
S T 5 8 5 0 A   D E C A T H L O N 8 5 0    SEAGATE
NO MORE PRODUCED                                      Native|  Translation
                                                      ------+-----+-----+-----
Form                 3.5"/SUPERSLIMLINE    Cylinders    4085| 1656|  827|  827
Capacity form/unform   850/      MB        Heads           4|   16|   16|   16
Seek time   / track  13.0/ 4.0 ms          Sector/track     |   63|   63|   63
Controller           IDE / ATA2 FAST/ENHA  Precompensation
Cache/Buffer           256 KB SEGMENTED    Landing Zone
Data transfer rate          MB/S int       Bytes/Sector      512
                     16.600 MB/S ext PIO4
Recording method     RLL 1/7                        operating  | non-operating
                                                  -------------+--------------
Supply voltage     5/12 V       Temperature *C         5 55    |    -40 70
Power: sleep              W     Humidity     %         8 80    |      5 95
       standby        1.0 W     Altitude    km    -0.305  3.048| -0.305 12.192
       idle           3.1 W     Shock        g         2       |     75
       seek           7.0 W     Rotation   RPM      5376
       read/write     5.0 W     Acoustic   dBA        32
       spin-up            W     ECC        Bit   88,REED SOLOMON
                                MTBF         h     500000
                                Warranty Month
Lift/Lock/Park     YES          Certificates     CSA,FCC,UL1950,UL478,VDE



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                        L   A   Y   O   U   T
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SEAGATE  ST5850A DECLATHON 850  PRODUCT MANUAL 36279-001, REV. B, 2/95

  +---------------------------------------------------------+
  |                                                         |XX I
  |                                                         |XX N
  |                                                         |XX T
  |                                                         |XX E
  |                                                         |XX R
  |                                                         |XX F
  |                                                         |XX A
  |                                                         |XX C
  |                                                         |XX E
  +--33                                                     |XX
  |  |Options                                               |XX  J4
  |  |Jumper                                                |XX
  |  |Block                                                 |XX1
  |  |                                                      |
  |  |                                                      |XX J3
  +--1                                                      |XX Power
  +---------------------------------------------------------+   1



**********************************************************************
                      J   U   M   P   E   R   S
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SEAGATE  ST5850A DECLATHON 850  PRODUCT MANUAL 36279-001, REV. B, 2/95

 Jumper Setting
 ==============


       Options Jumper Block
   +33--------23--+--17-----+9+7-5+3-1+
 --+ o o o o o o o|o o|o o o|o|o o|o *+----Circuit--
   | o o o o o o o|o o|o   o|o|o o|o o|    Board
   +34--------+---+---+-----+-+---+--2+----------------------------+
              |X X|o o|X o o|o|o o|o o|Spares                      |
              |X X|o o|X   o|o|o o|o o|                            |
              +---+---+-----+-+---+---+----------------------------+
                  |o o|o o o|o|o o|o o| One drive only             |
                  |o o|o   o|o|o o|o o|                            |
 NOTE             |   |     | |   |   |                            |
 ALL OTHER PINS   |o o|o o o|o|o o|X o| Drive is master;           |
 ARE RESERVED.    |o o|o   o|o|o o|X o| Slave present              |
 DO NOT USE THEM. |   |     | |   |   |                            |
                  |o o|o o o|o|o o|o X| Drive is Slave             |
                  |o o|o   o|o|o o|o X|                            |
                  +---+-----+-+---+---+----------------------------+
                  |o o|o o o|o|o X|X X| Cable Select               |
                  |o o|o   o|o|o X|X X|                            |
                  +---+-----+-+---+---+----------------------------+
                  |o o|o o o|X|o o|o o| Remote LED connection      |
                  |o o|o   o|X|o o|o o| Pin 9 (-), pin 10 (+)      |
                  +---+-----+-+---+---+----------------------------+
                  |X X|o o o|o|o o|o o| Dual drive emulation       |
                  |X X|o   o|o|o o|o o|                            |
                  +---+-----+-+---+---+----------------------------+

 Options jumper block
 ---------------------
 The ST5850A is manually configured using the options jumper block.
 The options jumper block allows you to:

 - Install a remote LED.

 - Install two drives on the hard disc controller.

 - Install the drive using dual-drive emulation.

 - Install the drive in systems that support cable select.

 The options jumper block is a 34-pin dual header. It uses 2-mm
 connectors and jumpers. Spare jumpers are attached to the header at
 the factory in the places shown. If you need additional jumpers, use
 Seagate part number 13211-001 or an equivalent.


