What was it like to program an early digital computer? [Woven Memories] wanted to know and wants you to know, too. [Maurice Wilkes] and his team wrote a book about their EDSAC and the 18 instructions that it used. These days, you can even run an EDSAC program on a number of emulators.
It is hard to realize how things we take entirely for granted had to be invented by [Wilkes] and his colleagues. The book, “The Preparation of Programs for an Electronic Digital Computers” has, among other things, the first recorded use of a software library and the first API. Even the subroutine needed inventing by [Wilkes’] student [David Wheeler], which was known for a while as the “Wheeler Jump.”
Like many things in old computers, the Wheeler Jump required code to modify itself. Even indexing modes were often implemented by changing an address inside the program.
While we frown on techniques like this today, you have to start somewhere. We are big fans of EDSAC and [Dr. Wilkes] had a long and distinguished career long after EDSAC, too. The original plans for EINIAC led to EDSAC, EDVAC, and a slew of other early machines. You can see a video of the machine with an introduction by [Wilkes] below.
If you want to try your hand with the EDSAC, try your browser. There’s also a very nice Windows emulator that runs fine under WINE.
At first glance, getting a computer program to run faster than the first electronic computers might seem trivial. After all, most of us carry enormously powerful processors in our pockets every day as if that’s normal. But [Mark] isn’t trying to beat computers like the ENIAC with a mobile ARM processor or other modern device. He’s now programming with the successor to the original Intel integrated circuit processor, the 4040, but beating the ENIAC is still little more complicated than you might think with a processor from 1974.
For this project, the goal was to best the 70-hour time set by ENIAC for computing the first 2035 digits of pi. There are a number of algorithms for performing this calculation, but using a 4-bit processor and an extremely limited memory of only 1280 bytes makes a number of these methods impossible, especially with the self-imposed time limit. The limited instruction set is a potential bottleneck as well with these early processors. [Mark] decided to use [Fabrice Bellard]’s algorithm given these limitations. He goes into great detail about the mathematics behind this method before coding it in JavaScript. Generating assembly language from a working JavaScript was found to be fairly straightforward.
[Mark] is also doing a lot of work on the 4040 to get this program running as well, including upgrades to the 40xx tool stack, the compiler and linker, and an emulator he’s using to test his program before sending it to physical hardware. The project is remarkably well-documented, including all of the optimizations needed to get these antique processors running fast enough to beat the ENIAC. We won’t spoil the results for you, but as a hint to how it worked out, he started this project using the 4040 since his original attempt using a 4004 wasn’t quite fast enough.
According to [Asianometry], in 1986 the Soviet Union had about 10,000 computers. At the same time, the United States had 1.3 million! The USSR was hardly a backward country — they’d launched Sputnik and made many advances in science and mathematics. Why didn’t they have more computers? The story is interesting and you can see it in the video below.
Apparently when news of ENIAC reached the USSR, many dismissed it as fanciful propaganda. However, there were some who thought computing would be the future. Sergey Lebedev in Ukraine built a “small” machine around 1951. Small, of course, is relative since the machine had 6,000 tubes in it. It performed 250,000 calculations for artillery tables in about 2 and half hours.
The success of this computer led to two teams being asked to build two different machines. Although one of the machines was less capable, the better machine needed a part they could only get from the other team which they withheld, forcing them to use outdated — even then — mercury delay lines for storage.
The more sophisticated machine, the BESM-1, didn’t perform well thanks to this substitution and so the competitor, STRELA, was selected. However, it broke down frequently and was unable to handle certain computations. Finally, the BESM-1 was completed and was the fastest computer in Europe for several years starting in 1955.
By 1959, the Soviets produced $59 million worth of computer parts compared to the US’s output of around $1 billion. There are many reasons for the limited supply and limited demand that you’ll hear about in the video. In particular, there was little commercial demand for computers in the Soviet Union. Nearly all the computer usage was in the military and academia.
Eventually, the Russians wound up buying and copying the IBM 360. Not all of the engineers thought this was a good idea, but it did have the advantage of allowing for existing software to run. The US government tried to forbid IBM from exporting key items, so ICL — a UK company — offered up their IBM 360-compatible system.
