
M H C - 2 0 3 2 A T    FUJITSU
                                                      Native|  Translation
                                                      ------+-----+-----+-----
Form                 2.5"/SUPERSLIMLINE    Cylinders        |     |     |
Capacity form/unform  3250/      MB        Heads            |     |     |
Seek time   / track  13.0/ 2.5 ms          Sector/track     |     |     |
Controller           IDE / ATA3 ULTRA      Precompensation
Cache/Buffer           512 KB              Landing Zone
Data transfer rate    9.800 MB/S int       Bytes/Sector      512
                     33.300 MB/S ext
Recording method     EPR4ML                         operating  | non-operating
                                                  -------------+--------------
Supply voltage     5 V          Temperature *C         5 55    |    -40 65
Power: sleep          0.1 W     Humidity     %         8 90    |      5 95
       standby        0.4 W     Altitude    km    -0.300  3.000| -0.300 12.000
       idle           0.9 W     Shock        g       100       |    500
       seek           2.4 W     Rotation   RPM      4000
       read/write         W     Acoustic   dBA        30
       spin-up            W     ECC        Bit   SMART
                                MTBF         h     300000
                                Warranty Month
Lift/Lock/Park     YES          Certificates                                  

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FUJITSU  MHC-2032AT/2040AT  PRODUCT MANUAL







    +-------------------------------------------------------------+
    |                                                             |
    |                                                             |
    |    +-----------------------------------------------C-A-+    |
    |    | * * * * * * * * * * * * * * * * * * * * * 1   * * |    |
    |    | * * * * * * * * * * * *   * * * * * * * * *   * * |    |
    +----+----------------------------------------------SWITCH----+
                                                         D B







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FUJITSU  MHC-2032AT/2040AT  PRODUCT MANUAL


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

    +-------------------------------------------------------------+
    |                                                             |
    |                                                             |
    |    +---------------------------------------------------+    |
    |    | * * * * * * * * * * * * * * * * * * * * * 1   * * |    |
    |    | * * * * * * * * * * * *   * * * * * * * * *   * * |    |
    +----+----------------------------------------------SWITCH----+


 Factory Default
 ---------------
 --------C-A-+
    *    * * |  OPEN
  * *    * * |
   ------D-B-+


 MASTER-device
    *    * * |
  * *    * * |
   ----------+
                Master drive (device #0) or slave (device #1) is
 SLAVE-device+  selected.
    *    * * |
  * *    xxx |  Note:
   ----------+  Pins A and C should be open.


 Master/slave
 ------------
 The disk drive can be connected to ATA interface as daisy chain
 configuration.

 Drive 0 is a master device, drive 1 is a slave device.



 -CSEL-------+
    *    xxx |CSEL signal is enabled.
  * *    * * |
   ----------+

 NOTE
 The CSEL setting is not depended on setting between pins B and D.

 By connecting the CSEL of the master device to the CSEL Line
 (conductor) of the cable and connecting it to ground further, the
 CSEL is set to low level.

 The device is identified as a master device. At this time, the CSEL
 of the slave device does not have a conductor. Thus, since the
 slave device is not connected to the CSEL conductor, the CSEL is set
 to high level. The device is identified as a slave device.



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FUJITSU  MHC-2032AT/2040AT  PRODUCT MANUAL

 Notes on installation
 =====================

 Installation direction
 ----------------------

     horizontally                           vertically
   +-----------------+             +--+                       +--+
   |                 |             |  +-----+           +-----+  |
   |                 |             |  |     |           |     |  |
 +-+-----------------+-+           |  |     |           |     |  |
 +---------------------+           |  |     |           |     |  |
                                   |  |     |           |     |  |
                                   |  |     |           |     |  |
 +---------------------+           |  +-----+           +-----+  |
 +-+-----------------+-+           +--+                       +--+
   |                 |
   |                 |
   +-----------------+

 The drive will operate in all axis (6 directions).


 Power save mode
 ---------------
 The power save mode feature for idle operation, stand by and sleep
 modes makes the disk drive ideal for applications where power
 consumption is a factor.


