Turing’s Pilot ACE

Alan Turing is undeniably the leading figure in the history of computers. It was he who was able to develop the concepts necessary for a general purpose computer. He introduced the world to the concepts of computation and algorithm. But among all his achievements, there is one that is not as highlighted as the rest. And that is his participation in the development of the Pilot ACE computer.

After his stint at cryptology and code-breaking operations, Turing joined the National Physical Laboratory at Teddington. By then, Turing had already detailed everything that is needed for a computer to function. The only thing missing is a team that would allow him to turn these theories into a reality so when NPL offered him a position, Turing immediately accepted. He and his team were supposed to proceed with creating a full scale Automatic Computing Engine. But this was an extremely huge project and they needed some backing up. To gather funds, they decided to build a smaller version in the form of the Pilot ACE.

Although just a prototype, the Pilot ACE succeeded in a lot of ways. It was the first advanced computing machines built in the United Kingdom. It performs floating point arithmetic which pinpoints a set of range in which the real number belongs to.  They did away with the initial fixed point arithmetic since the numbers would eventually fall out of range. Thus, using the floating point software is the most ideal. Pilot ACE made use of vacuum tubes and mercury delay lines. It uses a 4096 word drum memory and has the clock rate of 1 mega Hz, the fastest at that time.

The ACE prototype was highly successful. Sadly, Turing left in the middle of the production due to multiple delays by the management and Wilkinson and Huskey took over. Regardless of the case, the success of Pilot ACE is still highly attributed to Turing given the fact that it was his idea and design to begin with.

The Invention of EDSAC

When von Neumann wrote his draft on the report for EDVAC, it spurred a number of inventions in the history of computers. Many were attracted to the idea that a computer could store programs. Now, these computers need not solely rely on punched cards for instructions. They could compile these instructions and store them internally.

Maurice Wilkes was one of those developers who drew inspiration from von Neumann’s draft. He spearheaded a team over at the Mathematical Laboratory in University of Cambridge to develop what was to be known as the second digital stored program computer, the EDSAC.

EDSAC, short for Electronic Delay Storage Automatic Calculator, made use of mercury delay lines and derated vacuum tubes. At first, the delay lines were only sufficient to store 256 words but subsequent developments improved the limit to 512 then to 800 words. In the end, the delay lines were able to store 1024 words. There was also an accumulator, a multiplier register and an index register attached to it. The instructions available were more diverse than the previous calculators. There are the instructions for add, subtract, collate, multiply, store, accumulate, conditional skip, read, print, stop, shift left and shift right, among others.

Wilkes and his team also made use of the first ever assembler. Many believed that this assembler was the one that sparked the development of many other future software programs. They made use of uni-selector switches wherein the memory is loaded upon startup. EDSAC was also the first computer to make use of subroutine wherein a user can create programs, also termed as routines, by making use of an existing subroutine in the register. This allowed easier writing and overwriting of programs thus, promoting efficiency and speed for the user in writing the codes.

Once completed in 1949, EDSAC became instrumental in solving many real problems within the university. It was a success that soon, many were inspired to use the EDSAC as a foundation for their own inventions such as the LEO 1 computer.

The Selective Sequence Electronic Calculator of IBM

Before the time of computers, the best device in the market is the calculator. They weren’t as small as they are today. The first calculators were huge and bulky. It’s almost similar to the size of the computers. The only reason they were termed as calculators is because that’s all they do. They calculate. One of the most advanced calculators ever created was the Selective Sequence Electronic Calculator (SSEC) by IBM. It was so advanced that it contained a number of features present in the succeeding computers built.

SSEC was built out of the dispute involving both IBM and Howard Aiken. Aiken was the person credited to have built the Harvard Mark 1 computer. But in reality, IBM was the one who built the machine for Aiken. When the public began congratulating Aiken and disregarding the role of IBM in the project, the management of IBM was greatly displeased. They decided to break ties with Aiken and went on to build a separate machine that is better than the previous one. They hoped that this new project could elevate the status of the company and afford them to be recognized as a leader in the industry.

