Architecture and Hardware

The Computer That Got Down to Business

ICT 1301
Programmers used dials and switches to issue commands to Flossie.

In October, The National Museum of Computing (TNMOC) in Milton Keynes, U.K., took possession of one of the first computers to be mass-produced for business applications. The 5.5-ton machine, nicknamed "Flossie," is an ICT 1301, made in the early 1960s by the company then known as International Computers and Tabulators.

One of the first solid-state computers, the ICT 1301 used over 16,000 discrete germanium transistors, which helped it avoid the dedicated rooms and raised floors required by earlier computers based on vacuum tubes. "It’s a key machine, especially in the history of business computing," says museum trustee Kevin Murrell. "Machines before this were quite often based on laboratory systems."

The Computer Conservation Society had resurrected Flossie, but moving it to its new home required that it be dismantled. The machine should be capable of demonstrations such as handling punch cards and printing fairly quickly, Murrell says, but it will probably be several years before it can run applications.

Still, "having the machines working is very important," both for academic reasons and because it "brings these machines to life," says Murrell. "There’s very little more boring than a computer that’s switched off." He says a critical difference between TNMOC and the Computer History Museum in Mountain View, Calif., which also has a large collection of early computers, is that "we’re very keen to have the machines on and running."

"It’s fascinating to see the machine work, and it’s fascinating for the hardware engineers getting the machine working again," Murrell says, but it is equally interesting "restoring the original software and understanding the constraints of programming in the late 50s, early 60s, with the amount of memory that they had, and actually doing useful proper programs," such as payroll, inventory, and accounts payable. Although the museum team has the original programming manuals, the work will be tedious, because the machine uses a pseudo-assembly code rather than a high-level language.

In addition, in spite of the museum’s best efforts, "this machine will not be running forever," Murrell admits. So "one important thing that we will do is build an absolutely accurate simulation of this machine and emulate this machine in software at the discrete logic-gate level, so we can have an accurate representation of how the machine worked, and then we can verify that simulation against the physical machine."

Naturally, the U.K. museum tends to highlight British contributions to computer history, back to its origins in the World-War-II cryptography work of Alan Turing and his colleagues.

TNMOC is located about 70 kilometers northwest of London at Bletchley Park, the estate that housed the U.K.’s wartime code-breaking operation. But the museum operates as a registered charity, financially separate from the Bletchley Park Trust.

Flossie joins the museum’s array of early computers, including the tube-based Colossus machine that helped decipher messages between Hitler and his generals. The Lorenz encryption scheme used for these messages was much more complex than that based on the famous Enigma machine, which could be broken by electromechanical means. Colussus employed much more powerful electronic capabilities, which were so advanced that the project was kept classified until the 1970s. TNMOC has had a working Colossus, generally regarded as the first programmable digital electronic computer, since 2007.

Don Monroe is a science and technology writer based in Murray Hill, N.J.



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