
S T 1 2 0 1 E                 S W I F T    SEAGATE
NO MORE PRODUCED                                      Native|  Translation
                                                      ------+-----+-----+-----
Form                 3.5"/HH               Cylinders    1072|     |     |
Capacity form/unform   178/  201 MB        Heads           9|     |     |
Seek time   / track  15.0/ 4.0 ms          Sector/track   36|     |     |
Controller           ESDI                  Precompensation 65535
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               W     Shock        g        10       |     50
       seek          12.0 W     Rotation   RPM      3600
       read/write         W     Acoustic   dBA
       spin-up            W     ECC        Bit
                                MTBF         h      30000
                                Warranty Month
Lift/Lock/Park     YES          Certificates     CSA,FCC,IEC380,IEC435,UL47...


**********************************************************************
                        L   A   Y   O   U   T
**********************************************************************
SEAGATE  ST1111/ST1156/ST1201-E  PRODUCT MANUAL 36135-001, REV. B

  +---------------------------------------------------------+x Ground
  |                                                 +-J7--1 |X1
  |                                                 +-----+ |XXControl
  |                                                    ++   |XXCable
  |                                                    ||   |XX
  |                                                    ||   |XX
  |                                          Terminator++   |XX
  |                                          Resistor  ++   |XX
  |                                          Sip (2)   ||   |XX
  |                                                    ||   |XX
  |                                                    +++-+|
  |                                                    J6| ||
  |                                                      +-1|X1
  |                                                         |XXData
  |                                                         |XXCable
  |                                                         |XX
  |                                                         |   Power
  |                                                         |XXXXX J3
  +---------------------------------------------------------+



**********************************************************************
                      J   U   M   P   E   R   S
**********************************************************************
SEAGATE  ST1111/ST1156/ST1201-E  PRODUCT MANUAL 36135-001, REV. B

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

 x = Jumpers set at factory



 J3  Power Connector
 -------------------

          +---+---+---+---+
          | 1 | 2 | 3 | 4 |
          +--++--++--++--++
             |   |   |   +---------- + 5V
             |   |   +-------------- + 5V Return
             |   +------------------ +12V Return
             +---------------------- +12V



 J6   Drive select
 -----------------

        Drive |  1   |  2   |  3   |
        ------+------+------+------+
          0   |OPEN  |OPEN  |OPEN  |
   x      1   |CLOSED|OPEN  |OPEN  |
          2   |OPEN  |CLOSED|OPEN  |
          3   |CLOSED|CLOSED|OPEN  |
          4   |OPEN  |OPEN  |CLOSED|
          5   |CLOSED|OPEN  |CLOSED|
          6   |OPEN  |CLOSED|CLOSED|
          7   |CLOSED|CLOSED|CLOSED|


 Drive Select 0 is not allowed!


 Drive Select
 ------------
 The following characteristics apply to the Drive Select lines:

  1.   Logical unit designation for up to 7 drives is performed during
       installation by installing jumpers on pins on a connector
       header on the PWA. The jumpers are installed in a complemented
       binary coded position configuration to select device addresses
       1 through 7. Zero is not a valid address.

  2.   The controller shall not attempt to select the drive until one
       (1) second after DC power is applied. The Ready output will be
       valid (whether asserted or negated) within 1 us after the drive
       is selected.

  3.   The drive will be selected (and the Drive Selected Signal
       asserted) within 1 us after the Drive Select lines contain that
       unit's select address. The drive will be deselected (and the
       Drive Selected signal negated) within 1 us after the Drive
       Select lines contain another unit's select address.

  4.   The Drive Select lines must remain asserted for 1 us after a
       write operation.

  5.   When the Drive Select lines are asserted, a head change will
       occur, requiring a delay before a read or write operation can
       be initiated.



 J7  Motor Start Option
 ----------------------
     1   OPEN    Spindle motor starts on power-up
         CLOSED  Spindle motor start command required to start motor


 J7  Sector Mode
 ---------------
     2   OPEN    Hard sector mode
         CLOSED  Soft sector mode

 The SWIFT supports the use of the soft sector format as described in
 the CDC ESDI Specification, 77738076, Section 6.4.4.

 To implement the optional soft sectored format operation, select
 "Address Mark" mode in the SWIFT by installing configuration jumper.


