User's Guide

Commands: Read Data Buffer (3Ch) Page 113
READ DATA BUFFER Header
The following table shows the header layout for the READ DATA BUFFER
command.
Byte
Bits
7 6 5 4 3 2 1 0
0 0 0 0 0 0 0 0 0
1 MSB—Available length
2 Available length
3 Available length
READ DATA BUFFER Header Field Descriptions
The READ BUFFER header contains four bytes.
• The first byte is reserved and set to zero.
• Bytes one, two and three contain the capacity of the space available in the drive
buffer. This number is not reduced to reflect the Allocation Length nor is it
reduced to reflect the actual number of bytes using the WRITE DATA BUFFER
command.
Completion Status
The Completion Status for the READ DATA BUFFER command is shown in the
following table.
Code Message Description
00h Good
Status
• The drive is ready to perform any appropriate command.
• The drive remains in any previously set mode.
• The tape position is not changed.
02h Check
Condition
Extended Sense Byte 02h:
Code Message Description
04h Hardware Error Drive hardware failure detected.
05h Illegal Request
• The CDB contains an invalid bit.
• Allocation Length exceeds the maximum.
06h Unit
• Cartridge was changed prior to accepting
Attention this command
• The drive was reset prior to this command.