Specifications

Data Structures
1.15 SCSI Class Driver Request Packet (SCDRP)
Table 1–17 (Cont.) Contents of SCSI Class Driver Request Packet
Field Name Contents
SCDRP$W_PAD_BCNT Pad byte count. This field contains the number of bytes required to make the
size of the user buffer equal to the data length value required by a specific
SCSI command. A SCSI class driver uses this field to accommodate SCSI
device classes that require that the transfer length be specified in terms
of a larger data unit than the count of bytes expressed in the SCDRP$L_
BCNT. If the total amount of data requested in the SCSI command does not
match that specified in the SCDRP$L_BCNT, this field must account for the
difference.
SCDRP$B_TQE* Timer queue element, used by the port driver to time out pending
disconnected I/O transfers. When this TQE expires, the timer thread times
out expired pending I/O transfers.
SCDRP$L_TQE_DELAY* Delay time for next TQE delay.
SCDRP$L_SVA_DMA* System address of the section of the port DMA buffer allocated for the data
transfer.
SCDRP$L_SVA_CMD* System address of the segment of the port DMA buffer allocated for the port
command buffer.
SCDRP$W_MAPREG* Page number of the first port DMA buffer page allocated for the data
transfer.
SCDRP$W_CMD_
MAPREG*
Page number of the first port DMA buffer page allocated for the port
command buffer.
SCDRP$W_NUMREG* Number of port DMA buffer pages allocated for the data transfer.
SCDRP$W_CMD_
NUMREG*
Number of port DMA buffer pages allocated for the port DMA buffer.
SCDRP$L_SVA_SPTE* System virtual address of the system page-table entry that maps the first
page of the process buffer in S0 space.
SCDRP$L_SCSIMSGO_
PTR*
SCSI output message pointer.
SCDRP$L_SCSIMSGI_
PTR*
SCSI input message pointer.
SCDRP$B_SCSIMSGO_
BUF*
SCSI output message buffer.
SCDRP$B_SCSIMSGI_
BUF*
SCSI input message buffer.
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