Back in the early 80s, I visited the Police National Computer Unit at Hendon in North London. The computer room was the size of a football pitch. Most of the fl

Back in the early 80s, I visited the Police National Computer Unit at Hendon in North London. The computer room was the size of a football pitch. Most of the floor was covered with washing-machine-sized disk-pack drives, along with quite a lot of dedicated IO processors (also washing-machine-sized). The walls were lined with storage for offline disk-packs. This system was a triple Burroughs B7800. What distinguished mainframes from minicomputers back then wasn't their awesome processing power, or their resilience; it was their huge IO capacity. They could handle hundreds of storage devices, and hundreds of thousands of terminals. At least, that's how I was told it; I never worked on mainframes. Nowadays a single connection to the internet can connect you to a similar number of "terminals", and storage is also accessed over a network. So the advantages touted by the author are quite different from what they used to be; IO nowadays isn't the issue it was back then.