Code and ciphers: Julius Caesar, the Enigma and the internet

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chapter 12
as finding if the binary representation of a number contained just one
non-zero bit. It was, of course, a very exciting era for those who were
involved. It seemed that there was no need for large numbers of computers;
one estimate was that six machines of the power of the Manchester
computer would suffice for the whole world. It also seemed that programming
computers would remain an esoteric art accessible only to an elite. It
is doubtful if anyone could even imagine the tremendous advances that
would transform the computing situation within a few years.
The changes came swiftly. Within a few years programmers, tiring of
writing the same chunks of absolute machine code time after time, developed
compilers for what became known as higher level languages. Some of
these were specific to particular types of machines but before long others,
such as fortran, which stood for ‘formula translation’, became widely
available. These made it possible for programs to be written by many
more people, and in a much shorter time than hitherto, since large tracts
of machine code could now be produced by writing a few lines in the
higher level language. At the same time the technology was changing
rapidly, cathode ray tubes and delay lines were replaced by core store
memories which were faster and more reliable as well as providing far
greater capacity in a lot less space. Valves were replaced by transistors and
this soon led to integrated circuits with hundreds, then thousands, then
millions of transistors on a few square centimetres of silicon which
replaced bulky circuit boards. Within 20 years computer speeds had
increased a thousandfold and memory capacities a hundredfold. There
were myriads of programmers around the world, and countless numbers
of others who used ‘packages’ for word-processing, spread-sheets or just
‘games’, on the computers without having any idea of the hundreds of
thousands of lines of machine code that they were invoking.
Another major advance started in the 1960s when ‘multi-access’ computing,
in which many people used teletypes connected to a mainframe
computer, was developed and within a few years networks of computers
were established, allowing people to have access to more than one
machine and to communicate with others in distant places. The benefits
were obvious and people in different continents not only sent ‘electronic
mail’ to each other but also collaborated in research without ever actually
meeting. The cost of computers also fell, not just in real terms but in absolute
terms, by factors of 100 or more. All this rapidly became history and
might have been lost in the mists of time but some accounts of the history
of computing up to about 1980 were published and so preserved at least