In February 1971 I was twenty years old, and on my passport I was finally able to put Computer Programmer as my job title instead of Student. Geoff, my first line manager, had been part of the team who prepared the original PL/I Language Specification. It was a strange feeling, writing code in a language whose grammar had been shaped by the man sitting at the next desk.
The team had modified the existing PL/I Rolls‑Royce payroll system so it could handle decimal currency instead of pounds, shillings and pence.
As a Trainee I had been converting PICTURE format specifications from sterling to decimal. It was meticulous work — half archaeology, half translation — and I often wondered how much effort the PL/I compiler writers must have poured into supporting pounds, shillings and pence on a payslip. And how short‑lived their efforts had been. A whole subsystem built to preserve a monetary system that vanished almost overnight.
A whole machinery of formatting rules, symbol tables, and runtime behaviours — all built to print £‑s‑d neatly on a payslip. Decimalisation simplified the arithmetic, but it left behind a small archaeological dig in every PL/I shop in the country.
One function of the payroll system was coin analysis. Imagine thirty thousand workers being paid weekly in cash payslips. If a particular worker's payment were exactly twenty pounds, two ten-pound notes was not acceptable. Rules existed about minimum coinage quantity, in case the worker wished to buy something cheap on the way home.
In addition to allocating coinage to individual payslips, the coin totals were needed to allow coinage to be supplied by the bank. I imagined someone taking an empty big bag to the bank, filling it with coins and notes, and then delivering to a room full of payslip stuffers.
These rules became much simpler after decimalisation, because all the arithmetic became base-10 - use of base-12 and base-20 was no longer required. The original PL/I programmer's work was literally decimated!
All that engineering, all that care — gone in a single February morning.