Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!uflorida!gatech!amdcad!rpw3
From: rpw3@amdcad.AMD.COM (Rob Warnock)
Newsgroups: comp.misc
Subject: Re: computer follies
Message-ID: <23134@amdcad.AMD.COM>
Date: 5 Oct 88 08:29:55 GMT
References: <916@viscous> <1086@bucket.UUCP>
Reply-To: rpw3@amdcad.UUCP (Rob Warnock)
Organization: [Consultant] San Mateo, CA
Lines: 38

In article <1086@bucket.UUCP> leonard@bucket.UUCP (Leonard Erickson) writes:
+---------------
| On the Tandy Model 200 laptop, you can actually get "silly" ideas like
| thast to *work*!! "Off" is actually a low-power standby mode. You can
| turn the 100, 102 or 200 off while they are executing a program and they
| will resume where they left off when you turn them back on. (which allows
| for a number of ways of freaking novice users.... :-)
+---------------

On PDP-11's with real core (not this modern RAM stuff!), there was a
power-fail interrupt that gave you enough time to save critical state
and go into a loop before the CPU quit working. It you diddled things
right, you could take the power-on interrupt and restore your state and
continue where you left off. In particular, the FOCAL/F interpreter
contained the needed code,.

Now the hack: I used to use this feature to implement a super-simple "mail"
facility to a guy I once worked for. I was in college, and working for him
evenings, and by the time I finished each evening he was long gone home.
So when I had something really important to tell him first thing in the
morning (when I'd be in class or asleep), I'd run a FOCAL program that
paused for 10 seconds, then did a big "type" of my message.

Then I'd type "go" (FOCAL's "RUN"), and power off the PDP-11, while it was
executing the "pause". He'd come in the next morning and turn on the machine,
and instead of getting a boot-up he'd get the "mail"... and the program
would wipe itself out leaving no trace of how it had happened.

I guess you had to be there. (*sigh*)


Rob Warnock
Systems Architecture Consultant

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