Hard Drive: SEAGATE: ST1201E SWIFT 178MB 3.5"/HH ESDI
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...
Layout
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 +---------------------------------------------------------+
Jumpers
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.
Install
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, whetherin 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.
Features
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
General
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.
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