MVCIN was indeed a useful instruction. I encountered it (IIRC) on a 4381. I assumed that, like typical new instructions, it would stick around for the duration. I was later shocked to discover that it had been abandoned on a siding somewhere along the railway to the future. Probably still there somewhere in Nebraska with a smudged bar code.
. . . 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 Steve Thompson Sent: Tuesday, December 01, 2015 2:05 PM To: [email protected] Subject: (External):Re: Straightforward way to determine hardware architecture level? On 12/01/2015 10:27 AM, Tom Marchant wrote: > 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. > If I remember correctly, that led to FAM (a part of Macrocode), Fast Assist Mode. It allowed Amdahl to emulate instructions rather rapidly -- both on the machine and building the instruction emulation to install on machines. I do remember a very interesting thing that Amdahl did: MVCIN It was implemented on those machines, but not on the IBM 3090s. Which caused me a problem on a VSE to MVS migration, because I needed that inverse move. When I was working at Amdahl I was amazed at how that had been implemented. I miss those days. Regards, Steve Thompson ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
