Hard Drive: IMPRIMIS: SWIFT 94335-150 128MB 3.5"/HH RLL ST412
S W I F T 9 4 3 3 5 - 1 5 0 IMPRIMIS
NO MORE PRODUCED Native| Translation
------+-----+-----+-----
Form 3.5"/HH Cylinders 1072| | |
Capacity form/unform 128/ 151 MB Heads 9| | |
Seek time / track 14.5/ 4.0 ms Sector/track 26| | |
Controller RLL / ST412 Precompensation 300
Cache/Buffer KB Landing Zone
Data transfer rate 0.938 MB/S int Bytes/Sector 512
MB/S ext
Recording method RLL 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 8.0 W Shock g 2 | 50
seek 10.0 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 ST1100/ST1150R PRODUCT MANUAL 36136-001, REV. B
+---------------------------------------------------------+ | J7 +--------+1 |X1 | +--------+ |XX | ++ |XXControl | Terminator || |XXCable | Resistor || |XX | Sip || |XX | ++ |XX | |XX | |XX | | | |X1 | |XX | |XXData | |XXCable | |XX | |XX +---------------------------------------------------------+
Jumpers
SEAGATE ST1100/ST1150R PRODUCT MANUAL 36136-001, REV. B
Jumper setting
==============
x = Jumpers set at factory
J3 Power Connector
-------------------
+---+
| 1 +------- 12 V
| 2 +------- 12 V Return
| 3 +------- 5 V Return
| 4 +------- 5 V
+---+
J4 ST 506 Interface
--------------------
Signal Direction Signal Direction
+-----------+ +-------------+
| | |Signal Ground|
| | Terminated |No. No. |
| +------------------------------------->| 2 1 |
| | Head Select 2(3) | |
| +------------------------------------->| 4 3 |
| | Write Gate | |
| +------------------------------------->| 6 5 |
| | Seek Complete | |
| |<-------------------------------------+ 8 7 |
|Controller/| Track 0 | |
|Host |<-------------------------------------+ 10 9 |
|Interface | Write Fault | |
| |<-------------------------------------+ 12 11 |
| | Head Select 2(0) | |
| +------------------------------------->| 14 13 |
| | Reserved to J5 pin 7 | |
| +--------------------------------------+ 16 15 |
| | Head Select 2(1) | |
| +------------------------------------->| 18 17 |
| | Index | |
| |<-------------------------------------+ 20 19 |
| | Ready | |
| |<-------------------------------------+ 22 21 |
| | Step | |
| +------------------------------------->| 24 23 |
| | Drive Select 1 | |
| +------------------------------------->| 26 25 |
| | Drive Select 2 | |
| +------------------------------------->| 28 27 |
| | Drive Select 3 | |
| +------------------------------------->| 30 29 |
| | Drive Select 4 | |
| +------------------------------------->| 32 31 |
| | Direction In | |
| +------------------------------------->| 34 33 |
| | | |
+-----------+ +-------------+
SWIFT Control
Cable Connector
J4
All signals in the control cable are single ended signals.
Pin 2 in the command cable (Head Select 2(3)) is defined as Reduced
Write Current in the Seagate St412 interface. The SWIFT controls
write current internally, and thus the line is not needed for this
function and is used for head selection.
