On Mon, 26 Jul 2010 17:00:52 +0000, Bill Fairchild wrote: > >And isn't the maximum size of a PDS 65535 cylinders instead of 65535 tracks? >But Tom Conley has an excellent point that the maximum size of a PDS member >should be supported by any redesign. E.g., I have seen some large PDSes that >consisted of only a directory. One example is SMP. Another was a customer >file I ran across decades ago where an entire volume was a PDS with only a >directory in it; i.e., all directory entries and no members. > I believe SMP/E doesn't do that any more; rather it uses VSAM.
The design suffered a compatibility constraint: how do you divide up a 32-bit NOTE word to support both more members and more records. They might have done better by not allowing the soft blocking. But then they'd need to somehow index variable size blocks. -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