 Wide temperature range
 ----------------------
 The disk drive can be used over a wide temperature range (5*C to
 55*C).


 Low noise and vibration
 -----------------------
 In Ready status, the noise of the disk drive is only about 30 dBA
 (measured at 1 m apart from the drive under the idle mode).


 Connection to interface
 -----------------------
 With the built-in ATA interface controller, the disk drive can be
 connected to an ATA interface of a personal computer.


 512-KB data buffer
 ------------------
 The disk drive uses a 512-KB data buffer to transfer data between the
 host and the disk media.

 In combination with the read-ahead cache system and the write cache,
 the buffer contributes to efficient I/O processing.


 Read-ahead cache system
 -----------------------
 After the execution of a disk read command, the disk drive
 automatically reads the subsequent data block and writes it to the
 data buffer (read ahead operation). This cache system enables fast
 data access. The next disk read command would normally cause another
 disk access. But, if the read ahead data corresponds to the
 data requested by the next read command, the data in the buffer can
 be transferred instead.


 Write cache
 -----------
 When the disk drive receives a write command, the disk drive posts
 the command completion at completion of transferring data to the data
 buffer completion of writing to the disk media. This feature reduces
 the access time at writing.


 Frame
 -----
 The MR head bias of the HDD disk enclosure (DE) is zero. The mounting
 frame is connected to SG.

 IMPORTANT
 Use M3 screw for the mounting screw and the screw length should
 satisfy the specifications.

 The tightening torque must not exceed 3 kgcm.
 When attaching the HDD to the system frame, do not allow the
 system frame to touch parts (cover and base) other than parts to
 which the HDD is attached.


 Ambient temperature
 -------------------
 The temperature conditions for a disk drive mounted in a cabinet
 refer to the ambient temperature at a point 3 cm from the disk drive.
 The ambient temperature must satisfy the temperature conditions.
 And the airflow must be considered to prevent the DE surface
 temperature from exceeding 60*C.

 Provide air circulation in the cabinet such that the PCA side, in
 particular, receives sufficient cooling. To check the cooling
 efficiency, measure the surface temperatures of the DE. Regardless of
 the ambient temperature, this surface temperature must meet the
 standards.

 CAUTION
 -------
 Data corruption: Avoid mounting the disk drive near strong
 magnetic sources such as loud speakers. Ensure that the disk drive
 is not affected by external magnetic fields.


 Cable connector specifications
 ------------------------------
 Name                       Model         Manufacturer
 Cable socket (44-pin type) 89361-144     BERG
 Cable (44-pin type)        FV08-A440     Junkosha

 ATA interface and power supply cable (44-pin type)

 IMPORTANT
 ---------
 For the host interface cable, use a ribbon cable. A twisted cable or
 a cable with wires that have become separated from the ribbon may
 cause crosstalk between signal lines. This is because the interface
 is designed for ribbon cables and not for cables carrying
 differential signals.


 CSEL
 ----
 The CSEL setting is not depended on setting between pins Band D.
 By connecting the CSEL of the master device to the CSEL Line
 (conducer) of the cable and connecting it to ground further, the CSEL
 is set to low level. The device is identified as a master device. At
 this time, the CSEL of the slave device does not have a conductor.

 Thus, since the slave device is not connected to the CSEL conductor,
 the CSEL is set to high level. The device is identified as a slave
 device.


 Disk
 ----
 The DE contains disks with an outer diameter of 65 mm and an inner
 diameter of 20 mm. The MHC2040AT has three disks and MHC2032AT has
 three disks.

 The head contacts the disk each time the disk rotation stops; the
 life of the disk is 50,000 contacts or more. Servo data is recorded
 on top disk.

 Servo data is recorded on each cylinder (total 54). Servo data
 written at factory is read out by the read/write head.


 Head
 ----
 MHA2032AT has 5 read/write heads and MHC2040AT has 6 read/write
 heads. These heads are raised from the disk surface as the spindle
 motor the rated rotation speed.


