ACL 4/52 Software Interface Guide
Document 6211225-03
Version 3.0
3-80
SCSI Interface
Test Unit Ready (00h)
The host uses the Test Unit Ready Command to determine if a library
is ready.
The library responds in one of the following ways, depending upon
the state of the library:
•
Returns a Good status.
Whenever the library is ready to accept a medium access
command without returning a Check Condition status it returns
this status in response to a Test Unit Ready command.
•
Returns a Check Condition status.
When the library receives a Test Unit Ready command but is not
ready to accept a medium access command, it sets the Additional
Sense fields and returns this status. The meaning of the values in
the Additional Sense fields are described along with the Request
Sense command.
The format for the Test Unit Ready Command Descriptor Block is
shown in Table 53.
Table 53: Test Unit Ready
Command
Logical Unit Number
The Logical Unit Number must be set to 0. This field indicates
which logical unit the message is sent to.
Bit/Byte
7
6
5
4
3
2
1
0
0
Operation Code (00h)
1
Logical Unit Number
Reserved (00h)
2
Reserved (000000h)
3
4
5
Reserved (00h)