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Path: utzoo!mnetor!seismo!rutgers!dayton!viper!dave
From: dave@viper.UUCP (David Messer)
Newsgroups: comp.terminals
Subject: Re: Brain-damaged Terminal Contest
Message-ID: <429@viper.UUCP>
Date: Mon, 8-Dec-86 05:02:00 EST
Article-I.D.: viper.429
Posted: Mon Dec  8 05:02:00 1986
Date-Received: Sun, 7-Dec-86 20:59:24 EST
References: <3078@cbosgd.ATT.COM> <58000001@smu> <880@sfsup.UUCP>
Reply-To: dave@viper.UUCP (David Messer)
Organization: Lynx Data Systems, Minneapolis, MN
Lines: 41

In article <880@sfsup.UUCP> jeffj@sfsup.UUCP (J.S.Jonas) writes:
 >
 >Even sillier was the General Precision LGP-21 computer to which it was
 >attached.  It had NO CORE - just a fixed head disk (not drum).
 >The accumulator, accumulator extension, instruction address register
 >and instruction register were recirculated on the outermost track by
 >4 heads placed evenly around the circumference.  The baudot codes
 >corresponded to the 5 bit opcode (B for 'bring' - load the accumulator,
 >S for 'save' - store the accumulator, A for 'add', etc...).
 >The  display was an oscilloscope which displayed the square waves
 >for the accumulator, instruction register and instruction address
 >register. I guess that it was a serial machine -- there weren't enough
 >transistors to support parallel byte manipulation.
 >The manual mentioned a card that was used to find the optimal data addresses
 >to use so that execution was done with the least disk rotation.

Sounds like you have the new and improved model.  I have an LGP-30
in my garage that had 128 TUBES instead of transistors.  The main
memory is, as you said, a fixed head drum containing 4096x31 bit
words.  The instruction set has a total of eight instructions,
including add, subtract, multiply and divide (the original RISC
machine).  Error handling is pretty simple, if you divide by
zero the machine STOPS and waits for you to fix it.  The software
I got with the machine is pretty impressive though, two ALGOL-58
(ALGOL-58?) compilers/interpreters and an optimizing assembler
(optimizing in that it trys to place instructions around the drum
so that there is a minimum of delay between them.)  A properly
optimized program can run as fast as 200 instructions/second.

By the way, if anyone wants their own antique computer, (perhaps
starting their own museum?) I would be willing to part with the
LGP-30 ($60,000 new price) for $0.00 and you pay the shipping.
I haven't had the heart to scrap the thing, but I am sick of
transporting it everytime I move.  Software included of course.
(By the way, it worked the last time I turned it on, but I make
no gaurentees.)
-- 
Disclaimer:                       | David Messer 
I'm always right and I never lie. | Software Consultant 
My company knows this and agrees  | UUCP:  ihnp4!quest!viper!dave 
with everything I say.            |        ihnp4!meccts!viper!dave