System Control Blocks

Offset
Bytes and Field
A1ignment Name
-12 (-C) 4 XRBQMAJ
-8 (-8) 4 XRBSUC
-4 (-4) 4 XRBPRE
o (0) 8 XRBNM
Bytes 0-3:
Bytes 4-1:
8 (8) 2 XRBSZ
REQUEST BLOCK -- MFT
214 OS System Control Blocks (Release 21.1)
Field Description, Contents, Meaning
LPRB:
With subtasking only: The address of the major RB
for the program that contains the imbedded entry
point established by the IDENTIFY macro instruction
that created this LPRB.
Address of the XRBSUC field in the RB for the program
loaded just prior to the program represented by this
RB. If this is the RB for the first program loaded,
this field is zero. In an LRB or LPRB, THE RB
pOinted to is queued on the load list or on the job
pack area queue; if this is an FRB, the RB pointed to
is queued on the job pack area queue.
Address of the XRBSUC field in the RB for the program
loaded immediately after the program represented by
this RB. If this RB is for the most recently loaded
program, this field contains the address of the
TCBLLS field in the task control block, or the
address of the PIBJPQ field in the partition
information block if this RB is queued on the job
pack area queue.
In an LRB or LPRB, the RB pointed to is queued on the
load list or on the job pack area queue; if this is
an FRB, the RB pointed to is queued on the job pack
area queue.
Contents of this field depend on the use of this
block. The use of this request block is shown by
bits 0-3 of byte 1 of the XSTAB field at offset 10
(dec.), A (hex).
LPRB, LRB, PRB, FRB
Program name.
IRB
For timer, 1st byte contains flags; for all other
uses, contains no meaningful information.
SIRB
8 character name of the error routine currently
occupying the 400 byte I/O supervisor transient area.
SVRB
Type 2 SVC:
No meaningful information.
Type 3 or 4 SVC:
TTRN address, on the SVC library, of the load
module. N, the concatenation number, is o.
Four digit number of the form ysss. y - Number of
the current phase of the routine. (First or only
phase: y = 0) sss - SVC number in unpacked
decimal (signed) form.
The number of contiguous double words occupied by the
RB, the program (if applicable), and associated
supervisor work areas. Does not include program size
if a program extent list is present.
FRB: After the LPRB has been created, the number of
doublewords occupied by the LPRB and the program.
Before creation of the LPRB, contains zeros.