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Hard Drive: IMPRIMIS: WREN VHH 94221-125M 107MB 5.25"/HH SCSI1 MAC

W R E N   V H H   9 4 2 2 1 - 1 2 5 M    IMPRIMIS
NO MORE PRODUCED                                      Native|  Translation
Form                 5.25"/HH              Cylinders    1544|     |     |
Capacity form/unform   107/  125 MB        Heads           3|     |     |
Seek time   / track  18.0/ 4.0 ms          Sector/track     |     |     |
Controller           SCSI1 MAC             Precompensation
Cache/Buffer            32 KB              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          16.0 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     CSA,FCC,IEC380,UL478,VDE



  |                                   Terminator +--------+ |XX J1
  |                                   Connector  |  (3)   | |XX Power
  |                                   Mount PWA  +--------+ |xx
  |                                   (Visable from bottom) |+-+
  |                                                         || |J2
  |                                                         |+-+
  |                                                         |++
  |                                                         |||J4
  |                                                         |||
  |                                                         |++
  |                                                         |XX Inter-
  |                                                         |XX face
  |                                                         |XX J3
  |                                                         |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 V HH is enabled.

J4 Terminator Power/Test Seek

     Position A
 (3)| o    o    xxxxxxx   o    o    o    o |
        J3-26   TP  +5V        TST  GRD  M

     Position B
 (3)| o    xxxxxxx   o    o    o    o    o |
        J3-26   TP  +5V        TST  GRD  M

     Position C
 (3)| xxxxxxx   o    o    o    o    o    o |
        J3-26   TP  +5V        TST  GRD  M

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

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

     If a jumper is installed in position C the WREN V HH will supply
     terminator power to pin 26 of the interface cable. [Note: If a
     jumper is installed in position C a jumper must also be installed
     in Position A to power the internal terminators.

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 |
        J3-26   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 |
        J3-26   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 VDC
      | 1  2  3  4 |   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. 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 V HH mounting orientations are permitted: disk in the
horizontal plane and disks 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.

WREN V HH 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 HH 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 0.25 in. (6.35 mm).

Cabinet cooling must be designed by the customer so that the ambient
temperature immediately surrounding the WREN V HH 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 V HH precludes
the necessity for special tools. If field repair of items external to
the HDA is desired, a 6 point Torx T8 and T10 drivers are required.
It may be purchased through most commercial tool catalogs.

Physical Description
Model 94221 WREN V HH may be daisychained together or with other
compatible SCSI devices using a common cable. Both ends of the cable
must be terminated. The WREN V HH 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 94221 WREN V HH 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
terminated. For drives that are not to be terminated, remove the
terminator resistor packs, not the terminator power source selector

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
equipment. 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 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 94221 WREN V HH 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: DuPont 78963-001 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 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

T indicates termination required.

DC Cable and Connector
The WREN V HH 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 94221 WREN V HH 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
 V HH.

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

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

Terminator Requirements
Internal WREN V HH I/O termination consist of three resistor modules
which plug into sockets on the Main PWA. The WREN V HH 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 V HH 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. The 330 ohm
resistor to ground still affects the circuit operation.

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 as desired.

Terminator Power
The WREN V HH 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 V HH power connector.The WREN V HH
can also be configured to supply terminator power to Pin 26 o the
SCSI bus via an isolation diode.
Single ended 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

AC/DC Ground Separation
The 94221 WREN V HH is provided with the DC/HDA logic ground and
chassis tied together. An option is provided permitting the user to
isolate the ground planes by repositioning the "U" shaped grounding
washer. This option may be beneficial in reducing ground induced
noise in some system applications.



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

The WREN V HH is a UL Recognized component per UL 478 and a CSA
Certified component per CSA C22.2 No. 154-M1983. It also meets the
requirements of DIN IEC 380/VDE 0806/8.81.

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

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

The WREN V HH uses the Zone Bit Recording (ZBR TM) version of
variable track capacity recording, an advanced recording technique
that oprimize the recording media utilization. The ZBR technology
results in increased performance due to the higher transfer rates
associated with the outer data tracks. Reliability is also improved
by reducing the number of disks necessary to obtain the required

Media Description
The media used on the WREN V HH 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 V HH, 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 V HH
internal defect/error management and SCSI systems error
considerations (errors in communications between Initiator and WREN
V HH). 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 V HH Internal Defects/Errors
Identified defects are recorded on the WREN V HH 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 V HH
format operation. The WREN V HH 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 V HH 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 V HH, or can be reallocated when the host sends the Reassign
Blocks Command.

 Seek Time
                    Without Controller Overhead

                                          | 209 MB  | 184 MB  |
        Track-to-Track         msec. typ. |   4     |    4    |
                               msec. max. |   6     |    6    |
                       Average msec. typ. |  18     |   16.5  |
                       Average msec. max. |  20     |   18.5  |
                               msec. max. |  40     |   38    |
        Latency                msec. avg. |   8.33  |    8.33 |

                    Including Controller Overhead

                                          | 209 MB  | 184 MB  |
        Track-to-Track         msec. typ. |   4.6   |    4.6  |
                               msec. max. |   6.6   |    6.6  |
                       Average msec. typ. |  18.6   |   17.1  |
                       Average msec. max. |  20.6   |   19.1  |
                               msec. max. |  40.7   |   38.7  |
        Latency                msec. avg. |   8.33  |    8.33 |

Read Look-Ahead/Cache Control
The WREN V HH Model 94221 provides a selectable 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 V HH. The WREN V HH
protects against inadvertent writing during power up and down.
Daisychain operation requires that power be maintained on the
terminated WREN V HH to ensure proper termination of the peripheral
I/O cables.

Start/Stop Time
After DC power has been applied, the WREN V HH will become ready
within 20 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 25 seconds from removal of DC power.

If the Motor Start Option is enabled, the internal controller will
accept a Motor Start, Test Unit Ready, Inquiry or Request Sense
Command via the sCSI interface 3 seconds after DC power has been

After the Motor Start Command has been received the WREN V HH will
become ready for normal operations within 20 seconds. During this
time the drive will respond to the SCSI interface.

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 V HH 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 V HH. The temperature of the HDA is restricted to a maximum of
142*F (61.4* C) during operation.

Air Cleanliness
The WREN V HH 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, environmental conditions and environmental requirements.

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

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