On Tue, 30 Oct 2007 13:29:54 -0500, Dave Kopischke wrote: >On Tue, 30 Oct 2007 09:46:36 -0600, Howard Brazee wrote: > >>But why should a program care about block size? > >Funny you should ask this; We had a major project implement a couple weeks >ago. To deal with the number of object moves, many of the libraries were just >cloned and renamed at implementation time. During this, a couple pretty >important PDS's were reblocked. A pretty benign change from my point of view. > >It turns out a program update process allocates one of these PDS's >SHR,BLKSIZE=3200. This effectively reblocked the PDS. Every member in this >PDS that was longer than about 40 lines was corrupted and innaccessible. > >That's a reason to care, but probably not the point trying to be made. There >are code bombs waiting to explode. Even a seemingly benign change can >trigger one. > Ah, but if the programmer hadn't coded BLKSIZE in the DCB but left it zero and accepted whatever value was in the data set label, the problem would never have occurred. The problem was caused by the programmer's delusion that he needed to override BLKSIZE. And if the OS, according to my idea, had not updated the BLKSIZE, the data set would not have been corrupted.
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