Hard Drive: SEAGATE: ST325N 21MB 3.5"/SL SCSI1 SE
S T 3 2 5 N SEAGATE
NO MORE PRODUCED Native| Translation
------+-----+-----+-----
Form 3.5"/SLIMLINE Cylinders | | |
Capacity form/unform 21/ MB Heads 2| | |
Seek time / track 31.5/10.0 ms Sector/track 32| | |
Controller SCSI1 SINGLE-ENDED Precompensation
Cache/Buffer 2 KB Landing Zone
Data transfer rate 1.150 MB/S int Bytes/Sector 512
1.500 MB/S ext ASYNC
Recording method RLL 2/7 operating | non-operating
-------------+--------------
Supply voltage 5/12 V Temperature *C 10 50 | -40 60
Power: sleep W Humidity % 8 80 | 5 90
standby 1.4 W Altitude km -0.305 3.048| -0.305 9.144
idle 2.4 W Shock g 10 | 70
seek 7.0 W Rotation RPM 3600
read/write 6.3 W Acoustic dBA 40
spin-up W ECC Bit 32
MTBF h 50000
Warranty Month 12
Lift/Lock/Park YES Certificates CSA,IEC380,TUV,UL478,VDE
Layout
SEAGATE ST325N PRODUCT MANUAL 36144-001, REV. A
+---------------------------------------------------------+ | 1-------+J2 | | +-------+ |XX | ++ |XX J1 | || |XX SCSI | || |XX C | Resistor ++ |XX O | Termination ++ |XX N | Packs || |XX N | || |XX E | ++ |XX C | ++ |XX T | || |XX O | || |XX R | ++ | | |XX Power | |XX J3 +---------------------------------------------------------+
Jumpers
SEAGATE ST325N PRODUCT MANUAL 36144-001, REV. A
Jumper setting
==============
J2 SCSI Bus Adress and Parity Check
-------------------------------------
Select the desired SCSI ID with jumpers. Install the optional
P-jumper to enable parity.
+-------+---------------+
|SCSI ID| P LT 4 2 1 | Jumpers are provided on the drive for
+-------+---------------+ selecting the SCSI bus address. The
| 0 | o o o o o | microprocessor accesses this informa-
| 1 | o o o o x | tion at power-on. The address jumpers
| 2 | o o o x o | are accessed only during the power-on
| 3 | o o o x x | sequence. If the SCSI address is
| 4 | o o x o o | changed, the drive must be powered
| 5 | o o x o x | off and on.
| 6 | o o x x o |
| 7 | o o x x x |
+-------+---------------+
| |
| +---- Life Test
|
+------- Parity Bit Option
Some host systems require parity bit checking
Install the P-Jumper to enable Parity
Life Test
---------
This is a test function used during the manufacturing process and is
not recommended for field use. When the Life Test jumper is installed
the stepper motor will continuosly seek between Track 0 and the
maximum data cylinder and will ignore control signals sent via the
interface.
50-Pin SCSI Connector Pin Assignments
-------------------------------------
Signal Pin No. Signal Pin No.
----------------------------------------
-DB(0) 2 Ground 28
-DB(1) 4 Ground 30
-DB(2) 6 -ATN 32
-DB(3) 8 Ground 34
-DB(4) 10 -BSY 36
-DB(5) 12 -ACK 38
-DB(6) 14 -RST 40
-DB(7) 16 -MSG 42
-DB(P) 18 -SEL 44
Ground 20 -C/D 46
Ground 22 -REQ 48
Ground 24 -I/O 50
Terminator 26
Power
Note: All odd pins, except pin-25 are connected to ground. Pin-25
is not connected.
J3 DC Power and pin connector assignments
-------------------------------------------
+------------+ 1 = + 12 VDC
| 1 2 3 4 | 2 = + 12 Volts return
+------------+ 3 = + 5 Volts return
4 = + 5 VDC
Install
SEAGATE ST325N PRODUCT MANUAL 36144-001, REV. A
Notes on installation
=====================
Installation direction
----------------------
horizontally vertically
+-----------------+ +--+ +--+
| | | +-----+ +-----+ |
| | | | | | | |
+-+-----------------+-+ | | | | | |
+---------------------+ | | | | | |
| | | | | |
x x | | | | | |
+------x------x-------+ | +-----+ +-----+ |
+-+------x--x-------+-+ +--+ +--+
| xx |
| x x |
+---x--------x----+
x x
The drive may be mounted horizontally with the PC board down or on
either side (edge). The drive may 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.
There are 4 mounting holes on the bottom of the drive. There are no
side mounting points on the ST325N.
Required mounting screws: 4-40 UNC-2A.
Warning: The mounting screws must not extend beyond the inside of the
chassis mounting surface (or into drive mounting points) more than
0.093-inches max.
Mounting Screw Torque Requirements
----------------------------------
Do not exceed 3 inch-Ibs.
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. Shock measurements are based on a 11 msec., half-
sine-wave shock pulse. Nonoperating specifications assume that the
read/write heads are positioned in the shipping zone.