 Spindle
 -------
 The spindle consists of a disk stack assembly and spindle motor. The
 disk stack assembly is activated by the direct drive sensor-less DC
 spindle motor, which has a speed of 4,000 rpm. The spindle is
 controlled with detecting a PHASE signal generated by counter
 electromotive voltage of the spindle motor at starting.


 Actuator
 --------
 The actuator consists of a voice coil motor (VCM) and a head
 carriage. The VCM moves the head carriage along the inner or outer
 edge of the disk. The head carriage position is controlled by feeding
 back the difference of the target position that is detected and
 reproduced from the servo information read by the read/write head.


 Air filter
 ----------
 There are two types of air filters: a breather filter and a
 circulation filter.

 The breather filter makes an air in and out of the DE to prevent
 unnecessary pressure around the spindle when the disk starts or stops
 rotating. When disk drives are transported under conditions where the
 air pressure changes a lot, filtered air is circulated in the DE.
 The circulation filter cleans out dust and dirt from inside the DE.

 The disk drive cycles air continuously through the circulation filter
 through an enclosed loop air cycle system operated by a blower on the
 rotating disk.


 Power-on Sequence
 -----------------
 a) After the power is turned on, the disk drive executes the MPU bus
    test, internal register read/write test, and work RAM read/write
    test. When the self-diagnosis terminates successfully, the disk
    drive starts the spindle motor.

 b) The disk drive executes self-diagnosis (data buffer read/write
    test) after enabling response to the ATA bus.

 c) After confirming that the spindle motor has reached rated speed,
    the disk drive releases the heads from the actuator magnet lock
    mechanism by applying current to the VCM. This unlocks the heads
    which are parked at the inner circumference of the disks.

 d) The disk drive positions the heads onto the SA area and reads out
    the system information.

 e) The disk drive executes self-seek-calibration. This collects data
    for VCM tarque and mechanical external forces applied to the
    actuator, and updates the calibrating value.

 f) The drive becomes ready. The host can issue commands.


 Data transfer phase
 -------------------
 a) The Data transfer phase is defined as the period from The Ultra
    DMA burst initiation phase to Ultra DMA burst termination phase.

 b) The receiving side stops the Ultra DMA burst temporarily by
    negating DMARDY-signal, and then restarts the Ultra DMA burst by
    asserting again.

 c) The transmitting side stops the Ultra DMA burst temporarily by
    not-performing inversion of STROBE signal, and then restarts the
    Ultra DMA burst by restarting the inversion.

 d) When the transmitting side has stopped the inversion of STROBE
    signal, the receiving side should not output termination request
    signal immediately.

    The receiving side should negate DMARDY signal when no termination
    request signal has been received from the transmission side, and
    then should output the termination request signal when a certain
    wait time has elapsed.

 e) The transmitting side is allowed to send STROBE signal at a
    transfer speed that is lower than the one in the transferable
    fastest Ultra DMA mode, but is not allowed to send the STROBE
    signal at a higher speed than this. The receiving side should be
    able to receive the data in the transferable fastest Ultra DMA
    mode.


 Write Cache
 -----------
 The write cache function of the drive makes a high speed processing
 in the case that data to be written by a write command is physically
 sequent the data of previous command and random write operation is
 performed.

 When the drive receives a write command, the drive starts
 transferring data of sectors requested by the host system and writing
 on the disk medium. After transferring data of sectors requested by
 the host system, the drive generates the interrupt of command
 complete. Also, the drive sets the normal end status in the Status
 register.

 The drive continues writing data on the disk medium. When all data
 requested by the host are written on the disk medium, actual write
 operation is completed.

 The drive receives the next command continuously. If the received
 command is a "sequential write" (data to be written by a command is
 physically sequent to data of previous command), the drive starts
 data transfer and receives data of sectors requested by the host
 system. At this time, if the write operation of the previous
 command is still been executed, the drive continuously executes the
 write operation of the next command from the sector next to the last
 sector of the previous write operation. Thus, the latency time for
 detecting a target sector of the next command is eliminated. This
 shortens the access time.

 The drive generates an interrupt of command complete after completion
 of data transfer requested by the host system as same as at previous
 command.

