r I I Operand I Sta tus I Description I I -------------------------------------------------------1 IVARBLD=(nn) IRegister number if RECFORM=VARBLK and I I I records are built in the output area. , I I Omi t if WORKA=YES. I I IVERIFY=YES ICheck disk records after they are written. I I , IwLRERR=xxxxxxxx !Name of your wrong-length record routine. I 1 , IWORKA=YES IGET or PUT specifies work area. Omit IOREG.I I I Required for RECFORM=SPNUNB or SPNBLK. I Figure 40. CMS/DOS support of DTFSD Macro (Part 3 of 3) SEQUENTIAL ACCESS METHOD -- IMPERATIVE MACROS CMS/DOS supports the following imperative macros: • GET, PUT, PUTR, RELSE, lRUNC, CNTRL, ERET, and PRTOV. No code is generated for the CHNG macro. • fQ! gi§f: READ, WRIlE, CHECK, NOTE, POINTE, POINTW, and POINTS. • CLOSE and CLOSER CMS/DOS supports workfiles containing fixed-length unblocked records
and undefined records. Disk work files are supported as single volume,
single pack files. Normal extents and split extents are both supported. DOS/VS Transient Routines CMS/DOS uses the DOS/VS CMS/DOS accesses the LIOCS private library. For this
before you can use CMS/DOS. LIOCS transient routines without change.
routines directly from a DOS/VS system cr
reason, you must order and install DOS/VS However, CMS/DOS simulates the DOS/VS transients that are fetched by
macro expansion or by the LIOCS modules. These simulation routines
contain enough of the transient's function to support the DOS/VS COBeL compiler and DOS PL/I optimizing compiler. These routines that simulate
the DOS/VS transients execute in the CMS/DOS discontiguous shared
segment.
The following DOS/VS transients are simulated by CMS/DOS. Transient $$BOPEN-- Fetched by the DOS/VS OPEN LIoes modules. $$BOPEN dependent upon the device
operations. At entry to
list of fullword addresses
macro expansion or by the DOS/VS performs DTF initialization,
type, to ready the file for I/O $$BOPEN, register 0 points to a
containing a pointer to the DTFs. 30U VM/370 System Prograwmer's Suide

$$BOPNLB $$BCLOSE $$BDUMP $$BOPENR $$BOPNR3 $$BOPNR2 Function under $$BOPEN-checks for supported DTF types, and initializes DTFs
in accordance with the device type. In the case of disk
files and tape data files, default tLBLs with the NOCHANGE option are issued. (The CMS STATE command is issued to
verify the existence of the input files.) $$BOPEN is invoked to supply additional extent information
for multi-extent real DOS data sets. $$BOPEN is also called
to initialize DTFs with EXTENT information for private and
system DOS libraries. The OPEN transient is responsible for
providing the proper extent information as a result of POINTR/POINTS requests. If a VSIM file is being opened (Byte 20 = X'28
1 in the ACB), control is passed to the VSAM OPEN routine. When opening DTFSD files for output or DTFCP/DTFDI
disk files for output, if a file exists on a CMS disk with
the same filename, filetype, and filemode, the file is erased.
Fetched by COBOL Compiler Phase 00 to read the appropriate
system or private source statement library directory record
and to determine whether or not active members are present
for the library.
Fetched by DOS/VS CLOSE macro expansion to deactivate a
file.
Fetched when an abnormal termination condition is
encountered. Control is not passed to a STXlT routine= CMS/DOS performs a CP dump to a virtual printer. The routine
is canceled.
Fetched by a DOS/VS OPENR macro expansion. The function cf $$BOPENR is to relocate all DTF table address constants frcm
the assembled addresses to executable storage addresses. At
entry to $$BOPENR, register 0 points to an assembled address
constant followed by a list of DTF addresses tables that
require address modification.
Fetched by $$BOPENR to relocate all DTF table address
constants for unit record DTFs.
Fetched by $$BOPNR3 to relocate all DTF table address
constants for DTFDI or DTFCP. EXCP Support in CMS/DOS CMS/DOS simulates
extent necessary
preceding section CMS/DOS." the EXCP (execute channel program) routines to the
to support the LIOCS routines described in the "DOS/VS Supervisor and I/C Macros Supported by Because CMS/DOS uses the DOS/VS LIOCS routines unchanged, it must
simulate all I/O at the EXCP level. The EXCP simulation routines convert
all the I/O that is in the CCi format to eMS physical 1/0 requests.
That is, CMS macros (such as RDBUF/WRBUF. CARDRD/CARDFH, PRINTIO, and WAITRD/TYPLIN) replace the CCW strings. If CMS/DOS is reading from Des ctisks, _I/O requests are handled via the DIAGNOSE interface. Part 3. Conversational Monitor System (eMS) 305