Chapter 1 Introduction
Background Information About SCSI
DLT-S4 Interface Reference Guide
2
Format of data written to tape:
• Logical addressing (rather than physical addressing) is used for all
data blocks.
• Tape drives support block sizes from 4 bytes to 16,777,212 bytes.
• Fixed block sizes must be in multiple of 4 bytes.
• The DLT-S4 can read DLT-S4, SDLT 600, and SDLT 320 formatted
tapes and can write to DLT-S4 formatted tapes.
Parallel SCSI
Characteristics
1
The features of the DLT-S4 Parallel SCSI implementation include:
• The DLT-S4 tape drive is capable of negotiating and running at any of
the following protocols:
• Single Transition
• Dual Transition
• Information Units (Ultra 320 speeds)
• DLT-S4 tape drives support wide asynchronous and synchronous
data transfers.
• SPI-4 compliant
• Odd parity is generated and checked during all single edge
information transfer phases.
• CRC is generated and checked during all dual edge information
transfer phases.
• The DLT-S4 drive disconnects from the SCSI bus at regular intervals
during information transfer phases to allow other devices to access
the bus. These disconnects are user-configurable using the
Disconnect-Reconnect page of the
MODE SELECT
command.
• The DLT-S4 tape drive does not act as an initiator on the SCSI bus.
Therefore, the drive does not:
1
Generate unsolicited traffic on the network
2
Initiate its own SCSI commands
3
Assert bus reset.