 When the write operation of the previous command had been completed,
 the latency time occurs to search the target sector.
 If the received command is not a "sequential write", the drive
 receives data of sectors requested by the host system as same as
 "sequential write". The drive generates the interrupt of command
 complete after completion of data transfer requested by the host
 system. Received data is processed after completion of the write
 operation to the disk medium of the previous command.

 Even if a hard reset or soft reset is received or the write cache
 function is disabled by the SET FEATURES command during unwritten
 data is kept, the instruction is not enabled until remaining
 unwritten data is written onto the disk medium.

 The drive uses a cache data of the last write command as a read cache
 data. When a read command is issued to the same address after the
 write command (cache hit), the read operation to the disk medium is
 not performed.

 If an error occurs during the write operation, the device retries the
 processing. If the error cannot be recovered by retry, automatic
 alternate assignment is performed.


 IMPORTANT
 When Write Cache is permitted, the writing of the data transferred
 from the host by the abovementioned Write Cache permit command
 into the disk medium may not be completed at the moment a normal
 ending interrupt has occurred.
 In case a non-recoverable error has occurred during receiving more
 than one write command, it is difficult for the host to identify a
 command that caused the error.

 (However, the error is not reported to the hose if an error at
 writing has been processed normally.) Therefore, note that it is
 difficult for the host to retry an operation that caused a non-
 recoverable error.



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FUJITSU  MHC-2032AT/2040AT  PRODUCT MANUAL

 Functions and performance
 -------------------------
 - Compact
   The disk has 3 disks of 65 mm (2.5 inches) diameter, and its height
   is 12.5 mm (0.492 inch).

 - Large capacity
   The disk drive can record up to 1,083 MB (formatted) on one disk
   using the (16/17) EPR4ML recording method and 13 recording zone
   technology. The MHC2032AT and MHC2040AT have a formatted capacity
   of 3.25 GB and 4.09 GB respectively.

 - High-speed Transfer rate
   The disk drive has an internal data rate up to 9.8 MB/s. The disk
   drive supports an external data rate up to 33.3 MB/s (U-DMA).

 - Average positioning time
   Use of a rotary voice coil motor in the head positioning mechanism
   greatly increases the positioning speed. The average positioning
   time is 13 ms (at read).


 Mean time between failures (MTBF)
 ---------------------------------
 The mean time between failures (MTBF) is 300,000 H or more
 (operation: 24 hours/day, 7 days/week).

 This does not include failures occurring during the first three
 months after installation.

 MTBF is defined as follows:
 Total operation time in all fields
 MTBF= (H) number of device failure in all fields

 "Disk drive defects" refers to defects that involve repair,
 readjustment, or replacement. Disk drive defects do not include
 failures caused by external factors, such as damage caused by
 handling, inappropriate operating environments, defects in the power
 supply host system, or interface cable.


 Mean time to repair
 --------------------
 (MTTR) The mean time to repair (MTTR) is 30 minutes or less, if
 repaired by a specialist maintenance staff member.


 Service life
 ------------
 In situations where management and handling are correct, the disk
 drive requires no overhaul for five years when the DE surface
 temperature is less than 48*C.

 When the DE surface temperature exceeds 48*C, the disk drives
 requires no overhaul for five years or 20,000 hours of operation,
 whichever occurs first.


 Data assurance in the event of power failure
 --------------------------------------------
 Except for the data block being written to, the data on the disk
 media is assured in the event of any power supply abnormalities. This
 does not include power supply abnormalities during disk media
 initialization (formatting) or processing of defects (alternative
 block assignment).


 Error Rate
 ----------
 Known defects, for which alternative blocks can be assigned, are not
 included in the error rate count below. It is assumed that the data
 blocks to be accessed are evenly distributed on the disk media.


 Unrecoverable read error
 ------------------------
 Read errors that cannot be recovered by maximum 252 times read
 retries without user's retry and ECC corrections shall occur no more
 than 10 times when reading data of 10(14) bits. Read retries are
 executed according to the disk drive's error recovery procedure, and
 include read retries accompanying head offset operations.


