scsimgr SCSI Management and Diagnostics utility on HP-UX 11i v3 (March 2008)

• default value: the value used to initialize the attribute at system boot when there is no saved
value, or upon user request to reset the attribute. The default value is usually hard-coded by
the driver or is inherited from the current value at a higher level where the attribute is
explicitly set.
Note: For read-only attributes (also called non settable attributes), only the current value is defined.
Attributes can be set at the following levels:
• Global: A value of an attribute set at this scope, affects the default behavior for the SCSI
stack, a class driver or an interface driver. For instance, the default I/O timeout can be set to
60 seconds for all SCSI devices.
• Settable attribute scope: A settable attribute scope definition can include the following criteria
for devices bound to a certain driver: device type, vendor identifier, product identifier, and a
specific product revision. A value of an attribute set at this level, affects the default behavior
for the set of devices bound to the specified driver, and meeting the criteria specified by the
scope and only these devices. For instance, the default I/O timeout can be set to 60 seconds
for disk devices from HP managed by the esdisk driver, and to 120 seconds for all tape
devices managed by the estape driver.
• Specific instance of a SCSI object: A value of an attribute set at this scope overwrites the
default behavior for a specific instance of a SCSI object. For instance I/O timeout can be set
to 50 seconds for the disk device with instance number 0.
Not all attributes can be set at all levels. Some attributes can be set at all levels, others can only be set
at a global level, a settable attribute scope level, or a SCSI object instance level.
The current value of an attribute for a SCSI object instance is determined according to the following
algorithm in highest order of precedence:
1. If the attribute is explicitly set for the specific SCSI object instance, this value is used. The
attribute is explicitly set when either one or all of the following is true:
a. The user sets the saved and/or current values using scsimgr.
b. The driver has hard-coded a default value for the attribute for the object instance.
2. If the SCSI object matches a settable attribute scope and the attribute is set at this level, this
value is used.
3. If the attribute is set at the global level, this value is used.
The default value of an attribute is determined according to the following algorithm in the highest
order of precedence:
1. If the driver hard-codes a default value for this object instance, this value is used.
2. If the object matches a settable attribute scope and the attribute is set at this level, the current
value at this level is used.
3. If the attribute is set at a global level, the current value at this level is used.
Note: the saved value of an attribute is never inherited from higher level. Either it is defined or is not.
Rules governing the update of attribute current values
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