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Hard Drive: SEAGATE: ST4096 80MB 5.25"/FH MFM ST412

S T 4 0 9 6    SEAGATE
NO MORE PRODUCED                                      Native|  Translation
Form                 5.25"/FH              Cylinders    1024|     |     |
Capacity form/unform    80/   96 MB        Heads           9|     |     |
Seek time   / track  28.0/ 6.0 ms          Sector/track   17|     |     |
Controller           MFM / ST412           Precompensation 65535
Cache/Buffer               KB              Landing Zone
Data transfer rate    0.625 MB/S int       Bytes/Sector      512
                      0.625 MB/S ext
Recording method     MFM                            operating  | non-operating
Supply voltage     5/12 V       Temperature *C        10 45    |    -40 60
Power: sleep              W     Humidity     %         8 80    |      5 90
       standby       23.0 W     Altitude    km    -0.305  3.048| -0.305  9.140
       idle               W     Shock        g         5       |     25
       seek          55.0 W     Rotation   RPM      3600
       read/write         W     Acoustic   dBA
       spin-up            W     ECC        Bit
                                MTBF         h      40000
                                Warranty Month
Lift/Lock/Park     YES          Certificates     CSA,FCC,UL478,VDE            



  |                                        +JP6+            |XX
  |                                        +---+            |XX
  |                                                         |XX J2
  |                                   +JP1-+                |XX
  |                                   +----+                |
  |                             +-+                         |xx Frame
  |                          JP5| |      +-JP2-+    +-+     |   Ground
  |                             +-+      +-+ +-+    | J     |XX
  |                                        +-+      | 8     |XX
  |                                                 +-+     |XX J1
  |                                       +-----+       +-+ |XX
  |                                       +-J9--+       | | |XX
  |                                                     | | |XX
  |                                             Resistor+-+ |XX
  |                                             Termination |
  |                                             Pack        |XX Power
  |                                                         |XX J3



Jumper setting

The Write Fault jumpers at J8, JP5, and JP2 are jumpered at the

J8 Shipped with pins 11-12 shorted
JP5 Shipped with pins 2- 3 shorted
JP2 Shipped with pins 2- 3 shorted

JP1 DC-Unsafe option
A DC-unsafe condition occurs when the drive DC power input is out of
the specified tolerances.

If pins 1-2 are shorted, a DC-unsafe condition will cause a Write
Fault at the interface.

 JP2  Shipped with Pins 2-4 shorted
   1- 2  CLOSED   Write Fault will be true for the duration of the

   3- 2  CLOSED   Provides latched Write Fault. To recover, deselect
                  the drive. Note: If this option is enabled, pins
                  11-12 at J8 must remain shorted.

 x 4- 2  CLOSED   A Write Fault will occur when a fault is rue for a
                  minimum of 2 msec.

JP5 Shipped with Pins 2-3 shorted
If write data is present at pin-13 at the J2 interface connector and
Write Gate is false, a Write Fault will occur.
If write data is not present at pin-13 at the J2 interface connector
and Write Gate is true, a Write Fault will occur.

 JP6  Write Fault ready, Latch option
   1- 2  CLOSED   Ready will be false during a Write Fault

   1- 2  OPEN     Write Fault will not affect Ready.

 J8   Drive select
     |Drive Select | 8-7   | 6-5   | 4-3   | 2-1   |
     |Drive 4      | CLOSED| OPEN  | OPEN  | OPEN  |
     |Drive 3      | OPEN  | CLOSED| OPEN  | OPEN  |
     |Drive 2      | OPEN  | OPEN  | CLOSED| OPEN  |
     |Drive 1      | OPEN  | OPEN  | OPEN  | CLOSED|

The Drive Select line enables the controller to select and adress
the drive. Control cable interface options may use either a daisy-
chain or radial configuration.

 J8  Write Fault
 x11-12  CLOSED   Factory set
                  See also JP2, pins 2-3

 J8  Recovery Mode
  13-14  CLOSED   Recovery mode is a user-selectable option. It may be
                  enabled by shorting pins 13-14 at the J8 shunt
                  block. It is initiated when the controller asserts
                  the Recovery Mode line true at the interface. This
                  changes the step line to a microstep function after
                  100 nsec. A step pulse will now cause Seek Complete
                  to go false 100 nsec. after the drive receives the
                  pulse. The drive then microsteps off-track using
                  the optimum algorithm, allowing 8 msec. for the
                  read/write heads to settle and then takes the Seek
                  Complete line true.

 Note: Recovery Mode is optional and is not required for standard

J8 Daisy-Chain/Radial Drive Configuration
This drive family can be configured in either a daisy-chain or radial

  15-16  CLOSED   The Radial option is enabled by shorting pins 15-16
                  at J8. The resistor termination packs must remain
                  installed on any radially configured drives.

 x15-16  OPEN     In a daisy-chain configuration, the last drive in a
                  chain must have the resistor termination pack



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!

The drive may be mounted horizontally with the PC board down or on
either side. Mounting vertically on either end is a prohibited orien-
The drive should not be tilted front or back, in any position, by
more than 5*. For optimum performance, the drive should be formatted
in the same position as it will be mounted in the host system.

