“Cambridge Computing: The first 75 years”, written by Prof Haroon Ahmed, Professor of Microelectronics at the University, charts the development of computing in Cambridge from 1938 when the staff and students of the Anatomy School at the University of Cambridge moved to a new site with a two man “Mathematical Laboratory”. From there EDSAC was developed in 1949, the first programmable computer ever brought into general service, and microprogramming was pioneered by Maurice Wilkes, the Lab’s second Director, using EDSAC 2.
Cambridge’s Computer Lab was the home of the world’s first webcam. It was the place where Michael Burrows, the leading computer scientist in search engine development, learned his trade, and where Bjarne Stroustrup, inventor of the C++, did his PhD. Without the Lab, early home computers like the BBC Micro, or the low-power chip technology used in iPads and mobile phones, or the Raspberry Pi, might well never have emerged.
“Today, the establishment mentality seems to be that you can industrialise innovation, or innovate on demand,” said Andy Hopper, Professor of Computer Technology and the current Head of the Lab. “You can’t do that any more than you can ask an artist to paint the next brilliant masterpiece. The success of the Cambridge Computer Lab has come about because we created a culture of innovation and nurtured innovative people within it.”
Even the beginnings of the Computer Lab disrupted the norm. When John Lennard-Jones, a Theoretical Chemist who was to become its first Director, submitted proposals for a computing facility in 1936, the very idea would have struck most people as extraordinary. At the time, a “computer” was a person, very frequently a mathematically gifted woman, employed to carry out tedious numerical calculations by hand.
Lennard-Jones’ proposal was for a facility that would carry out complicated calculations in support of wider University research, with the human computers using “recent developments in mechanical and electrical aids to computation”. The Lab’s early hardware consisted of these machines, and two analog computers which were designed to solve linear differential equations.
In the decades that followed, however, the Lab’s role evolved far beyond Lennard-Jones’ own imaginings, and at a pace matched only by advances in computing itself. Much of this took place under the stewardship of Maurice Wilkes, the other inaugural staff member, and the pre-eminent figure in Cambridge’s computing story. Originally, Wilkes had the post of “University Demonstrator” at the Lab. When he returned to Cambridge after service during the war, he found that Lennard-Jones had moved on, and replaced him as Director.
Rightly remembered as a computing pioneer, Wilkes spent more than 30 years in charge of the Lab, transformed it into a centre of excellence, and oversaw many of its greatest triumphs. His era began in 1946, when the Lab still comprised a smattering of mechanical machines arranged on benches. Under his leadership, EDSAC was pieced together in a former dissecting room of the Anatomy School. In the summer, there was an overwhelming stench of formalin, a solution used by the previous occupants to preserve dead bodies for study, which had soaked into the floorboards and vaporised in the heat. It must have been an odd atmosphere in which to give birth to foundational technology.
After three years of development, EDSAC came into general use on May 6, 1949, and successfully completed its first programmed task by accurately calculating the squares of numbers from 0 to 99. Users prepared programs by punching them on to paper. Finished programs then hung on a line, waiting for machine operators to load them in (the original “job queue”). As academics themselves queued up to use EDSAC, they were thwarted by frequent breakdowns, often having worked into the night. The almost hopelessly complex task of designing the computer’s memory was solved by creating a mercury delay-line system, based on the principle of ultrasonic waves being pulsed through a tube filled with the element. Unfortunately, this sometimes leaked during the filling of the tubes, compelling users and technicians to negotiate hazardous globules of mercury on the floor.
Compared with anything that had gone before, however, EDSAC was revolutionary. Today it is celebrated not only as a feat of computer engineering, but because of the usability that Wilkes had emphasized from the outset. Researchers across Cambridge – including astronomers, economists, crystallographers, molecular biologists and others – were able to benefit from its existence. Sir Richard Stone, Sir John Kendrew, and Sir Martin Ryle, all won Nobel Prizes as a result of work which relied on EDSAC’s use.
As the progress of computing technology accelerated, computers became less expensive, more compact, easier to user and, ultimately, ubiquitous, Wilkes’ response was to take the Lab in new directions, still guided by the ethos of innovating to solve problems, but ensuring practical usability as an outcome. From the mid-1960s on, for example, the Lab began to specialise in computer-aided design (CAD), developing 3D-modelling hardware and software. This became so important to the manufacturing sector that in 1968 the Government opened a CAD centre in Cambridge.
The book describes how, as computers became more widely available, the ability to share information across systems also became hugely important. From the 1970s, pivotal research took place which addressed this. The Cambridge Digital Ring was the result of an early attempt to create a local area network which could transmit data between interconnected machines. In the years that followed, research students including Hopper and Ian Leslie – both future Heads of the Lab – were involved in refining and improving it further.
As a continuation of the concept, the Cambridge Model Distributed System tackled the problem of allowing multiple computers to communicate and interact with each other by creating a pool of processing servers from a network of microcomputers. Its features included a forerunner of the Domain Name concept now used to identify areas of control on the internet. By the time it reached its second iteration, the System had linked up 50 different computers and was so successful that members of the Lab preferred to use it for their research projects, rather than rely on the mainframe.
The book then takes up the story of the years after Maurice Wilkes retired, and Roger Needham took over as Director. The advances that followed during the 1980s included “UNIVERSE”, which interconnected several Cambridge Digital Rings using the European Space Agency’s Orbital Test Satellite, and demonstrated the feasibility of linking several local area networks on this basis. The follow-up, UNISON, improved the approach with a focus on Email, document transfer, and the exchange of multimedia information in real time.
One famous by-product of this type of research occurred in 1993. A team of researchers working in multimedia systems who shared the same coffee pot had decided to keep tabs on whether it was full or not by using a lashed-up camera to relay a live display to their desktops. An even better system, which emerged that year, was to display the image online through a web browser. The coffee pot thus became the object of the world’s first webcam, and gained a global cult following until it was switched off in 2001.
Many case studies of this phenomenon are discussed in depth by Haroon Ahmed in the pages of Cambridge Computing. The better-known number the likes of Acorn, which became a household name after developing the BBC Micro, part of the Corporation’s nationwide computer literacy campaign in the 1980s. Famously, the contract to do so was won after co-founder Hermann Hauser promised to deliver a prototype within a week, well aware that no such demonstration computer existed. He then assembled a team which successfully built the prototype, completing it five hours before the BBC arrived to sample it.