
S T 3 2 8 5 N    SEAGATE
                                                      Native|  Translation
                                                      ------+-----+-----+-----
Form                 3.5"/SLIMLINE         Cylinders    1689|     |     |
Capacity form/unform   248/      MB        Heads           3|     |     |
Seek time   / track  12.0/ 4.0 ms          Sector/track     |     |     |
Controller           SCSI2 SI/FAST         Precompensation
Cache/Buffer           128 KB SEACACHE     Landing Zone
Data transfer rate    2.000 MB/S int       Bytes/Sector      512
                     10.000 MB/S ext SYNC
Recording method     ZBR RLL1/7                     operating  | non-operating
                                                  -------------+--------------
Supply voltage     5/12 V       Temperature *C                 |
Power: sleep              W     Humidity     %                 |
       standby        1.0 W     Altitude    km                 |
       idle           3.0 W     Shock        g                 |
       seek           5.7 W     Rotation   RPM
       read/write         W     Acoustic   dBA
       spin-up            W     ECC        Bit
                                MTBF         h     250000
                                Warranty Month
Lift/Lock/Park     YES          Certificates                                  

**********************************************************************
                        L   A   Y   O   U   T
**********************************************************************
SEAGATE  ST3285N  INSTALLATION GUIDE



 Rear                   +- 50 pin SCSI Interface I/O connector
 View                   |
                        |                    DC power
    (TOP)      +------------- -----------+ +-5-G-G-12+
  -------------+||||||||||||||||||||||||1+-+ O O O O +----
    (BOTTOM)   +-------------------------+ +---------+
                  xxxxxx1 xxxxxx1 xxxxxx1
                Terminating Resistor Packs


 ST-3285N                       +-----+
 Left View                      |o o o1
               (TOP)            |o o o|    +-+
      Front --------------------++-+-++----+X|I/O connector
                                 | | |     +-+
              SCSI Address ID 1 -+ | |
                           ID 2 ---+ |
                           ID 4 -----+


 ST-3285N
 Right View
            +-----+  +-------+
            | o o4|  | o o o6|        (TOP)
        +-+ |1o o |  |1o o o |
 DC PowerX+-+-----+--+-------+-------------------------------
        +-+



**********************************************************************
                      J   U   M   P   E   R   S
**********************************************************************
SEAGATE  ST3285N  JUMPER SETTING

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


 Rear                   +- 50 pin SCSI Interface I/O connector
 View                   |
                        |                    DC power
    (TOP)      +------------- -----------+ +-5-G-G-12+
  -------------+||||||||||||||||||||||||1+-+ O O O O +----
    (BOTTOM)   +-------------------------+ +---------+
                  xxxxxx1 xxxxxx1 xxxxxx1
                Terminating Resistor Packs


 ST-3285N                       +-----+
 Left View                      |o o o1
               (TOP)            |o o o|    +-+
      Front --------------------++-+-++----+X|I/O connector
                                 | | |     +-+
              SCSI Address ID 1 -+ | |
                           ID 2 ---+ |
                           ID 4 -----+


 ST-3285N
 Right View
            +-----+  +-------+
            | o o4|  | o o o6|        (TOP)
        +-+ |1o o |  |1o o o |
 DC PowerX+-+--+--+--+--+----+-------------------------------
        +-+    |        |
               |     +--+----+
               |      Active/Passive Termination
             +-+-+   +--+----+
  Terminator Power  +---+----------------------------+
             +-+-+  | Active: Pins 1 & 2 shorted     |
               |    |         only (+2.85V to        |
               |    |         110  ) for FAST        |
               |    |         SCSI;                  |
               |    |Passive: Pins 2 & 4 shorted     |
               |    |         AND pins 5 & 6 shorted |
               |    |         (+5V and GND to        |
               |    |         220/330  ) for         |
               |    |         standard SCSI.         |
               |    +--------------------------------+
               |
 +-------------+---------------------------------------------------+
 |Terminator Power: From SCSI Connector ---------------- Pins 1 & 2|
 |                  -----------------------------------------------+
 |                  From Power Connector --------------- Pins 1 & 3|
 |                  -----------------------------------------------+
 |                  To SCSI Connector Only ------------- Pins 3 & 4|
 |                  -----------------------------------------------+
 |                  From Power Connector and ----------- Pins 1 & 2|
 |                  AND to SCSI Bus ------------------------- 3 & 4|
 |                  -----------------------------------------------+
 |                  Terminating Resistors not Installed -Pins 2 & 4|
 +-----------------------------------------------------------------+


