474:, at least in 1962 and 1963. One of the teaching assistants, a graduate student at UCLA, reported that one was used to check syntax of Fortran programs before they could be submitted to the 7094. The son of the engineer who arranged the use of the computer was a student in 1963. The program began as a six week residential science enrichment course for advanced rising high-school seniors, at the Thacher School in Ojai, CA, as a collaboration between the Headmaster, Stanford University, Caltech, and Harvey Mudd College, in response to Sputnik. The curriculum was focused on astronomy, with a lab project that consists of photographing an asteroid three times and computing its orbit. It is now a nonprofit program wholly owned and operated by alumni, offering biochemistry, genomics, and synthetic chemistry, in addition to the original astronomy (now astrophysics) program.
369:
addressed in the G-15 by what the Bendix literature calls "minimum-access coding". Each instruction carries with it the address of the next instruction to be executed, allowing the programmer to arrange instructions such that when one instruction completes, the next instruction is about to appear under the read head for its line. Data can be staggered in a similar manner. To aid this process, the coding sheets include a table containing numbers of all addresses; the programmer can cross off each address as it is used. Bendix has an operating system of the same name.
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127:
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430:(March 1965), while some maintain that only microcomputers, such as those which appeared in the 1970s, can be called personal computers. Nevertheless, the machine's low acquisition and operating costs, and the fact that it does not require a dedicated operator, meant that organizations could allow users complete access to the machine.
271:
A consequence of this design was that, unlike other computers with magnetic drums, the G-15 does not retain its memory when it is shut off. The only permanent tracks are two timing tracks recorded on the drum at the factory. The second track is a backup, as the tracks are liable to erasure if one of
398:
is implemented in software. The "Intercom" series of languages provide an easier to program virtual machine that operates in floating point. Instructions to
Intercom 500, 550, and 1000 are numerical, six or seven digits in length. Instructions are stored sequentially; the beauty is convenience, not
323:
characters u-z) and about three characters per second for alphabetical characters. The machine's limited storage precludes much output of anything but numbers; occasionally, paper forms with pre-printed fields or labels were inserted into the typewriter. A faster typewriter unit was also available.
275:
The serial nature of the G-15's memory was carried over into the design of its arithmetic and control circuits. The adders work on one binary digit at a time, and even the instruction word was designed to minimize the number of bits in an instruction that needed to be retained in flip-flops (to the
162:
of 2,160 29-bit words, along with 20 words used for special purposes and rapid-access storage. The base system, without peripherals, cost $ 49,500. A working model cost around $ 60,000 (equivalent to $ 672,411 in 2023). It could also be rented for $ 1,485 per month. It was meant for scientific
368:
A problem peculiar to machines with serial memory is the latency of the storage medium: instructions and data are not always immediately available and, in the worst case, the machine must wait for the complete recirculation of a delay line to obtain data from a given memory address. The problem is
349:
The CA-1 "Punched Card
Coupler" can connect one or two IBM 026 card punches (which were more often used as manual devices) to read cards at 17 columns per second (approximately 12 full cards per minute) or punch cards at 11 columns per second (approximately 8 full cards per minute). Partially full
327:
The high-speed photoelectric paper tape reader (250 hexadecimal digits per second on five-channel paper tape for the PR-1; 400 characters from 5-8 channel tape for the PR-2) read programs (and occasionally saved data) from tapes that were often mounted in cartridges for easy loading and unloading.
466:
A Bendix G-15 was used at
Fremont High School (Oakland Unified School District) in the 1964-65 school year for the senior seminar math class. Students were taught the fundamentals of programming. One such exercise was the calculation of a square root using the method of Newtonian approximation. A
251:
This arrangement allows the designers to create "delay lines" of any desired length. In addition to the twenty "long lines" of 108 words each, there are four more short lines of four words each. These short lines recycle at 27 times the rate of the long lines, allowing fast access to frequently
247:
on a track, is determined by the spacing of the read and write heads, the delay corresponding to the time required for a section of the drum to travel from the write head to the corresponding read head. Under normal operation, data are written back without change, but this data flow can be
356:
The MTA-2 can interface up to four drives for half-inch Mylar magnetic tapes, which can store as many as 300,000 words (in blocks no longer than 108 words). The read/write rate is 430 hexadecimal digits per second; the bidirectional search speed is 2500 characters per second.
242:
implementation in other serial designs. Each track has a set of read and write heads; as soon as a bit was read off a track, it is re-written on the same track a certain distance away. The length of delay, and thus the number of
402:
As mentioned above the machine uses hexadecimal numbers, but the user never has to deal with this in normal programming. The user programs use the decimal numbers while the OS resides in the higher addresses.
