Re: Designing database tables for performance?

From: Anne & Lynn Wheeler <>
Date: Fri, 23 Feb 2007 16:48:21 -0700
Message-ID: <>

paul c <> writes:
> I don't remember when I first heard or read the term "logical I/O".
> It might have been the in the early 1970's when IBM's VSAM access
> method first hit the streets. I'm pretty sure it was current in some
> circles then. Codd had written his first papers then but practically
> nobody in industry was even aware of them as IBM was pushing IMS and
> Vandl hard and people who knew him then told me later that there were
> big marketing forces at IBM that made working at the same company very
> difficult for him both personally and professionally. The term is a
> very unfortunate one since I'm sure misleads many newcomers to IT. As
> we can see here, it misleads many others.
> (Anybody who was programming then has an historical advantage over
> younger people because it is so much easier to see what a revolution
> Codd started.)

original relational/sql implementation was system/r done all on vm370 ... misc. collected posts mentioning system/r activity:

recent thread mentioning various things from system/r days: Jim Gray Is Missing Jim Gray Is Missing Jim Gray Is Missing Jim Gray Is Missing Jim Gray Is Missing

vm370 was a follow-on to cp67 ... what had implemented both virtual memory and virtual machines in the mid-60s ... done at the cambridge science center. some of the people from CTSS had gone to the science center on the 4th flr of tech sq (worked on cp67, cms and other things)

GML (precursor to sgml, html, xml, etc) was also invented at the science center in 1969.

others from CTSS went to the 5th flr and worked on multics. the multics group managed to bring out the first commercial relational database product (MRDS):

it was into the 80s before tech. transfer from SJR to Endicott succeded with SQL/DS product ... and even longer for tech. transfer of SQL/DS from Endicott back to STL for DB2.

when virtual memory for 370 was announced, for whatever reason, they chose the term "virtual storage" (instead of virtual memory) ... from that comes dos/vs, vs1, vs2, svs, mvs, vsam, etc (all the "VSs")

various past posts mentioning quote from the mid-60s about "A system of that period that had implemented virtual memory was the Ferranti Atlas computer, and that was known not to be working well" TSS ancient history, was X86 ultimate CISC? designs) VM: checking some myths. TECO Critique a.f.c history checkup... (was What specifications will the standard year 2001 PC have?) Disk drives as commodities. Was Re: Yamhill SR 15,15 was: IEFBR14 Problems Robert Creasy, RIP virtual memory

lots of collected posts mentioning virtual memory, demand paging, and replacement algorithms (virtual memory and/or various kinds of "caches") Received on Sat Feb 24 2007 - 00:48:21 CET

Original text of this message