SCSI Description
3-14
Quantum DLT 8000 Tape System
If no higher priority SCSI ID bit is true on the DATA BUS, the SCSI
device wins the arbitration and asserts the SEL signal.
•
The winning SCSI device waits at least one bus clear delay plus one bus
settle delay after asserting the SEL signal before changing any signals.
3.5.3 SELECTION Phase
The SELECTION phase allows an initiator to select a drive to initiate a drive function.
The SCSI device that won the arbitration has both the BSY and SEL signals asserted
and has delayed at least one bus clear delay plus one bus settle delay before ending the
ARBITRATION phase. The SCSI device that won the arbitration becomes an initiator by
not asserting the I/O signal.
During SELECTION, the I/O signal is negated so that this phase can be distinguished
from the RESELECTION phase.
Selection Sequence
The initiator
:
1.
Sets the DATA BUS to the OR of its SCSI ID bit and the drive’s SCSI ID
bit.
2.
Asserts the ATN signal (signaling that a MESSAGE OUT phase is to follow
the SELECTION phase).
3.
Waits at least two deskew delays.
4.
Releases the BSY signal.
5.
Waits at least one bus settle delay.
6.
Looks for a response from the drive.
The drive
:
7.
Determines that it is selected when the SEL signal and its SCSI ID bit are
true and the BSY and I/O signals are false for at least one bus settle delay.
8.
Can examine the DATA BUS to determine the SCSI ID of the selecting
initiator.
9.
Asserts the BSY signal within a selection abort time of its most recent
detection of being selected (this is required for correct operation of the
selection time-out procedure).
The drive does not respond to a selection if bad parity is detected. Also, if
more than two SCSI ID bits are on the DATA BUS, the drive does not
respond to selection.
Summary of Contents for DLTtape DLT 8000
Page 1: ...DLTTM 8000 Tape System Product Manual Nov 10 2003 81 60118 06...
Page 5: ...USER MANUAL STATEMENTS FOR CLASS B EQUIPMENT continued...
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Page 26: ...Table of Contents xxiv Quantum DLT 8000 Tape System...
Page 36: ...About This Manual Quantum DLT 8000 Tape System xxxii...
Page 54: ...General Description and Specifications 1 18 Quantum DLT 8000 Tape System...
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Page 376: ...Appendix A Definition of Vendor Unique Sense Data Information A 4 Quantum DLT 8000 Tape System...
Page 386: ...Appendix C Updating the Firmware C 6 Quantum DLT 8000 Tape System...
Page 396: ...Appendix E Visual Inspection Procedure for DLTtape Cartridges E 8 Quantum DLT 8000 Tape System...
Page 406: ...Appendix G DLT 7000 Emulation Feature G 8 Quantum DLT 8000 Tape System...
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