Andy Larkham – History of Computing

15th May 2026

A Journey Through the History of Computing

At our latest Probus meeting, we welcomed back Andy Larkham, who had previously spoken to the club on the history of telephony. This time his subject was broader still: the history of computing, a story that took us from mechanical calculators and punch cards through to home computers, smartphones and artificial intelligence.

Andy began with Charles Babbage, often described as the father of computing, whose 19th-century Difference Engine was designed to calculate mathematical tables mechanically. Although Babbage never saw his machine completed, a later reconstruction proved that his ideas were sound.

From there, the talk moved through the great milestones of computing: IBM mainframes, punch cards, magnetic core memory, tape drives, floppy disks, hard drives and the astonishing increase in storage capacity. Andy illustrated this beautifully with examples familiar to many in the room — from 8-inch floppy disks and zip drives to the tiny USB memory sticks that can now hold what once required rooms full of equipment.

The early days of home computing brought back plenty of memories. Andy recalled machines such as the Commodore PET, Sinclair ZX80/ZX81, Amstrad 1512, and his own NASCOM 1, bought in 1979 and assembled by hand with over a thousand solder joints. These were the machines that introduced a generation to programming, BASIC, cassette storage and the occasional frustration of losing everything when a memory pack wobbled.

The talk also touched on the people behind computing history, including Katherine Johnson, whose calculations helped NASA’s space programme, Margaret Hamilton,

who led the software team for the Apollo guidance computer, and Grace Hopper, associated with the famous story of the first computer “bug”.

Andy then brought the story forward to the modern age: Moore’s Law, the rise of Microsoft, the personal computer revolution, the Millennium Bug, computer animation in Toy Story, smartphones, social media and finally artificial intelligence. His closing section raised some thought-provoking questions about AI, autonomous vehicles and the difficult decisions that machines may one day be expected to make.

It was a wide-ranging and entertaining talk, full of technical insight, humour and nostalgia. For many members, it was also a reminder of just how quickly computing has moved from room-sized machines and punched cards to the powerful devices now sitting in our pockets.

Members then enjoyed a formal Spanish themed lunch and a good hour of conversation, with the usual funny stories and questionable jokes!

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