Historically in the O/S360-z/OS line of systems, a zero length record on disk has indicated End-of-File for either PS or PO organizations. In the PDS, each member is a PS file, so there are potentially many zero length records in a PDS. OS Simulation knows how to handle them, but, as noted, CMS does not like them.
CMS does allow empty files in SFS. (As I found out when FTP APPEND started creating empty files where there had been sometimes 10s of thousands of records. It was a problem triggered by a timeout on a data connection request. PTF UK3370, if anyone is interested.) Regards, Richard Schuh > -----Original Message----- > From: CMSTSO Pipelines Discussion List > [mailto:[EMAIL PROTECTED] On Behalf Of Paul Gilmartin > Sent: Wednesday, April 02, 2008 2:37 PM > To: [email protected] > Subject: Re: Writing an empty file to set RecFM and LRecL > > On Apr 2, 2008, at 15:21, SPITZ, HOBART CTR DFAS wrote: > > It's been a long day. Does this look right? If so why? > > > No, but it's likely WAD. CMS is historically hostile to > empty files; even more to empty records, and will do anything > it can to frustrate the programmer who attempts to employ them. > > I suppose the rationale is that in the absence of any record > to establish the record length it reports a default value. > > I remember a similar problem when I once FILEDEFed a file as > V 137. Later, when I re-opened the file for append (MOD), it > loaded in the DCB not my specified 137, but the length of the > longest record previously written. Ugh. > > > Ready; T=0.01/0.01 17:15:57 > > > > pipe hole | > test data . f 10 allowempty > > > > Ready; T=0.01/0.01 17:16:49 > > > > l test data * (iso > > > > FILENAME FILETYPE FM FORMAT LRECL RECS BLOCKS DATE > > TIME > > TEST DATA O1 F 80 0 0 2008-04-02 > > 17:16:49 > > Ready; T=0.01/0.01 17:17:21 > > > What happens if you initialize by writing a 10-byte record, > then overwrite with an empty file? > > --gil >
