Specifications

Data Structures
1.17 SCSI Port Descriptor Table (SPDT)
Table 1–19 (Cont.) Contents of SCSI Port Descriptor Table
Field Name Contents
SPDT$L_SPTE_BASE* System virtual address of the system page-table entry mapping the first
page of the port’s DMA buffer.
SPDT$L_SPTE_SVAPTE* System virtual address of the system page-table entry that double-maps
the data transfer buffer.
SPDT$L_ADP* Address of the adapter control block managing port resources.
SPDT$L_PORT_RING* 64-byte field recording the PCs of port channel request and release
transactions.
SPDT$L_PORT_RING_PTR* Pointer to the current port channel ring buffer entry.
SPDT$L_OWNERSCDT* Address of the SCDT of the connection that currently owns the port.
SPDT$L_SCDT_VECTOR* 256-byte vector, recording the SCDT addresses associated with connections
active for a given SCSI device ID (0 through 7).
SPDT$L_DLCK* Address of device lock that—in a multiprocessing environment—
synchronizes access to device registers and those fields at the SPDT
accessed at device IPL. The port driver initializes this field from UCB$L_
DLCK when it creates the SPDT.
SPDT$B_DIPL* Interrupt priority level (IPL) at which the device requests hardware
interrupts. The port driver initializes this field from UCB$L_DLCK when
it creates the SPDT.
SPDT$L_AUXSTRUC Address of auxiliary structure.
SPDT$L_SEL_SCDRP* SCDRP used during selection interrupt.
SPDT$L_ENB_SEL_SCDRP* SCDRP used to enable selection.
SPDT$L_MAP_BUFFER* Address of the port driver routine that executes in response to a class
driver’s SPI$MAP_BUFFER macro call. The port driver initializes this
field.
SPDT$L_UNMAP* Address of the port driver routine that executes in response to a class
driver’s SPI$UNMAP_BUFFER macro call. The port driver initializes this
field.
SPDT$L_SEND* Address of the port driver routine that executes in response to a class
driver’s SPI$SEND_COMMAND macro call. The port driver initializes this
field.
SPDT$L_SET_CONN_
CHAR*
Address of the port driver routine that executes in response to a class
driver’s SPI$SET_CONNECTION_CHAR macro call. The port driver
initializes this field.
SPDT$L_GET_CONN_
CHAR*
Address of the port driver routine that executes in response to a class
driver’s SPI$GET_CONNECTION_CHAR macro call. The port driver
initializes this field.
SPDT$L_RESET* Address of the port driver routine that executes in response to a class
driver’s SPI$RESET macro call. The port driver initializes this field.
SPDT$L_CONNECT* Address of the port driver routine that executes in response to a class
driver’s SPI$CONNECT macro call. The port driver initializes this field.
SPDT$L_DISCONNECT* Address of the port driver routine that executes in response to a class
driver’s SPI$DISCONNECT macro call. The port driver initializes this
field.
SPDT$L_ALLOC_
COMMAND_BUFFER*
Address of the port driver routine that executes in response to a class
driver’s SPI$ALLOCATE_COMMAND_BUFFER macro call. The port
driver initializes this field.
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