Specifications

ATAPI For Streaming Tape QIC-157 Rev B
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6.8.3. LOAD UNLOAD Command
The LOAD UNLOAD command requests that the Device enable or disable further media access
operations. Media access commands are defined in Table 6-4 Packet Commands Supported by
Streaming Tape Devices. This command may also be used to request a re-tension function. Prior to
performing the load or unload operation, the Device shall ensure that all buffered data, and filemarks
have been transferred to the medium.
Table 6-11 Load Unload Command
Bit
Byte
7 6 5 4 3 2 1 0
0 Operation code (1Bh)
1 Reserved Reserved
(Immed)
2 Reserved
3 Reserved
4 Reserved EOT Re-Ten Load
5 Reserved
6 Reserved
7 Reserved
8 Reserved
9 Reserved
10 Reserved
11 Reserved
An end-of-tape (EOT) bit of one indicates that an unload operation (Load bit set to zero) shall
position the medium at end-of-medium for removal from the Device. An EOT bit of zero indicates
that an unload operation shall position the medium at beginning-of-medium for removal from the
Device.
An EOT bit of one and a Load bit of one shall cause the Device to return “Check Condition” status
and the Sense Key shall be set to ILLEGAL REQUEST in the sense data.
A Re-Tension (Re-Ten) bit of one indicates that the medium on the Device shall be correctly
tensioned. Implementation of the re-tensioning function is Device specific that typically consists of
one end-to-end pass on the cartridge.
If the Load bit is set to one, the medium shall be loaded and positioned to the beginning-of-partition
zero. If the Load bit is zero, the medium in the Device shall be positioned for removal at the extreme
position along the medium specified by the EOT bit. Following successful completion of an unload
operation, the Device shall return “Check Condition” status with the Sense Key set to NOT READY
for all subsequent medium-access commands until a new volume is mounted or a load operation is
successfully completed.