Metrovick 950 facts for kids
| Manufacturer | Metropolitan-Vickers |
|---|---|
| Release date | 1956 |
The Metrovick 950 was an early computer. It was special because it used transistors instead of big, hot vacuum tubes. This made it smaller and use less power. The British company Metropolitan-Vickers built these computers starting in 1956. They made about six or seven of them. These machines were mostly used inside the company itself. The Metrovick 950 was the first and last computer model that Metropolitan-Vickers sold.
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What is a Transistor Computer?
A transistor computer uses tiny electronic parts called transistors. These parts act like switches. Before transistors, computers used vacuum tubes. Tubes were much bigger and used a lot of electricity. They also got very hot and broke easily. Transistors made computers smaller, faster, and more reliable.
Building the First Transistor Computer
In 1953, two smart people, Richard Grimsdale and Douglas Webb, built a test computer. They worked at Manchester University in the UK. Their goal was to see if transistors could make computers more dependable. They used 92 point-contact transistors and 550 diodes. This test machine was similar to an older computer called the Manchester Mark 1.
The prototype computer did not use Williams tubes for memory. Instead, it used a magnetic drum for all its storage. This drum was actually reused from the Manchester Mark 1. The computer worked with 48-bit "words" of data. However, four of these bits were used for timing. This meant only 44 bits were available for programs.
How the Prototype Worked
The only way this computer stored information was on a drum. This meant it took a bit longer to find data. Imagine looking for a specific song on a record album. You have to wait for the right part of the record to spin around. This computer was slower than the Mark 1 because it lacked faster memory.
Both versions of the computer used a special way to run programs. Each instruction told the computer where to find the next instruction. This helped the computer run programs more efficiently. Even important parts like the calculator (called the Accumulator) were stored on the drum.
An Improved Version of the Computer
By 1955, the design was made better. The new version had a special part called a B-line. This part helped the computer do calculations and keep track of things. It also had a hardware multiplier, which made multiplying numbers faster.
The improved machine used 250 transistors in total. It only needed 150 watts of power to run. This was amazing for its time! Older computers with vacuum tubes often used tens of thousands of watts. The new model could add two 44-bit numbers very quickly. It took about 30 milliseconds for each addition. Even though it was faster inside, it still ran slower overall than the Mark I. This was because it didn't have the fast Williams tubes.
The first prototype computer had a simple set of seven commands. It could store 64 words of data. The full-size computer from 1955 had many more commands. It also had much more storage. It even had a special drum track for faster access to 8 words of data.
The expanded 1955 machine had 200 point-contact transistors. It also had 1300 point diodes. Its power use was still very low at 150 watts. However, the early transistors had problems. The computer could only run without errors for about 1.5 hours on average in 1955.
The Metrovick 950 Computer
Metropolitan-Vickers became interested in this computer design. They saw how successful Manchester University was selling time on their Mark I computer. So, Metropolitan-Vickers decided to use the 1955 Manchester University design. They called their version the Metrovick 950.
Metropolitan-Vickers had some experience with calculating machines. In the 1930s, they built a mechanical calculator. This was done with Douglas Hartree from Manchester University.
For the Metrovick 950, they changed the circuits. They used more reliable types of junction transistors. It seems they might have built one machine with the older transistor types first. The company built six or seven Metrovick 950 machines from 1956 onwards. These computers were mainly used for tasks within the company.
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