Thank you for a better memory than mine. Yes, those were the terms the instructor used when I heard the story – AM1 (Access Method 1) for the original grand design, and AM0 for what we got instead.
Peter From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> On Behalf Of Tony Harminc Sent: Saturday, May 25, 2024 1:12 AM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: VTOCs vs. catalogs On Fri, 24 May 2024 at 15:59, Farley, Peter < 0000031df298a9da-dmarc-requ...@listserv.ua.edu<mailto: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. -- This message and any attachments are intended only for the use of the addressee and may contain information that is privileged and confidential. If the reader of the message is not the intended recipient or an authorized representative of the intended recipient, you are hereby notified that any dissemination of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by e-mail and delete the message and any attachments from your system. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
