Specifications

Data Structures
1.13 I/O Request Packet Extension (IRPE)
Table 1–15 Contents of the I/O Request Packet Extension
Field Name Contents
IRPE$W_SIZE* Size of IRPE. EXE$ALLOCIRP writes the constant IRP$C_LENGTH to this
field.
IRPE$B_TYPE* Type of data structure. EXE$ALLOCIRP writes the constant DYN$C_IRP to
this field.
IRPE$W_STS IRPE status field. If bit IRPE$V_EXTEND is set, it indicates that another
IRPE is linked to this one.
IRPE$L_SVAPTE1 System virtual address of the page-table entry (PTE) that maps the start of
region 1. FDT routines write this field. If the region is not defined, this field
is zero.
IRPE$W_BOFF1 Byte offset of region 1. FDT routines write this field.
IRPE$L_BCNT1 Size in bytes of region 1. FDT routines write this field.
IRPE$L_SVAPTE2 System virtual address of the PTE that maps the start of region 2. Set by
FDT routines. This field contains a value of zero if region 2 is not defined.
IRPE$W_BOFF2 Byte offset of region 2. This field is set by FDT routines.
IRPE$L_BCNT2 Size in bytes of region 2. FDT routines write this field.
IRPE$L_EXTEND Address of next IRPE for this IRP, if any.
1.14 Object Rights Block (ORB)
The object rights block (ORB) is a data structure that describes the rights a
process must have to access the object with which the ORB is associated. The
ORB is not normally accessed by device drivers.
The ORB is usually allocated when the device is connected by means of the
SYSGEN command CONNECT. SYSGEN also sets the address of the ORB in
UCB$L_ORB at that time. The object name is normally stored at the end of the
ORB (ORB$T_OBJECT_NAME).
The object rights block is illustrated in Figure 1–17 and described in Table 1–16.
1–51