Timeframe was 1980 plus or minus. I was a true novice sysprog and kept an arm's length from OS innards. It was during that two-year gig that MVS/SP was announced, so not likely available just yet. I only remember being impressed with the clever workaround that kept the Amdahl useful.
P.S. The same machine had a load button on the system keyboard. One day an operator's purse fell over and caused a midmorning IPL. Amdahl installed a little box around the button. They were clever folks. ;-) . . . J.O.Skip Robinson Southern California Edison Company Electric Dragon Team Paddler SHARE MVS Program Co-Manager 626-302-7535 Office 323-715-0595 Mobile [email protected] -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Tom Marchant Sent: Tuesday, December 01, 2015 7:27 AM To: [email protected] Subject: (External):Re: Straightforward way to determine hardware architecture level? On Tue, 1 Dec 2015 12:52:05 +0000, Bob Shannon wrote: >> Amdahl responded by shipping some code that was loaded early in IPL >>to accommodate the new instructions > >SE and SP Assist. They trapped the abend in the FLIH. I remember it well. That's SE Assist. And it led to the design on the 580 series of computers that provided a third state of operation called (IIRC) System state. The 580 design included hardware to virtualize the user's processor. The code that ran in System state was called Macrocode and it was loaded from the console processor into memory that was outside of the memory available to customers. Macrodode routines emulated new instructions. A side benefit of all that was that it made Multiple Domain Facility possible. The hardware that supported the virtualization included additional registers for the use of Macrocode and other facilities that made MDF quite efficient. -- Tom Marchant ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
