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DLT1/VS80 SCSI Interface Guide
81-81276-01 Rev A01
July 2004
2-3
2.5
Behavior Around Power-On and SCSI BUS
RESET
In the following situations, the tape drive generates these responses:
The tape drive recognizes multiple bus resets in succession and bus resets of arbitrarily long duration.
It recovers within the time limits specified above following the last bus reset.
2.6
Data Cache and Medium Write Interaction
The tape drive contains a data cache that buffers blocks (records) until writing them. This section
defines specific times that the tape drive writes blocks to medium. A MODE SELECT parameter
allows disabling the data cache (unbuffered mode). In this mode, every WRITE command causes the
tape drive to write data to the data cartridge before returning the STATUS byte and the COMMAND
COMPLETE messages to the host.
N
OTE
:
We do not recommend unbuffered mode because it produces poor
performance.
Table 2-1.
Tape Drive Behavior after a Power-On and SCSI BUS RESET
Situation
Tape Drive Response
Tape drive power off
All tape drive SCSI lines go to high impedance.
Tape drive power on
The tape drive does not generate any spurious signals on
the SCSI bus
Within 5 seconds of power on and within 250
milliseconds (typically under 4
ms) after a BUS
RESET
The tape drive responds to SCSI bus selections and
returns appropriate, normal responses. The tape drive
returns medium motion commands with CHECK
CONDITION status, Sense Key Not Ready, until the
media is ready.
The tape drive implements the Hard BUS RESET option.
The tape drive rewinds the medium to BOP (Beginning
of Partition, i.e. Beginning of Medium).
Summary of Contents for DLTtape DLT1
Page 1: ...DLT1 VS80 SCSI Interface Guide...
Page 6: ...DLT1 VS80 SCSI Interface Guide vi July 2004 81 81276 01 Rev A01 Notes...
Page 12: ...Table of Contents xii July 2004 81 81276 01 Rev A01 Notes...
Page 16: ...List of Figures xiv July 2004 81 81276 01 Rev A01 Notes...
Page 20: ...List of Tables xviii July 2004 81 81276 01 Rev A01 Notes...
Page 24: ...Chapter 1 Introduction 1 4 July 2004 81 81276 01 Rev A01 Notes...
Page 32: ...Chapter 2 General SCSI Bus Operation 2 8 July 2004 81 81276 01 Rev A01 Notes...
Page 42: ...Chapter 3 SCSI Messages 3 10 July 2004 81 81276 01 Rev A01 Notes...
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