Even at the onset, SSEC was created to be more superior than a regular computer and being so, it was way beyond the qualifications of a typical calculator. The SSEC was huge. It occupied almost a third of a room. It used a combination of vacuum tubes and relays that gave them control and allowed the instructions to be completed in a rapid manner. The memory was enough for 19-digit words and instructions were sent via punched cards. They made use of all these to ensure that SSEC is way faster than Harvard Mark 1. And it was! Arithmetic operations were completed in less than 20 milliseconds.

SSEC was also the first device to store data for interpolation. It was able to store instructions and use it as data in subsequent operations. In short, it was a programmable calculator. This feature was enough to attract the interest of the public upon its release. And true to the goal of IBM. SSEC skyrocketed the company to fame and worldwide recognition.

ENIAC: The First General-Purpose Computer

Both the first and second world war prompted the government to look into more advanced technology to aid them in their calculations. It was around the time when technology was still in the raw stages and the computing machines prevalent during those times were unable to meet the needs of the government. This is the very reason why the government would allot a huge sum to the experiments and manufacture of new devices. One of their funded projects includes the ENIAC which became the first general-purpose computer ever created.

ENIAC, short for Electronic Numerical Integrator and Computer, was used to aid in the artillery firing calculations of the United States Army. It all started when the U.S. Army tasked the University of Pennsylvania to come up with a computing machine that would help them solve a large data of mathematical problems. Some were skeptical about the project but both Mauchly and Eckert believed otherwise. They went on to design the machine and headed the team that will oversee its development.

They believed that to serve its main purpose, this new machine has to be a modular computer. There are multiple panels that will enable multiple calculations. These will in turn receive and send messages and instructions that were given through punched cards. Speed is a priority and the team addressed this by assigning different functions to the different panels. Some of the panels can only serve as accumulators meaning they could only do simple arithmetic operations while other panels are tuned to perform more complex operations. These panels would then be regulated by a multiplier or divider unit to regulate the more complex operations. Doing so allows precision, speed and accuracy.

When it was finally launched, ENIAC was considered the fastest among all the other existing computers. Its only drawback lies in the vacuum tubes. Transistors were not yet invented at that time and all computers have to make do with tubes. Like other computers, ENIAC was not spared from overheating tubes. It was even more prone to overheating given the amount of operations and high speed the computer operates on. There were overheated and faulty tubes every other day. Although numerous efforts were done to improve ENIAC, the most that they could do was to prevent any tubes from overheating up to five days.

Von Neumann’s First Draft of a Report on the EDVAC

Computers have come a long way. From merely being used as a device for simple arithmetic calculations, it has become the most dependable machine technology has to offer. It allows users to store data, access the net and produce the best output that is quite unthinkable to a lot of us. But before computers became who they are nowadays, it has undergone a number of developments and enhancements. Perhaps, one of the more essential breakthroughs in the history of computers is the time when humans tinkered with the idea that these devices could store logical programs. In fact, the first time the idea was ever considered was during the year 1945 by von Neumann.

John von Neumann explored the possibility of a stored-program computer. Being an expert in all aspects of these mechanical device, von Neumann saw the impracticality of using punched paper tapes to send instructions and programs to a computer. He knew that something has to be done. He went on to explore different options until he finally thought about storing the programs within. It was something new in his time and many thought that it was quite an impossible task. But von Neumann thought otherwise.

He detailed the layout and the design of this new computer in a report in what was to be known as the First Draft of a Report on the EDVAC. For him, this device has to contain six essential parts namely, a central control, a central arithmetic division, an input, an output, a memory and another external memory. The computer will be able to perform all arithmetic functions with possible interpolation when necessary. It will use a 32-digit binary notation. It was here that he introduced the use of vacuum tubes in computers. At that time, relays were commonly used but von Neumann preferred the tubes because of the speed they operate in. He likewise noted the delay line and the iconoscope tube as his preferred types for the computer’s memory.

Von Neumann’s design contributed to the development of the EDVAC stored-program computer. His plans likewise inspired many other developers to experiment with stored programs and come up with their own computer versions.