 J7  Sector Configuration
 ------------------------
     3   CLOSED
     4   OPEN    34 sectors per track at 512 bytes pro sector
     --------------------------------------------------------
         3   OPEN
         4   OPEN   36 sectors per track at 512 bytes per sector
         -------------------------------------------------------
              3   OPEN
              4   CLOSED  64 sectors per track at 256 bytes per sector
              --------------------------------------------------------
                   3   CLOSED
                   4   CLOSED  Factory test
                   -------------------------


 J7  External Spindle Clock (optional)
 -------------------------------------
      5   OPEN    Spindle sync disabled
          CLOSED  Spindle sync enabled

 The external spindle clock option allows for synchronized rotation of
 multiple disk drives in a system. Each drive can be configured to one
 of the following modes:

       a. Use internal spindle clock, omit spindle reference clock.
       b. Use external spindle clock with a line terminator.
       c. Use external spindle clock without the line terminator.


 System Configuration
 --------------------
 The spindle rotation synchronization uses one of the following
 methods:
       a. Reference clock is generated by the controller. All the disk
          drives are connected radially to the controller. Each end
          must be terminated.
       b. Reference clock is generated by the controller. All the disk
          drives are connected in parallel (daisy chain) to the
          controller. The controller end and the last drive in the
          chain must be terminated.
       c. Reference clock is generated by a master disk drive. The
          controller receives the clock and provides all other drives
          in the system with the reference clock using the radial or
          the daisy chain connection method. Each end (master disk
          drive and controller) must be terminated.
       d. Reference clock is generated by a master disk drive. All
          disk drives are connected in parallel (daisy chain) to the
          master disk drive. The master disk drive end and the last
          drive in the chain must be terminated.



**********************************************************************
                      I   N   S   T   A   L   L
**********************************************************************
SEAGATE  ST1111/ST1156/ST1201-E  PRODUCT MANUAL 36135-001, REV. B

 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!
      Never install PC board on the Top!



 Drive Orientation
 -----------------
 The permissible drive mounting orientations include operation in the
 horizontal plane with PCB down and in the vertical plane. Mounting
 with either end down (front or rear) is not permissible.


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


 Front Panel
 -----------
 The SWIFT is available with a black front panel. The panel has a
 a single green rectangular lens through which ligth from a LED
 mounted on the PWA radiates. The LED indicates the drive is selected
 when glowing. A flashing LED indicates the presence of a non-
 recoverable fault. A fault indication is displayed irrespective of
 DRIVE SELECT status.


 Cooling
 -------
 Cabinet cooling must be designed by the customer so that the ambient
 temperature immediately surrounding the SWIFT does not exceed
 temperature conditions.

 Sway
 ----
 The sway of the HDA left to right and front to rear is within the
 envelope. The sway of the HDA up and down is   0.05 inch outside the
 envelope.



 Interface Cabling Options
 -------------------------

 View A
    +---------------------Host-Controller---------------------+
    |                                                         |
    |Data Control   Data Control  Data Control   Data Control |
    +--+-----+--------+-----+--------+-----+--------+-----+---+
       |     |        |     |        |     |        |     |
       |     |        |     |        |     |        |     |
       |     |        |     |        |     |        |     |
       |     |        |     |        |     |        |     |
    +-++-+--++-+-+ +-++-+--++-+-+ +-++-+--++-+-+ +-++-+--++-+-+
    | |T |  |*T| | | |T |  |*T| | | |T |  |*T| | | |T |  |*T| |
    | +--+  +--+ | | +--+  +--+ | | +--+  +--+ | | +--+  +--+ |
    |   SWIFT    | |   SWIFT    | |   SWIFT    | |   SWIFT    |
    +------------+ +------------+ +------------+ +------------+

    Each control cable length must not exceed 10 feet (3.00m). Each
    data cable length must not exceed 10 feet (3.00m).


   *T  indicates removable terminator resistor pack.
    SWIFT data ports are permanently terminated.



 Radial Configuration
 --------------------
 View A shows each drive interfaced to its own control cable, which
 allows interfacing an arbitrary number of drives and a variety of
 system operational techniques. Each drive has its data cable and
 control cable connected to the host controller. The length of each
 individual cable must not exceed 10 feet (3.00 meters). Terminator
 resistors must be installed in the host controller for each data
 cable and for each control cable. For this configuration, a
 terminator resistor pack must be installed in each SWIFT Disc Drive.




