The various S/360 emulator programs relied on a combination of hardware and microcode. There was a 1401 simulator that used only S/360 ISA, but IBM never referred to it as an emulator. On the System/370, IBM had a program that could simulate a 1401 using only the S/370 ISA, but that would use the instructions added by the compatibility feature when running on a machine that had it installed.
-- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 ________________________________________ From: IBM Mainframe Discussion List [[email protected]] on behalf of René Jansen [[email protected]] Sent: Wednesday, December 22, 2021 9:53 AM To: [email protected] Subject: Re: Another old mainframe comparison Thank you for the pointers to those two very interesting articles. I never the introduction of microcode linked to the 1401 compatibility of S/360 - I thought this was an emulator that used the 360 ISA as-is? In the other one, I think what we need to take away from that is how the scarcity of nearly everything led to enormous efficiency, and the plenitude of today leads to the enormous waste we experience. In not having to worry too much about segment registers some fundamental mental imagery of what computing is, got lost. Part of the mainframe still running those important workloads is linked to how very well a small, efficient kernel can cope with layers of abusively inefficient software piled on top of it. So we need a different scale for those comparisons. Otherwise, we need to go investigate into the reality of my phone not being able to run all transactions of a medium size commercial bank. Best regards, René. > On 22 Dec 2021, at 08:15, Mike Schwab <[email protected]> wrote: > > https://spectrum.ieee.org/building-the-system360-mainframe-nearly-destroyed-ibm > > On Wed, Dec 22, 2021 at 6:26 AM Tom Brennan <[email protected]> > wrote: >> >> I don't know what's going on with the comparisons lately, but here's a >> fun one. Paging the fact checkers... >> https://spectrum.ieee.org/ibm-mainframe >> >> ---------------------------------------------------------------------- >> For IBM-MAIN subscribe / signoff / archive access instructions, >> send email to [email protected] with the message: INFO IBM-MAIN > > > > -- > Mike A Schwab, Springfield IL USA > Where do Forest Rangers go to get away from it all? > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
