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IEEE Computer Volume 15 Number 12 -- THE OPEN CHANNEL Disclosure Number: IPCOM000131567D
Original Publication Date: 1982-Dec-01
Included in the Prior Art Database: 2005-Nov-11
Document File: 5 page(s) / 23K

Publishing Venue

Software Patent Institute

Related People

Charles McCabe: AUTHOR [+2]


THE OPEN CHANNEL * The myth of the hardware/software cost ratio * References * A modest proposal (with apologies to J. Swift)

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Charles McCabe

San Francisco Chronicle

"Any clod can have the facts, but having opinions is an art.

The Open Channel Is exactly what the name Impiles: a forum for the free exchange of technical ideas. Try to hold your contrlbutlone to one page maximum In the final magazine format (about 1000 words.)

We'll accept anything (short of libel or obscenity) DO long as It's submitted by a member of the Computer Society. It It's really bizarre we may require you to get another member to cosponsor your item.

Send everything to Jim Haynes, Computer Center, UC Santa Cruz. CA 95064.

The myth of the hardware/software cost ratio

One of the "folk laws" of the computer industry that surfaces from time to timed 2 is "the cost of user's programming represents approximately 70% of cost, with hardware accounting for the remaining 30%." The law further states that by the end of this decade, software will be 85 percent of total cost (Figure 1). The ratio varies depending on the author. For example, a 70:30 percent ratio is sometimes quoted,3 as is 80:20 percent.4 Nevertheless, the general thrust of this "law" is that, today, soft ware costs are two to four times the cost of hardware.

On the surface, this law has the ring of truth. People costs are increasing, and hardware costs are going down. However, with the apparent slow growth in the ranks of computer programmers and the constant growth in yearly computer hardware sales, one has the very uneasy feeling that something is wrong with this folk law.

(Image Omitted: Figure 1. Branscomb's hardwarelsoftware cost trend.)

The origin of the famous hardware/ software cost trend curve in Figure 2 is a paper by B. Boehm,5 in which he reports the results of an Air Force study, "Information Processing/Data Automation Implications of Air Force Command Control Requirements in the 1980's," or "CCIP- 85." The four examples of hard" ware and software costs used in the study and cited by Boehm were, with one exception, for dedicated systems: the World-Wide Command and Control System, SAGE, and the Manned Space Program 1960-70. The examples of limited production systems have no relation to today's "user cost ratio." The one exception was the cost to IBM of developing the OS/360. This cost reflects development and is not a recurring user cost, except as reflected in the amortized cost of developing the computer systems.

The only acceptable interpretation of Boehm's hardware/software cost trend curve is that it represents the nonrecurring costs of developing a system. The curve does not...