 View B
    +--------------Host Controller-------------+
    |                                          |
    |Data Control   Data          Data         |
    +-+------+-------+--------------+----------+
      |      |       |              |
      |      |       |              |
      |      |       |              |
      |      +-**----+-Control------+Control+
    +++-+----+---+ +++-+-----+--+ +++-+----++-++
    ||T |        | ||T |        | ||T |    |*T||
    |+--+        | |+--+        | |+--+    +--+|
    | SWIFT/ESDI | | SWIFT/ESDI | | SWIFT/ESDI |
    +------------+ +------------+ +------------+

    Total control cable length must not exceed 10 feet (3.00m). Each
    data cable length must not exceed 10 feet (3.00m).

   *T  indicates removable terminator resistor pack.
   SWIFT data ports are permanently terminated.
   ** May be up to seven (7) devices in daisychain.


 Daisychain Configuration
 ------------------------
 A daisychain configuration connects a maximum of seven drives in
 parallel on a common control cable. Only the drive selected by the
 host system has its control signals enabled through this
 common interface. View B illustrates a daisy chain of SWIFT Disk
 Drives or other ESDI devices. A terminator resistor pack is
 required in the host controller for each data cable. Only the last
 ESDI device in the daisychain requires a terminator resistor pack
 for the control cable. Terminator resistor packs for the control
 cable or other drives must be removed. The total combined control
 cable length (from the controller to the first drive, to the second
 and subsequent drives) must not be more than 10 feet (3.00 meters).


 DC Cable and Connector
 ----------------------
 The SWIFT receives DC power through a 4 pin connector mounted on the
 HDA. Recommended part numbers of the mating connector are provided,
 but equivalent parts may be used.

 Type of cable:      18 AWG
 Connector:          AMP 1-480424-0
 Contacts:           AMP 60619-4 (Loose Piece); AMP 61117-4 (Strip)


 Ground Connection
 -----------------
 A quick disconnect, Amerlock MTL-1802-A, is provided on the drive
 chassis.

 Type of cable:      26-24 AWG
 Connector:          WALDOM ST-2750
 Contacts:           Quick Disconnect (Ground)



 Data Cable and Connector
 ------------------------
 The I/O connector for the data interface is a 20 pin board edge
 connector. The odd pins are located on the side of the printed
 circuit board facing towards the HDA. The even pins are on the side
 of the printed circuit board facing away from the HDA. A key slot is
 provided between pins 3 and 5. CDC recommends keying this connector
 to prevent installing it upside down. However, the SWIFT will not be
 damaged if the connector is installed upside down.

 Recommended part numbers for the mating connector are included below,
 but equivalent parts may be used.

 Connector:          20 pin, 3M-3461-0001, AMP 88373-6
 Cable:              Flat Cable (Stranded AWG 28) 3M-3365-20
                     Flat Cable (Stranded AWG 28) 3M-3517-20 (Shielded
                     Cable)
 Key:                AMP 583274-1, 3M-3439-0000



 Command Cable and Connector
 ---------------------------
 The I/O connector for the control interface is a 34 pin board edge
 connector. The odd pins are located on the front side of the
 printed circuit board facing towards the HDA and are connected to the
 ground plane. The even pins are on the side of the printed circuit
 board facing away from the HDA. A key slot is provided between pin 3
 and 5. CDC recommends keying this connector to prevent installing it
 upside down.

 Recommended part numbers for the mating connector are provided, but
 equivalent parts may be used.

 Connector:          34 pin, 3M-3463-0001, AMP 88373-3
 Key:                AMP 583274-1, 3M-3439-0000
 Cable:              Flat cable (Stranded AWG 28) 3M-3365-34
                     Flat cable (Stranded AWG 28) 3M-3517-34 (Shielded
                     Cable)
                     Spectra Strip Twist'n Flat 455-248-34 (Stranded
                     AWG 28 Twisted Pair)


 Spindle reference clock Cable and Connector
 -------------------------------------------
 The connector for the spindle reference clock signal is a 2-pin 2.0
 mm pitch connector. The recommended connector consists of:

        a.  DuPont Housing  69305-002
        b.  DuPont Terminal 77138-001

 or equivalent.

