Specifications

Data Structures
1.10 Driver Prologue Table (DPT)
Table 1–12 (Cont.) Contents of Driver Prologue Table
Field Name Contents
The driver-loading procedure compares the name of a driver to be loaded
with the values in this field in all DPTs already loaded into system memory
to ensure that it loads only one copy of a driver at a time.
DPT$Q_LINKTIME* Time and date at which driver was linked, taken from its image header.
DPT$L_ECOLEVEL* ECO level of driver, taken from its image header.
DPT$L_UCODE* Address of associated microcode image, if DPT$V_UCODE is set in DPT$L_
FLAGS. Use of this field is reserved to Digital.
DPT$Q_LMF_1* First of eight quadwords reserved to Digital for the use of the license
management facility. (The others are DPT$Q_LMF_2, DPT$Q_LMF_3,
DPT$Q_LMF_4, DPT$Q_LMF_5, DPT$Q_LMF_6, DPT$Q_LMF_7, and
DPT$Q_LMF_8.)
DPT$W_DECW_SNAME* Offset to counted ASCII string used by decoding drivers.
1.11 Interrupt Dispatch Block (IDB)
The interrupt dispatch block (IDB) records controller characteristics. The driver-
loading procedure creates and initializes this block when the procedure creates a
CRB. The IDB points to the physical controller by storing the virtual address of
the CSR. The CSR is the indirect pointer to all device unit registers.
The interrupt dispatch block is illustrated in Figure 1–14 and described in
Table 1–13.
Figure 1–14 Interrupt Dispatch Block (IDB)
IDB$L_CSR* 0
IDB$L_OWNER 4
IDB$W_SIZE*IDB$B_TYPE*IDB$B_VECTOR* 8
IDB$W_UNITS*IDB$B_TT_ENABLE*IDB$B_COMBO_CSR* 12
IDB$B_COMBO_VEC*IDB$B_FLAGS*Unused 16
IDB$L_SPL* 20
IDB$L_ADP* 24
IDB$L_UCBLST* (32 bytes) 28
*A read-only field
1–42