
S T 4 1 6 5 0 N    SEAGATE
NO MORE PRODUCED                                      Native|  Translation
                                                      ------+-----+-----+-----
Form                 5.25"/FH              Cylinders    2107|     |     |
Capacity form/unform  1415/ 1650 MB        Heads          15|     |     |
Seek time   / track  15.0/ 2.5 ms          Sector/track     |     |     |
Controller           SCSI2 SINGLE-ENDED    Precompensation
Cache/Buffer           256 KB SEGMENTED    Landing Zone
Data transfer rate    3.500 MB/S int       Bytes/Sector      512
                      5.000 MB/S ext SYNC
Recording method     RLL 1/7                        operating  | non-operating
                                                  -------------+--------------
Supply voltage     5/12 V       Temperature *C        10 50    |    -10 54
Power: sleep              W     Humidity     %         8 80    |      5 95
       standby            W     Altitude    km    -0.305  3.048| -0.305 12.210
       idle          21.0 W     Shock        g         2       |     32
       seek          25.0 W     Rotation   RPM      3597
       read/write         W     Acoustic   dBA
       spin-up            W     ECC        Bit   64
                                MTBF         h     150000
                                Warranty Month        12
Lift/Lock/Park     YES          Certificates     CSA,FCC,IEC380,IEC435,UL47...


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                        L   A   Y   O   U   T
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SEAGATE  ST41650N (WREN 8)  PRODUCT MANUAL 77765470-A JUNE 1991

  +---------------------------------------------------------++-1
  | +-+ J6                                                  || |J4
  | | |                                                 ++  |+-+
  | +-+                                                 ||  |XX
  |                                                     ||  |XX
  |                                                     +1  |XX
  |                                     Terminator      ++  |XX J3
  |                                     resistor        ||  |XX SCSI
  |                                     (SIPs)          ||  |XX I/O
  |                                                     +1  |XX
  |                                                     ++  |XX
  |                                                     ||  |XX
  |                                                     ||  |XX
  |                                                     +1  |XX
  |                                                  (J8+-+)|X1
  |                                                  (  +-+)|
  | +-+J7                                                   |XX Power
  | +-+ LED                                                 |XX  J1
  +---------------------------------------------------------+  1



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                      J   U   M   P   E   R   S
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SEAGATE  ST41650N (WREN 8)  PRODUCT MANUAL 77765470-A JUNE 1991

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


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


 Drive ID/Option Select Header (Addendum)
 ----------------------------------------
                        SCSI I/O
                    +-----J3----   -+      +J1-
 --+------J4-------++:::::::      ::++-J8+-+O O O  Power
   |2 o o o o o o o|+-------      --+|o o| +-------
   |1 o o o o o o o|                 |1 o|
   +----+-+-+------+                 +---+
    +++ 4 2 1 | | + (6)               (4)
    (7)       | +-- (3)
              +---- (2)


 The figure above shows the drive ID select and configuration option
 select jumper headers (J4 and J8) that apply to some early customer
 development units. Only a few of these will be shipped. This
 addendum figure will be included in the preliminary Product Manual
 until the drives being shipped change over to the PWA that has the
 configuration shown in the first figure. The notes (1) through (7)
 apply the same to either figure.

      +------------+----------+
      |            | 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  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 8 is enabled.

 (4)  If the unit is not be terminated, remove terminator resistor
      module SIPs. TP Jumper in left vertical position means
      terminator power (+5V) is from WREN 8 power connector. Jumper
      in horizontal position means terminator power is taken from
      interface cable. Jumper in right TP position means +5V is
      supplied to the interface cable pin 26. Jumpers can be in both
      vertical positions at same time. 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)  CLOSED  Configures the drive for non-synchronized Spindle
              option. A four pin connector plugs here to provide the
              Reference Index Signal.