 Positioning error
 -----------------
 Positioning (seek) errors that can be recovered by one retry shall
 occur no more than 10 times in 10(7) seek operations.


 Media Defects
 -------------
 Defective sectors are replaced with alternates when the disk is
 formatted prior to shipment from the factory (low level format).
 Thus, the host sees a defect-free device.
 Alternate sectors are automatically accessed by the disk drive. The
 user need not be concerned with access to alternate sectors.

 IMPORTANT
 HA (host adaptor) consists of address decoder, driver, and receiver.
 ATA is an abbreviation of "AT attachment". The disk drive is
 conformed to the ATA-3 interface. At high speed data transfer (PIO
 mode 3, mode 4, or DMA mode 2 U-DMA mode 2), occurence of ringing or
 crosstalk of the signal lines (AT bus) between the HA and the disk
 drive may be a great cause of the obstruction of system reliability.

 Thus, it is necessary that the capacitance of the signal lines
 including the HA and cable does not exceed the ATA-3 standard, and
 the cable length between the HA and the disk drive should be as short
 as possible.


 Circuit Configuration
 ---------------------
 Read/write circuit
 The read/write circuit consists of two LSIs; read/write preamplifier
 (PreAMP) and read channel (RDC).

 The PreAMP consists of the write current switch circuit, that flows
 the write current to the head coil, and the voltage amplifier
 circuit, that amplitudes the read output from the head.
 The RDC is the read demodulation circuit using the extended partial
 response class 4 (EPR4), and contains the Viterbi detector,
 programmable filter, adaptable transversal filter, times base
 generator, and data separator circuits. The RDC also contains the
 16/17 group coded recording (GCR) encoder and decoder and servo
 demodulation circuit.

 Servo circuit
 The position and speed of the voice coil motor are controlled by 2
 closed-loop servo using the servo information recorded on the data
 surface. The servo information is an analog signal converted to
 digital for processeing by a MPU and then reconverted to an analog
 signal for control of the voice coil motor. The MPU precisely sets
 each head on the track according on the servo information on the
 media surface.

 Spindle motor driver circuit
 The circuit measures the interval of a PHASE signal generated by
 counter-electromotive voltage of a motor at the MPU and controls the
 motor speed comparing target speed.

 Controller circuit
 Major functions are listed below.

 - Data buffer (512 KB) management

 - ATA interface control and data transfer control

 - Sector format control

 - Defect management

 - ECC control

 - Error recovery and self-diagnosis


 Self-calibration
 ----------------
 The disk drive occasionally performs self-calibration in order to
 sense and calibrate mechanical external forces on the actuator, and
 VCM tarque. This enables precise seek and read/write operations.


 Self-calibration contents
 -------------------------
 (1) Sensing and compensating for external forces
     The actuator suffers from torque due to the FPC forces and winds
     accompanying disk revolution. The torque vary with the disk drive
     and the cylinder where the head is positioned. To execute stable
     fast seek operations, external forces are occasionally sensed.
     The firmware of the drive measures and stores the force (value of
     the actuator
     motor drive current) that balances the torque for stopping head
     stably. This includes the current offset in the power amplifier
     circuit and DAC system.

     The forces are compensated by adding the measured value to the
     specified current value to the power amplifier. This makes the
     stable servo control. To compensate torque varing by the
     cylinder, the disk is divided into 8 areas from the innermost to
     the outermost circumference and the compensating value is
     measured at the measuring cylinder on each area at factory
     calibration. The measured values are stored in the SA cylinder.

     In the self-calibration, the compensating value is updated using
     the value in the SA cylinder.

 (2) Compensating open loop gain
     Torque constant value of the VCM has a dispersion for each drive,
     and varies depending on the cylinder that the head is positioned.

     To realize the high speed seek operation, the value that
     compensates torque constant value change and loop gain change of
     the whole servo system due to temperature change is measured and
     stored.