J5 ST 506 Interface
---------------------
Signal Direction Signal Direction
+-----------+ +-------------+
| | |Pin No. Type*|
| | Drive Selected | |
| |<-------------------------------------+ 1 SE |
| | Ground | |
| +--------------------------------------+ 2 |
| | Reserved | |
| +--------------------------------------+ 3 SE |
| | Ground | |
| +--------------------------------------+ 4 |
|Controller/| Motor On (Optional) | |
|Host +--------------------------------------+ 5 SE |
|Interface | Ground | |
| +--------------------------------------+ 6 |
| | Reserved to J4 Pin 16 | |
| +--------------------------------------+ 7 SE |
| | Ground | |
| +--------------------------------------+ 8 |
| | Reserved | |
| +--------------------------------------+ 9 |
| | Reserved | |
| +--------------------------------------+ 10 |
| | Ground | |
| +--------------------------------------+ 11 |
| | Ground | |
| +--------------------------------------+ 12 |
| | +MFM (RLL) Write Data | |
| +------------------------------------->| 13 DIFF|
| | -MFM (RLL) Write Data | |
| +------------------------------------->| 14 DIFF|
| | Ground | |
| +--------------------------------------+ 15 |
| | Ground | |
| +--------------------------------------+ 16 |
| | +MFM (RLL) Read Data | |
| |<-------------------------------------+ 17 DIFF|
| | -MFM (RLL) Read Data | |
| |<-------------------------------------+ 18 DIFF|
| | Ground | |
| +--------------------------------------+ 19 |
| | Ground | |
| +--------------------------------------+ 20 |
| | | |
+-----------+ +-------------+
SWIFT Data
Cable Connector
J5
* SE = Single ended signals DIFF = Differential signal
J7 Drive Select/Radial Select/External Spindle Clock
------------------------------------------------------
+-------------------+
| 1 3 5 7 9 11 |
| 2 4 6 8 10 12 |
+-+--+--+--+--+--+--+
| | | | | +------------ External Spindle Clock Connector
| | | | +--------------- Radial Select
| | | +------------------ Drive Select 4
| | +--------------------- Drive Select 3
| +------------------------ Drive Select 2
+--------------------------- Drive Select 1
J7 Drive Select
----------------
+----------------------------------------------------+ | SELECT 1-2 3-4 5-6 7-8 | +----------------------------------------------------+ |Drive Select 1 CLOSED OPEN OPEN OPEN | |Drive Select 2 OPEN CLOSED OPEN OPEN | |Drive Select 3 OPEN OPEN CLOSED OPEN | |Drive Select 4 OPEN OPEN OPEN CLOSED | +----------------------------------------------------+
Drive Select 1-2-3-4
--------------------
These lines are used to activate a device's drivers and receivers
for up to four drives in a daisychained operation.
The following characteristics apply to the DRIVE SELECT lines:
1. Logical unit designation is accomplished at the time of
installation by setting the jumper plug located on the printed
Circuit board.
2. All command cable lines are gated with DRIVE SELECT. No data
cable signal lines are gated with DRIVE SELECT.
3. DRIVE SELECT must remain asserted during any communication with
the host controller.
4. When the radial select jumper is installed, the drive is
selected all the time.
5. The drive should not be selected until 1 second after DC power
is applied. The Drive READY input is valid within 500 ns
after the drive is selected (DRIVE SELECT true) and after the
power on delay.
6. The drive is selected within 1 us after the assertion of
DRIVE SELECT, if the power on sequence is complete. The drive
will be the deselected within 1 us after the negation of
DRIVE SELECT.
7. The drive activates the data cable DRIVE SELECTED signal within
1 us after receipt of DRIVE SELECT if the drive is selected.
The drive negates DRIVE SELECTED within 1 us after the
DRIVE SELECT signal is negated.
8. DRIVE SELECT must be valid 100 ns minimum before the first step
pulse is received and 100 ns minimum after the last step pulse
is received.
9. At the completion of a write operation, DRIVE SELECT must
remain asserted for 1 us.
10. When the DRIVE SELECT line is asserted, a head change occurs,
thus requiring a delay of 5 us before a read or write operation
can be initiated.
J7 Radial Select
-----------------
9-10 OPEN Radial disable
CLOSED Radial enable
J7 External Spindle Clock (Option)
-----------------------------------
11-12 OPEN Spindle Sync disabled
CLOSED Spindle Sync enabled
The external spindle clock options allow for synchronized rotation
of a few disk drives in a system. Each drive can be configured to one
of the following modes:
a. Use internal spindle clock, output spindle reference clock.
b. Use internal spindle clock with a line terminator.
c. Use external spindle clock without the line terminator.
Motor On Command (Optional) --------------------------- When the Motor On Command option is installed, the Motor On input line controls the drive spin up and spin down operation. This line is terminated with 220 ohm to +5V and with 330 ohm to ground. The terminator is not removable. The Motor On signal is asserted when high. There is no need to select the drive for spin up/spin down operation.
Install
SEAGATE ST1100/ST1150R PRODUCT MANUAL 36136-001, 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 the OEM's system, whetherin a factory or field environment.
Front Panel
-----------
The SWIFT is available with a black front panel. The panel has 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 nonrecoverable
fault. A fault indication is displayed irrespective of DRIVE SELECT
status.
Cooling
-------
The 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 Command Data Command Data Command Data Command |
+--+-----+--------+-----+--------+-----+--------+-----+---+
| | | | | | | |
| | | | | | | |
| | | | | | | |
| | | | | | | |
| | | | | | | |
+-++-+--++-+-+ +-++-+--++-+-+ +-++-+--++-+-+ +-++-+--++-+-+
| |R | | T| | | |R | | T| | | |R | | T| | | |R | | T| |
| +--+ +--+ | | +--+ +--+ | | +--+ +--+ | | +--+ +--+ |
| SWIFT | | SWIFT | | SWIFT | | SWIFT |
+------------+ +------------+ +------------+ +------------+
Each cable command length must not exceed 20 feet (6.10m). Each
data cable length must not exceed 20 feet (6.10m).
