Specifications

Data Structures
1.17 SCSI Port Descriptor Table (SPDT)
Table 1–19 (Cont.) Contents of SCSI Port Descriptor Table
Field Name Contents
SPDT$L_PORT_FLAGS* Port-specific flags. The following bits are defined:
SPDT$V_SYNCH Port supports synchronous mode data transfers.
SPDT$V_ASYNCH Port supports asynchronous mode data transfers.
SPDT$V_MAPPING_
REG
Port supports map registers.
SPDT$V_BUF_DMA Port supports buffered DMA transfers.
SPDT$V_DIR_DMA Port supports direct DMA transfers.
SPDT$V_AEN Port supports asynchronous event notification.
SPDT$V_LUNS Port supports logical unit numbers.
SPDT$V_CMDQ Port supports command queuing I/O.
Bits <31:25> Contain the recommended byte count divisor for
the class driver to derive a proper DMA byte count
for the port.
SPDT$L_VERSION_
CHECK*
Value used to check driver versions.
SPDT$B_CUR_STAT* Copy of CUR_STAT register.
SPDT$B_STATUS* Copy of STATUS register.
SPDT$B_MODE* Copy of MODE register.
SPDT$B_EVENT_CNT* Count of events while servicing current interrupt.
SPDT$L_TVDRV_ISR Address of the TVDriver’s ISR.
SPDT$L_TVDRV_DMA_
BASE
Address of the TVDriver’s DMA buffer.
SPDT$L_TVDRV_DMA_SIZE Size of the TVDriver’s DMA buffer.
SPDT$L_TVDRV_UCB Address of the TVDriver’s UCB.
SPDT$L_CUR_SCDT_VEC Pointer into SCDT_VECTOR for CMDQ.
SPDT$L_QMAN_RESUME Address to resume QUEUE_MANAGER.
SPDT$L_OWNER_TAG Tag value of bus owner thread.
SPDT$L_PORT_IO_COUNT I/O number in port using SEND/QUEUE_CMD.
SPDT$L_QUEUE_SPINS Number of passes over port queues.
SPDT$L_QUEUE_EXITS Number of exits from the queue manager.
1–80