 Master/Slave configuration
 --------------------------
 The drive is configured at the factory for single-drive operation. If
 your computer has two drives, you must configure the ST5850A as
 either the master or the slave. Use the following guidelines to
 configure the drive.

 - If you are installing it as the master with another ST5850A or
   ATA-compatible drive that supports DASP- in the slave position,
   leave the jumpers in the positions shipped from the factory. The
   drive automatically detects the presence of a slave drive.

 - If you are installing it as the master with a non-ATA compatible
   slave present, place a jumper on pins 3 and 4 of the options jumper
   block.

 - If you are installing it as the slave, place the jumper on pins 1
   and 2 of the options jumper block.


 Cable select option
 -------------------
 Computers that use the cable-select method for determining the master
 and slave drive do so by selecting or deselecting pin 28, CSEL, on
 the interface bus. Master and slave drives are determined by their
 physical position on the bus:

 - The drive plugged into the I/O connector that carries the CSEL
   signal is the master.

 - The drive plugged into the I/O connector that does not carry the
   CSEL signal is the slave.

 To configure the ST5850A for computers using cable select:

 - Install jumpers on pins 1 and 2, pins 3 and 4 and pins 5 and 6.

 - Connect the drives to the bus.


 Remote LED connection
 ---------------------
 Pins 9 (-) and 10 (+) on the options jumper block are used to connect
 the drive to a remote LED. LEDs are polarized. Incorrect pin
 alignment can damage the LED.


 Dual-drive emulation
 --------------------
 Dual-drive emulation is a feature designed into drives with physical
 capacities greater than 528 Mbytes for computers whose BIOS limit the
 effective drive capacity to 528 Mbytes. This feature splits the drive
 into two logical drives with capacities the computer can manage. The
 one drive emulates two drives. Each logical drive is assigned a drive
 type in System Setup and must be partitioned and formatted
 independently.


 Dual-drive emulation configuration
 ----------------------------------
 Dual-drive emulation is a jumper setting on the options jumper block
 that allows you to configure the drive as two logical drives. Each
 logical drive is assigned a drive type in CMOS and is partitioned and
 formatted. When dual-drive emulation is used, a second physical
 drive cannot be used on the controller.

 +--------------------------------+--------+---------+
 |ST5850A                         | CHS    | LBA     |
 +--------------------------------+--------+---------+
 |Cylinders                       | 827    | N/A     |
 +--------------------------------+--------+---------+
 |Heads                           |  16    | N/A     |
 +--------------------------------+--------+---------+
 |Sectors                         |  63    | N/A     |
 +--------------------------------+--------+---------+
 |Total sectors                   | 833,616| 834,374 |
 +--------------------------------+--------+---------+
 |Formatted capacity(Mbytes)      | 426.8  | 427.2   |
 +--------------------------------+--------+---------+



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                      I   N   S   T   A   L   L
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SEAGATE  ST5850A DECATHLON 850  PRODUCT MANUAL 36279-001, REV. B, 2/95

 Notes On Installation
 =====================

 Drive Mounting
 --------------
 Mount the drive securely in the computer using either the bottom or
 side mounting holes as described below. Position the drive so that
 you do not strain or crimp the cables.

 Bottom mounting holes
 Insert 6-32 UNC-2A mounting screws in the four available bottom
 mounting holes. Do not insert the screws more than 0.20 inches (6
 turns) into the drive frame.

 Side mounting holes
 Insert 6-32 UNC-2A mounting screws in any two of the side mounting
 holes on each side of the drive. Do not insert the screws more than
 0.20 inches (6 turns) into the drive frame.

 CAUTION
 To avoid damaging the drive:

 - Use mounting screws of the correct size and length.

 - Gently tighten the mounting screws_do not apply more than 6 inch-
   pounds of torque.


 I/O Connector
 -------------
 The ST5850A uses a 40-pin, male I/O connector having two rows of
 twenty pins each. The even numbered pins are closest to the printed
 circuit board's edge. Pin 1 is near the 4-pin power connector. Pin 20
 is removed for keying purposes.

 We recommend the following part numbers or their equivalents for the
 mating connector.
  +-----------+---------------+--------------+
  |Part       |Description    |3M part number|
  +-----------+---------------+--------------+
  |Connector  |40-pin         |3M-3417-7000  |
  +-----------+---------------+--------------+
  |Connector  |40-pin         |3M-3448-2040  |
  +-----------+---------------+--------------+
  |Flat cable |AWG28(stranded)|3M-3365-40    |
  +-----------+---------------+--------------+
 The drive supports 40-connector, noshielded I/O cable with a maximum
 length of 18 inches (0.46 meters).


