Although one can trace the origins of digital computers to the Analytical Engine of Charles Babbage or the punched card tabulating machines of Herman Hollerith, the real beginning of the computer age was in the late 1930s and early 1940s, sparked in large part by various aspects of World War II. In Britian, Alan Turing’s group at Bletchley Park was trying to build a computer for code-breaking purposes. In Germany, Konrad Zuse built a relay-type machine that could store 64 floating point numbers for rocketry calculations. In the U.S., several developments were proceeding in parallel, but by far the most influential was the work of John Mauchly and J. Presper Eckert at the University of Pennsylvania on a machine which was eventually christened ENIAC (Electronic Numerical Integrator and Computer).

The Purpose of ENIAC was to integrate ballistic equations for gunnery tables. Such tables show the required angle of elevation of a gun for various target distances, shell weights, and wind speeds. A significant accomplishment at the dedication of ENIAC in February 1946 was the computation of the trajectory of a 16″ naval shell in less than real time. Since World War II had ended by the time ENIAC was operational, there was no longer the urgent need for the firing tables that motivated its design. Thus, after it was moved to Aberdeen Proving Ground, it was put to use in atomic energy calculations, cosmic ray studies, thermal ignition research, wind tunnel design, and weather prediction as well as for its original purpose of computing ballistic tables for the Army and Air Force.

Unfortunately, today we tend to get a somewhat distorted view of the history of digital computers. Books written by writers in the computer field tend to focus on the early technology (vacuum tubes, mercury delay lines, paper tape), capacity, speed, and occasionally, people. On the other hand, general history books tend to focus on data processing and financial applications, and ignore the incredibly important role of the military in perhaps the most momentous development of the 20th century.

Equally salient is the fact that virtually all of the early applications of digital computers were simulations—of an artillery weapon, a nuclear reaction, a wind tunnel, the weather. It was not until some years later that computers were put to work in data processing, financial applications, and communications.


In 1957, just 11 years after the first digital computer was demonstrated, in my sophomore year at Cornell University, I got my first taste of computing. By then, of course, computers were being widely used for data processing and related applications, but I was far more fascinated with their ability to simulate the real world. Summers during college, I worked at Grumman Aircraft refurbishing war-worn airplanes, testing antenna configurations, and writing programs with the computer group. I’ll never forget the countless hours I spent in the computer room as our project team tried to simulate the actions of an airplane pilot in various situations.

The following summer, I was in a group charged with writing programs to simulate the movements of an early satellite, the orbiting astronomical observatory (OAO). The experience I gained working on these simulations put me in a good position to undertake my senior project at Cornell, a massive program (in ALGOL) that simulated the acoustics of a concert hall. Given the size, shape, seating configuration, wall covering, and ceiling material of the hall, the program calculated the acoustical properties of various seating locations. Today, such a program seems almost primitive, but in 1960 it was a major accomplishment.

A year later, in the MBA program at Carnegie-Mellon University, I had the opportunity to work with the team that wrote the first management game, a simulation of three companies competing in the detergent market. Since then, as my career has progressed through positions at Management Science Associates, Digital Equipment Corp., AT&T, and Creative Computing, I have had fewer and fewer opportunities to program. However, over the years, in the back of my mind I tucked away ideas for future programs.

Thus, when Ziff-Davis decided to fold Creative Computing magazine, it was with a sense of anticipation that I remembered some of these program ideas. Claudette Moore, formerly an editor at Creative Computing, now at Microsoft Press, and I were chatting one day and I mentioned the idea of doing a series of travel simulations. She, with some enthusiasm, asked me to put together a proposal for a book. I did, and this is it. Now, I can only hope that you, the reader, learn as much from the stories and have as much fun taking the simulated journeys as I had researching and writing them.

In closing let me thank Betsy Staples for her enormous help and fanatic attention to detail in editing the manuscript, Claudette Moore for encouraging me to write the book in the first place, and Jody Gilbert, David Rygmyr, and all the other folks at Microsoft Press for seeing the project through to completion.


As I looked back at the preface that I wrote some 25 years ago for Basic Computer Adventures, I was pleasantly surprised to not find any glaring blunders or lame predictions. However, my comments about ENIAC must be updated. As a result of Britain finally declassifying the details of the Colossus computer developed for cracking the so-called German Tunny code, we now know that the first electronic digital computer was designed by Thomas H. Flowers and not by Mauchly and Eckert at the University of Pennsylvania.

The first working Colossus computer was delivered to Bletchley Park in early December 1943. It had 1,600 valves (vacuum tubes) and operated at 5,000 characters per second. It first ran on December 8, 1943 and decoded its first Tunny message on February 5, 1944.

The second version of Colossus, of which nine more were built, had 2,400 valves and operated at a speed of 25,000 characters per second.

Interestingly, the people at Bletchley never saw an actual Tunny machine until after the war, but they had described it exactly and programmed it into Colossus. In fact, Tunny was a 12-wheel Lornez SZ40 cipher machine. Bear in mind, Colossus was not a general purpose, stored program computer. It had just one purpose—breaking the Tunny codes. Nevertheless, it was these 10 Colossus machines that led to the first general purpose programmable computer built at the University of Manchester after the war.

What happened to the Colossus machines? At the express orders of Winston Churchill, all ten of them were broken up and secretly discarded.

What happened to Tommy Flowers, the true and sole inventor of the electronic digital computer? Britain gave him £1,000 for his 6 years at Bletchley, barely enough to cover his debts and said, “don’t tell anyone what you’ve done.” He went to work for British Telcom who thought his idea for using computers for telephone switching was ridiculous and he died a bitter and frustrated man. He gets practically no mention or recognition in any book or history of computers.

I might mention that one of the first computers I learned to program (1961) was the Bendix G15, which was one of the direct commercial descendents of Colossus. It used a language called GATE that was a cross between machine code and a few Algol-like commands. It’s so obscure, it’s not even mentioned in the Encyclopedia of Computer Science.

Unlike many educators today, I believe there is a great deal that can be learned from history. I urge you to make a pilgrimage to Bletchley Park, pick up some books about Alan Turning, Tommy Flowers, and Colossus and start looking at computers and the Internet from a vastly broadened perspective.

Oh, and have fun with the adventures in this book!

David Ahl
Morristown, New Jersey
October 2010