 The cable consists of two 28 AWG wires. The maximum cable length is
 20 feet (6.1 metres).



 Interface Drivers/Receivers
 ---------------------------
 The SWIFT uses both single ended and balanced differential signals on
 the I/O. The data signals use balanced differential drivers and
 receivers. All other signals use single ended drivers and receivers.


 Single Ended Drivers/Receivers
 -------------------------------
 Transmitter Characteristics
 The SWIFT uses the 74F38 open collector quad invertor buffer/driver
 to transmit status to the host. This driver is capable of sinking a
 current of 40 mA with a low level output voltage of 0.7 V.


 Receiver Characteristics
 The SWIFT uses a custom receiver with hysteresis gate as a line
 receiver. The input of each receiver is terminated with a 150 ohm
 pull-up resistor.


 Terminator Characteristics
 The terminator are resistor modules which plug into  sockets in the
 last drive in a daisychain. Each drive is furnished with terminators.
 Terminators must be removed from all except the last drive on the
 cable prior to daisychain operation. Equivalent terminators must be
 provided in the controller on each input signal line from the drive
 to the controller. Only the command cable resistor modules are
 removable. The removable terminators are Beckman Industrial P/N
 L081C151F or equivalent.


 Balanced Differential Drivers/Receivers
 ---------------------------------------
 Transmitter Characteristics
 The SWIFT uses 75158 type balanced differential drivers. An assertion
 on  the interface is defined when the "+" output is more positive
 than the "-" output.


 Receiver Characteristics
 The SWIFT uses 75157 type balanced differential receivers. An
 assertion on the interface is defined when the "+" input is more
 positive than the "-" input.


 Terminator Requirements
 Each differential receiver in the drive is terminated with a 100 ohm
 resistor. These terminators are not removable. An equivalent
 terminator must be provided in the controller on each input signal
 line from the drive to the controller.



**********************************************************************
                      F   E   A   T   U   R   E  S
**********************************************************************
SEAGATE  ST1111/ST1156/ST1201-E  PRODUCT MANUAL 36136-001, REV. B

 General Description
 -------------------
 The SWIFT 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 Model 94356 SWIFT supports the Enhanced Small Device Interface
 (ESDI) as deccribed in Control Data's ESDI Specification (77738076).
 This product specification was created to be used in conjunction with
 this industry standard interface specification.


 Standards
 ---------
 The SWIFT has been developed as a system peripherals to the highest
 standards of design and construction. The SWIFT 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 SWIFT complies with CDC standards.


 The SWIFT is a UL Recognized component per UL478 and a CSA Certified
 product per CSA C22.2, No. 220-M1986. It also meets the requirements
 of DIN IEC 380/IEC 435/IEC 950/VDE 0806/8.81.

 The SWIFT, as delivered, is designed for system integration before
 use. It is supplied as a Class A Computing device per the FCC Rules
 and Regulations, Part 15, Subpart J governing EMI of computing
 devices.


 The SWIFT uses a dedicated landing zone at the innermost radius of
 the media, where there is no user data, thus eliminating the
 possibility of destroying or degrading customer data. Read/write
 heads are automatically moved to the landing zone upon loss of power.

 The SWIFT incorporates an automatic shipping look which prevents
 potential damage to the heads and discs caused by movement during
 shipping and handling. The shipping lock is automatically disengaged
 when power is applied to the drive and nominal spindle speed is
 achieved.

 The SWIFT decodes Track locations from the dedicated servo surface
 thereby eliminating mechanical transducer adjustments and
 related reliability concerns.

 The SWIFT uses a high performance actuator assembly consisting of a
 low inertia, patented straight arm driven by a highly efficient
 pancake coil assembly. This actuator mechanism provides excellent
 performance with minimal power dissipation.

 Media Description
 -----------------
 The media used in the SWIFT has a diameter of approximately 95 mm.
 The aluminum substrate is coated with a thin film magnetic material,
 and lubricated to permit the heads to contact the surface when start-
 ing and stopping.

 Each data surface has a total of 1072 tracks and is capable of
 recording 22,383,360 bytes of unformatted data.

