On Fri, 24 May 2024 at 15:59, Farley, Peter < 0000031df298a9da-dmarc-requ...@listserv.ua.edu> wrote:
> In the mid-1970’s (or it may have been the early 1980’s, the memory is > fainter now) I took an operating systems overview class at a technical > college nearby, and the instructor was an IBM Fellow whose name I have long > since forgotten, but in one class he told us a story about how VSAM came to > be as we know it today. The following is my (perhaps faulty) memory of the > story he told us. > > The original Virtual Storage Access Method design was created by a group > of people within IBM as a complete replacement for ALL then-existing access > methods. When it was presented to the IBM powers, one of the > marketing/sales honchos screamed loudly that the conversion costs for > existing customers would clobber sales (and therefore profits) and that > this could not be tolerated as the way forward. When the group that > invented the idea refused to reduce the scope of the project, he took home > the design paper and took out all the parts that would require IBM > customers to convert existing code and processes, and the resulting design > document became known as VSAM0 (VSAM zero) and this is the VSAM design that > was implemented. > I too heard a similar story from an IBMer at a course in the 1980s. The terminology he used was AM0 (what we got) vs a proposed much grander AM1. I think the story of the original VSAM catalogue design must be related. If anyone set out to design a VSAM catalogue they would surely produce roughly the ICF catalogues we know today. But the original VSAM catalogues were Just Weird, were hard to use, performed poorly, were missing basic function, and so on and so on - things we have mostly forgotten about now. There must surely have been some reason for such a design, and perhaps that is also a relic of AM1. Tony H. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
