ORIGINS OF TIMESHARING

Computer History Vignettes

By Bob Bemer

Purpose of This Story

I know how Philo Taylor Farnsworth must have felt for much of his life. "Philo Who?" You know, the guy that invented television. "But I thought television was invented by RCA or Allen DuMont?" No, friends, Farnsworth invented electronic TV. But it had to be proved in court, and the truth was seldom acknowledged until after his death. RCA paid royalties. Seems they agreed.

I'm damned if I want to be a Farnsworth. (See)  I lay at least a partial claim to the genesis of the timesharing concept, the basic reason you can read this on this Web site today. The myth that Christopher Strachey was first with the concept has been perpetuated in Datamation, Scientific American, and the Annals of the History of Computing. The remarkable aspect is that Strachey himself didn't agree! Nor does Prof. John McCarthy [6].

My claim is that I published the first paper to describe the aspects of computer timesharing for commercial usage, with users acting individually. It was in the public domain, published nationally. See what you think.

REFERENCES

Let's lay them up front, because they're more than references one may wish to make secondary referral to. They're the basis for the argument!

  1. R.W.Bemer, "How to consider a computer", Data Control Section,
    Automatic Control Magazine, 1957 Mar, 66-69
  2. R.W.Bemer, "The status of automatic programming for scientific computation",
    Proc. 4th Annual Computer Applications Symposium, Armour Research
    Foundation, 1957 Oct 24-25, 107-117 (Panel discussion, pp. 118-126).
  3. W.F.Bauer, "Computer design from the programmer's viewpoint",
    Proc. Eastern Joint Computer Conf., Philadelphia, PA, 1958 Dec 3-5,
    American Institute of Electrical Engineers, 1959 Jul, 46-51.
  4. C. Strachey, "Time Sharing in Large Fast Computers", Proc. Intl. Conf. on
    Information Processing, UNESCO, June 1959, B336-B341 (not on Web).
  5. R.M.Fano, F.J.Corbató, Time-Sharing on Computers", Scientific American Magazine, 1966 September, 129-140.
  6. See J.McCarthy, "Reminiscences on the History of Time Sharing",
    1983 Winter or Spring.
  7. M.Campbell-Kelly, "Christopher Strachey, 1916-1975, A Biographical Note", Annals History of Computing, 7, No. 1, 1985 Jan, 19-42.
My Unlikely Source for the Concept

I have told somewhere about attending Curtiss-Wright Technical Institute of Aeronautics prior to World War II. The school was in Glendale, CA. The date was the Fall of 1940. Another well-known institution there was the Bob's Big Boy hamburger. The original! At least it made the owner Mayor of Glendale. I went crazy for them, sometimes eating two in a row (I was young).

The drive-in was fascinating to this Midwestern boy. Parked cars around the restaurant, serviced by girls in attractive garb. But on going inside you saw what was to me an absolute first -- a revolving drum with elasticized or expanding bands. The waitresses put the orders in there, and the cooks referred to them often. The key word is "interspersion". Hardly any order ever got produced in its entirety at one time. The production sequence was "shared" by all customers and by all cooks. That idea stuck with me for 17 years!

Contribution of Robert W. Bemer (Ref. [1] - 1957 March)

The final section of this paper, commissioned by Editor Evan Herbert, described aspects of future commercial timesharing:

"Future computer operation, which strongly influences the design of the programming languages, has some vitally interesting possibilities. In this glimpse, the picture presented here is dependent upon three features:

"Assuming the availability of practical micro-wave communications systems, it is conceivable that one or several computers, much larger than anything presently contemplated, could service a multitude of users. They would no longer rent a computer as such; instead they would rent input-output equipment, although as far as the operation will be concerned they would not be able to tell the difference. This peripheral equipment would perhaps be rented at a base price plus a variable usage charge on a non-linear basis. The topmost level of supervisory routine would compute these charges on an actual usage basis and bill the customer in an integrated operation.

These program features are, of course, recognizable to Operations Research people as the Scheduling and Queuing problems. Using commutative methods, just as motion pictures produce an image every so often for apparent continuity, entire plant operations might be controlled by such super-speed computers.

These future hardware capabilities (and few competent computer manufacturers will deny the feasibility, even today, of super-speed and interleaved programs) demonstrate a pressing need for an advanced common language system so all users can integrate their particular operations into the complex of control demanded by an automated future ..."

(Note: This call for a "common language" was issued two years before the start of COBOL work.)

This excerpt shows two biases. 1) Equipment rental as a way of life, for I was then an IBM employee, and rental was then their policy, and 2) Manufacturing control as a primary example, for this was the audience for the publication.

Contribution of Robert W. Bemer (Ref. [2] - 1957 October)

On p. 126, Bemer's reply was:

Q: (Omitted from the publication, but I think the word "time-sharing" was used in the question. I used the word myself in a talk to the Franklin Institute the previous February, but you can find several previous papers, particularly from the SAGE project, that used the same phrase. But strictly in a hardware sense.)

A: "I am in favor of the short-order-cook policy that I think will come into effect perhaps five or ten years from now. It might resolve at least a certain class of problems as between the small and large computers. If one had an extremely large, extremely fast centralized computer with various lines radiating out, and with terminal facilities such as a person now only gets in in the form of input-output devices at the computer, and if one could have high-speed transmission to and from this centralized computer, it would be like a short-order cook. It takes the orders off the lines and, so to speak, heats up the griddle and sees that the toast is ready while it is pouring the coffee. It will be self-scheduling, self-regulating, and self-billing to the customer on the basis of use of the input-output device. I think, since the larger and faster computers, as far as production problems are concerned, always produce more problems solved per dollar once the problems are in the machine, that this is the obvious direction to go. I agree that at the present time there are many small computers that seem to take less trouble than a large one; but I think that, in the long run, we will use the largest computers and will start thinking in terms of compatibility of languages and ultimately in terms of a single language."


