Input IREG 1 Notes Module 1 The initialization procedures include: DMSREA • Saving registers. • Setting return code to zero. • Issuing DIAGNOSE X'2C' to locate
beginning of error recording area
and number of cylinders. • Setting and checking "first time" switch_ • Checking CCBOR address passed
for validity.
Note: A CCSOR disk address is a
disk addressing format devised
solely for use in CPEREP and
resembles the commonly used CCHHR disk address. In a CCBOR the fields have the following
meanmg:
Field Meaning CC Relative cylinder within
the VM/370 error record-
ing area, for example: CC = X'OOOO' for the first
cylinder of the error
recording area.
= X '0001 , for the sec-
ond cylinder of the
error recording area.
B The number of the desired
4K block within the cyl-
inder. The first 4K block
in a cylinder is X'01'. 0 Zero. R The number of the desired
record within the 4K block.
The first record in a block
is X'01'. Diagram 11-2. DMSREA Processing Output Initialize and find error recording
area on disk.
2 Obtain block containing the
requested record, read a page and
handle errors. , T6 DMSREA830E 3 If the requested record could not
be read (I/O error) or if there is Ib no such record, continue reading
consecutive blocks until the next
record is found. Calculate its CCBOR address; this becomes the
corrected CCBOR. 4 Clean up and return to caller. Label Ref NotlS DMSREA Diagram 2 DMSREA converts the CCBOR 11-2 address to a VM/370 Control Program Internal Format address and issues a DIAGNOSE X'30' to read the block
into the buffer. If the requested block
is found, return to caller. If specified FIRSTSW cylinder is outside error recording area,
sets error code in register 15 for invalid OPER4 cylinder. If end of cylinder and
no more cylinders are available, sets register 0 to zero, indicating
end-of-file to caller; otherwise,
advance to next cylinder. If an I/O error occurs so that the block
could not be read, issue message DMSREA830E_ 3 If requested record was not found, read
next block and return first record from
this block_ If block is empty or unread- able, continue reading blocks until a
record is found or until end-of-file is reached_ Use CCBOR address of the
record found as the corrected CCBOR value to be returned to the caller. Make
register 1 point to this CCBOR address.
Note: The CCBOR record addresses
are passed back to OSIVS EREP (as a
result of the EXCP simulation) as if
they were CCHHR addresses. EREP
never notices the difference and, as a
result, EREP uses CCBOR addresses in all its I/O operations to the SYS1.LOGREC data set.
4 Restore registers (except output para-
meter registers) and return to caller.
REG 15 r&r;I Module Label OPER5 OPER7 OPER16
OPER17 OPER7 OPER9 OPER10 OPER15
214 IBM VM/370 Service Routines Prograa Logic
Ref

Program Organization
This secticn includes program descriptions
of modules DMSIFC and DMSREA. DMSIFC Allows virtual users to edit and print VM/370 error recordings under eMS via the OS/VS EREP Edit and Print Program (IFCEREP1) ..
Routines Called --IFCEREp'--via LINK to edit and print VM/370 error recording cylinders. DMSREA via BlLR to read a specified
record from the VM/310 error recording
cylinders. DMSLlD via BlLR to determine which
read/write disk has the most space. DMKIOG via DIAGNOSE to clear requested
recording cylinders. STATE/STATEi via SiC to perform CMS functicns. ERASE via SiC to perform eMS functions. INCLUDE via SVC to perform CMS functions.
Attributes
- Nonreusable, CMS User Area, and called by CMS. R1: CMS parameter list address
R13: Save area address
R14: Return address at Exit RO-R14: -Restored R15: One of the following return codes
Return
Cede -'2- 24 28
32
56 60 62 CLEAR specified with
other parameters.
An invalid parameter or
no filetype was specified.
The file Was not found.
The file was not a
fixed-length format.
GLOBAL command was not
issued for CPEREP's TITLlBs ..
An I/O error caused one
or more of the 4K blocks of error records
to be skipped. More than the maximum number of characters in
options specified. RO-Rl: R2-R 9:
88 100 to set to zerc was sUFpressed. Requires privilege
class F.
Error reading file frem
disk.
Register Parameter registers Scratch R1O-R11: Spares, not used
Base register
Link registers
R12:
R14-R15:
External References --CoRRslvi----Contains address of the
current system save area when
control is received to handle
an SVC as requested by the HUDsve macro. OSSFLAGS OS simulation flags in the NUCON area. rOSFLAGS DOS simulation flags in the HUCON area. JJDTLKi Contains address of routine
that aetermines which
read/write disk has the mcst
space. (In the HUCON.) TITLIES Indicates whether or net any TITLIBs have been globaled.
(In the HUCCD.) TXTDIRC Indicates whether or net any
TITLIBs havE been globaled.
(In the HUCCH; Ioints to the
first directory in the chain
of global TITLIE
directories. )
The functions performed by CMSIFC can be
summarized as follows:
1.
2.
3.
4. Performs standard linkage
addressatility functions.
and
Invokes CMS LOAD function te load
and resolVE VCONs in about a dozen FREP object decks. !ote: All other EBEP object decks
are brought into storage later, as
needed, by OS LOAD and LINK macres
issued by CS/VS EREf. Invokes STRINIT function.
Indicates that area above presently
loaded programs is the beginning ef
free storage.
Turns off the DCSSVC flag in the CMS nucleus so that OS simulation can be used. SEts CCMPSWT in CMS nucleus so that OS LCAD and LINK macros bring in TEXT files rather
than module files. Invokes OS LCAt Chapter DMSIFC and DMSRI1--EREP/Error Recording Interface 215