User Manual

SCSI Commands Reference Manual, Rev. J 389
www.seagate.com Parameters for direct access devices
EN_BMS (Enable Background Medium Scan) bit
0 An enable background medium scan (EN_BMS) bit set to zero specifies that background medium scan is disabled.
1 An EN_BMS bit set to one specifies that background medium scan operations are enabled. If the EN_PS bit is also set to one then a back-
ground medium scan operation shall not start until after the pre-scan operation is halted or completed.
If a background medium scan operation is in progress when the EN_BMS bit is changed from one to zero, then the logical unit shall suspend
the background medium scan operation before the device server completes the MODE SELECT command, and the background medium scan
shall remain suspended until the EN_BMS bit is set to one, at which time the background medium scan operation shall resume, beginning with
the logical block being tested when the background medium scan was suspended.
EN_PS (enable pre-scan) bit
0 An enable pre-scan (EN_PS) bit set to zero specifies that pre-scan is disabled. If a pre-scan operation is in progress when EN_PS is
changed from a one to a zero then pre-scan is halted.
1 An EN_PS bit set to one specifies that a pre-scan operation is started after the next power on cycle.
Once this pre-scan has completed, another pre-scan shall not occur unless the EN_PS bit is set to zero, then set to one, and another power on
cycle occurs.
BACKGROUND MEDIUM SCAN INTERVAL TIME field
The BACKGROUND MEDIUM SCAN INTERVAL TIME field specifies the minimum time, in hours, between the start of one pre-scan or background
medium scan operation and the start of the next background medium scan operation. If the current background medium scan operation takes
longer than the value specified in the BACKGROUND MEDIUM SCAN INTERVAL TIME field, then the logical unit shall:
a) continue the current background pre-scan operation or background medium scan operation until that background scan operation is
complete; and
b) the logical unit shall start the next background medium scan operation starts upon completion of the current background pre-scan
operation or background medium scan operation.
BACKGROUND PRE-SCAN TIME LIMIT field
The BACKGROUND PRE-SCAN TIME LIMIT field specifies the maximum time, in hours, for a background pre-scan operation to complete. If the
background pre-scan operation does not complete within the specified time then the device server shall halt the background pre-scan opera-
tion. A value of zero specifies an unlimited timeout value.
MINIMUM IDLETIME BEFORE BACKGROUND SCAN field
The MINIMUM IDLE TIME BEFORE BACKGROUND SCAN field specifies the time, in milliseconds, that the logical unit shall be idle after suspend-
ing a background scan operation before resuming a background scan operation (e.g., after the device server has completed all of the com-
mands in the task set).
MAXIMUM TIME TO SUSPEND BACKGROUND SCAN field
The MAXIMUM TIME TO SUSPEND BACKGROUND SCAN field specifies the time, in milliseconds, that the device server should take to start pro-
cessing a command received while a logical unit is performing a background scan operation.