on 6/1/05 3:27 PM, Paul Gilmartin at [EMAIL PROTECTED] wrote: > In a recent note, Barry Merrill said: > >> Date: Wed, 1 Jun 2005 13:56:17 -0500 >> >> It's my understanding that the Exclusive ENQUEUE on SYS1.UADS >> for a TSO user came about during the last night of testing for >> the initial release of TSO, the design of which was based on >> models of how TSO should work by Alan Scheer >> (and when TSO didn't match his model, unlike most modelers, >> he changed TSO to match the model, rather than changing the model). >> >> The TSO development group had a room with a dozen or so terminals, >> and Alan took a break about midnight, and came back to a terminal, >> logged on, but was unable to get any reply messages to his commands, >> although the commands were obviously being accepted. A few minutes >> later, a compatriot called from across the room "There are a bunch >> of messages to you on this terminal over here, Alan", and he realized >> that he had remained logged on at one terminal, and had then logged >> on a second time from the second terminal, and there had been no >> specification for protection for multiple logons by a single user! >> >> The exclusive Enqueue was added to prevent duplicate logons about 2am, >> and the first iteration of TSO Product was delivered, on schedule, >> to PID at 6am that same morning. >> > So an onerous restriction, peculiar to IBM, came about through > a late-night patch for a bad design. > > If there was no specification of preventing multiple logons, > then preventing multiple logons to circumvent misrouting of > messages was a change in the specification, and, I'd say, of > the model. The correct fix would have been to route messages > to the originating session, rather than brute-force prohibition > of multiple sessions. > > It was a fundamental design flaw to confuse session-id with > user-id. TSO has institutionalized this rather than attempting > to correct it. >
Gil, You are beating a dead horse TSO is comatose or not breating take your pick. Ed ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