 ST-3285N
 Front View

             +------------------ SCSI ID's (none for ID0)
             |                   not used if ID set on side jumpers
             |   +-------------- Ext. Spindle Clock Synch
             |   |               pin-5 is Clock Ground
             |   | +------------ Remote LED
 TOP)      +-+-+ | | +---+---+-- Reserved
         +-4-2-1-+-+-+---+---++
         | o o o o o-o o o o o|+-------+
         |1o o o o o+o o o o o||o o o o|+
       --+--------------------+1o o o o+---------------
                               ++-+-+-++
 (BOTTOM)                       | | | +-- Remote LED
                                | | +---- Ext. Spindle Clock Sync
                                | |       pin-5 is Clock Ground
                                | +------ Remote Start Enable
                                +-------- Parity Enable


 Terminator power source jumper block
 ------------------------------------
 To select the termination power source, install jumpers as follows:
 - To provide terminator power to the SCSI connector and the drive
   terminator packs, install jumpers on pins 1 and 2 and pins 3 and 4
   of the terminator power source jumper block. This is the default.

 - To select the drive power connector as the termination power source
   for the resistor packs, install a jumper on pins 1 and 3 of the
   terminator power source jumper block.

 - To select the SCSI connector as the termination power source for
   the resistor packs, install a jumper on pins 1 and 2 of the
   terminator power source jumper block.

 - To provide terminator power to the SCSI connector from the drive
   power connector only, install a jumper on pins 3 and 4 of the
   terminator power source jumper block.


 Active/passive termination jumper block
 ---------------------------------------
 To select active termination (the default), install a jumper on pins
 1 and 2 of the active/passive termination jumper block. To select
 passive termination, install jumpers on pins 5 and 6 and pins 2 and
 4 of the active/pas-sive termination jumper block, and change the
 terminating resistor packs.

 Caution. When installing jumpers on the options jumper block and the
 user-configuration jumper block, be careful to install jumpers on the
 correct pins. Install jumpers only on pins 1 through 4 of the options
 jumper block and pins 1 through 6 of the user-configuration jumper
 block. If you install jumpers on pin pairs that are meant to accept
 only twisted pair connectors, the drive may not function properly.


 Remote LED connection
 ---------------------
 Remote LED pins are located on two separate jumper blocks: the
 options jumper block and the user-configuration jumper block. Attach
 a two-pin remote LED connector to either jumper block, as follows:

 - User-configuration jumper block, pins 9 and 10. Use any 2-pin, 2-mm
   connector and an LED from LiteOn , part number LTL-3231A.

 - Options jumper block, pins 7 and 8. Use any 2-pin, 0.1-inch
   connector and an LED from LiteOn , part number LTL-3231A.


 External spindle synchronization option
 ---------------------------------------
 You can synchronize the spindle motors of an array of drives by
 connecting a twisted pair to each drive. The maximum cable length is
 6 feet (1.8 meters).

 Spindle synchronization pins are located on two separate jumper
 blocks: the options jumper block and the user-configuration jumper
 block. Use either jumper block to synchronize an array of drives, as
 follows:

 - User-configuration jumper block. Use one strand of the twisted pair
   to connect together pin 7 of the user-configuration jumper block of
   each drive. Use the other strand to connect together pin 8 of the
   user-configuration jumper block of each drive.

