Quantum Atlas 10K II 9.2/18.4/36.7/73.4 GB Product Manual page 323

Appendix B. SCSI Bus Signal Timing
Table B–1 SCSI Bus Timing Values -- ANSI SCSI-2 Standard (continued)
Timing Description
Cable Skew Delay
Data Release Delay
Deskew Delay
Disconnection Delay
Hold Time
Negation Period
Power-On to
Selection Time
Reset to Selection Time
Reset Hold Time
Selection Abort Time
Selection Time-Out Delay 250 ms *
Transfer Period
* Recommended time
B–2 Quantum Atlas 10K II Ultra 160/m SCSI Hard Disk Drives
Value Description
10 ns Maximum difference in propagation time allowed
between any two SCSI bus signals measured
between any two SCSI devices.
400 ns Maximum time for an initiator to release the
DATA BUS signals following the transition of the
I/O signal from false to true.
45 ns Minimum time required to wait for all signals
(especially data signals) to stabilize at their
correct, final value after changing.
200 µs Minimum time that a drive waits after releasing
BSY before participating in an ARBITRATION when
honoring a DISCONNECT message from the
initiator.
45 ns Minimum time added between the assertion of
REQ or ACK and changing the data lines to
provide hold time in the initiator or drive while
using standard (slow) synchronous data transfers.
90 ns Minimum time that a drive negates REQ while
using standard synchronous data transfers; also,
the minimum time than an initiator negates ACK
while using standard (slow) synchronous data
transfers .
10 s *
Recommended maximum time from power
application until a drive is able to respond with
appropriate status and sense data to the TEST
UNIT READY, INQUIRY, and REQUEST SENSE
commands.
250 ms *
Recommended maximum time after a hard RESET
condition until a drive is able to respond with
appropriate status and sense data to the TEST
UNIT READY, INQUIRY, and REQUEST SENSE
commands.
25 µs Minimum time for which RST is asserted; there is
no maximum time.
200 µs Maximum time that a drive (or initiator) takes
from its most recent detection of being selected
(or reselected) until asserting a BSY response.
Recommended minimum time a SCSI device
should wait for a BSY response during SELECTION
or RESELECTION before starting the time-out
procedure.
Minimum time allowed between the leading
edges of successive REQ pulses and of successive
ACK pulses while using standard or fast
synchronous data transfers. The period range is
200 to 500 ns minimum, standard, or 100 to 500
ns minimum, fast-synchronous.
Note: negotiated and set during an SDTR
message.
(continued)