Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 exptools 1/6/84; site ihuxn.UUCP Path: utzoo!watmath!clyde!burl!we13!ihnp4!ihuxn!res From: res@ihuxn.UUCP (Rich Strebendt) Newsgroups: net.misc Subject: Re: Nearly Prehistoric Computers Message-ID: <548@ihuxn.UUCP> Date: Fri, 10-Feb-84 15:51:15 EST Article-I.D.: ihuxn.548 Posted: Fri Feb 10 15:51:15 1984 Date-Received: Sat, 11-Feb-84 08:51:38 EST References: <584@ihuxq.UUCP> <510@dalcs.UUCP> Organization: AT&T Bell Labs, Naperville, IL Lines: 69 > The machine I learned to program on was an "LGP-30" with 4K > (24 bit) words of drum memory. The only language available was machine > language (not assembler) though it was easy to learn as there were > only 16 machine language instructions. The hardest part was learning > the (now lost) art of optimising(sp?) drum accesses (NOT easy). I/O > consisted of a terminal like thing called (I think) a flexowriter, and > a "high speed" paper tape reader and punch (also many buttons & lights). FANTASTIC --- someone else that worked with this fun machine! I once found a flier by an outfit that reconditioned these machines then sold them. A few quotes might be interesting/entertaining to the "younger generation" that has become jaded with computer power that fits on a desk-top. "Control Data [ours had a Royal-McBee nameplate] LGP-30 Low Cost, Desk Size Computer "The LGP-30 is compact and can be installed anywhere without special preparation. The computer is mounted on casters, can be freely moved from place to place, and is simply plugged into a convenient grounded outlet. "The LGP-30 is a stored program binary computer with a 4,096 word memory of 32 bits per word. It is the size of a standard office desk. The powerful but compact repertoire of 16 single-address instructions includes all basic arithmetic operations and logical decisions necessary to provide a broad capability, including alphanumeric input-output. ... Standard input-output equipment consists of a typewriter [actually, a Frieden Flexowriter] with standard keyboard, paper tape punch and paper tape reader. ... Optionally available is a high speed, 200 character-per-second photoelectric paper tape reader that completely loads memory in only 5 minutes. "Operation Times Access: 6 milliseconds minimum, 15 milliseconds maximum Transfer: 1 millisecond minimum, 15 milliseconds maximum Addition/Subtraction: 0.26 milliseconds, excluding access Multiplication/Division: 15 milliseconds, excluding access Physical Description Size: 26" deep by 33" high by 44" long, excluding typewriter and shelf Weight: 800 pounds Mounting: on sturdy casters Power Requirements Full: 1500 watts from 115-volt, single phase, 60-cycle supply Standby: 350 watts" This was taken from a flier or an advertisement copyrighted in 1968 by Mutual Computer Systems of Culver City, California. (No, I have not attempted to obtain permission to quote this material ... Is this company still in business?) Not mentioned in this description is the programming language that I used to program it. It was called the "24.2 Floating Point Interpretive System" and was about -><- that far above machine coding. The instructions consisted of a single character opcode and a 4 digit address, where the address 0000 completely changed the meaning of the opcode. For example: s2420 meant subtract the contents of location 2420 from the accumulator (which was a circulating track on the drum). The instruction s0000 meant take the sine function of the contents of the accumulator. It really was a fun machine to work with ... we discovered that the Blackjack program was cheating because it took it several seconds to search the deck for an Ace ... a perceptable delay in playing its next card! Rich Strebendt ...!ihnp4!ihuxn!res