     For sensing, the firmware mixes the disturbance signal to the
     position signal at the state that the head is positioned to any
     cylinder. The firmware calculates the loop gain from the position
     signal and stores the compensation value against to the target
     gain as ratio.

     For compensating, the direction current value to the power
     amplifier is multiplied by the compensation value. By this
     compensation, loop gain becomes constant value and the stable
     servo control is realized. To compensate torque constant value
     change depending on cylinder, whole cylinders from most inner to
     most outer cylinder are divided into 8 partitions at calibration
     in the factory, and the compensation data is measured for
     representive cylinder of each partition. This measured value is
     stored in the SA area. The compensation value at self-calibration
     is calculated using the value in the SA area.


 Execution timing of self-calibration
 ------------------------------------
 Self-calibration is executed when:
 - The power is turned on.

 - The disk drive receives the RECALIBRATE command from the host.

 - The self-calibration execution timechart of the disk drive
   specifies self-calibration.

 The disk drive performs self-calibration according to the timechart
 based on the time elapsed from power-on. After power-on, self-
 calibration is performed about every five or ten or fifteen minutes
 for the first 60 minutes or six RECALIBRATE command executions, and
 about every 30 minutes after that.


 Spindle motor control
 ---------------------
 Hall-less three-phase twelve-pole motor is used for the spindle
 motor, and the 3-phase full/half-wave analog current control circuit
 is used as the spindle motor driver (called SVC hereafter). The
 firmware operates on the MPU manufactured by Fujitsu. The spindle
 motor is controlled by sending several signals from the MPU to the
 SVC. There are three modes for the spindle control; start mode,
 acceleration mode, and stable rotation mode.

 (1) Start mode
     When power is supplied, the spindle motor is started in the
     following sequence:
     a) After the power is turned on, the MPU sends a signal to the
        SVC to charge the charge pump capacitor of the SVC. The
        charged amount defines the current that flows in the spindle
        motor.

     b) When the charge pump capacitor is charged enough, the MPU
        sets the SVC to the motor start mode. Then, a current (approx.
        0.7A) flows into the spindle motor.

     c) The SVC generates a phase switching signal by itself, and
        changes the phase of the current flowed in the motor in the
        order of (V-phase to U-phase), (W-phase to U-phase), (W-phase
        to V-phase), (U-phase to V-phase), (U-phase to W-phase), and
        (V-phase to W-phase) (after that, repeating this order).

     d) During phase switching, the spindle motor starts rotating in
        low speed, and generates a counter electromotive force. The
        SVC detects this counter electromotive force and reports to
        the MPU using a PHASE signal for speed detection.

     e) The MPU is waiting for a PHASE signal. When no phase signal is
        sent for a specific period, the MPU resets the SVC and starts
        from the beginning.
        When a PHASE signal is sent, the SVC enters the acceleration
        mode.

 (2) Acceleration mode
     In this mode, the MPU stops to send the phase switching signal to
     the SVC. The SVC starts a phase switching by itself based on the
     counter electromotive force.
     Then, rotation of the spindle motor accelerates. The MPU
     calcurates a rotational speed of the spindle motor based on the
     PHASE signal from the SVC, and accelerates till the rotational
     speed reaches 4,000 rpm. When the rotational speed reaches 4,000
     rpm, the SVC enters the stable rotation mode.

 (3) Stable rotation mode
     The MPU calcurates a time for one revolution of the spindle motor
     based on the PHASE signal from the SVC. The MPU takes a
     difference between the current time and a time for one revolution
     at 4,000 rpm that the MPU already recognized. Then, the MPU keeps
     the rotational speed to 4,000 rpm by charging or discharging the
     charge pump for the different time. For example, when the actual
     rotational speed is 3,800 rpm, the time for one revolution is
     15.789 ms. And, the time for one revolution at 4,000 rpm is 15ms.
     Therefore, the MPU discharges the charge pump for 0.789 ms ??k
     (k: constant value). This makes the flowed current into the motor
     lower and the rotational speed down. When the actual rotational
     speed is later than 4,000 rpm, the MPU charges the pump the other
     way. This control (charging/discharging) is performed every 1
     revolution.