380:(SOAP), was introduced in the late 1950s and includes routines for minimum-access coding. Other programming aids include a supervisor program, a floating-point interpretive system named "Intercom", and
328:
Not unlike magnetic tape, the paper tape data are blocked into runs of 108 words or less since that is the maximum read size. A cartridge can contain many multiple blocks, up to 2500 words (~10
353:
The PA-3 pen plotter runs at 1 inch per second with 200 increments per inch on a paper roll 1 foot wide by 100 feet long. The optional retractable pen-holder eliminates "retrace lines".
1042:
350:
cards were processed more quickly with an 80-column-per-second skip speed). The more expensive CA-2 Punched Card
Coupler reads and punches cards at a 100-card-per-minute rate.
307:, but its instruction addressing architecture can reduce this dramatically for well-written programs. Its addition time is 270 microseconds (not counting memory access time).
360:
The DA-1 differential analyzer facilitates solution of differential equations. It contains 108 integrators and 108 constant multipliers, sporting 34 updates per second.
346:
and HSR-8 paper tape reader and HSP-8 paper tape punch. The mechanical reader and punch can process paper tapes up to eight channels wide at 110 characters per second.
335:
While there is an optional high-speed paper tape punch (the PTP-1 at 60 digits per second) for output, the standard punch operates at 17 hex characters per second (510
1037:
750:
How Much Is That in Real Money? A Historical Price Index for Use as a
Deflator of Money Values in the Economy of the United States: Addenda et Corrigenda
158:, California. It is about 5 by 3 by 3 feet (1.52 m × 0.91 m × 0.91 m) and weighs about 966 pounds (438 kg). The G-15 has a
257:
392:
committee. Users also developed their own tools, and a variant of
Intercom suited to the needs of civil engineers is said to have circulated.
319:
One of the G-15's primary output devices is the typewriter with an output speed of about 10 characters per second for numbers (and lower-case
785:
202:
was one of the Bendix engineers on the G-15 project. He would later become famous for his work in computer graphics and for starting up
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191:
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Bendix G-15 was still in use for the UC Berkeley extension summer class in programming, at
Oakland Technical High School, in 1970.
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519:
377:
770:
How Much Is That in Real Money? A Historical Price Index for Use as a
Deflator of Money Values in the Economy of the United States
915:
848:
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problems. Some have survived and have made their way to computer museums or science and technology museums around the world.
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addition, multiplication, and division in addition to a one single-word accumulator. This use of the drum rather than
509:
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415:, because it has the Intercom interpretive system. The title is disputed by other machines, such as the
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extent of leveraging another one-word drum line used exclusively for generating address timing signals).
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multiplication takes 2,439 microseconds and double-precision multiplication takes 16,700 microseconds.
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are implemented as drum lines: three double-word lines are used for intermediate storage and
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649:"Bendix G-15 All Purpose Computer: Selling the Computer Revolution: Computer History Museum"
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Between
Dependency and Autonomy: India's Experience with the International Computer Industry
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Huskey received one of the last production G15s, fitted with a gold-plated front panel.
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622:"4. Digital Computer & Differential Analyzer Combination, Bendix Computer Division"
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intercepted at any time, allowing the machine to update sections of a track as needed.
199:
183:
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1016:
1001:
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677:. T10-3_G15_Tech_Bulletin_Apr60.pdf, p. 16; JH-039_G-15_Installation_Mar59.pdf, p. 4
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835:"Coders At Work", chapter 12: "Ken Thompson", page 494 by Peter Seibel, 2009
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287:. It has a total of about 450 tubes (mostly dual triodes). Its magnetic
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in the 1950s. He made most of the design while working as a professor at
147:
60:
433:
Over 400 G-15s were manufactured. About 300 G-15s were installed in the
863:
373:
26:
442:
416:
549:"New Products and Ideas: Electronic Roulette Demonstrates Computers"
399:
speed. Intercom 1000 even has an optional double-precision version.
342:
Optionally, the AN-1 "Universal Code
Accessory" included the "35-4"
163:
and industrial markets. The series was gradually discontinued when
825:. A Third Survey of Domestic Electronic Digital Computing Systems.
427:
389:
284:
133:
125:
471:
423:
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336:
897:
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Extensive G15 site list, photos & technical info
537:"Harry Huskey's Obituary on San Francisco Chronicle"
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978:
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84:
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644:(850 + 965 + 1050 + 1000) / 4 = 966.25 850 lbs:
167:took over the Bendix computer division in 1963.
437:and a few were sold in other countries such as
514:. University of California Press. p. 57.
1043:Science and technology in Greater Los Angeles
909:
879:Describes Harry Huskey's involvement with ACE
590:. Cambridge Scholars Publishing. p. 44.
411:The G-15 is sometimes described as the first
8:
88:US$ 49,500 (Base system without peripherals)
19:
916:
902:
894:
587:Birthing the Computer: From Drums to Cores
384:, an algebraic language designed from the
25:
18:
31:The G15 pictured in a marketing brochure
786:"Consumer Price Index (estimate) 1800–"
500:
234:. It uses the drum as a recirculating
1038:Computer-related introductions in 1956
194:(where his graduate students included
784:Federal Reserve Bank of Minneapolis.