 - Options jumper block. Use one strand of the twisted pair to
   connect together pin 5 of the options jumper block of each drive.
   Use the other strand to connect together pin 6 of the options
   jumper block of each drive.

 The spindle-synchronization characteristics can be controlled by the
 Mode Select command using the RPL bits in byte 17 of the Rigid Disc
 Geometry page.

 In the default mode, all drives arbitrate during startup to see which
 drive will be the synchronized master. When the drives are
 calibrating their heads, they each check for a reference signal
 pulse. The drive that becomes ready first checks for the reference
 signal, and when it does not detect a pulse, it takes over as the
 master and begins sending reference pulses. All other drives
 synchronize their spindles to the reference signal as they in turn
 become ready.



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                      I   N   S   T   A   L   L
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SEAGATE  ST3655 FAMILY  PRODUCT MANUAL

 Notes On Installation
 =====================

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

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

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


 Drive mounting
 --------------
 You can mount the drive in any orientation. Follow the guidelines
 below appropriate to the set of mounting holes you elect to use:
 either bottom mounting holes or side mounting holes.
 Caution. Do not remove factory-installed labels from the drive or
          cover them with additional labels. If you do, you may void
          your warranty. Factory-installed labels contain information
          required when servicing the product.


 Bottom mounting holes
 ---------------------
 Use 6-32 UNC screws in three of the four available bottom mounting
 holes.

 Caution. Do not insert the bottom mounting screws more than 0.20
          inches (6 turns) into the drive frame. If you use a screw
          that is too long, you could damage the drive.


 Side mounting holes
 -------------------
 Use 6-32 UNC screws in three of the six available side mounting
 holes. Do not use all three mounting holes on the same side of the
 drive.

 Caution. Do not insert side mounting screws more than 0.13 inches (4
          turns) into the drive frame. If you use a screw that is too
          long, you could damage the drive.


 Shock and vibration
 -------------------
 All shock and vibration specifications assume that the drive is
 mounted in a recommended mounting configuration. Inputs are measured
 at the drive mounting screws. Shock measurements are based on an 11
 msec, half sine wave shock pulse, not to be repeated more than twice
 per second.

 During operating shock and vibration, there is no physical damage to
 the drive or performance degradation. During nonoperating shock and
 vibration, the read/write heads are positioned in the shipping zone.


 DC power
 --------
 Except during the write procedure, you can apply power to the drive
 or remove power from the drive in any sequence without losing data or
 damaging the drive. If you remove the power from the drive during the
 write procedure, you may lose the data currently being written.


 Power management
 ----------------
 The drive supports power-management modes that reduce its overall
 power consumption. The drive automatically changes from one mode to
 another based in response to interface activity. You do not need to
 change any parameters or send any special commands to make the drive
 change modes. The power-management modes are described below.

 - Spinup. The spindle is coming up to operating speed. The power
           consumed in this mode is equivalent to the average power
           during the first 10 seconds after the drive begins to spin
           up.

 - Seeking. The servo electronics are active and the read/write heads
            are moving to a specific location on the disc. The
            read/write electronics are powered-down. The power
            consumed in this mode is equivalent to the average power
            measured while executing random seeks with a 2-revolution
            (26.6 msec) dwell between seeks. The drive enters this
            mode from the Idle mode.

 - Read/write. The drive is reading or writing. All electronics are
               active and the read/write heads are on track. The drive
               enters this mode from the Idle mode.

 - Idle. The drive spindle motor is up to speed and the servo
         electronics are active. The heads are on track, ready to
         accept and execute any command without delay. The read/write
         electronics are powered down. The drive can enter this mode
         from any other mode (except the Standby mode).

 - Standby. This mode is not implemented.


 Hardware and interface
 ----------------------
 The SCSI-2 interface consists of a 9-bit bidirectional bus (8 data
 bits and 1 parity bit) plus 9 control signals supporting multiple
 initiators, disconnect and reconnect, and self-configuring host
 software. Logical block addressing is used.

