Ferranti Argus facts for kids
Ferranti's Argus computers were a series of special computers made from the 1960s to the 1980s. They were designed to control machines and processes in factories and other places. The first Argus computer was actually planned for military use, but a changed version became the very first digital computer to control an entire factory! These computers were used a lot in Europe, especially in the UK. Even today, a few Argus computers are still working, helping to monitor and control things in nuclear reactors.
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Early Argus Computers
The Blue Envoy Project
The idea for the Argus computer first came from a military project called "Blue Envoy." This was a plan for a very long-range surface-to-air missile that could fly about 200 miles. To fly so far, the missile would shoot almost straight up into the sky. This helped it get to a high altitude quickly, where there was less air resistance. While it was climbing, the missile couldn't "see" its target, so it needed to be guided from the ground.
The Argus computer was designed to read information from radar, figure out the best path for the missile, and then send those instructions to the missile as it flew. It didn't just plan the path; it also directly controlled the missile's steering parts. Maurice Gribble at Ferranti's Automation Division started developing this system in 1956. The computer used small electronic parts called transistors, which were originally made for hearing aids. These transistors were slow, working at 25 kHz, but that was fast enough for the job.
The Blue Envoy project was stopped in 1957. But Ferranti decided to keep developing the computer for other uses. In November 1957, they showed off the computer to Prince Philip, Duke of Edinburgh. They set up a demonstration where someone could move a car headlamp by hand to shine on a wall. The computer then tried to move a second headlamp to shine on the exact same spot.
The First Argus Prototype
Ferranti kept working on the computer. In 1958, they finished a test version of a computer they could sell. They showed it to the public for the first time in November. This new machine used faster electronic parts, running at 500 kHz. The name "Argus" was chosen the next year. It came from the Greek God Argus, who was said to be "all-seeing." This name was perfect for a computer that would control many complex systems.
The new Argus computer was different from the earlier version. It could now use "interrupts." Imagine the computer is doing a job, and suddenly, new information arrives. With interrupts, the computer gets a signal (an "interrupt") that new data is ready. This means the computer doesn't have to constantly check if new data has arrived, saving a lot of time. The system also got core memory for storing information temporarily. This was a big improvement over the older system. For programming, it used a "plugboard," where you could insert small pegs into holes to create the program.
The very first Argus computer was delivered to Imperial Chemical Industries (ICI) in 1962. It was used to control ICI's soda ash and ammonia factory in Fleetwood. This was a huge step, as it was the first large factory to be controlled directly by a digital computer! Other companies in Europe soon bought Argus computers too.
The Argus computer used special germanium transistors. It worked with "words" of 12 bits (a bit is a tiny piece of information, like a 0 or 1). It also had 24-bit instructions. The computer could do math using two smaller parts called ALUs. Simple instructions took about 20 microseconds (a microsecond is a millionth of a second). It could store 4,096 words of data in its core memory.
Argus for Military Missiles
After the Blue Envoy project was cancelled, Ferranti and another company, Bristol Aerospace, decided to combine parts of the Blue Envoy with an existing missile called the Bristol Bloodhound. This created the Bloodhound Mark II, which could fly much farther (about 75 miles). It also had new radar systems that helped it track targets closer to the ground and resist radar jamming.
Unlike Blue Envoy, the Bloodhound missile was expected to see its target throughout the entire flight. The computer had to make very precise calculations for this to work. It also had to figure out the "Doppler shift," which is how the radar signal changes frequency as the target moves. This helped the missile's receiver filter out unwanted signals.
An engineer named Derek Whitehead realized that a digital computer could easily do these complex calculations. He suggested placing these computers at radar sites to help guide the missiles. Whitehead knew about the Argus computer, and soon, the Argus was chosen for this important role. It handled many tasks, from testing the missiles to controlling their launch and even calculating special radar points.
Argus 200 and 100
In 1963, a new version called the Argus 100 was released. It was simpler, with only one ALU, and cost about £20,000 (which is like £430,000 today!). The Argus 100 used a simpler way to find information in its memory, storing both data and program code in one place. Its basic operations took longer, about 72 microseconds. One famous use of the Argus 100 was controlling the Jodrell Bank Mark II telescope in 1964. After the Argus 100 came out, the original Argus design was renamed Argus 200.
