/*REXX*/ 
/*                                                               */
/*To use this exec, put a question mark after the parameter for
  block size in your DCB statement. Then call this exec with your
  record length as the parameter.                                */
/*                                                               */
/* Example:  / /      DCB=(RECFM=FB,LRECL=134,Blksize=?          */
/*                                                               */
/*                                                               */
/* For the above example, on the command line enter "DCB 134".   */
/*                                                               */
/*                                                               */
ADDRESS  "ISREDIT"  "MACRO"  (LRECL )"
/*                                                               */
/* un-comment the next line for 3380 DASAD                       */
/*BLKSIZE = TRUNC (23482 / LRECL )                               */
/*                                                               */
/* un-comment the next line for 3390 DASAD                       */
/*BLKSIZE = TRUNC  (28076 / LRECL )                              */
/*                                                               */
BLKSIZE = BLKSIZE  *  LRECL
NEWBLK = "'BLKSIZE="  ||  BLKSIZE  ||  " '  FIRST":
ADDRESS USREDIT  "CHANGE 'BLKSIZE=?'   "NEWBLK;
EXIT