 The physical interface consists of single-ended drivers and receivers
 using asynchronous or synchronous communication protocols that
 support cable lengths of up to 6 meters (3 meters for Fast SCSI) and
 a bus interface transfer rate up to 5 Mbytes per second asynchronous
 and 10.0 Mbytes per second synchronous. The bus protocol supports
 multiple initiators, disconnect and reconnect, additional messages,
 and 6-byte and 10-byte command descriptor blocks.


 SCSI-2 compatibility
 --------------------
 The drive interface is described in the Seagate Wren SCSI-2 Interface
 Product Manual, publication number 77765466. The drive complies with
 the mandatory subset of the ANSI SCSI-2 interface. The Fast SCSI-2
 interface is based on the ANSI Small Computer System Interface-2
 (SCSI-2): document number ANSI X3.131-199 x (X3T9.2/86-109 Rev. 10h).


 Handling and static-discharge precautions
 -----------------------------------------
 After you unpack the drive, and before you install it in a system, be
 careful not to damage it through mishandling. Observe the following
 standard handling and static-discharge precautions:

 Caution:
 - Keep the drive in its static-shielded bag until you are ready to
   complete the installation. Do not attach any cables to the drive
   while it is in its static-shielded bag.

 - Before handling the drive, put on a grounded wrist strap, or ground
   yourself frequently by touching the metal chassis of a computer
   that is plugged into a grounded outlet. Wear a grounded wrist strap
   throughout the entire installation procedure.

 - Handle the drive by its edges or frame only.

 - The drive is extremely fragile_handle it with care. Do not press
   down on the drive top cover.

 - Always rest the drive on a padded, antistatic surface until you
   mount it in the host system.

 - Do not touch the connector pins or the printed circuit board. Do
   not touch the printed circuit cable between the circuit board and
   the head/disc assembly.

 - Avoid wool or synthetic clothing, carpeting, plastics and
   Styrofoam; these items cause static discharge.

 - Do not remove the factory-installed labels from the drive or cover
   them with additional labels. If you do, you may void the warranty.
   Some factory-installed labels contain information needed to service
   the drive. Others are used to seal out dirt and contamination.


 Hot-plugging
 ------------
 If there is more than one SCSI device daisy-chained on the bus, you
 can connect and disconnect the drive I/O and power connector if the
 following conditions are met:

 - The drive you are disconnecting (or connecting) is not the device
   supplying terminator power or terminating resistance to the bus.

 - During hot-plugging, do not add or remove terminator power or
   resistors from the bus.

 - During hot-plugging, do not use the bus for I/O transactions. If
   you are installing a drive on the bus, there must be no I/O
   transactions until the drive is connected and ready. If you are
   removing a drive from the bus, there must be no I/O transactions
   until the drive is completely disconnected.

 To avoid damage to the disc and head, the spindle must be completely
 stopped and the heads must be parked before you remove the drive from
 the system. There are two ways to stop the spindle and park the
 heads:

 - If the drive is not configured to use the remote start/stop
   feature, disconnect the DC power cable from the drive DC power
   connector and wait 30 seconds.

 - If the drive is configured to use the remote start/stop feature,
   issue the SCSI stop command and wait 30 seconds.


 SCSI connector
 --------------
 You can daisy-chain the drive with a maximum of seven other SCSI
 devices (including the host) that have single-ended drivers and
 receivers using a common cable. SCSI ID 7, by convention, is usually
 used for the host adapter. No drive can have the same SCSI ID as the
 host adapter.

 All signals are common between all SCSI devices. The SCSI devices at
 both ends of the daisy-chain must be terminated; the intermediate
 SCSI devices should not be terminated.

 The 50-conductor, nonshielded mating cable connector consists of two
 rows of 25 female contacts with adjacent contacts 0.100 inches apart.

