Easy to do by accident: - a valid VB dataset - open and write DISP=MOD,RECFM=FB (erroneous JCL or program with hard-coded DCB) - open and read with explicit RECFM=VB in JCL or program - crash and burn
Easy enough to do when hastily cobbling JCL together from different sources. You typically end up with EBCDIC characters where the RDW is supposed to be. Charles -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of Bill Woodger Sent: Tuesday, July 19, 2016 3:13 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Bsam VS Qsam for VB records I previously acknowledged that the data looks OK. No, it is not an attempt to "extend" a block. It is to write a lump of data which, once the "correction" has been done (else the data can't be read as a VB anyway) will appear to be a VB "block", but which will start with binary zeros. Someone had commented that they didn't know how a BDW with zero length could be created. It wasn't done in this case, but here's a way it could be done. Not by *really* writing a block with a zero BDW, but sticking in a lump of data which will later *look like* a block (very superficially) but will presumably cause something weird to ensue. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