T indicates terminator resistor pack.
SWIFT data cables are permanently terminated.
R indicates discrete terminator.
Radial Configuration
--------------------
View A shows each drive interfaced to its own command cable, which
allows interfacing of any number of drives and a variety of
system operational techniques. Each drive has its data cable and
command cable radially connected to the host controller. The length
of each individual cable must not exceed 20 feet (6.10 meters).
Terminator resistors must be installed in the host controller for
each data cable and for each command cable.
View B
+--------------Host Controller----------------------------+
| |
|Data Command Data Data Data |
+-+------+-------+--------------+---------------+---------+
| | | | |
| | | | |
| | | | |
| | | | |
| +-------+Command+------+-------+Command+-------+
+++-+----+---+ +++-+-----+--+ +++-+-----+--+ +++-+----++-++
||R | | ||R | | ||R | | ||R | | T||
|+--+ | |+--+ | |+--+ | |+--+ +--+|
| SWIFT | | SWIFT | | SWIFT | | SWIFT |
+------------+ +------------+ +------------+ +------------+
Total command cable length must not exceed 20 feet (6.10m). Each
data cable length must not exceed 20 feet (6.10m).
T indicates terminator resistor pack. SWIFT data cables are permanently terminated. R indicates discrete terminator.
Daisychain Configuration
------------------------
A daisychain configuration incorporates parallel interfacing of the
disk drives on a common command cable. A maximum of four drives may
be daisychained on the command cable. Only the drive which is
selected by the host system has its control and data signals enabled
through this common interface. View B consists of four SWIFT disk
drives only. A terminator resistor pack is required in the host
controller for each data cable. Only the last SWIFT in the daisychain
requires a terminator resistor pack for the command cable. Terminator
resistor packs for the command cable or other drives are removed. The
total combined command cable length (from the controller to the first
drive, to the second and subsequent drives) must not be more than 20
feet (6.1 meters).
DC Cable and Connector
----------------------
The SWIFT receives DC power through a 4 pin connector mounted on the
HDA. Recommended part numbers for the mating connector are included
below, 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.
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 command 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 included below,
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)
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. Du Pont Housing 69305-002
b. Du Pont Terminal 77138-001
or equivalent.
The cable consists of two 28 AWG wires. The maximum cable length is
20 feet (6.1 meters).
The external spindle clock connector header is mounted on the disk
drive main PCB. J7 pins 11 and 12 are used for the external spindle
clock connection.
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 a custom driver to transmit status to the host. This
driver is capable of sinking a current of 24 mA with a low level
output voltage of 0.4 V.
Receiver Characteristics
The SWIFT uses a custom receiver with hysteresis gate as a line
receiver. The input of each receiver is terminated in a 220/330 ohm
resistor network.
Terminator Characteristics
The terminator consists of a resistor module which plugs into a
socket in the last drive in a daisychain. Each drive is furnished
with a terminator. Terminators must be removed from all except the
last drive on the cable prior to daisychain operation. The terminator
can be easiliy removed with tweezers or needlenose pliers. Terminator
installation, however, requires some disassembly of the drive. An
equivalent terminator must be provided in the controller on each
input signal line from the drive to the controller. Only the Command
cable resistor module is removable.
Balanced Differential Drivers/Receivers --------------------------------------- Transmitter Characteristics The SWIFT uses 75158 type balanced differential drivers. A signal on the interface is defined as asserted when the "+" output is more positive than the "-" output.
Receiver Characteristics ------------------------ The SWIFT uses 75157 type balanced differential receivers. A signal on the interface is defined as asserted when the "+" input is more positive than the "-" input.
Terminator Requirements
-----------------------
Each differential receiver in the drive is terminated with a 100 ohm
resistor. The terminator is a Beckman Industrial P/N L105C221/331F or
equivalent. An equivalent terminator must be provided in the
controller on each input signal line from the drive to the
controller.
Driver and Receiver ------------------- The external spindle clock signal utilized a balanced differential driver and receiver the same as those used for data transfer. The + signal is connected to J7 Pin 11 and the - signal is connected to J7 pin 12. The terminator used is the same as the one used for data transfer.