Read/Write Head Auto-Park
-------------------------
Upon power-down, the read/write heads automatically move to the ship-
ping zone. All portions of the head/slider assembly will park inboard
of the maximum data cylinder.
When power is applied, the heads will recalibrate to Track 0.
FCC Verification
----------------
The ST325N is a device intended to be contained solely
within a personal computer or similar enclosure (not attached to
an external device). As such, it is considered to be a subassembly
even when individually marketed to the customer. As a subassembly, no
Federal Communications Commission authorization, verification or
certification of the device is required.
Formatting and defect management
--------------------------------
Media defects are identified and recorded on the disc during the ma-
nufacturing process. This defect map is used during formatting and
enables the drive to bypass these defects. During the formatting
operation, the controller uses the sector-slip technique to reassign
defect sectors.
DC Power specifications
-----------------------
Power may be applied/removed in any sequence without loss of data
or damage to the drive. Typical seek currents are measured on re-
petitive one-third stroke buffered seeks with two spindle rotations
between each seek.
Voltage tolerance, all conditions, including ripple: 5%.
Typical seeking/nonseeking current and power specifications assume
nominal voltages applied, 25* C ambient temperature, sea level and
spindle rotating.
Input Noise
-----------
Maximum permitted input noise ripple: 100 mV (peak-to-peak)
Maximum permitted input noise: 20 MHz.
(Measured at the host system power supply across an equivalent 20 resistive load on the +12 V line and an equivalent 8 load on the +5 V line.)
Cable specification
-------------------
A 50-conductor flat cable or 25-conductor twisted pair cable is
required. The maximum cable length is 6 meters (19.7 ft). Each SCSI
bus connection may have a 0.1 meter (0.33 ft) maximum stub length.
The characteristic impedance for unshielded flat or twisted pair
ribbon cable should be 100 10%. A characteristic impedance greater
than 90 is preferred for shielded cables.
To minimize discontinuities and signal reflections it is desirable
to minimize the use of cables of different impedances in the same
bus.
Connector Requirements
----------------------
The drive connector is a 50-conductor connector with two rows of 25
male pins on 100 mil centers.
The cable connector is a 50-conductor nonshielded connector
consisting of two rows of 25 female contacts on 100 mil centers.
Recommended strain-relief connectors are AMP part number 1-499506-2
or DUPONT part number 66900-X50.
Onboard Drive Diagnostics
-------------------------
At power-on the drive will execute a series of diagnostic tests. Any
failure will be indicated by a series of LED (front panel) flashes.
The first failure will be preserved. The drive is ready to read/write
if no error codes are received within 22 seconds.
+-------+---------------------------------------------------------+ |Flashes|Failures codes | +-------+---------------------------------------------------------+ | 1 |Microprocessor/Internal Memory Test | +-------+---------------------------------------------------------+ | 2 |Microprocessor ROM Checksum Test | +-------+---------------------------------------------------------+ | 3 |Controller Chip Test | +-------+---------------------------------------------------------+ | 4 |Read Record ID Mark/Microprocessor RAM Test | +-------+---------------------------------------------------------+ | 5 |Data Buffer RAM Test | +-------+---------------------------------------------------------+ | 7 |Drive Ready Test | +-------+---------------------------------------------------------+ | 8 |Read Operating System Microcode From Drive | | | If the controller is unable to read the operating system| | | from the drive | +-------+---------------------------------------------------------+
Drive formatting
----------------
All Seagate SCSI interfaces drives are low-level formatted at the
factory. You may wish to low-level format the drive to optimize its
performance for your system. Consult the controller documentation for
information on low-level formatting.
Partitioning and high-level formatting can be done through DOS.
Features
SEAGATE ST325N PRODUCT MANUAL 36144-001, REV. A
ST325N Configuration
--------------------
Seagate intelligent drive feature an onboard SCSI-compatible
controller. This embedded controller performs all of the functions
that were previously implemented by the host-supplied controller.
With the controller onboard, the diagnostic capabilities of the
drive are enhanced because the controller is able to optimize drive
performance and error recovery.
The embedded controller supports the SCSI interface as defined in the
ANSI X3T9.2/82-2 document. The interface hardware is capable of
transferring up to 12 Mbits/sec. using asynchronous data transfer.
Devices on the SCSI interface are daisy-chained together using a
common cable. Both ends of the cable are terminated. All signals on
the interface are common between all devices.
Formating and Defect Management
-------------------------------
Because Seagate SCSI interface drives have the controller onboard,
bad sectors are mapped out and become transparent to the user; this
allows Seagate to specify "guaranteed megabytes" for SCSI drives and
eliminates the requirement for a media defect specification.
Error Recovery
--------------
The controller provides error recovery routines which are necessary
to assure data integrity. These techniques include ECC, seek-retry,
read-retry, head-offset and defect management. To assure a high de-
gree of data reliability, the controller utilizes a 32-bit error
checking and correction polynominal.
RAM Buffer
----------
The drive may be purchased with a standard 2K RAM Buffer or an
optional 8K RAM buffer.
UL/CSA Listing
--------------
The ST325N 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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