The Soviets have been known to borrow tech before. Not that the west didn’t do some borrowing, too, at least temporarily.
The ENIAC, or Electronic Numerical Integrator and Computer, is essentially the Great Great Grandfather of whatever device you’re currently reading these words on. Developed during World War II for what would be about $7 million USD today, it was designed to calculate artillery firing tables. Once word got out about its capabilities, it was also put to work on such heady tasks as assisting with John von Neumann’s research into the hydrogen bomb. The success of ENIAC lead directly into the development of EDVAC, which adopted some of the now standard computing concepts such as binary arithmetic and the idea of stored programs. The rest, as they say, is history.
But ENIAC wasn’t just hugely expensive and successful, it was also just plain huge. While it’s somewhat difficult for the modern mind to comprehend, ENIAC was approximately 100 feet long and weighed in at a whopping 27 tons. In its final configuration in 1956, it contained about 18,000 vacuum tubes, 7,000 diodes, 70,000 resistors, 10,000 capacitors, and 6,000 switches. All that hardware comes with a mighty thirst for power: the ENIAC could easily suck down 150 kW of electricity. At the time this all seemed perfectly reasonable for a machine that could perform 5,000 instructions per second, but today an Arduino would run circles around it.
This vast discrepancy between the power and size of modern hardware versus such primordial computers was on full display at the Vintage Computer Festival East, where Brian Stuart demonstrated his very impressive ENIAC emulator. Like any good vintage hardware emulator, his project not only accurately recreates the capabilities of the original hardware, but attempts to give the modern operator a taste of the unique experience of operating a machine that had its heyday when “computers” were still people with slide rules. Continue reading “VCF East 2018: The Desktop ENIAC”→
When I first got interested in computers, it was all but impossible for an individual to own a computer outright. Even a “small” machine cost a fortune not to mention requiring specialized power, cooling, and maintenance. Then there started to be some rumblings of home computers (like the Mark 8 we recently saw a replica of) and the Altair 8800 burst on the scene. By today’s standards, these are hardly computers. Even an 8-bit Arduino can outperform these old machines.
As much disparity as there is between an Altair 8800 and a modern personal computer, looking even further back is fascinating. The differences between the original computers from the 1940s and anything even remotely “modern” like an Altair or a PC are astounding. If you are interested in that kind of history, you should read a paper entitled “Electronic Computing Circuits of the ENIAC” by [Arthur W. Burks].
These mid-century designers used tubes and were blazing new ground. Part of what makes the ENIAC so different is that it had a different design principle than a modern computer. It was less a general purpose stored-program computer and more of a collection of logic circuits that could be configured to solve problems — sort of a giant vacuum tube FPGA, if you will. It used some internal representations that proved to be suboptimal which also makes it seem strange. The EDSAC — a later device — was closer to what we think of as a computer. Yet the ENIAC was a major step in the direction of a practical digital computer.
Cost and Size
Programming the ENIAC in 1951 (±4 years) [Image Source: Public Domain]The size of ENIAC is hard to imagine. The device had about 18,000 tubes, 7,000 diodes, 70,000 resistors, 10,000 capacitors, and 6,000 switches. There were 5 million hand-soldered joints! ([Thomas Haigh] tells us that while this is widely reported, the real number was about 500,000.) Physically, it stood 10 feet tall, 3 feet deep, and 100 feet long. The tube filaments alone required 80 kW of power. Even the cooling system consumed 20 kW. In total, it took 150 kW to run the beast.
The cost of the machine was about $487,000. Almost a half-million dollars in 1946 is plenty. But that’s nearly seven million dollars in today’s money. What was worth that kind of expenditure? The military built firing tables for shell trajectories. From the [Burks] paper:
“A skilled computer with a desk machine can compute a 60-second trajectory in about twenty hours…”
Keep in mind that in 1946, a computer was a person. [Burks] goes on to say that a differential analyzer can do the same job in 15 minutes. ENIAC, on the other hand, could do it in 30 seconds and with a greater precision than the differential analyzer.