Features
SEAGATE ST1100/ST1150R 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 SWIFT interface consists of a 34 pin command interface cable and
a 20 pin data interface cable which is compatible with the industry
standard ST506/ST412 disk drive interfaces. The 34 pin command inter-
face is designed to allow daisy chained or radial connections to
additional SWIFT disk drives.
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 is no user data, thus eliminating the possibility
of destroying or degrading customer data. Read/write heads are auto-
matically 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 movements 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 0 location 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.
Each data surface has a total of 1072 tracks and is capable of
recording 11,165,952 (16,748,928 RLL) bytes of unformatted data.
Media defects are characterized as beeing either 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 uncorrectable error is one greater than 11 bits in
length.
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 tracks per surface.
2. Track 0 to be error free on each data surface.
3. 15 bad tracks per surface maximum (MFM Models).
20 bad tracks per surface maximum (RLL Models).
4. Accumulative defects not to exceed 1 per megabyte, based on
total available unformatted drive capacity.
Service Tools
-------------
No special tools are required for site installation or recommended
for site maintenance.
Defect and Error Management
---------------------------
The SWIFT, as delivered, complies with all aspects of this
specification. The read error rate and specified storage capacity
are not dependent upon the use of defect management routines.
However, carefully chosen defect management methods can significantly
enhance overall system performance. The application of error
correction codes (ECC), and/or sector reallocation permits the
continued use of the major portion, or perhaps all of a track when a
defect is found.
ECC is highly recommended since the majority of defects are correct-
able. If ECC is not used, then all flagged defects will be essenti-
ally uncorrectable and must be reallocated. Sector or track realloca-
tion schemes are effective methods for relocating media defects.
Sector reallocation in general is more efficient and may offer
significant performance improvement.
Acoustic Noise Level
--------------------
Acoustic noise power level of the SWIFT should be less than TBD
numbers bels during idle/operation mode. Equivalent typical average
sound pressure level should be less than TBD numbers dba when
measured with microphone at a distance of one meter from the drive.
Custom Formatting
-----------------
CDC maintains custom formatting capability which can accommodate many
of the unique formats used in the Winchester marketplace. A majority
of special format requirements can be implemented as specified by the
customer. Unique format requirements should be identified as soon as
possible to facilitate timely implementation.
Drive/Receiver Characteristics
------------------------------
Interface signals levels and logical sense at the SWIFT I/O
Connector are defined as follows:
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
---------
Models
|16.5 MS |25 MS |
----------------------------------+--------+--------+
Track-to-track msec. max. | 4 | 5 |
Average msec. typ. | 15 | 22 |
Average msec. max. | 16.5 | 25 |
Latency msec. avg. | 8.33 | 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 a 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
disc 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 5.0 Mbits per second,
for MFM models and 7.5 Mbits per second for the RLL models.
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 peripheral I/O cables.
Power sequencing can be obtained by using the motor on command
option, if the drive has been configured for its use.
Heat/Power Dissipation
----------------------
Each SWIFT will typically dissipate 10 watts (34 BTU per hour) of
power during operation (seeking). Idle mode power dissipation is less
than 8 watts, typically.
Temperature
-----------
50*F 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* 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 operation. System cooling consideration should
avoid large thermal gradients between points A and B.
Air Cleanliness
---------------
The SWIFT is designed to operate in a typical office environment
with minimum environmental control.
Electromagnetic Emissions
-------------------------
The SWIFT meets the performance requirements for electromagnetic
emissions set forth in CDC-STD 1.03.208 which assures compliance
with FCC rules and regulations.
Chassis/DC ground separation
----------------------------
The SWIFT is provided with the chassis groung tied to DC logic
ground. An option is provided for the user to isolate the chassis and
logic grounds. This option may be beneficial in reducing ground
induced noise in some system applications.
Write Precompensation
---------------------
RLL write data must conform to the conventional RLL encoding rules
and must write precompensated by 12 ns per the industry standard
RLL data write precompensation rules. Write precompensation is re-
commended on all tracks; however, write precompensation must be
performed on tracks greater than Track 300.
No write precompensation is required for MFM.
Options
-------
All options are either incorporated or packaged at the manufacturing
facility.
Reliability
-----------
The following reliability specifications require that correct
host/drive operational interface has been implemented, including all
interface timings, power supply voltages, environmental conditions,
and appropriate data handling circuits in the host system.
MTBF 30,000 hours
Service Life 5 years
Preventive Maintenance None required
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