 The drive connector is a nonshielded, 50-pin connector consisting of
 two rows of 25 pins with adjacent pins 0.100 inches apart. The
 connector is keyed with a slot.


 Cable requirements
 ------------------
 The characteristic impedance of the cable should be between 90 ohms
 and 140 ohms. However, most available cables have a somewhat lower
 characteristic impedance. To minimize discontinuities and signal
 reflections, do not use cables of different impedances in the bus.
 Your design may require trade-offs in shielding effectiveness, the
 length of the interface cable, the number of loads, and the transfer
 rates. If your design uses both shielded and nonshielded cables
 within the same SCSI bus, you must allow for the effects of impedance
 mismatch.

 To minimize noise effects, use a minimum conductor size of 28 AWG.
 Use only nonshielded cable connectors. Use a 50-conductor flat cable
 or 25-conductor twisted-pair cable. The recommended nonshielded flat
 cable part numbers are shown in the following table:

 Part Manufacturer
 Flat Cable 3M-3365-50 Twisted Pair
 Spectra Twist-N-Flat 455-248-50


 Single-ended cable
 ------------------
 The single-ended SCSI cable must meet the following requirements:

 - The cable cannot be longer than 6.0 meters.

 - A cable stub cannot be longer than 0.1 meter, from the mainline
   interconnection to any device. Stubs must be separated by at least
   0.3 meter.

 Fast synchronous data transfer
 ------------------------------
 When using fast synchronous data transfer rates, the SCSI interface
 cable must meet the following additional requirements:

 - The cable cannot be longer than 3.0 meters.

 - A characteristic impedance of 90 ohms to 132 ohms is recommended
   for nonshielded flat cable or twisted-pair ribbon cable.

 - The signal attenuation at 5 MHz must not be greater than 0.095 dB
   per meter.

 - The DC resistance at 20*C must not exceed 0.230 ohms per meter.

 - The propagation delay delta of a shielded, twisted-pair cable must
   not exceed 20 nsec per meter.


 DC power connector
 ------------------
 The drive is equipped with a 4-pin power connector.


 Terminators
 -----------
 The interface is terminated with three SIP resistor modules that plug
 into sockets on the printed circuit board. You can order the drive in
 the active (default) or passive configuration, or without
 terminators, depending on your application. When installing or
 removing terminators, follow these guidelines:

 - If you are installing only one drive, and your system contains only
   one initiator (for example, a stand-alone host computer) leave the
   terminators installed on the drive.

 - If you are installing multiple drives in a daisy-chain
   configuration, remove the terminators from all drives except the
   drives (or initiators) connected to the ends of the cable.

 - If your application requires no terminators, remove the terminators
   from the drive circuit board. Removing the terminator power source
   selection jumper does not disconnect the terminator resistors from
   the circuit.

 - If you use Fast SCSI transfer rates, you must use the active
   termination options. If the transfer rate is 5.0 Mbytes per second
   or less, you can use either method of termination.


 Active termination
 ------------------
 All interface signals are single-ended and must be terminated at the
 drive with a 110-ohm resistor to +2.85V. This is the default. The
 Seagate  part number for the 110-ohm terminator is 502155-001.


 Passive termination
 -------------------
 All interface signals with the drive are single-ended and must be
 terminated with 220 ohms to +5V and 330 ohms to ground at each end
 of the cable. All signals use open-collector drivers or three-state
 drivers. The Seagate part number for the 220/330-ohm terminator is
 75916526-9.


 Single-ended drivers and receivers
 ----------------------------------
 The drive uses single-ended drivers and receivers.

 - Transmitter characteristics. The drive 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 volts.

 - Receiver characteristics. The drive uses an ANSI SCSI single-ended
   receiver with hysteresis gate or equivalent as a line receiver.
   The loss in the cable is defined as the difference between the
   voltages of the input and output signals.