The Argus 200 sold 63 machines, and the Argus 100 sold 14.
Argus 300
The Argus 300 was designed starting in 1963 and first delivered in 1965. This was a much faster machine because it could do many calculations at the same time, unlike the older, slower ones. Even though it was faster, its instructions worked just like the Argus 100. The Argus 300 was very popular and used in many factories throughout the 1960s.
A special version, the Argus 350, allowed other devices to access its memory directly. This made it much faster to move information in and out of the computer. The Argus 350 was used in many military training simulators. For example, the Royal Navy used it for training on frigates, submarines, and helicopters. The Royal Air Force used it for a Bloodhound missile simulator and a Vickers VC10 flight simulator.
Newer Argus Computers: Silicon Era
The Argus 400 was designed at the same time as the Argus 300. It was similar to the Argus 100 in how it worked, but it used a completely new electrical system. Older machines used germanium transistors, but the Argus 400 used newer, more reliable silicon transistors. Ferranti also developed special ways to make the circuit boards for this computer, which were quite advanced for 1963. The first Argus 400 was delivered in 1966.
The Argus 500 was designed about three years later and was much faster because it could do calculations in parallel. It was made to fit into a larger frame with up to four memory units. The Argus 400 was also redesigned to fit the same frame, so the two machines could be swapped easily.
Both the Argus 400 and 500 used the same 24-bit instructions and could access 14-bit memory addresses. They both ran at a basic speed of 4 MHz, which was much faster than the older machines' 500 kHz. The Argus 500 was faster than the 400, especially for complex math. For example, dividing numbers took 156 microseconds on the Argus 400 but only 9 microseconds on the Argus 500! Of course, the Argus 500 was also more expensive.
A special programming language called CORAL 66 was created for the Argus 500. This helped engineers program it for industrial control and automation projects.
Argus 500 computers were often used in chemical plants to control processes and in nuclear power stations to monitor systems. They were also used in police control centers, like the one in Glasgow, Scotland. This system even showed police resource locations on maps using slide projectors!
An Argus 400 replaced the Argus 100 at Jodrell Bank in 1971. A special version of the Argus 400 was made for BOAC's seat booking system. The Argus 500 became one of Ferranti's best-selling products. It was especially popular on North Sea oil platforms in the 1970s.
Argus 600 and 700
The next series of Argus computers, the Argus 600 and 700, were completely new designs and not compatible with the older ones.
The Argus 600 was an 8-bit computer. It was made for companies that needed a simpler computer or a programmable control device. It had a basic memory of 1,024 "words" (groups of bits), which could be expanded up to 8,192 words. A simple programming language called ASSIST was developed for it. When it came out in 1970, the Argus 600 cost about £1,700, making it the cheapest digital computer available in the UK at the time. It could connect to larger computers directly or through phone lines.
The Argus 600 was followed by the Argus 700, which used a 16-bit design. The Argus 700 was designed around 1968-1969 and was still being made in the mid-1980s. It was very successful around the world for both factory and military uses. Some Argus 700 computers are still working in British nuclear power stations today (as of 2020)! It was also used to control production for companies like Kodak.
| Model (single processor) |
Approximate Million instructions per second |
|---|---|
| Argus 700 GDL | 0.7 |
| Argus 700 GL | 0.8 |
| Argus 700 GX | 2 |
| Argus 700 GZ | 4 |
The Argus 700 could be set up with multiple processors sharing memory. Different models offered various features, like more memory or faster access for input and output.
The Argus 700 also played an important part in the early development of packet switching networks in the UK. These computers were used by Ferranti in early tests by the General Post Office as the basis for early routers. This is similar to how other computers were used in the US to help develop the Internet.
More than 70 Argus 700G processors were used to control the Torness Nuclear Power Station. This power station had a very advanced control system, including direct digital control of its reactors. When it was first installed, it was probably the most complex computer-controlled nuclear power station in the world.
M700 Series
The M700 series of computers were based on the design and instructions of the Ferranti Argus 700 computers. Both the M700 and Argus 700 computers shared a common set of instructions. This meant they were very compatible, making it easy to swap hardware and software between them. Different companies made various M700 models to fit specific business and application needs.