 J6  Write Protect/Remote LED Header
 -----------------------------------
  +-+J7 LED          +------- GND              Pin 1 (+5V)
 -+-+-----------+----+----+----                Pin 2 LED ON/OFF signal
                | 2  o  x +---- Factory use only!
                | 1  o  x +---- Factory use only!
                +----+----+
                     +------- Write Protect, Remote switch Cable
                              Connection

 The Write Protect/Remote LED Header is a 6-pin, 3 jumper (or
 connector) position header behind the front panel at the right side
 of the drive, opposite the LED. The pins are on 0.100 inch (2.54 mm)
 centers both vertically and side to side. A suggested mating two pin
 connector is the DuPont Mini Latch housing P/N 65291-008 or
 equivalent. The drive front panel must not be present in order to
 access the header. For a remote LED capability, plug the remote LED
 cable connector vertically to the leftmost two pins of the header (as
 viewed from the front of the drive). The center two pins provide a
 drive write protect capability. A shorting jumper plug may be
 plugged vertically onto these two pins to write protect the drive or
 a two-pin cable connector may be plugged there to connect the two
 pins to a remote Write Protect switch. The rigthmost two pins are
 RESERVED for factory use only.


 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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SEAGATE  ST41650N (WREN 8)  PRODUCT MANUAL 77765470-A JUNE 1991

 Notes on installation
 =====================

 Installation direction
 ----------------------

     horizontally                           vertically
   +-----------------+             +--+                       +--+
   |                 |             |  +-----+           +-----+  |
   |                 |             |  |     |           |     |  |
 +-+-----------------+-+           |  |     |           |     |  |
 +---------------------+           |  |     |           |     |  |
                                   |  |     |           |     |  |
                                   |  |     |           |     |  |
 +---------------------+           |  +-----+           +-----+  |
 +-+-----------------+-+           +--+                       +--+
   |                 |
   |                 |
   +-----------------+

 The drive will operate in all axis (6 directions).


 Drive Orientation
 -----------------
 The balanced rotary arm actuator design of the WREN 8 allows it to
 be mounted in any orientation. All drive performance characteriza-
 tion, however, has been done with the drive in horizontal (discs
 level) and vertical (drive on its side) orientations, and these are
 the two preferred mounting orientations.

 The WREN 8 is designed, manufactured, and tested with a "Plug-in and
 Play" installation philosophy. This philosophy minimizes the
 requirements for highly trained personnel to integrate the WREN 8
 into the OEM's system, wether in a factory or field environment.


 Mounting Holes
 --------------
 Four on bottom. Two on each side. 6-32-INC. max. screw length into
 side of chassis 3.17 mm (0.125 in). Max. screw length into bottom of
 chassis is 3.17 mm (0.125 in).


 Cooling
 -------
 Cabinet cooling must be designed by the customer so that the
 ambient temperature immediately surrounding the WREN 8 will not
 exceed temperature conditions. Specific consideration should be given
 to make sure adequate air circulation is present around the PWAs.


 Service Tools
 -------------
 No special tools are required for site installation or recommended
 for site maintenance. The depot repair philosophy of the WREN 8
 precludes the necessity for special tools. Field repair of the drive
 is not practical since there are no user purchasable parts in the
 drive.


 Air Cleanliness
 ---------------
 The WREN 8 is designed to operate in a typical office environment
 with minimal environment control.


 Drive Termination
 -----------------
 This option may be incorporated during manufacture at the request of
 the customer. For single ended interface drives, termination consists
 of three 220/330 ohm resistor modules (SIPs) which are installed on
 the Main PWA via sockets.


 Power Sequencing
 ----------------
 Power sequencing is not required for the WREN 8. The WREN 8 protects
 against inadvertent writing during power up and down. Daisychain
 operation requires that power be maintained on the terminated WREN 8
 to ensure proper termination of the peripheral I/O cables.


 Synchronized Spindle Operation
 ------------------------------
 The synchronized spindles operation allows several drives operating
 from the same host to operate their spindles at the same synchronized
 rotational rate. Drives operating in a system in synchronized mode
 increase the system capacity and transfer rate in a cost effective
 manner.

 The interface consists of a twisted pair cable that connects the
 drives in the synchronized system in a daisy chain. Master/Slave
 operation will be automatically set by the druves in the system at
 power-up time, or each drive in the system can be configured by the
 host (using a Mode Select command) to operate in either the master or
 slave mode. While loading heads after power up, a drive checks for
 occurrences of the Reference Index signal. If there are no Reference
 Index pulses occuring, the drive takes over as master and begins
 sending the reference Index signal. Drives can be re-configured by
 the host any time after power up to be master or slave by use of the
 Mode Select command Rigid Disc Drive Geometry page.