 Logical Interface
 -----------------
 The device can operate for command execution in either address-
 specified mode; cylinder-head-sector (CHS) or Logical block address
 (LBA) mode. The IDENTIFY DEVICE information indicates whether the
 device supports the LBA mode. When the host system specifies the LBA
 mode by setting bit 6 in the Device/Head register to 1, HS3 to HS0
 bits of the Device/Head register indicates the head No. under the LBA
 mode, and all bits of the Cylinder High, Cylinder Low, and Sector
 Number registers are LBA bits.

 The sector No. under the LBA mode proceeds in the ascending order
 with the start point of LBA0 (defined as follows).

              LBA0 = [Cylinder 0, Head 0, Sector 1]

 Even if the host system changes the assignment of the CHS mode by the
 INITIALIZE DEVICE PARAMETER command, the sector LBA address is not
 changed.


 EXECUTE DEVICE DIAGNOSTIC (X'90')
 ---------------------------------
 This command performs an internal diagnostic test (self-diagnosis) of
 the device. This command usually sets the DRV bit of the Drive/Head
 register is to 0 (however, the DV bit is not checked). If two devices
 are present, both devices execute self-diagnosis.

 If device 1 is present:
 - Both devices shall execute self-diagnosis.

 - The device 0 waits for up to 5 seconds until device 1 asserts the
   PDIAG-signal.

 - If the device 1 does not assert the PDIAG- signal but indicates an
   error, the device 0 shall append X'80' to its own diagnostic
   status.

 - The device 0 clears the BSY bit of the Status register and
   generates an interrupt. (The device 1 does not generate an
   interrupt.)

 - A diagnostic status of the device 0 is read by the host system.

 When a diagnostic failure of the device 1 is detected, the host
 system can read a status of the device 1 by setting the DV bit
 (selecting the device 1).

 When device 1 is not present:
 - The device 0 posts only the results of its own self-diagnosis.

 - The device 0 clears the BSY bit of the Status register, and
   generates an interrupt.

 If the device 1 fails the self-diagnosis, the device 0 "ORs" X'80'
 with its own status and sets that code to the Error register.


 Address Translation
 -------------------
 When the IDD receives any command which involves access to the disk
 medium, the IDD always implements the address translation from the
 logical address (a host-specified address) to the physical address
 (logical to physical address translation).

 LBA mode
 Logical address assignment in the LBA mode starts from physical
 cylinder 0, physical head 0, and physical sector 1. If the last
 sector in a zone of a physical head is used, the track is switched
 and the next LBA is assigned to the initial sector in the same zone
 of the subsequent physical head. After the last physical sector of
 the last physical head is used in the zone, the subsequent zone is
 used and LBA is assigned from physical head 0 in the same way.

 Standby mode - Sleep mode
 The drive moves from the Active mode to the idle mode by itself.
 Regardless of whether the power down is enabled, the device enters
 the idle mode. The device also enters the idle mode in the same way
 after power-on sequence is completed.
 And, the automatic power-down is executed if no command is coming for
 30 min. (default)

 Active mode
 In this mode, all the electric circuit in the device are active or
 the device is under seek, read or write operation.
 A device enters the active mode under the following conditions:
 - A command other than power commands is issued.

 - A reset command is received.

 Idle mode
 In this mode, circuits on the device is set to power save mode.
 The device enters the Idle mode under the following conditions:
 - After completion of power-on sequence.

 - After completion of the command execution other than SLEEP and
   STANDBY commands.

 - After completion of the reset sequence

 Standby mode
 In this mode, the VCM circuit is turned off and the spindle motor is
 stopped.

 The device can receive commands through the interface. However if a
 command with disk access is issued, response time to the command
 under the standby mode takes longer than the active or Idle mode
 because the access to the disk medium cannot be made immediately.
 The drive enters the standby mode under the following conditions:
 - A STANDBY or STANDBY IMMEDIATE command is issued in the active
   or idle mode.

 - When automatic power down sequence is enabled, the timer has
   elapsed.

 - A reset is issued in the sleep mode.