 Power connector
 ---------------
 The drive uses a standard 4-pin, male power connector. We recommend
 the following part number or their equivalents for the mating
 connector.
  +-----------+------------------+----------------+
  |Part       | Description      | Part number    |
  +-----------+------------------+----------------+
  |Connector  | Housing          | AMP 1-480424-0 |
  +-----------+------------------+----------------+
  |Connector  | Pin (loose piece)| AMP 60619-4    |
  +-----------+------------------+----------------+
  |Connector  | Pin (Reel)       | AMP 6117-4     |
  |Cable      | 18 AWG           |                |
  +-----------+------------------+----------------+

    --+-----J3-----+-- pin 1    +12 VDC
      | 1  2  3  4 |   pin 2    +12 Volts Return
      +------------+   pin 3    + 5 Volts Return
                       pin 4    + 5 VDC


 Multisegmented cache buffer
 ---------------------------
 The drive uses a 256-Kbyte multisegmented cache buffer to improve
 performance by eliminating access times under certain conditions.

 Read look-ahead
 ---------------
 The drive uses the read segments to store additional logical sectors,
 after the last requested sector, into a buffer before the computer
 requests the additional sectors. The cache buffer stores data from
 the start of a read until the buffer segment is full or until another
 command is received.

 Write immediate and write merging
 ---------------------------------
 Segments of the cache are reserved for write data. The drive will
 accept contiguous and sequential write commands and execute them as
 one command. When the buffer has received all of the data, the drive
 issues a write complete and writes the data to the disc. The last
 data written by the drive is retained in the buffer for future write
 or read use.



**********************************************************************
                      F   E   A   T   U   R   E  S
**********************************************************************
SEAGATE  ST5850A DECATHLON 850A  PRODUCT MANUAL 36279-001, REV. B 2/95

 Introduction
 ------------
 The ST5850A is a high-capacity, high-performance, energy-efficient
 drive that comes in the mini 3.5-inch form-factor. It is capable of
 meeting the needs of PCI, VL, ISA and EISA bus computers.

 The drive has a high-performance Fast ATA-2 interface that supports
 PIO modes 3 and 4, multiword DMA modes 0, 1 and 2 and Multiple Block
 Read/Write. It is capable of burst transfer rates of up to 16.6
 Mbytes per second and can store multiple blocks of data in cache for
 transfer in a single burst.

 The interface is supported with a 256-Kbyte segmented cache and
 embedded servo technology. The segmented cache aids the flow of read
 and write data. The embedded servo allows for accurate positioning of
 the heads over the data and eliminates periodic thermal recalibration
 to assure data transfer without interruption.

 Energy-saving features are designed into the ST5850A drive. The drive
 complies with the ATA interface specifications for Active, Idle and
 Standby power modes. Power-saving modes are entered upon request by
 the computer. Standby mode reduces the drive's power consumption to a
 typical 1 watt while retaining drive accessibility.

 Decathlon drives conform to the standard 3.5-inch footprint but have
 a 0.75-inch (19-mm) high profile. The lower height gives the designer
 or integrator more room for air circulation, other peripherals or a
 smaller drive bay.

 The following is a summary of the drive's features:

 - 855 Mbytes formatted

 - 1 watt typical power dissipation rating in Standby mode

 - 30-dBA typical idle acoustic sound pressure level

 - Mini 3.5-inch form-factor

 - 19-mm-high profile

 - LBA translation support

 - Dual-drive emulation, which turns the drive into two logical
   drives for DOS computers that limit the drive's capacity to 528
   Mbytes

 - Available software device driver to surpass the 528-Mbyte barrier
   imposed by parameter restrictions in some BIOSs

 - The drive uses the Fast ATA-2 interface. This interface supports
   multiword DMA modes 0, 1 and 2 and PIO modes 3 and 4 for up to
   16.6-Mbytes-per-second transfer rates.

 - 5,400-RPM rotational speed

 - 256-Kbyte segmented buffer

 - 12-msec average seek time

 - Implements an ATA-compliant power-management system using Active,
   Idle and Standby modes


 Access time
 -----------
 Access time is the interval between the time the actuator begins to
 move and the time the head has settled over the target track. Seek
 time is a statistical average of at least 10,000 measurements of seek
 time. All measurements for maximum values are taken under nominal
 conditions of temperature and voltage with the drive mounted
 horizontally. The specifications in the table below are defined as
 follows:

 - Track-to-track seek time is the average of all possible single-
   track seeks in both directions.
 - Average seek time is measured by executing seeks in both directions
   between random cylinders.
 - Full-stroke seek time is half the time needed to seek from track 0
   to the maximum track and back to track 0.

