ICT 1301 facts for kids
The ICT 1301 was an early computer built by a company called International Computers and Tabulators (ICT). It was designed for businesses. Imagine a computer from the 1960s! These machines used special types of memory like core memory and drum storage. They also used punched cards to put information in and get it out.
What made the ICT 1301 special was that it used decimal logic. This means it worked with numbers based on 10, just like we do every day. Most computers then (and now) use binary logic, which is based on 0s and 1s.
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What Was the ICT 1301 Like?
The 1301 was the main computer in its series. Its main memory, called core memory, held information in blocks of 400 words. Each word was like a small chunk of data, made of 48 bits. This was enough to store 12 decimal numbers. The computer could have up to 4,000 words of memory. This was the first time ICT used core memory in their machines.
For storing larger amounts of information, the 1301 used a magnetic drum. You could also add optional magnetic tape systems. These tapes came in different widths.
To get information into the computer, you would use 80-column punched cards. Sometimes, 160-column cards or punched paper tape were also used. For getting information out, the computer could punch 80-column cards, print on a line printer, or punch paper tape.
The 1301 worked at a speed of 1 megahertz (MHz). Its arithmetic logic unit (ALU), which does all the math, processed data in a special way. It handled the 48-bit words four bits at a time. A simple addition took 21 clock cycles. More complex math like multiplication and division took longer.
A typical 1301 computer needed a lot of space, about 700 square feet (65 square metres). It also weighed around 5.5 tons! It used a lot of electricity, about 13,000 kVA of three-phase electric power. Inside, it had over 4,000 printed circuit boards. These boards were filled with many electronic parts like germanium diodes and transistors. There were also resistors, capacitors, and inductors. A few vacuum tubes and relays were also used, especially when buttons were pressed. Integrated circuits, which are tiny chips with many parts, were not yet available for sale.
How the ICT 1301 Was Made
The ICT 1301 was designed by a company called Computer Developments Limited (CDL). This company was a joint effort between ICT and another company called GEC. CDL started in 1956 at GEC's factory in Coventry, England. Later, ICT took over CDL. Even so, the 1301 computers were built at the GEC factory. This was because ICT didn't have the right factories to build them at the time.
The computer was first announced in May 1960. However, the work to create it had started much earlier. The very first ICT 1301 was delivered to a customer in 1962. This first machine went to the University of London.
One of the best things about these computers was their ability to handle British money calculations directly. This included pounds, shillings, and pence. This was a big help for businesses in the UK. Another great feature was that programmers didn't need to learn binary or octal numbers. The computer's instructions were all in decimal, and its math unit only worked with decimal numbers or British currency. The computer at London University was even fixed up and made to work again by a group of computer fans in 2012!
More than 200 of these computers were sold. This made the ICT 1301 the most popular British computer of its time. If it had been developed faster, it might have been even more successful.
Parts That Connected to the Computer
Standard Parts
The card reader could read 600 standard punched cards every minute. Each card could hold up to 80 characters. The card punch could create 100 new cards per minute.
The line printer could print 600 lines of text per minute. Each line could have 120 characters. It used a special spinning barrel with 120 print wheels. Each wheel had 50 characters on its edge. When a character needed to be printed, a small hammer would quickly press the paper and an inked ribbon against the spinning barrel. This created the print. This printer is thought to be the first commercially made barrel printer.
A magnetic drum could store 12,000 words of data. It also had a special area of 400 words. This area stored the computer's starting program, called "Initial Orders" back then. You could connect up to 8 drums to the computer. It took about 5.7 milliseconds to find data on the drum.
Optional Parts
The standard magnetic tape system used half-inch-wide tape. It had ten tracks for data. Four tracks held the data, and four more held the opposite of that data. There was also a special bit to check for errors. This system could fix small errors and find bigger ones. You could connect up to eight tape machines. These machines could read data very fast, at 22,500 digits per second. The tape reels were a special three-prong design.
There was also a "High Speed" magnetic tape system. This used one-inch-wide tape and was even faster. It had sixteen tracks and could transfer 90,000 digits per second. Like the standard system, it could also correct and detect errors. These tape reels also used the three-prong design.
A system using quarter-inch magnetic tape was also available. This one had a single head for writing data and two heads for reading it. The two reading heads each read from half the width of the tape. Each number was stored using two magnetic changes on the tape. This meant the amount of data a tape could hold depended on the data itself. Interestingly, damaged parts of these tapes could be used with regular audio tape recorders, so they were often recycled!
You could connect one or two paper-tape readers. Each could read 1,000 characters per second. A paper-tape punch was also available, which could create 300 characters per second.
An online teleprinter was an option, but very few computers had them. Later on, a special connection was added to the 1301. This allowed it to write data to the newer, industry-standard magnetic tapes.
ICT 1300 Computer
The ICT 1300 was a smaller version of the 1301. It was almost the same, but its card reader was slower, reading only 300 cards per minute. Its line printer was also slower, printing 300 lines per minute. The 1300 usually came with less core memory and drum storage. It often didn't include magnetic tape systems. A drum with fewer reading and writing parts was often used, providing 3,000 words of storage.
ICT 1302 Computer
The ICT 1302 was a bigger version of the 1301. It included a new standard way to connect other devices. This new connection system was later used on the ICT 1900 series of computers.
Where Are ICT 1301 Computers Now?
Very few ICT 1301 computers still exist today. Sadly, none of them are currently working.
One ICT 1301, nicknamed "Flossie," is stored at The National Museum of Computing in Bletchley Park, England. This computer was originally used to calculate exam results for students at the University of London. People hope that one day, Flossie will be fixed and made to work again.
Another ICT 1301 is on display at the Toitū Otago Settlers Museum in Dunedin, New Zealand. This computer is almost working. It was the first computer in Dunedin. It was used by the Cadbury chocolate factory to calculate bills and employee payments.
There is a third machine named Arthur in Cumbria, UK. This computer belongs to the Time-Line Computer Archive museum. It is almost complete, but it is not working.
