IBM OS/390 User Manual

OPEN

TAPE

VSE

PUT

TAPE

.

CLOSE TAPE

RECORD1

DS

2000C

TAPE

DTFMT DEVADDR=SYS005,TYPEFLE=OUTPUT,

C

FILABL=STD,IOAREA1=RECORD1,

C

HDRINFO=YES,IOREG=(5),

C

RECFORM=FIXBLK,BLKSIZE=2000,

C

RECSIZE=100,REWIND=NORWD

MTMOD RECFORM=FIXBLK

OPEN

(TAPE,(OUTPUT,LEAVE))

LA

5,RECORD1

MVS

PUT

TAPE,(5)

.

CLOSE (TAPE,(LEAVE))

RECORD1

DS

CL100

TAPE

DCB

DDNAME=TAPEDD,DSORG=PS,MACRF=(PM),

C

RECFM=FB,BLKSIZE=2000,LRECL=100

Figure 36. Tape File Programs i n VSE and MVS

Under VSE, when using the DTFDI macro to define your file, your entire program
should be device-independent. Under MVS, every program should also be
device-independent for optimum use from the operating system. In revising a
VSE program with a DTFDI to run under MVS:

•

Code RECFM=F in the MVS DCB macro. DTFDI does not need the RECFORM
parameter because only fixed, unblocked records are supported. If you omit
RECFM in MVS, undefined is assumed.

•

If the DTFDI specified DEVADDR=SYSLST or DEVADDR=SYSPCH, the MVS
DCB must specify RECFM=FM because the first byte of the VSE output area
contains a control character. For increased flexibility, supply the RECFM and
DEVADDR parameters, and all other parameters describing data set
characteristics in the DD statement instead of in the problem program.

Figure 37 on page 304 shows a comparison between the VSE DTFDI and the
MVS DCB macros.

Chapter 13. A s s e m b l e r