What did computers without screens do?

[Noel Chiappa]

      > From: Mike

      > The one question I do have for the older gentlemen on here is what in
      > the world did the computers without a screen to look at do?

There are a number of different generations, and the way they were used
generally depended on what the computer in question had for I/O capabilities.

In the very earliest machines, the computations tended to be mathematical
modeling; things that needed a lot of computing, but had very modest I/O
requirements. The classic example was the hydrogen bomb calculations
performed on ENIAC (which was originally built to do ballistics
computations), but other similar ones included structural modeling, etc.

That class of application continued (and does so, to this day), but over
time, more and more things got done using computers, as their capabilities
(online storage, I/O, etc) grew. In general, the new applications were added
to the existing ones, but did not supplant the earlier ones.

Starting with a computer in England called LEO:

  https://en.wikipedia.org/wiki/LEO_(computer)

they were also applied to business applications (inventory, payroll, billing,
etc), which typically did more modest computations, but more I/O, which
required better I/O capability (cards, tapes, printers, etc).

With the advent of timesharing in the early 1960's, it became common to add
individual character-output terminals (initially printing, moving mostly to
video terminals circa the mid-70's), and with the ability of users to
interact with applications running on a computer, applications broadened even
further; online text preparation was one common one.

The final phase came with the introduction of bit-mapped video terminals,
which allowed the interactive users to use graphics, and images; the very
earliest such systems were on time-sharing mainframes, but with the growth of
personal computers, that technology migrated there (note that the very
earlist PC's had only character-output terminals, mimicing their main-frame
big brothers of the time).

	Noel