Maintenance › VLS Utility (VLSUTIL) › VLSUTIL Function Descriptions › FORMAT Function

FORMAT Function

The FORMAT function formats a new VLS file or reformats an existing VLS file for processing. Any existing members in the file you format are destroyed.

Important! You must recycle CICS after you extend a VLS library. When changing the blocksize of a VLS library, you must also change the CICS FCT entry that accesses that VLS library. Failure to make this change can result in storage violations.

►►─ FORMAT ─┬─────────────────────────┬─┬───────────────────────┬─────────────►
            └─ BLKSIZE= ─┬─ 4000 ◄ ─┬─┘ └─ NAMELEN= ─┬─ 27 ◄ ─┬─┘
                         └─ bbbb ───┘                └─ nn ───┘           
►───────┬─────────────────────┬─────────────►◄   
        └─ LIBFMT= ─┬─ H ◄ ─┬─┘ 
                    └─ F ───┘

FORMAT

Specifies the FORMAT function.

BLKSIZE=

Specifies the blocksize. Blocksize can range from 960 bytes through 32760 bytes. However, the blocksize cannot be larger than the track size of your storage device. The default blocksize is 4000 bytes.

Because larger block sizes bring increased efficiency, you should specify a minimum value of 4000 bytes.

Only specify a blocksize smaller than 4000 bytes under two conditions:

• If your VLS library contains a large number of members that contain fewer than 100 records. In this case, a smaller blocksize provides efficient use of space and reduced I/O time.
• If your VLS library is primarily used to hold block data members that have, on the average, fewer than 960 bytes. In this case, specify a blocksize of 960.

NAMELEN=

Specifies the number of characters in member names. All of the members in a VLS file must have unique names of equal length. The default name length is 27 characters.

LIBFMT=

Specifies the format of the VLS library. H (half word) uses 2-byte block values, F (full word) uses 4-byte block values.

To allocate and format a VLS file, use the following sample JCL:

// JOB VLFRMT
//  EXEC       PGM=VLSUTIL
//STEPLIB DD DSN=LOAD,DISP=SHR
//        DD DSN=LOAD,DISP=SHR
//        DD DSN=LOAD,DISP=SHR
//SYSPRINT     DD  SYSOUT=A
//VLSFILE      DD  DSN=dsname,DISP=(,CATLG),UNIT=DISK,
//             VOL=SER=volser,DCB=DSORG=DA,
//             SPACE=(TRK,nn)
//SYSIN        DD *
FORMAT      [BLKSIZE=bbbb][,NAMELEN=nn][,LIBFMT=H|F]
/*
/&

The primary space allocation for the VLS library does not have to be contiguous. A secondary space allocation is not allowed. If you specify a secondary space allocation, it is ignored. For more information, see How to Estimate Space Requirements for a VLS File.