 Media defects are characterized as beeing ether correctable or
 uncorrectable as a function of the type and magnitude of the media
 flaw. Various error correction codes may be implemented to correct
 errors in the data read from the disk. However, the code chosen
 should be consistent with Control Data media testing and
 certification methods. In the SWIFT media certification is performed
 using the following standards:

            An error burst of 11 bits or less is a correctable error.

            An error burst greater than 11 bits in length is an un-
            correctable error.

 Host systems using the SWIFT should have, as a minimum, resident
 capabilities to recognize and map defective tracks and perform track
 reallocation routines.

 At the time of shipment from the point of manufacture, the SWIFT
 recording surfaces meet the following requirements.

       1. 1072 total data tracks per surface.

       2. Track 0 to be error free on each data surface.

       3. 40 bad tracks per surface maximum.

       4. Cumulative defects not to exceed 1 per megabyte, based on
          total available unformatted drive capacity.



 Defect and Error Management
 ---------------------------
 The SWIFT, as delivered, complies with this specification. The read
 error rate and specified storage capacity are not dependent upon use
 of defect management routines. However, a carefully chosen defect
 management plan can significantly enhance overall system performance.

 Identified defects are recorded on the defects list tracks per CDC
 ESDI specification. It is recommended that these known defects be re-
 allocated during the initial format operation. Sector reallocation is
 suggested because, in general, it is more efficient and may offer
 significant performance improvement. Error Correction Code (ECC)
 should be used to correct additional flaws as they occur. ECC is re-
 commended since most of the defects are recoverable with ECC. If ECC
 is not used, defects are usually unrecoverable and need to be re-
 allocated as they are discovered.


 Acoustic Noise Level
 --------------------
 Acoustic noise power level of the SWIFT should be less than TBD bels
 during idle/operating mode. Equivalent typical average sound pressure
 level should be less than TBD dba when measured with microphone at a
 distance of one meter from the drive.


 Custom Formatting
 -----------------
 The SWIFT is formatted during production. CDC maintains custom
 formatting capability which can incorporate many of the unique
 formats used in the Winchester marketplace. A majority of special
 format requirements can be implemented as specified.


 Drive/Receiver Characteristics
 ------------------------------
 Logic Level                   Drive Output         Receiver Input
 --------------------------------------------------------------------
 High (false/negated) (0)      2.5 V;   5.25 V      2.0 V;   5.25 V
 Low  (true/asserted) (1)      0.4 V;   0.0 V       0.5 V;   0.0 V

 The difference in the voltages between input and output signals is
 due to the losses in the cable.


 Seek Time
 ---------

                                          |  SWIFT |
        ----------------------------------+--------+
        Track-to-track         msec. max. |   4    |
                       Average msec. typ. |  15    |
                       Average msec. max. |  16.5  |
        Latency                msec. avg. |   8.33 |
        ----------------------------------+--------+
 Seek time is defined as the time required from the receipt of a seek
 or position command by the SWIFT until the drive signals the
 controller that it is ready to perform another seek or  read/write
 function on the new cylinder. Average seek time is determined by
 dividing the sum of the time for all possible movements by the total
 number of movements.


 Spindle Speed and Latency
 -------------------------
 The spindle speed is 3600   0.5% r/min. The speed tolerance includes
 motor performance and motor control circuit tolerances.

 The average latency time is 8.33 milliseconds, based on a nominal
 disk speed of 3600 r/min. The maximum latency time is 16.75 milli-
 seconds based on a minimum disc speed of 3582 r/min.


 Read Data Transfer Rate
 -----------------------
 The nominal read serial data transfer rate is 10.0225 MHz   1% Mega-
 bits per second, 1.25 Megabytes per second.


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


 Temperature
 -----------
 50* to 122*F (10*C to 50*C) (dry air) operating ambient with a
 maximum gradient of 18* F (10* C) per hour. Above 1000 feet (305
 meters) altitude the maximum temperature is derated linearly to 112*F
 (44.0*C) at 10,000 feet (3048 meters). Cabinet packaging designs
 must provide ample air circulation around the SWIFT to make sure
 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
 SWIFT. The temperature of the HDA is restricted to a maximum of
 TBD during operations.


 Reliability
 -----------
 The following reliability specifications assume correct host/drive
 operational interface has been implemented, including all interface
 timings, power supply voltages, and environmental conditions and
 appropriate data handling circuits in the host system.

