User guide

122 DC 900-1338I
Protocol Software Toolkit Programmer Guide
Next Buffer This field contains the address of the next buffer of the queue
element. In general, this field must be zero in the last buffer. In
the data buffer of a host request queue element, XIO uses this
field for a special purpose, as described in Section 7.2.4.1 on
page 131.
Partition ID This field contains the partition ID if the buffer was obtained
from a partition.
Data Length This field contains the number of valid bytes of data in the
buffer (excluding the system buffer header).
Disposition Flag This field, in combination with the disposition modifier, indi-
cates the action to be taken by XIO when processing of the
queue element is complete (when the request completion is
received from the host). This flag has the following possible val-
ues:
POST_QE Post queue element to queue
FREE_QE Zero disposition modifier to mark queue ele-
ment free
TOKEN_QE Release queue element to a resource
POST_BUF Post buffer to queue
FREE_BUF Zero disposition modifier to mark buffer free
TOKEN_BUF Release buffer to a resource
REL_BUF Release buffer to partition
POST_QE, FREE_QE, and TOKEN_QE are valid only in the first
buffer of a queue element and apply to the entire queue ele-