**********************************************************************
                      F   E   A   T   U   R   E  S
**********************************************************************
SEAGATE  ST3655  FAMILY  PRODUCT MANUAL

 Reliability
 -----------
 Read error rates are measured with automatic retries and data
 correction with ECC enabled and all flaws reallocated. MTBF is
 measured at nominal power at sea level and 40*C ambient temperature.

 Nonrecoverable read errors 1 per 10           13 bits transferred

 Seek errors 1 per 10                           7 physical seeks

 MTBF                                     250,000 power-on hours

 Service life                                   5 years


 Acoustics
 ---------
 Sound pressure is measured at idle from 1 meter above the drive top
 cover.

 Sound pressure, typ 34 dBA
 Sound pressure, max 38 dBA


 Seek time
 ---------
 All seek time measurements are under nominal conditions of
 temperature and voltage with the drive mounted horizontally. In the
 table below:

 - Track-to-track seek time is the average of all possible
                  single-track seeks in both directions.

 - Average seek time is a true statistical random average of at least
           5,000 measurements of seeks in both directions between
           random cylinders, less overhead.

 - Full-stroke seek time is one-half the time needed to seek from
               logical block address zero (LBA 0) to the maximum LBA
               and back to LBA 0.

 Note. Host overhead varies between systems and cannot be specified.
       Drive internal overhead is measured by issuing a no-motion
       seek. Drive overhead is typically less than 1.0 msec.


 Read look-ahead and caching
 ---------------------------
 The drive uses algorithms that improve seek performance by storing
 data in a buffer and processing it at a more convenient time. Three
 methods are employed: read look-ahead, read caching and write
 caching.


 Thermal compensation
 --------------------
 The thermal compensation feature compensates for position offset of
 the selected head due to variations in temperature. The drive
 automatically performs thermal compensation during startup and every
 2 minutes thereafter.

 You can preempt the automatic compensation by issuing a Rezero Unit
 command (01H). The drive performs the thermal calibration and then
 sets a timer and waits 2 minutes before performing the calibration
 again.

 Thermal compensation increases the execution time of the command
 during which it is performed by 100 msec (typ) to 350 msec (max).


 FCC verification
 ----------------
 ST3655 family drives are intended to be contained solely within a
 personal computer or similar enclosure (not attached to an external
 device). As such, a drive is considered to be a subassembly even when
 individually marketed to the customer. As a subassembly, no Federal
 Communications Commission authorization, verification or
 certification of the device is required.

 Seagate Technology, Inc. has tested these drives in an enclosure as
 described above to ensure that the total assembly (enclosure, disc
 drive, motherboard, power supply, etc.) does comply with the limits
 for a Class B computing device, pursuant to Subpart J of Part 15 of
 the FCC rules. Operation with noncertified assemblies is likely to
 result in interference to radio and television reception.

 Radio and television interference. This equipment generates and uses
 radio frequency energy and, if not installed and used in strict
 accordance with the manufacturer's instructions, may cause
 interference to radio and television reception.

 This equipment is designed to provide reasonable protection against
 such interference in a residential installation. However, there is no
 guarantee that interference will not occur in a particular
 installation. If this equipment does cause interference to radio or
 television, which can be determined by turning the equipment on and
 off, you are encouraged to try one or more of the following
 corrective measures:

 - Reorient the receiving antenna.

 - Move the device to one side or the other of the radio or TV.

 - Move the device farther away from the radio or TV.

 - Plug the equipment into a different outlet so that the receiver
   and computer are on different branch outlets.

 If necessary, you should consult your dealer or an experienced
 radio/television technician for additional suggestions. You may find
 helpful the following booklet prepared by the Federal Communications

 Commission: How to Identify and Resolve Radio-Television Interference
 Problems. This booklet is available from the Superintendent of
 Documents, US Government Printing Office, Washington, DC 20402. Refer
 to publication number 004-000-00345-4.

 Note. This digital apparatus does not exceed the Class B limits for
 radio noise emissions from computer equipment as set out in the radio
 interference regulations of the Canadian Department of
 communications.


