Specifications

Data Structures
1.16 SCSI Connection Descriptor Table (SCDT)
SCDT$L_QUEUE_FLAGS* 260
SCDT$Q_TAG_MAP* 264
SCDT$W_DEV_IO_COUNT*SCDT$W_PORT_IO_COUNT* 272
SCDT$W_WAIT_TAG*SCDT$W_MAX_TAG_USED* 276
SCDT$W_MAX_QUEUE_DEPTH*Reserved 280
SCDT$L_SEQUENCE* 284
SCDT$L_NEXT_SEQUENCE* 288
SCDT$L_SCDRP_MAP* 292
*A read-only field from a class driver point of view
Table 1–18 Contents of SCSI Connection Descriptor Table
Field Name Contents
SCDT$L_FLINK* SCDT forward link. This field points to the next SCDT in the port’s SCDT
list (at SPDT$L_SCDT_VECTOR). The SCSI port driver initializes this
field when it creates the SCDT in response to an SPI$CONNECT call.
SCDT$W_SIZE* Size of SCDT. The port driver, after allocating sufficient nonpaged pool for
the SCDT, writes the constant SCDT$C_LENGTH into this field.
SCDT$B_TYPE SCS structure type.
SCDT$B_SUBTYP SCSI structure subtype for CDT.
SCDT$B_FLCK* Index of the fork lock that synchronizes access to this SCDT at fork
level. The SCSI port driver, when creating the SCDT, initializes this field
with SPL$C_IOLOCK8. The SCDT fork block is used during an ABORT
command request on the connection.
SCDT$L_FPC* Address of instruction at which the suspended port driver thread is to be
resumed.
SCDT$L_FR3* Value of R3 when the request is stalled during disconnection. The value in
R3 is restored before a suspended driver thread is resumed.
SCDT$L_FR4* Value of R4 when the request is stalled during disconnection. The value in
R4 is restored before a suspended driver thread is resumed.
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