 MTBF                     30,000 hours
 Service Life             5 years
 Preventive Maintenance   None required



**********************************************************************
                      G   E   N   E   R   A   L
**********************************************************************
SEAGATE   SCSI CONNECTOR

 Evolution of the SCSI Connector:
 The Single Connector Standard
 -----------------------------

 Introduction
 ------------
 The advent of SCSI as the interface of choice among high-performance
 system designers has provided several benefits for the computing
 industry. Unlike traditional interface designs which usually only
 allow two data storage peripherals, SCSI allows the use of multiple
 peripherals operating on a common bus. Because of the expandability,
 power and flexibility afforded by this implementation, system
 designers quickly embraced SCSI as the optimal interface for
 performance intensive computing platforms.

 Unfortunately, the very elements which provide this flexibility and
 expandability also created difficulty in the configuration and
 installation of several peripherals within a single enclosure.
 Furthermore, the increasing popularity of disc arrays and
 mass-storage subsystems has created the need for efficient and
 simplified component designs.

 Currently, installing a SCSI drive is a complex procedure. Apart from
 physically mounting the drive within the system chassis, there are
 the additional tasks of attaching the interface and power cables to
 their appropriate connectors, and placing several jumpers on the
 circuit board to configure the drive for proper operation within the
 SCSI subsystem.

 These jumpers are used to designate mandatory options such as a
 specific SCSI ID for that drive, and application specific
 options such as a delayed or remote start of the spindle motor. If a
 visual indication of drive operation is desired, an additional cable
 attachment is necessary for the activity LED. For applications which
 require several drives to synchronize their spindle rotation, yet
 another connection must be made to provide the drive with an external
 clock signal.

 To complicate matters, the SCSI interface itself is specifically
 designed to accommodate the concurrent operation of several
 peripherals simultaneously. Under such circumstances, the task of
 configuring, installing and connecting several peripherals multiplies
 the number of necessary operations. Maintenance of such an
 arrangement can become very complicated -- the proverbial "Plumber's
 nightmare."

 The Single Connector Standard as proposed by Sun Microsystems,
 Seagate Technology and other drive manufacturers is an ideal design
 solution for these problems. The Single Connector was created to
 facilitate the expandability and flexibility of the SCSI interface,
 while simplifying the  intricacies of peripheral installation and
 interconnection. In addition to vastly simplifying this process, the
 standard also encompasses all of the critical elements necessary for
 migration to the Fast and Wide implementations of SCSI.


 Evolution of the Connector
 --------------------------
 In short, the Single Connector is true to its name. It integrates the
 power connector, the interface connector, the SCSI ID jumpers, the
 LED signal, and several other functions into a single unit. The
 intent of the design is to create a single point of contact for all
 electrical and electronic connection necessary to operate a SCSI
 peripheral. As such, it represents an evolution from earlier,
 disjoint methods to a single, unified system of peripheral
 attachment.

 Present within the connector is the full complement of interface
 signals required for the 8-bit bandwidth of the standard SCSI
 interface. Also present, are the additional signal lines required for
 Fast/Wide SCSI, which support 16-bit operation as well. The Fast/Wide
 SCSI specification also extends the maximum number for peripherals
 common to a SCSI bus from eight units to 16 units. The Single
 Connector Standard provides support for all requirements for the
 operation of Fast/Wide SCSI. Therefore, the migration to Fast/Wide
 SCSI from standard SCSI is already built into the specification.

 In addition to the interface signals, the standard also includes the
 provision of setting a device's SCSI ID via system software. Four
 signal lines have been designated to allow the host system to assign
 a device's SCSI ID. This includes option of dynamically reassigning
 and software device selection. For applications which require
 on-the-fly adjustment of the peripheral ID and selection status on
 the SCSI bus, this feature is invaluable.

 Special features required by specific types of applications have also
 been integrated in to the Single Connector specification. First, the
 inclusion of a specific Spindle Synchronization signal will provide
 an essential feature to the design of many disc array and RAID array
 systems. The synchronization process begins with a clock pulse
 generated by an external source, such as the host, or perhaps another
 drive. An individual drive is able to coordinate the rotation of its
 spindle motor to the clock signal, which insures all drives within
 that subsystem are rotating in concert. Many disc arrays require this
 feature for coherent operation of multiple components as a unified
 whole.

