[author : Curt Noll] #Mathematics #Book

Extract : «  About three years ago, Laura and I set out on a project that was to pay off with tremendous results. In fact, it seems that it will not level off for quite some time. The project to which I am referring is the search for the 25th Mersenne prime. [...]

California State University at Hayward was nice enough to let us use their CDC Cyber 174. The Cyber 174 was an ideal machine for the Lucas-Lehmer test for several reasons:

1. The Cyber 174 has two very fast CPU’S.
2. The Cyber 174 has a word size of 60 bits which makes it ideal for multiprecise multiplication.
3. The Cyber 174 is a very reliable machine because of its single correct double detection parity error feature.

Another good reason was that the Cyber 174 is a timeshare system for the California State University system, and usually one of the two CPU’s is idle due to the inherent nature of time-share on a fast machine. Therefore the program could reside as an idle time job and run about 90% of the time in the CPU. The last and best reason was that the computer time was free. [...]

References

1. Burton, David M., "Elementary Number Theory" (1976), p. 218-233, Allyn & Bacon, Inc.

2. Kirch, Allan M., "Elementary Number Theory" (1974), p.148, 149, 308, Intext Eductional Publishers.

3. Knuth, Donald E., "Art of Computer Programming, Volume 2" (1968), Section 4.3, Addison-Wesley.

4. Lehmer, D.H., "Lucas-Lehmer test". Journal of the London Math Society, Volume 10, (1935), p. 162-165.

5. Lehmer, D.H., private communication with, University of California at Berkeley, Department of Mathematics, 94720.

6 . LeVeque, William J., "Fundamentals of Number Theory" (1977), p. 3, Addison-Wesley.

7. Tuckerman, B., private communication with. International Business Machines Corporation, Thomas J. Watson Research Center, P.O. Box 812, Yorktown Heights, New York 10589.

8. Wagstaff, Jr., S., private communication with. University of Illinois, Urbana, Illinois 61801.  »

[author : J. Nievergelt, H. P. Frei, H. Burkhart, C. Jacobi, B. Plattner, H. Sugaya, B. Weibel, J. Weydert] #Pascal #Programming #Education #Book

Extract : «  This report describes a project whose aim is to develop an interactive system that serves as a self-explanatory school computer. Particular attention has been devoted to making the man-machine dialog easy to follow for the inexperienced user. The system includes a course on computer programming, a programming system for writing, editing, executing, and debugging programs interactively, and a filing system containing private and public libraries. The language offered to the user is a version of PASCAL. The system is realized on a small stand-alone computer which supports a small number of graphic terminals. This hardware consists of the most cost-effective components currently on the market. [...]

1. Goals of the Project

The XS-O project was started in summer 1975 at the Institute for Informatics of the Swiss Federal Institute of Technology, with partial support of the Nationalfond. It has three major goals:
— to provide a focus for research on interactive systems and man-machine dialogs;
— to make a contribution to computer science education and computer literacy, by creating a tool for teaching computer programming which is superior to current practice;
— to develop a low-cost but flexible computer-assisted instruction system, that supports the interactive preparation and delivery of computerized course material on any subject.

[...]

References

[ALL 77] Allan, J. J. (ed.), CAD Systems, Amsterdam: North Holland Publ. Co., 1977.

[ALP 70] Alpert, D., and Bitzer, D. L., "Advances in Computer-Based Education," Science, Vol. 167 (1970), 1582-1590.

[BUN 73] Bunderson, C. V., "The TICCIT Project: Design Strategy for Educational Innovation," ICUE Technical Report, Provo, Utah: Brigham Young University, September, 1973.

[BUS 45] Bush, V., "As We May Think," Atlantic Monthly, 176, No. 1 (July 1945), 101-108.

[CUL68] Culler, G. J., "Mathematical Laboratories: A New Power for the Physical Sciences," in [KLE 68], 355-384.

[ENG 73] Engelbart, D. C., et al., "The augmented knowledge workshop," AFIPS Conference Proceedings, Vol. 42 (1973), 9-21.

[FEI 67] Feingold, S. L., "PLANIT — A Flexible Language Designed for Computer-Human Interaction," AFIPS Conference Proceedings, Vol. 31 (1967), 545-552.

[FEU 71] Feurzeig, W., et al., "Programming-Languages as a Conceptual Framework for Teaching Mathematics," Final Report on BBN Logo Project, June 1971.

