Digital Equipment RW504-ZA, Service Manual

Page: 177 / 220

Table 6–4 (Cont.) Group 0 Commands (6-byte command)
Code (Hex.) Name Description
17 Release Releases a specified logical unit from the
reservation state
1A Mode Sense Reads optical disk, drive unit, or controller
unit parameters
1B Start/Stop Unit Starts or stops rotating the optical disk, ejects
the optical disk from the drive unit, or both
1C Receive Diagnostic
Results Requests analysis data be sent to the initiator
1D Send Diagnostic Requests the disk controller to perform
diagnostic tests
1E Prevent/Allow Medium
Removal Prevents or allows removal of the optical disk
in the logical unit
Table 6–5 Group 1 and 2 Commands (10-byte command)
Code (Hex.) Name Description
25 Read Capacity Reads the capacity of the optical disk
28 Read Reads data from the specified logical block
address
2A Write Writes data to the specified logical block
address
2B Seek Moves the optical head to the physical track
where the specified logical block exists
2C Erase Executes erase operation from the specified
logical block address on rewritable disks only
2E Write and Verify Writes data to the optical disk and then
verifies the written data by checking the
error correction code
2F Verify Verifies the data starting from the specified
logical block address by checking the error
correction code
34 Pre-Fetch Reads the data from the specified logical
block address into the drive’s controller cache
memory
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Theory of Operation 6–29