372:A symbolic assembler, similar to the
7:
702:
227:
272:their amplifier tubes shorted out.
264:for the registers helped to reduce
170:The chief designer of the G-15 was
718:G15D Programmer's Reference Manual
14:
459:This was the first computer that
378:Symbolic Optimal Assembly Program
112:5 by 3 by 3 ft (1.5m by 1m by 1m)
606:"2. Bendix Aviation Corporation"
419:(shipped in late 1956), and the
252:needed data. Even the machine's
445:. The machine found a niche in
470:A Bendix G-15 was used at the
120:about 966 pounds (438 kg)
1:
484:List of vacuum-tube computers
449:, where it was used to solve
218:The G-15 was inspired by the
778:American Antiquarian Society
758:American Antiquarian Society
584:Kaisler, Stephen H. (2017).
198:), and other universities.
671:"Index of /pdf/bendix/g-15"
626:Digital Computer Newsletter
610:Digital Computer Newsletter
224:serial-architecture machine
72:; 68 years ago
1074:
715:Bendix Computer Division.
508:Grieco, Joseph M. (1984).
301:Average memory access time
220:Automatic Computing Engine
150:introduced in 1956 by the
130:Bendix G-15 computer, 2015
864:Bendix G-15 documentation
396:Floating-point arithmetic
283:packs and 3000 germanium
24:
817:Weik, Martin H. (1961).
556:Computers and Automation
165:Control Data Corporation
653:www.computerhistory.org
541:San Francisco Chronicle
386:1958 Preliminary Report
859:Another G-15 reference
472:Summer Science Program
204:Evans & Sutherland
174:, who had worked with
139:
131:
1028:Vacuum tube computers
238:, in contrast to the
154:, Computer Division,
137:
129:
955:Bendix (automobile)
874:info page with photo
16:1956 computer design
854:Bendix G15 computer
666:965 lbs, 1050 lbs:
632:(4): 3–5. Oct 1956.
616:(2): 1–2. Apr 1956.
21:
1058:Bendix Corporation
1048:1956 in California
939:Bendix Helicopters
344:Friden Flexowriter
152:Bendix Corporation
140:
138:Module from a G-15
132:
85:Introductory price
51:Bendix Corporation
1010:
1009:
806:"The Bendix G-15"
675:www.bitsavers.org
562:(3): 13. Mar 1957
447:civil engineering
426:(March 1962) and
413:personal computer
279:The G-15 has 180
240:analog delay line
236:delay-line memory
124:
123:
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1053:Serial computers
995:Related articles
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309:Single-precision
258:double-precision
222:(ACE). It is a
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819:"BENDIX G 15"
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791:February 29,
789:. Retrieved
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726:. Retrieved
724:. p. 12
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657:. Retrieved
655:. p. 15
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564:. Retrieved
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461:Ken Thompson
458:
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451:cut and fill
432:
410:
407:Significance
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305:milliseconds
291:holds 2,160
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254:accumulators
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217:
214:Architecture
172:Harry Huskey
169:
143:
141:
93:Discontinued
67:Release date
47:Manufacturer
41:Harry Huskey
970:Bendix G-20
965:Bendix G-15
762:1700–1799:
742:1634–1699:
489:Bendix G-20
463:ever used.
321:hexadecimal
315:Peripherals
289:drum memory
281:vacuum tube
266:vacuum tube
228:main memory
186:and on the
176:Alan Turing
160:drum memory
156:Los Angeles
144:Bendix G-15
20:Bendix G-15
1017:Categories
691:Weik, 1961
688:1000 lbs:
681:2018-06-08
659:2018-06-08
566:2020-09-05
495:References
262:flip-flops
109:Dimensions
101:Units sold
932:Companies
703:Weik 1961
439:Australia
330:kilobytes
37:Developer
948:Products
767:(1992).
747:(1997).
478:See also
364:Software
303:is 14.5
192:Berkeley
148:computer
61:computer
388:of the
374:IBM 650
268:count.
182:in the
178:on the
75: (
979:People
925:Bendix
728:Mar 6,
594:
518:
443:Canada
417:LGP-30
285:diodes
869:photo
774:(PDF)
754:(PDF)
722:(PDF)
552:(PDF)
428:PDP-8
390:ALGOL
337:bytes
293:words
245:words
230:is a
206:with
146:is a
793:2024
730:2020
592:ISBN
516:ISBN
441:and
424:LINC
382:ALGO
297:bits
188:SWAC
142:The
117:Mass
96:1963
77:1956
70:1956
57:Type
421:DEC
376:'s
332:).
299:.
180:ACE
104:400
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Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