[FRE 74] Frei, H. P., "The Author Language and the System THALES," Zurich: Berichte des Instituts fuer Informatik ETH, No. 9 (September 1974).

[FRE 75] Frei, H. P., THALES, an Interactive System and its Application to Teaching Programming, Zurich: Juris Druck & Verlag, 1975.

[GOL 76] Goldberg, A., et al., Personal Dynamic Media, Palo Alto, Calif.: Xerox Research Report SSL 76-1, 1976.

[IVE62] Iverson, K. E., A Programming Language, New York: John Wiley, 1962.

[KEM 67] Kemeny, J. G., and Kurtz, T. E., BASIC Programming, New York: John Wiley, 1967.  »

[author : Greg B. Scott] #TradeAndLaws #Software #Experience #Business #Book

Extract : «  By 1980, over 125,000 microcomputer systems will have been sold to small businesses. The success or failure of each of these installations will be greatly dependent on how well the selected software addresses the business problems of the buyer. Hence the software becomes a major portion of the decision process when selecting a computer system.

But how does one “shop around” for software? And what guidelines can a prospective buyer follow to ensure that his specific requirements will actually be satisfied?

This article presents the answers to these questions by examining what types of software are available, the sources for software, and an acquisition procedure that should be followed to insure a “good match” between the software and the business.

[...]

SUMMARY

Software selection for small business applications can be approached in a manner that will help insure the buyer receives maximum value for his investment. This procedure can be summarized as follows:
1) Analyze the business needs.
2) Gather information on available software.
3) Make initial selection.
4) Meet with vendors.
5) View demonstrations.
6) Interview current users.
7) Make the final decision according to the evaluation criteria.
8) Negotiate a sound and favorable contract.

The user who is willing to follow the above guidelines will most likely be one of the successful microcomputer installations which selected the correct software system as a cost effective automated approach to his business requirements.

REFERENCES

1) “How to Buy Software Packages,” Datapro 70, Datapro Research Corporation, 1805 Underwood Blvd, Delran, NJ 08075

2) “Software — Make or Buy?”, ibid.

3) “All About Small Business Computers,” ibid.

4) Wm. F. Kluckas and J.M. D‘Allegro, “Evaluating Software Packages,” ICP INTERFACE Mini-Small Business Systems, International Computer Programs, Inc., 9000 Keystone Crossing, Indianapolis, IN 46420

Reprinted from Volume 1, No. 1 of Business Computing Newsletter. Free subscriptions available at P.O. Box 55056, Valencia, CA 91355.  »

[author : Karl Mosgofian] #Microprocessor #Review

Extract : «  Recently, computers based on the Cosmac 1802 microprocessor chip have become very popular. Many magazines are printing articles on the Cosmac computers and the 1802. But despite the rather sudden discovery of the 1802 by the microcomputer world, it is not new, and there have been computers based on the 1802 available for several years. So why has it taken so long for people to notice the 1802? And why is it all of a sudden so popular? Well, the answer to both questions is that it is different. Things that are different are thought to be either better or worse than the normal. In the case of the 1802, there is a little bit of both. But since it is such a different processor, it deserves some looking into. [...]  »

[author : Don Colburn] #OperatingSystem #Programming #Assembly

Extract : «  The fastest and easiest way to complete any task is with the right tools. This statement is as true with software as it is with hardware. The person that assembles a CPU card with a 60 watt soldering iron, 1/8” solder, and a pair of lineman’s pliers is in the same boat as the one who hand assembles an 8K assembly language program. Although it is possible to assemble a CPU card with limited tools or to hand assemble large assembly language programs, few people who are seriously developing software can afford the time and resources required to do the job without the right tools.

This article describes a software development tool kit which provides the “right tools” required to efficiently and effectively both generate and modify 6500 assembly language programs. The level of capability is equal to that of some minicomputer operating systems. [...]

EXOS software is delivered on prime 450ns 2708 or 2716 EPROMS and each piece of software is accompanied by a comprehensive user manual. Both of the above sources offer the manuals for $5.00 each or $15.00 for the entire set (cost is applied towards purchase price). EXOS is now available on AIM/KIM/VIM compatible cassettes for $30 each from RCS.  »

[author : Charles M. Phelan] #Electronic #Audio

Extract : «  A simple and very inexpensive method for producing voice output from a microcomputer was described by Phil Mork in “Vocal Memory Dump,” Dr. Dobb’s Journal, Vol. 3, Issue 8. Voice signals are processed by first differentiating the input waveform and then sampling the sign of the derivative at a rate determined by software. This information (one bit per sample) is then stored in memory. These bits can then be output at the same rate through an integrator, producing a fair reproduction of the original waveform. The fidelity improves to some degree with higher sampling rates.

