with Center Key
(for cable 3M-3425-7650 With Strain Relief, with Center Key
ends) Dupont-66900-290 With Strain Relief, with Center Key

Open end 3M-3425-6600 W/O Strain Relief, with Center Key
(In Daisy- 3M-3425-6650 With Strain Relief, with Center Key
chain) Dupont-66900-250 With Strain Relief, with Center Key

The Model 94211 WREN 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.

    |       +--+ 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 end type (in-line application) Connector used.

T indicates termination required.

Total interface cable length must not exceed 6.0m (20 feet)

DC Cable and Connector
The WREN 3 receives DC power through a 4 pin right angle connector
mounted on the servo PWA. Recommended part number for 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
 All interface signals with the Model 94211 WREN 3HH are single ended
 and 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

Single Ended Drivers/Receivers
Single ended drivers and receivers are used by the WREN 3HH.

Transmitter Characteristics
The WREN 3HH 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 3HH uses a ANSI SCSI single ended receiver with hysteresis
gate or equivalent as a line receiver.

Terminator Requirements
Internal WREN 3HH I/O termination consist of three resistor modules
which plug into sockets on the underside of the Main PWA. The WREN
3HH may be ordered with or without these termination resistors to
facilitate a particular application. All single initiator/single
target (nondaisychain) applications require that the Initiator and
WREN 3HH 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. Physically remove
terminator resistor packs where terminators are not required. Removal
of power source selection jumper does not disconnect the terminator
resistors from the circuit.

Drive Termination
This option may be incorporated during manufacture at the request of
the customer. Termination consists of three 220/330 ohm resistor
modules which are installed on the Main PWA via sockets. The user
may install or remove these.

Terminator Power
The WREN 3HH does not supply Terminator power for the SCSI bus. The
WREN 3HH may be optionally 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 3HH power connector.

AC/DC Ground Separation
The 94211 WREN 3HH is provided with the AC groung (chassis) tied
to DC logic ground. An option is provided for the user to isolate the
AC and DC grounds. This option may be beneficial in reducing ground
induced noise in some system applications.



General Description
The WREN 3HH 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.

The WREN 3HH has 8K byte data buffer (32K optional).
Selectable data block sizes from 256 to 2048 bytes in one byte

The WREN 3HH has been developed as a system peripherals to the
highest standards of design and construction. The WREN 3HH 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 3HH complies with Seagate standards.

The WREN 3HH 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, DIN IEC435/VDE 0805/11.84
and EN 60950/09.87.

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

The Head/Disc/Actuator Assembly (HDA) is environmentally sealed at
the factory. Air is recirculated within the HDA through a nonreplace-
able filter to maintain a contamination free disc/actuator

The WREN 3HH 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 3HH incorporates an automatic shipping look which prevents
potential damage to the heads and discs caused by movements during
shipping and handling. The shipping lock is automatically disengaged
when power is applied to the drive.

The WREN 3HH decodes Track 0 location from the dedicated servo
surface thereby eliminating mechanical transducer adjustments and
related reliability concerns.

The WREN 3HH 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 3HH 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 3HH, 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 3HH
internal defect/error management and SCSI systems error
considerations (errors in communications between Initiator and WREN
3HH). 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 3HH Internal Defects/Errors
Identified defects are recorded on the WREN 3HH defects list tracks
(referred to as the promary or ETF defect list). It is recommended
that these known defects be reallocated during the initial WREN 3HH
format operation. The WREN 3HH 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 3HH automatic retries and data
correction by ECC features are not used, defects are usually un-
recoverable and need to be reallocated as they are discovered.

 Seek Time
               Not Including Controller Overhead

                                          | WREN 3  |
        Track-to-Track         msec. typ. |    4    |
                               msec. max. |    6    |
                       Average msec. typ. |   18    |
                       Average msec. max. |   20    |
        Full Stroke            msec. typ. |   35    |
                               msec. max. |   40    |
        Latency                msec. avg. |    8.33 |

               Including Controller Overhead

                                          | WREN 3  |
        Track-to-Track         msec. typ. |    6    |
                               msec. max. |    9    |
                       Average msec. typ. |   20    |
                       Average msec. max. |   23    |
        Full Stroke            msec. typ. |   37    |
                               msec. max. |   43    |
        Latency                msec. avg. |    8.33 |

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

Start/Stop Time
After DC power has been applied to the WREN 3HH the Unit will become
ready within 30 seconds if the Motor Start Option is disabled.
During this time, the internal controller will not respond to the
SCSI interface until the drive has loaded the heads and positioned
them to track zero. Stop time will be less than 30 seconds from
removal of DC power.

If the Motor Start Option is enabled, the internal controller will
respond to the SCSI interface 3 seconds after DC power has been
applied to the unit. After the Motor Start Command has been received
the Unit will become ready for normal operations within 28 seconds.

There is no power control switch on the drive.

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 metres)
altitude the maximum temperature is derated linearly to 112*F
(44.4*C) at 10,000 feet (3048 metres). Cabinet packaging designs must
provide ample air circulation around the WREN 3HH 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 3HH. The temperature of the HDA is restricted to a maximum of
142*F (61.4* C) during operation.

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

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

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

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