Shock and vibrations
All shock and vibration specifications assume that the drive is moun-
ted in an approved orientation with the input levels at the drive
mounting screws.

Shipping zone
AT power-down, the actuator will automatically position the read/
write heads over the shipping zone and the carriage lock will engage.
All portions of the head/slider assembly park inboard of the maximum
data cylinder.

When power is applied, the heads will recalibrate to Track 0 and the
lock will automatically disengage.

FCC Verification
These drives are devices which are intended to be contained solely
within a personal computer or similar enclosure and not attached to
an external device. As such, they are considered to be subassemblies
even when individually marketed to the customer.

 Input Noise
 Maximum permitted input noise ripple: 100 mV (peak-to-peak)
 Maximum permitted input noise: 20 MHz.
 Ripple measured at the host system power supply across an equivalent
 8  resistive load on the +12 V line and an equivalent 3  load on the
 +5 V line.

Handling Precautions
After unpacking, and prior to system integration, the drive may be
exposed to potential handling and ESD hazards.
Do not touch the PCB edge-connectors, board components or the printed
circuit able without observing static-disccharge precautions.
Handle the drive by the frame only.
Always rest the drive on a padded surface until it is mounted in the
host system.

Bit Jitter
Bit jitter reduction determines the relationship between the leading
edge of read data and the center of the data window.
The data separator must provide at least -40dB of bit jitter
reduction at 2F with an offset of less than 1.5 nsec. shift from the
center of the data window.

Interface and Recording Method
The ST4053 and ST4096 are designed for operation with the ST412
interface with MFM encoding at 5.0 Mbits/sec. data transfer rate.
Operation of an MFM drive with an RLL controller is not approved by
Seagate and will void the drive warranty.

The SR4144R is designed to operate with the ST412 interface with Run
Length Limited (2,7) encoding at 7.5 Mbits/sec. data transfer rate.

The drive will enter the auto-truncation mode if the controller
issues an excessive number of step pulses, which would place the
read/write heads outward beyond Track 0 or inward beyond the
maximum data cylinder.

With auto-truncation active, the drive will ignore additional pulses,
take control of the actuator, and recalibrate the heads to Track 0.

 Caution: If the controller is still issuing slow-step pulses after
          the drive issues Seek Complete from auto-truncation mode,
          the drive will either reenter auto-truncation mode with
          Direction In true.

DC Power Requirements
Power may be applied or removed in any sequence without loss of data
or damage to the drive.

The drive family does not require precompensation.

Step Pulse Period and Seek Method
The Step signal is a 1.5 sec. minimum width pulse which initiates
read/write head motion. The Step pulse period determines the access
method. The number of pulses determines the seek length.

Buffered-Seek: 3 sec. to 75 sec.
Slow-Step: Greater than or equal to 3 msec.

Step pulses may be lost at periods between 75 sec. and 3 msec.

Seek-Retry is an internally generated command implemented by the
drive to enhance seek performance.

If the drive detects an off-track condition, or the seek was not com-
pleted, the drive will recalibrate the heads to Track 0 and retry the
seek. All writing is inhibited during retry. The maximum time that
Seek Complete will be false is 6 seconds, during a seek-retry.

If the target track is still not archieved, or the seek was not com-
pleted after two retries, the drive will set Write-Fault true, and
Ready and Seek Complete false. Write-Fault will reamin active until
the condition that causes the fault is corrected and the reset is



Media Defects
A media defect is a read error when the data, which has been
correctly written, cannot be recovered within 16 retries.
A printout will be provided with each drive shipped listing the
location of any defect by head, cylinder, sector and byte. The defect
map will specify the number of bytes from index. For MFM this will be
based on 1.6 sec./byte. RLL encoding is based on 1.056 sec./byte.
Some drives will have the defect map fixed to the drive top cover.

 ST4053  There will be no more than 44 defects total per drive.
         Cylinders 0, and 1 will be free defects.

 ST4096  There will be no more than 80 defects total per drive.
         Cylinders 0, and 1 will be free defects.

 ST4144R There will be no more than 122 defects total per drive.
         Cylinders 0, and 1 will be free defects.

Access Time Definition and Timing
Access time is defined as the time from leading edge of the first
step pulse received to Seek Complete (including setting).
All seek times are true statistical averages and are calculated with
a step pulse period of 10 sec. at nominal power and temperature.
Access times may be degraded at step pulse periods greater than
20 sec.

                                          | ST4*** |
        Track-to-Track         msec. typ. |   8    |
                               msec. max. |  10    |
                       Average msec. typ. |  28    |
                       Average msec. max. |  30    |
        Full Stroke            msec. typ  |  55    |
                               msec. max. |  57    |
        Latency                msec. avg. |   8.33 |

UL/CSA Listing
The drive family is listed in accordance with UL 478 and CSA
C22.2 (0-M1982), and meets all applicable sections if IEC 380 and
VDE 0806/08.81, as tested by TUV-Rheinland, North America.

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