Andrew and Kathleen Booth

Being a woman is a terribly difficult trade since it consists principally of dealings with men.
Joseph Conrad

Andrew Booth and Kathleen Britten programming their first computer-ARC, London, Nov. 1946
Andrew Booth and Kathleen Britten wiring their first computer-ARC, London, Nov. 1946

In 1946, Kathleen Hylda Valerie Britten, a young 24 y. o. BSc in mathematics (1944) from the University of London, joined a team of mathematicians at London’s Birkbeck College who were performing calculations for scientists using X-ray images to determine crystal structures. There she met Andrew Donald Booth (1918-2009), a Ph.D. in crystallography, whom she is going to marry in 1950.

In those days crystallographic research required huge amounts of laborious analysis and calculation with desk calculators, so Booth was sent to the US to learn about developments in computing. He visited many of the computers that were under development in the US, returning to Birkbeck in 1946, where he and Britten collaborated on a very early digital computer, the Automatic Relay Calculator (ARC). Booth designed it, but Kathleen and her fellow research assistant Xenia Sweeting built the hardware.

In 1947 Booth returned to the US together with Britten, for 6 months to take up a Rockefeller Fellowship at the Institute of Advanced Study at Princeton, where John von Neumann explained his concept of what is now called the von Neumann computer architecture. Booth and Britten returned to the UK, where they wrote an interesting article for all purpose computer, and redesigned their ARC calculator based on these ideas, leading to the ARC2 and in the process inventing a drum memory to provide enough storage to hold both program information and data. Building the ARC2 from relays proved too much, so in 1948, Booth and Britten moved on to the Simple Electronic Computer (SEC) and then the All Purpose Electronic X-Ray Computer or APE(X)C.

Andrew and Kathleen Booth in 2007
Andrew and Kathleen Booth in 2007

In 1950, Kathleen and Andrew married, the same year that she got a PhD in applied mathematics, again from the University of London. To secure further funding for their work, the Booths again went to the Rockefeller Foundation, which provided it on condition that the APE(C)X worked with human languages as well as just mathematics. The result was a demonstration of machine translation in November 1955. As well as building the hardware for the first machines, Kathleen wrote all the software for the ARC2 and SEC machines, in the process inventing what she called Contracted Notation. This language, through evolution and contributions by others, is today known as assembly language.

The Booth family moved to Canada in the early 1960s, where Kathleen and Andrew continued working in academia until their retirement in 1978 when the couple founded a computer consulting business on Vancouver Island. They had remarkably long and meaningful life (Andrew died at 91 in 2009, and Kathleen died at 100 in 2022), let’s mention some of their achievements:
• Several early British computers (Andrew)
• Booth’s multiplication algorithm (Andrew)
• An early rotating storage device (Andrew)
• First assembler program, bootstrapping software development up from machine code in binary to simple logical instructions (Kathleen)
• A natural language translation program in the mid-1950s translating from French into English (Kathleen)
• One of the first books on programming: Programming for an Automatic Digital Computer (1958) (Kathleen)
For Booth’s achievements in England, see the interesting material of Roger G. Johnson.