Contribution of Dr. Walter F. Bauer (Ref. [3] - 1958 December)

Here Walter Bauer describes his "Ultradatic, A Conjectural Computer". The part of the paper pertinent to timesharing says:

"It is fostered by the idea that the large computer is more economical to use today than the small computer, or a number of small computers, as long as the total workload is sufficient to keep the large computer busy, or as long as unnecessary expense is not incurred by idle time. The idea further stems from the fact that with increasing frequency one sees computers being operated from remote locations by means of communications over voice channels, or at least extensive input or output of data is being fed to computers from remote locations.

The central idea here is that each large metropolitan area would have one or more of these super computers. The computers would handle a number of problems concurrently. Organizations would have input-output equipment installed on their own premises and would buy time on the computer much the same way that the average household buys power and water from utility companies. In fact, the charges for the services would depend on the type of services rendered. If the problem required extensive use of the higher priced circuits, for example, high-speed multiplying, the rental rate for the time used would be higher than in other cases. The user would be charged for that time used and only that time used, and the accounting procedure would reflect the customer's detailed use."

Bauer further says that "the Ultradatic idea was first described in talks given by the author to the San Diego and Rio Grande chapters of the Association for Computing Machinery in late 1957 and early 1958".

He refers to "parallel programming" and Stan Gill's 1957 paper on that subject.

At the Munich IFIP meeting in August of 1962, someone mentioned my paper to Bauer, who until that time thought he had published the first paper on commercial timesharing. We met in a restaurant to discuss the timings and content. Dr. Bauer, with his Ramo Wooldridge experience, and as founder of Informatics (later bought by Sterling Software), was usually quite up-to-date in the computer field.

Contributions of Fano and Corbató (Ref. [5] - 1966 September)

This paper goes into much detail about working TSS systems. Only the beginning is pertinent to the purpose of this history, where the authors credit Christopher Strachey of the United Kingdom as the one "who first proposed (in 1959) a time-sharing system".

Contributions of McCarthy (Ref. [6])

This paper has problems of inaccuracies, suppositions, and bad dates. McCarthy's first thinking about time-sharing "might have been around 1955". But he does say that his "first attempts to do something about time-sharing was in the Fall of 1957 ..." And that to get the requisite hardware from IBM "took a long time ... perhaps a year, perhaps two." One suspects he did not keep his records.

Nor did he publish, for this paper [6] has no references. He admits that "In all this, there wasn't much publication. I wrote a memo to Morse dated January 1, 1959 ..." But in the next sentence he admits that "it has been suggested that the date ... should have been 1960."

I also complained to Eric A. Weiss, of the Annals of the History of Computing, re the genesis of timesharing. I cannot find an answer. What I appreciate is that McCarthy complained about Strachey's credits in [5] to the Scientific American. So did I. They replied to me that "The point you raise is most interesting, and I have put it before Professors Fano and Corbató".

The authors did reply to Scientific American, but oddly enough backed off to the 1959 Jan 01 internal paper by McCarthy, 22 months after my external paper. But McCarthy says that "Corbató was surprised to find my 1959 memo in the files".

Also in their reply they credited Strachey with "substantial detail". I am sure that both Bauer and I could have engendered detail to go with the concept. I, in particular, was limited by space available in a popular journal.

And so we come full circle. The entire chorus of credits for Strachey hits a bad chord.

The really interesting part of McCarthy's paper is its Appendix, containing Strachey's reply to a query from Don Knuth about origins. Here are the significant parts of Strachey's reply:

"It was mainly about multi--programming ... I did not envisage the sort of console system which is now so confusingly called time sharing ... Halsbury ... was certainly right to say that in 1960 'time sharing' as a phrase was much in the air. It was, however, generally used in my sense rather than in John McCarthy's sense ..."
Strachey's reply also said that the IFIP Conference was in 1960. It was in 1959. As he died just a year after writing the letter, the memory failure is forgivable.

Contribution of Christopher Strachey (Ref. [7])

This remarkably complete story of Strachey's life confirms my tale in many ways:

(TIME)Sharing the Credit

It has been said that great ideas often occur simultaneously to several people. In the pertinent period there was a ferment, and one probably cannot ascribe the entire idea to a particular person as we are able to do with Da Vinci.

Much could have been gotten from me. As my first publication elicited a suggestion from a Dr. Franz (???) that I should be fired because it was not IBM's policy, that may be why IBM instigated no patent applications. Maybe I had put it in the public domain, as I did with publication of my escape sequence concept. But it is no secret that I was very active professionally in the 1957-1959 period.

So I stand by my original claim. I did not create a timesharing system. I did not create a practical design for such. But I was the very first person to publish in some medium (and it was national) the concept of sharing a computer remotely amongst many users via input/output equipment for commercial usage!

Final Note on Historical Accuracy

As I prepare historical material for this site, I am astounded at how many dates the historians (and those they write about) have gotten wrong. In the fast-moving computer industry, I would think it important to keep accurate records of idea generation, patents, public talks and publications.

Accordingly I submit for general use the nonpersonal subset of my travel log from 1954 (when I first kept records) to date. I hold no copyright, and anyone wishing to flesh out the time line may use it as a starting point. After all, busy though I was in computer activities, I could not go to every meeting!

Each trip is identified as the nth in that year. These could be interspersed in the text as identifiers, if anyone thinks that a useful idea.

You can find the path to these logs in the "Interesting Computer History" page, but I must admit that their interest is limited to this one purpose. Otherwise, I agree. They're pretty dull!

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