I have performed some experiments with this technique, and have discovered a pitfall or two in its application. [...]  »

[author : Curtis Roads] #Audio #History #HowItWorks

Extract : «  A slightly longer version of this paper was written at the prompting of the Pascal Special Interest Group of DECUS, for a “Pascal Applications Seminar” at the DECUS Symposium in San Francisco. The presentation was accompanied by a demonstration tape which was compromised of both historical examples of computer music as well as contemporary examples. The talk was geared to a technically sophisticated audience who presumably knew little about computer music. The subjects of Pascal and computer music were intertwined throughout the original paper. This version focuses mainly on just computer music itself, and in particular sound synthesis and composition with computers. Due to the brief and introductory nature of the paper, some important developments and names have been omitted, for which I apologize. Although the early history of electronic music is extremely well-documented, a good comprehensive history of computer music has yet to be written.

The Early History of Computer Music

Although the history of computer music is intimately tied to the history of other forms of electronic music, I’m going to treat it separately, for purposes of brevity.

The sound generating programs developed by Max Mathews and his associates at Bell Laboratories in the 50’s are the earliest known computer music attempts. While various experimental sound synthesis systems were set up at the University of Illinois Argonne National Laboratories and MIT in the early 60’s, it was not until the publication of Max Mathew’s book The Technology of Computer Music by MIT Press in 1969 that wider interest and activity in computer music began to take off. Concurrent to this software advance, the introduction of the minicomputer at about the same time was another influential factor. [...]  »

[author : Les Hancock] #Algorithm #Listing #C #Programming #Book

Extract : «  Alexander Graham Bell invented the tin ear, so maybe it’s not surprising that Bell Labs’ best software should have names like UNIX and C. The UNIX operating system, which really has nothing to do with keeping a harem, has become fairly well known, but the C language it’s written in is just beginning to be heard from. The purpose of this article is to show you what C looks like and how much it can do, even in a tiny avatar.

C’s popularity has probably suffered from the fact that there’s nothing racy or showy about it. If programming languages were horses, C would be a hard-working quarter horse and not a show horse like PASCAL or a race horse like APL. C is docile, regular, predictable, sometimes all but invisible—certainly nothing you’d buy a ticket to watch. In a word, C is pragmatic —but remember that pragmatism can be a rigorous philosophy.

C was written in 1972 by Dennis M. Ritchie, and has the coherence that often comes from single authorship (think of APL, PASCAL, TRAC). Ritchie’s goal was to provide high- level controls for low-level programming—in other words, to get as many jobs as possible done with the least possible fuss. He was successful. [...]  »

[author : Charles Wetherell] #Practice #GameBoard

Extract : «  OBSERVATION VERSUS ANALYSIS:TWO PROBLEM SOLVING METHODS

Analysis

In my first column (January), I proposed a little draw poker machine as an interesting programming project. Although this subject no doubt led to my evil reputation for frivolity, there was a deeper, hidden motive for the column. Readers who persevered to the end noticed that the real problem was not to write a poker game program. Rather, it was to answer a question in economic strategy—to wit, what are all the possible choice points in this version of poker and what is the optimal choice of alternatives for each situation. [...]

Simulation

The second solution technique, simulation, is much less likely to be familiar. Mathematically trained programmers are particularly apt not to try simulation if an analytic solution appears at all possible. [...]  »

[author : Lloyd Rice] #Mathematics

Extract : «  Like author Gabrielson (DDJ #31), I also encountered Ackermann’s Function years ago, and also gave my 5 minutes penance to A(2,3) and beyond. Like so many others, I worked out the table as far as somewhere in the 4th row and then set it aside for other diversions. [...]

Gabrielson’s presentation of a bit of software and the dangling mystery of the final question in his article did for me what the acquisition of an 8080 system had not done, namely implanting the desire to explore that beckoning 5th row. Once again, I took pencil in hand and proceeded to explore the multiple recursions expressed here. A(4, 1) is not so bad. A(4, 2) is the killer. [...]  »