Read Element Status Data - Sun Microsystems storagetek sl500 Reference Manual

Read Element Status
Number of Elements
CurData
DvcID
Allocation Length

Read Element Status Data

The library returns data for a Read Element Status command with this structure:
An eight-byte Element Status Data header, followed by
■
One to four element pages, one page per element type.
■
A page consists of:
An eight-byte Element Status Page header, followed by
■
One or more Element Descriptors. The format of the descriptor is based on the
■
element type reported in this page. Each element type receives a separate
Element Descriptor format.
Data can be truncated based on the length specified in the allocation field.
182 SL500: Interface Reference Manual • July 2008
This field represents the maximum number of element descriptors to be
transferred. This is an actual number of element descriptors to be transferred,
not an element address range.
The current data bit specifies that the library shall return element status data
without causing device motion.
0 = Library operations are normal, and library mechanics may become active
■
if needed to gather element static data.
1 = The library is responding with data only; no mechanical operations are
■
active
The CurData bit is effectively ignored by the library. The library will perform
or not perform mechanical operations to obtain proper information at it's
discretion independently of the setting of this bit.
The device identification bit indicates whether the return data will contain
device identification information.
0 = The library will not return device identification information.
■
1 = The library will return device identification information only for data
■
transfer elements.
This field specifies the length in bytes of the space allocated by the initiator for
the transfer of element descriptors. Only complete element descriptors are
transferred. Element descriptors are transferred until one of the following
conditions is met:
All available element descriptors of the type specified in the Element Type
Code have been transferred, or
The number of element descriptors specified in the Number of Elements field
have been transferred, or
There is less allocation length space available than required for the next
complete element descriptor or header to be transferred.
Revision: F • 96122