      +---------------+----------------+------------+---------+
      |Track-to-track |Average/typical |Full-stroke |Average  |
      |seek time      |seek time       |seek time   |latency  |
      +---------------+----------------+------------+---------+
      |4.5 msec max   |14 msec write   |27 msec max |5.56 msec|
      |3.5 msec typ   |12 msec read    |25 msec typ |         |
      +---------------+----------------+------------+---------+
 NOTE
 Host overhead varies between systems and cannot be specified.
 Drive internal overhead is measured by issuing a no-motion seek.
 Overhead is typically less than 0.5 msec.


 Formatted Capacity
 ------------------
 Decathlon drives are low-level formatted at the factory. You do not
 need to low-level format them.

 You can operate the drive using many different address
 configurations, provided the number of sectors per track does not
 exceed 63. The following tables show CHS and LBA translation
 geometries for standard and dual-drive emulation configurations. You
 can verify the parameters using the Identify Drive (ECH) command.


 528-Mbyte capacity barrier
 --------------------------
 Computers using some BIOSs impose a 528-Mbyte barrier on the hard
 disc drive. The BIOS in these systems use a CHS addressing scheme
 that does not acknowledge more than 1,024 cylinders in the
 translation geometry. To access the ST5850A's entire capacity, you
 must:

 - Use a BIOS that does acknowledge more than 1,024 cylinders or uses
   LBA addressing

 - Use a host adapter that accepts more than 528 Mbytes

 - Use dual-drive emulation

 - Use a software driver that surpasses the 528-Mbyte barrier to
   install the drive


 Reliability
 -----------
 Read error rates are measured with automatic retries and data
 correction with ECC enabled and all flaws reallocated (88 bit Reed
 Solomon code using 22 bit ECC span with 11 bit on-the-fly is used).
 Mean time between failures (MTBF) is measured at nominal power at sea
 level and an ambient temperature of 40*C.

 MTBF                              500,000 power-on hours
 Nonrecoverable read errors        1 per 10 13 bits transferred
 Seek errors                       1 per 10 7 physical seeks
 Contact Start/Stop                40,000 cycles
 Service life                      5 years


 Auto-park
 ---------
 Upon power-down, the read/write heads automatically move to the
 shipping zone. The heads park inside the maximum data cylinder and
 the magnetic actuator-lock engages. When power is applied, the heads
 recalibrate to track 0.


 Active mode
 -----------
 During the Active mode, the drive is involved in spinup, seeking or
 read/write activities. The table shows the typical power consumption
 rates for these activities.

 Spinup
 Spinup mode is entered from the Standby mode. The drive brings the
 spindle and discs up to operating speed. Power in this mode is
 defined as the peak power after starting spinup.

 Seeking
 Seek mode is entered from Idle mode. The read/write heads
 are moved to a specific location on the disc surface in preparation
 for reading from or writing to the disc. Read/write electronics are
 powered down but servo electronics are active.

 Read/write mode
 Read/write mode is entered from Idle mode. Read/write  electronics
 are activated and the servo is on track. The drive reads  from or
 writes to the disc.


 ATA interface
 -------------
 The ST5850A uses a Fast ATA-2 interface. The interface is in
 compliance with ANSI ATA (AT Attachment) Interface X3T9.2/143 Rev.
 4.0; SFF 8011: ATA Timing Extension for Local Bus Attachments, Rev.
 2.0 and SFF 8019: Identify Drive Data for Drives Under 8 GB.

 The ATA interface consists of single-ended, TTL-compatible receivers
 and drivers using an asynchronous interface protocol. The drivers can
 sink up to 24 mA and drive a load up to 300 pF. We recommend that you
 use a 40-conductor, nonshielded, flat-ribbon interface cable with a
 maximum length of 18 inches (0.46 meters) for optimum performance.


 PIO and DMA data-transfer modes
 -------------------------------
 You can set the multiword DMA mode and identify the PIO data-transfer
 mechanism and transfer mode with the Set Features command. To set the
 multiword DMA mode:

 Write Set Features command value 03H (Set Data Transfer mode) to the
 Features register.

 Write a transfer types value to the Sector Count register. The upper
 5 bits of this value define the type of data transfer, and the lower
 3 bits encode the mode value.

 This changes word 63 of the Identify Drive command to the mode you
 enter in the Sector Count register.