 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 synchronized mode when powered up.
 Each drive can later be reconfigured to the non-synchronized mode in
 which it ignores the reference index signal that might be present.

 The connection 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.

 Each drive can be configured for the non-synchronized mode in which
 it ignores any reference signal that might be present. The connection
 of the synchronized 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 reference signal (REFSIG+) is provided by the servo/read-write
 LSI on the master drive. It is 60 Hz crystal generated signal. The
 signal is normally false/negated (nominal 0V) and makes a transition
 to the true/asserted (nominal +5V) level to indicate the reference
 position during the revolution period. The trailing (falling) edge of
 the reference signal is used by the master and the slave drives to
 phase lock their spindles. A maximum of 10 seconds is allowed for a
 slave to synchronize with the reference signal.


 Electrical Description
 ----------------------
 The electrical interface consists of on edigital TTL reference index
 signal and ground. The Reference Index Signal (REFSIG+) is an output
 if the drive is configured as a master and is an input otherwise.


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

  Negated (Flase): 0.0 V to +0.4 V @ I = -48 mA (max).
  Asserted (True): +2.24 V to +5.25 V @ I = +250 uA.


 Termination
 -----------
 The Reference Index Signal should be terminated with a 2K ohm
 resistor. Each drive has a termination resistor located on the Main
 PWA. Each drive has a terminator resistor which is not removable and
 is always in the circuit.


 J4 (20-Pin) Physical Interface
 ------------------------------
 The rightmost four pins of the Select Header are used as the
 Reference Index Signal (REFSIG+) interface. It is a 20-pin gold
 header type connector, Seagate part number 77612203 DuPont
 Electronics part number 65624-140 (or equivalent). A recommended
 mating connector is a DuPont Electronics Mini-Latch Housing, crimp-
 to-wire pins part number 65043-035 (4 pins)(or equivalent).


 Front Panel
 -----------
 The normal front panel available is black plastic. Other panel colors
 may be special ordered. Each panel has a single rectangular LED
 indicator lens which, when glowing indicates the drive is selected.
 LED lens colors available are red, amber or green.



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                      F   E   A   T   U   R   E  S
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SEAGATE  ST41650 (WREN 8)  PRODUCT MANUAL 77765470-A JUNE 1991

 Standards
 ---------
 The WREN 8 has been developed as a system peripherals to the
 highest standards of design and construction. The WREN 8 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 8 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 0806/08.81, DIN IEC 435/VDE 0805/
 11.84 and EN 60 950/9.87.

 The WREN 8, as delivered, is designed for system integration
 before use. It is supplied as a component or subassembly as defined
 in the FCC Rules and Regulations, Part 15, Subpart J governing EMI
 of computing devices end the Radio Interference Regulations of the
 Canadian Department of Communications. The WREN 8 is, therefore,
 not directly subject to the FCC rules and regulations or the Radio
 Interference Regulations of the Canadian Department of Communica-
 tions.

 The head, disc and actuator chamber (HDA) is environmentally sealed
 at the factory. Air is recirculated within the HDA and passes through
 a nonreplaceable filter to ensure the maintenance of a contamination
 free disc/actuator environment.

 The WREN 8 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 drive automatically goes to the
 landing zone when the power goes off.

 The WREN 8 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 8 decodes Track 0 location from the dedicated servo surface
 thereby eliminating mechanical transducer adjustments and related
 reliability concerns.

 The WREN 8 use 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 in the WREN 8 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
 ---------------------------
 The WREN 8, 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 the WREN 8
 internal defect/error management and SCSI systems error considera-
 tions (error in communications between host and WREN 8). 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 8 Internal Defect/Errors
 -----------------------------
 Identified defects are recorded on the WREN 8 defects list tracks
 (referred to as the primary or ETF defect list). These known defects
 are reallocated during the initial WREN 8 format operation at the
 factory. The WREN 8 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 8 automatic retries and data correction
 by ECC are disabled, defects are usally unrecoverable and need to be
 reallocated as they are discovered. 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 8, or can be reallocated
 when the host sends the Reassign Blocks Command.


