Path: csiph.com!eternal-september.org!reader02.eternal-september.org!.POSTED!not-for-mail From: Anne & Lynn Wheeler Newsgroups: alt.folklore.computers Subject: Re: bootstrap, was What is the oldest computer that could be used today for real work? Date: Thu, 30 Sep 2021 09:16:00 -1000 Organization: Wheeler&Wheeler Lines: 32 Message-ID: <87k0ixc1sf.fsf@localhost> References: <874ka9p19x.fsf@bogus.nodomain.nowhere> <61531446.14588537@news.dslextreme.com> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: reader02.eternal-september.org; posting-host="ac177fc69d0bde9c3d6fe6762af1d29b"; logging-data="4944"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/pGNsgSLophQ1PvKWq6B582ZIiJKtfgQI=" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) Cancel-Lock: sha1:M5ty8VXfXe/89Oru8NKR11lcrwQ= sha1:wkSJo8g4wvW3F0z2685fSf1ik2M= Xref: csiph.com alt.folklore.computers:219165 Dan Espen writes: > I think that was characteristic of OS/VS. > > DOS and DOS/VS managed a minute or 2. > > The IBM 1401 booted just about the same as the other machines mentioned. > Clear 1-80, read a card into 1-80, branch to 1. > > Unlike the S/360, I don't remember any way to make a 1401 boot from > other media. CP/67 and VM/370 came up in several seconds. Early on CP/67 (that carried over to VM/370) for being up 7/24 dark room with no operator. There was even special handling for system crash, automatically take dump core image ... and automagically re-ipl and be back up and running. Also back to days when all IBM mainframes were rented and charges based on "system meter" reading that ran whenever the CPU and/or any channel was running ... CP/67 developed special channel programs that let channel go idle but would immediately wake-up for any characters arriving on a line ... to reduce offshift, light load costs (and help encourage leaving system up and available 7x24, also goes for running w/o an operator/human present). All activity had to be idle for 400ms before "system meter" would actually stop running. Note: long after IBM had switched mainframes from lease/rent to sales ... MVS (VS/2) still had a timer task that woke up every 400ms (to guarantee that system meter never stopped) -- virtualization experience starting Jan1968, online at home since Mar1970