Grosch's law is the following observation of computer performance, made by
Herb Grosch
Herbert Reuben John Grosch (September 13, 1918 – January 18, 2010) was an early computer scientist, perhaps best known for Grosch's law, which he formulated in 1950. Grosch's Law is an aphorism that states "economy is as the square root of th ...
in 1953:
I believe that there is a fundamental rule, which I modestly call ''Grosch's law'', giving added economy only as the square root of the increase in speed — that is, to do a calculation ten times as cheaply you must do it hundred times as fast.
This
adage
An adage (; Latin: adagium) is a memorable and usually philosophical aphorism that communicates an important truth derived from experience, custom, or both, and that many people consider true and credible because of its longeval tradition, i.e. ...
is more commonly stated as
Computer performance increases as the square of the cost. If computer A costs twice as much as computer B, you should expect computer A to be four times as fast as computer B.
Two years before Grosch's statement,
Seymour Cray
Seymour Roger Cray (September 28, 1925 – October 5, 1996 ) was an American
economies of scale
In microeconomics, economies of scale are the cost advantages that enterprises obtain due to their scale of operation, and are typically measured by the amount of output produced per unit of time. A decrease in cost per unit of output enables ...
: the more costly is the computer, the
price–performance ratio
In economics, engineering, business management and marketing the price–performance ratio is often written as cost–performance, cost–benefit or capability/price (C/P), refers to a product's ability to deliver performance, of any sort, for it ...
linearly becomes better. This implies that low-cost computers cannot compete in the market.
An analysis of rental cost/performance data for computers between 1951 and 1963 by Kenneth E. Knight found that Grosch's law held for commercial and scientific operations (a modern analysis of the same data found that Grosch's law only applied to commercial operations). In a separate study, Knight found that Grosch's law did not apply to computers between 1963-1967 (also confirmed by the aforementioned modern analysis).
Debates
Paul Strassmann
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*Paul (given name), a given name (includes a list of people with that name)
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Christianity
* Paul the Apostle (AD c.5–c.64/65), also known as Saul of Tarsus or Saint Paul, early Chri ...
asserted in 1997, that "it was never clear whether Grosch's Law was a reflection of how IBM priced its computers or whether it related to actual costs. It provided the rationale that a bigger computer is always better. The IBM sales force used Grosch's rationale to persuade organizations to acquire more computing capacity than they needed. Grosch's Law also became the justification for offering time-sharing services from big data centers as a substitute for distributed computing." Grosch himself has stated that the law was more useful in the 1960s and 1970s than it is today. He originally intended the law to be a "means for pricing computing services".
- article discussing Grosch's Law and Herb Grosch's personal career.
See also
*
Metcalfe's law
Metcalfe's law states that the value of a telecommunications network is proportional to the square of the number of connected users
of the system (''n''2). First formulated in this form by George Gilder in 1993, and attributed to Robert Metcalf ...
*
Moore's law
Moore's law is the observation that the number of transistors in a dense integrated circuit (IC) doubles about every two years. Moore's law is an observation and projection of a historical trend. Rather than a law of physics, it is an empir ...