 Seek Time
 ---------
       +----------------------------------+--------+
       |Track-to-Track         msec. typ. |   2.5  |
       |                       msec. max. |   4.0  |
       |               Average msec. typ. | <15    |
       |               Average msec. max. |  17.0  |
       |Maximum Seek Time      msec. typ. |  34    |
       |                       msec. max. |  38    |
       +----------------------------------+--------+


    Including Controller Overhead
    -----------------------------
       +----------------------------------+--------+
       |Track-to-Track         msec. typ. |   3.20 |
       |                       msec. max. |   4.70 |
       |               Average msec. typ. |  15.70 |
       |               Average msec. max. |  17.70 |
       |Maximum Seek Time      msec. typ. |  34.70 |
       |                       msec. max. |  38.70 |
       +----------------------------------+--------+


 Temperature
 -----------
 The drive will meet all specifications over a 50*F to 122*F (10*C to
 50*C) drive 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. Operation at case
 temperatures above these values may adversely affect the drives
 ability to meet specifications.


 Heat/Power Dissipation
 ----------------------
 For drives with single ended interface WREN 8 will dissipate no more
 than 25 watts (85.4 BTUs per hour) of DC power average under worst
 case operating conditions at nominal voltage. Typical power
 dissipation under idle operating conditions is less than 21 watts
 (71.7 BTUs) per hour.


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

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


 Prefetch/Multi-Segmented Cache Control
 --------------------------------------
 The WREN 8 provides a Prefetch/Multi-Segmented Cache algorithm that
 in many cases can enhance system performance. This feature is
 selected by issuing the Mode Select Command with the proper values in
 the applicable bytes in pages 08h and 38h.

 In general, 192 Kbytes of the 240 Kbytes physical buffer space in the
 WREN 8 can be used as a cache. The cache is divided into logical
 segments from which data is read and to which data is written. WREN 8
 keeps track of the logical block addresses of the data stored in each
 segment of the cache. If the cache is enabled, data requested by the
 host with a Read command is retrieved from the cache, if possible,
 before any disc access is initiated. Data in contiguous logical
 blocks immediately beyond that which was requested by the Read
 command can be retrieved and stored in the cache for immediate
 transfer to the initiator can limit the amount of prefetch data to
 optimize system performance. The WREN 8 never prefetches more sectors
 than the number specified in bytes 8 and 9 of Mode Page 08h. If the
 cach eis not enabled, 240 Kbytes of the buffer is used as a circular
 buffer for Read/Writes, with no prefetch operation and no segmented
 cache operation.


 Unformatted and Formatted Capacities
 ------------------------------------
 Unformatted Capacity of the WREN 8 ST41650N is 1.65 GB
 Formatted capacity depends on the number of spare reallocatin sectors
 reserved and the number of bytes per sector. The following table
 shows som etypical formatted capacities:
   +---------------------------+--------------------------------+
   |Spare Sectors per Cylinder |         Sector Size*           |
   |Reserved for reallocation  | 512 Bytes/Sec.| 1024 Bytes/Sec.|
   +---------------------------+---------------+----------------+
   |No Spares                  | 1432 MB       | 1524 MB        |
   +---------------------------+---------------+----------------+
   |One Spare Sectors Per Track| 1415 MB       | 1490 MB        |
   |    Two Spare Cylinders per|               |                |
   |    Unit**                 |               |                |
   +---------------------------+---------------+----------------+
   |Five Spare Sectors per cyl.| 1427 MB       | 1513 MB        |
   |    One Spare Cyl. per Unit|               |                |
   +---------------------------+---------------+----------------+
 * 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. See Mode Select Command and
 Format Command in the WREN SCSI Interface Product Manual P/N
 77765466.

 ** Spare cylinders are on the inner tracks.

 The standard OEM model is as follows:
   +---------+-------------------------+------------+
   |         |Formatted Data Block Size|Unformatted |
   +---------+-----------+-------------+------------+
   |ST41650N | 1024 Byte | 512 Byte    |            |
   |         | 1490 MB   | 1415 MB     | 1650 MB    |
   +---------+-----------+-------------+------------+


