IBM DTTA-351010 - Deskstar 10.1 GB Hard Drive, Specifications

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The use of bit 4 is command dependent. After the D M A Queued commands, it is used as SERV. After any
other commands or reset, it is used as DSC.
Bit Definitions
BSY Busy. B S Y = 1 whenever the device is accessing the registers. The host should not
read or write any registers when B S Y = 1 . If the host reads any register when
B S Y = 1 , the contents of the Status Register will be returned.
DRDY (RDY) Device Ready. R D Y = 1 indicates that the device is capable of responding to a
command. R D Y will be set to 0 during power on until the device is ready to accept
a command. If the device detects an error while processing a command, R D Y is set
to 0 until the Status Register is read by the host, at which time R D Y is set back to 1.
DF Device Fault. D F = 1 indicates that the device has detected a write fault condition.
D F is set to 0 after the Status Register is read by the host.
DSC Device Seek Complete. D S C = 1 indicates that a seek has completed and the device
head is settled over a track. DSC is set to 0 by the device just before a seek begins.
When an error occurs, this bit is not changed until the Status Register is read by the
host, at which time the bit again indicates the current seek complete status.
When the device enters into or is in Standby mode or Sleep mode, this bit is set by
device in spite of not spinning up.
SERV (SRV) Service. SRV is set to one when the device is ready to transfer data after it releases
bus for execution of a D M A Queued command.
DRQ Data Request. D R Q = 1 indicates that the device is ready to transfer a word or byte
of data between the host and the device. The host should not write the Command
register when D R Q = 1 .
CORR (COR) Corrected Data. Always 0.
IDX Index. I D X = 1 once per revolution. Since I D X = 1 only for a very short time during
each revolution, the host may not see it set to 1 even if the host is reading the Status
Register continuously. Therefore the host should not attempt to use IDX for timing
purposes.
ERR Error. E R R = 1 indicates that an error occurred during execution of the previous
command. The Error Register should be read to determine the error type. The
device sets E R R = 0 when the next command is received from the host.
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O E M Specifications for DTTA-3xxxxx