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Harvest, also known as the IBM 7950, was a one-of-a-kind adjunct to the Stretch computer which was installed at the US National Security Agency (NSA). Built by IBM, it was delivered in 1962 and operated until 1976, when it was decommissioned. Harvest was designed to be used for cryptanalysis. Download high resolution version (1076x844, 139 KB)The operating area of the Harvest (computer), Feburary 1962. ...
Download high resolution version (1076x844, 139 KB)The operating area of the Harvest (computer), Feburary 1962. ...
The IBM 7030, also known as Stretch, was IBMs first attempt at building a supercomputer. ...
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Cryptanalysis (from the Greek kryptós, hidden, and analýein, to loosen or to untie) is the study of methods for obtaining the meaning of encrypted information, without access to the secret information which is normally required to do so. ...
Development In April 1958, the final design for the NSA-customized version of IBM's Stretch computer had been approved, and the machine was installed in February 1962[1]. The design engineer was James H. Pomerene[2], and it was built by IBM in Poughkeepsie, New York. Its electronics (fabricated of the same kind of discrete transistors used for Stretch) were physically about twice as big as the Stretch to which it was attached. Harvest added a small number of instructions to Stretch, and could not operate independently. International Business Machines Corporation (IBM, or colloquially, Big Blue; NYSE: IBM) is a computer technology firm headquartered in Armonk, NY, USA. The company, which was founded in 1888 and incorporated June 15, 1911, manufactures and sells computer hardware, software, infrastructure services, hosting services, and consulting services. ...
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An NSA-conducted evaluation found that Harvest was more powerful than the best commercially-available machine by a factor of 50 to 200, depending on the task[3].
Architecture
 A HARVEST tape cartridge. The equipment added to the Stretch computer consisted of the following special peripherials: A tape cartridge from the HARVEST computer. ...
A tape cartridge from the HARVEST computer. ...
- IBM 7951 - Stream coprocessor
- IBM 7952 - High performance core storage
- IBM 7955 - Magnetic tape system also known as Tractor
- IBM 7959 - High speed I/O exchange
With the stream processing unit, Harvest was able to process 3 million characters a second[3].
The Tractor tape system which was part of the Harvest system was unique for its time. It included 6 tape drives which handled 1.75 inch wide tape in cartridges, along with a library mechanism which could fetch a cartridge from a library, mount it on a drive, and restore it in the library. The transfer rates and library mechanism were balanced in performance such that the system could read two streams of data from tape, and write a third, for the entire capacity of the library, without any time wasted for tape handling.
Programming Harvest's most important mode of operation was called 'setup' mode, in which the processor was configured (with several hundred bits of information) and the processor then operated by streaming data from memory (possibly taking two streams from memory) and writing a separate stream back to memory. The two byte streams could be combined, used to find data in tables, or counted to determine the frequency of various values. A value could be anything from 1 to 16 contiguous bits, without regard to alignment, and the streams could be as simple as data laid out in memory, or data read repeatedly, under the control of multiply-nested "do"-loop descriptors which were interpreted by the hardware.
Two programming languages, Alpha and Beta (not be confused with Simula-inspired BETA programming language) were designed for programming it, and IBM provided a compiler for the former around the time the machine was delivered. Computer code (HTML with JavaScript) in a tool that uses syntax highlighting (colors) to help the developer see the purpose of each piece of code. ...
BETA is a pure object-oriented language from the Scandinavian School in System Development where the first object-oriented language Simula was developed. ...
A diagram of the operation of a typical multi-language compiler. ...
Usage One purpose of the machine was to search text for key words from a watchlist. From a single foreign cipher system, Harvest was able to scan over seven million decrypts for any occurrences of over 7,000 key words in under four hours[3].
The computer was also used for codebreaking, and this was enhanced by a system codenamed Rye, which allowed remote access to Harvest. According to a 1965 NSA report, "RYE has made it possible for the agency to locate many more potentially exploitable cryptographic systems and `bust' situations. Many messages that would have taken hours or days to read by hand methods, if indeed the process were feasible at all, can now be `set' and machine decrypted in a matter of minutes"[4]. Harvest was also used for decipherment of solved systems; the report goes on to say that, "Decrypting a large batch of messages in a solved system [is] also being routinely handled by this system"[4].
Harvest remained in use until 1976, having been in operation at the NSA for fourteen years[5].
References - ↑ Bamford, 2001, p. 586
- ↑ J.A.N. Lee, March in computing history, looking.back, Computer, 29(3), March 1996 (online)
- ↑ a b c Bamford, 2001, p. 587
- ↑ a b NSA, "Remote-Access Computer Systems" in Cryptologic Milestones, August 1965, pp. 1–4 (as referenced by Bamford, 2001, pp. 589, 699)
- ↑ Bamford, 2001, p. 589
Sources James Bamford in a publicity photo James Bamford is an author and journalist who writes about the world of United States intelligence agencies. ...
External links - Eric Smith, IBM Stretch (aka IBM 7030 Data Processing System)
- Timeline of the IBM Stretch/Harvest Era (1956-1961)
- Tractor (IBM history page)
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