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Manufacturer Bendix Identification,ID G-15 Date of first manufacture 1956 Number produced about 300 Estimated price or cost "$50,000 in late 1950 dollars" location in museum - donor -
Contents of this page:
- Special Features
- Historical Notes
- This Specimen
- Interesting Web Sites
- Other information
Bendix G-15 Opened for detail 74 K Bytes
Bendix G-15 - by Ron Mak
- Two address, drum main memory,
- Word length - 29 bits
- Optional magnetic tape storage
- Double-length arithmetic registers for machine supported double precision
- Block I/O permitted movement of up to 108 words with a single command
- Simultaneous I/O and computation
- The following interesting peripherals were available
- An accessory "DIGITAL DIFFERENTIAL ANALYZER DA-1" greatly eased and speeded certain engineering work.
- Graphical Plotter PA-3
- Punched Card Coupler CA-2
- Punched Paper Tape Reader PR-1 (250 character/sec), PR-2 (430 characters/sec, can read 5, 6, 7, or 8 bit tape, searchable)
- Special Input-Putput Registers
- Gordon S. Becker - firstname.lastname@example.org - says " I was in charge of a scientific computing division for the U.S. Army Map Service and the cost for G-15D computer (The D postscript denotes an alphabetic capability) was in the neighborhood of $50,000.00 in late 1950 dollars. I also have retained copies of the coding for a number of double precision computer programs. ..."
- Same year, similar use of circulating registers on drum as LGP-30
- Followed by the transistorized Bendix G-20
Interesting Web Sites
Bendix G-15 spotted by Richard Ellis (who owns a G-15 and would like to make it work again :-) - Lots of info with
- EE Dept. History from CAL POLY, found by Keith Smillie
- G-15 showing IBM peripherals found by LaFarr Stuart
- G-15 Manuals 20 manuals scanned and stored by David Green who also points out 5 more G-15 manuals posted by Paul Pierce.
Other information - bitsavers.org
from Rob Kolstad, Dec 2008
I have identified perhaps half a dozen extant G-15s, including one at the [Computer History Museum]. I have built a paper tape reader so I hope to get all the software (!) up and running on the simulator that I'm reworking from the australians (who originally wrote the simulator in SIMULA-60).
Its architecture is so simple that it lends itself to a fabulous evolution-of-computer-architecture exhibit -- especially since it's arguably the first Personal Computer (!).====================================================================== ((__)) Rob Kolstad USACO Head Coach (00) email@example.com 15235 Roller Coaster Road -nn--(o__o)--nn- +1 719 481 6542 Colorado Springs, CO 80921 ---- http://www.usaco.org Cell: +1 719 321 7333 ======================================================================
from Douglas Drummond, April 2016
I used a G-15 from 1963-1965 at Rose Polytechnic Institute in Terre Haute Indiana. The school is now known as Rose-Hulman Institute after Tony Hulman (Owner of the Indianapolis 500 Race Track) died and left them a ton of money. I am a retired hardware/software engineer and currently tutor computer science and teach it at a community college in the Chicago suburbs.
For my own research, I am currently writing a G-15 simulator in Java on a PC, with a fairly decent GUI representing the front panel display. My typewriter simulation uses Alt-codes to simulate Enable codes, with a few additions. When I was in college 50 years ago, I programmed the G-15 in machine language. At the time, we G-15 machine language programmers said we will probably never see an instruction set any weirder that the G-15. Although the CDC-6500 and the Burroughs D-Machine came close, I still believe that.
On your web site, you asked for feedback from anyone who knew anything about the G-15, so I am emailing. One result of my research is that I am pretty sure of the alphanumeric codes, which I extracted from the schematics of the Alpha hardware.
Previously I wrote a simulator for the LGP-21, the transistorized version of the LGP-30, with MUCH better I/O. I re-used much of that code for the G-15 simulator, and plan an RPC-4000 sim. Since that instruction set is so simple I am working on tutorials using that simulator as a "generic" binary computer for teaching embedded programming and machine/assembly language principles. I did have "hands on" an LGP-21 in graduate school in 1970, which was really an "antique restoration project" even 45 years ago. I also used an RPC-4000 at Purdue in the late 1960s, a direct descendant of the LGP-21/30.
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Updated April, 2016