 Other special features supported by the connector are Delayed Spindle
 Start and Remote Spindle Start.
 Delayed motor start is usually necessary for systems which need time
 to initialize the host system before the drives are needed on-line.
 Certain systems have special power consumption requirements which
 also require the Delayed Spindle.

 Start option. The Remote Spindle
 Start option is a feature which allows the host to control when the
 drive initiates spin-up of the spindle motor. In large disc arrays
 some drives are assigned special functions (such as data backup), and
 consequently are used rarely. In such cases there is no need for the
 drive to be spinning, as long as the electronic circuitry on the
 drive is active. Remote Spindle Start allows the drive's electronics
 to remain active, while the spindle is at rest. When data is
 necessary from the drive, the command is sent to start the spindle
 motor. This feature conserves system power and minimizes wear on the
 spindle motor.

 The last elements integrated into the Single Connector are the power
 lines. The specification provides both +5 Volt and +12 Volt power,
 with dedicated ground for each. Specifically, there are four +12 Volt
 and 12 Volt ground lines, with three +5 Volt and 5 Volt ground lines.
 The power and ground lines are strategically positioned on the
 connector to mitigate the effects of electro-magnetic interference
 with the signal lines.

 Finally, the connector was originally designed to fit onto the
 chassis of low profile (1-inch height) 3.5" disc drive.
 However, the connector itself can fit 1.6-inch high 3.5-inch disc
 drives and 2.5-inch drives as well. This flexibility provides
 for the migration to smaller form-factor drives as well.


 Advantages
 ----------
 The structure of the connector connotes modifications to the host
 chassis. The impetus for the development of the Single Connector was
 the need for simplification of the host design. The chief objectives
 included the reduction of complexity in attaching or replacing a
 peripheral. Essential to the simplification process is the
 implementation of a series of mating connectors mounted on the host
 system backplane. Properly designed backplanes would allow the
 installation of a drive without the need for attaching any cables. In
 fact, backplane mounting provides an immediate solution for two
 common problems associated with traditional installment. First, the
 Single Connector backplane avoids the tangle of interface cables,
 power cables, LED activity indicators and so forth. Fears of
 malfunctioning wires and twisted cables are also allayed. One
 connection provides for all of the functions and helps alleviate all
 of the problems.

 More importantly, electro-magnetic noise which is incurred from
 adjacent cables is completely eliminated, since there are no cables
 necessary in the interface connection. This helps preserve the
 integrity of the data on the SCSI bus and prevents signal corruption.

 Probably the best feature of the of Single Connector implementation
 is the capability it provides for blind mating the drive to the host.
 Since all necessary functions are integrated within the connector, a
 single action is all that is necessary to install a drive. Blind
 mating greatly simplifies peripheral attachment in critical
 applications such as network data servers, RAID arrays and data
 backup systems. With proper design of the backplane and mounting
 frame, a technician will be able to install a drive by simply sliding
 the drive along the mounting rails until it mates with the
 connector. The installation would be done without the need for
 reaching in to the mounting enclosure, without setting any
 configuration jumpers, or attaching any cables. Even the drive
 configuration can be done by the host via the ability to softselect
 the drive's SCSI ID and operating parameters. Blind plane mating
 gives the Single Connector unparalleled ease and time savings for
 peripheral installation.


 Summary
 -------
 The manifold advantages of Single Connector are largely self-evident.
 The spindle synchronization and ease of mounting create an excellent
 solution for RAID implementations. The capability to remotely
 configure the drive and ease of installation naturally lends the
 Single Connector for use in networked environments.

 Furthermore, the ability to migrate to other platforms is a key
 factor in the viability and growth potential of the Single Connector
 Standard. Therefore, the single Connector is an excellent choice for
 system designers wishing to simplify the host design process through
 streamlining and integration. The ability to migrate upward to
 Fast/Wide SCSI, or down-size to the 2.5-inch form-factor,
 concurrently allows the system to accommodate higher bus bandwidths
 and upcoming peripheral form-factors.

 The Single Connector provides unprecedented ease, speed and
 integrated upgradability within a single specification. It has a high
 potential for simplifying a vast number of applications while
 simultaneously reducing installation time and costs. The Single
 Connector signifies an evolution of the SCSI connector. It provides
 the rarest of combinations:

 enhanced simplicity, reduced cost, and an increased time savings.


