Reading Herb Sutter's comments on changes in computer hardware ("The
Free Lunch Is Over", from 2004
(http://www.gotw.ca/publications/concurrency-ddj.htm), and "Welcome
to the Jungle", from 2011
(http://herbsutter.com/welcome-to-the-jungle) led me to think about the computers I have engaged
with over the years.
I had fleeting encounters with computers as a university student;
this was at a time when a whole university had just a handful of
computers. My first real engagement with computers was in the
late 1960s when I got a summer job at a computing laboratory run by
CSIRO, the Commonwealth (of Australia) Scientific and Industrial
Research Organisation. The machine was a Control Data 3200,
which had (I think) 32,000 24-bit words of memory. That is 96
kilobytes (though the byte wasn't in use then), less than one
thousandth of the memory of any video card today, let alone the
memory of a whole computer. It occupied the whole of a large
room, being made of discrete transistors (not integrated circuits,
i.e. "chips"). Input was by punched card, one card per line of
program; you put the bundle of cards in a box, and waited some hours
for the program to be run, since the computer required specialised
human operators. Then you looked at the printed output, found
the missing comma in your program and tried again. The machine
had four magnetic tape units (one tape held about 5 megabytes), and
there was a monstrous line printer. I think there was also a
pen plotter, though I didn't use it. As a great privilege I
got to go once or twice into the machine room and actually sit at
the console and type commands.
Despite all the obvious differences, the basic architecture of both
the hardware and the software was remarkably similar to that which
prevailed across the whole of Sutter's "Free lunch" period, 1975-2005.
There was a single processing unit, a quantity of memory (RAM), and
slower but more capacious external storage, in this case provided by
the magnetic tape drives. I did some programming in assembly
language, and the underlying operations that the machine carried out
(load, store, add, shift, jump, and so forth) are still there,
though the way these operations are carried out inside the CPU has
become much more complex and there are new types of operation (I
don't think there were any stack manipulation instructions then, let
alone vector instructions). The higher-level language
was Fortran, and far as I remember the cycle of compile (separately
for each "compilation unit"), link, load, run was the same as that
still used today with languages like C++.
I went to England for further study, and encountered my first
"departmental" computer, meaning that it belonged to the Mathematics
Department, not the University as a whole. It was a PDP-8
computer, the size of a bar fridge, it had (I think) the
equivalent of 8 kilobytes of memory, and the program was input via paper
tape. I took a course on Lisp using this machine; it was the
first interactive language I encountered, where I could change
things on the fly. Around this time I visited a friend at
Cambridge University and encountered for the first time the
arrangement of numerous terminals connected to a single
computer. By this time integrated circuits were being used,
though the single-chip microprocessor didn't arrive until a little
later. Also hard drives were arriving, though they were the
size of washing machines or bigger.
My working life was spent in University mathematics departments, so computers were always there, though often just in the background. The system of numerous terminals connected to a single computer, probably in
another building, remained dominant for quite some time. For a
while the terminals were teletypes; they physically typed onto
paper. The Control key on computer keyboards dates from the
teletype era: it was used to control the teletype by, for example,
advancing the paper a line (control-J), or ringing the bell on the
teletype (control-G). The resulting non-printing "control
characters" are still used in computer text files. In the 1960s a character set only held 64 characters including the
control characters; there was only room for UPPER CASE
letters. When character sets with 128 characters (7
bits) came into use, lower case letters became available, and
computer output became much more readable.
The teletypes gave way to the ubiquitous green-screen monitors, 80
characters across and 24 or 25 lines deep. What look like
descendants of these can still be seen in shop checkout counters.
At some point the mathematics typesetting program TeX arrived, and
we all became amateur typesetters. Before that, mathematical
typing was done by administrative staff, and it was a specialised
skill, using IBM golfball typewriters. TeX allowed the
production of better-looking results than any typewriter could
achieve, but it wasn't easy to use, and really only people from
mathematics and related disciplines took to it. It was and is
open-source software and remains the standard method of producing
mathematical documents.
The next big change was the spread of personal
computers. The first one of these I got to use was an Apple
II that belonged to a friend. I went round to his place,
and he sat me down in front of the machine and then went out to do
some errand. I knew that in principle I couldn't harm the
computer just by pressing keys, but I was still a bit nervous (it
was expensive). I touched a key, there was a loud bang, and
the computer stopped working. The machine was full of plug-in
cards, and it turned out that a sharp protrusion on one card had
managed to eat its way into a capacitor on a neighbouring card,
resulting in a destructive short circuit.
The first computer that I owned myself (1985) was a Commodore 64;
the name indicated that it had 64 kilobytes of memory in its small
plastic box, that is two thirds of the memory of the room-filling
machine of the late 1960s. It also had an inbuilt
sound synthesiser chip, and it was the only computer I have ever
used that had a genuine random number generator. Usually there
is a pseudo-random number generator, a small program that generates
a determinate sequence of numbers once the starting point is set,
but the Commodore 64 could read the analogue noise generator circuit
in the sound chip, which gave genuine physically-based random
numbers. The Commodore was much cheaper than the Apple, but it
didn't have a floppy disk drive, only a very slow unit that stored
data on audio cassettes. It has been said that the Commodore
64 was the last computer that one person could understand all of; it
even came with a circuit diagram.
These home computers had some of the attributes of a video game
console and certainly helped the evolution of computers into
multi-media machines.
In 1989 the Internet proper arrived in Australia with a satellite
link from Australia to the mainland U.S. via Hawaii, and the
establishment of what was called AARNET by a consortium of
Australian universities and the CSIRO. Previously there had
been more local Australian networks, with international email
available, though not easy to use. A lot of the network
developments happened in University computer science departments,
with mathematics, physics and engineering departments not far
behind. General use outside Universities didn't start in
Australia until about 1993.
At home I bought an Atari, also in 1989; I was getting involved in
electronic music, and the Atari was well adapted for that.
Meantime at work workstations had arrived, desktop computers in
their own right, with much better displays than the old terminals,
and networked together. A little later I got a Sun desktop
computer at work. It had 4 megabytes of memory (I
think), but by default it only had an 80 megabyte hard drive.
This was nowhere near enough, and I got an additional 600 megabyte
disk drive, which cost over $2000. Twenty years later, a drive
with 1,000 times the capacity costs around one twentieth of the
price, not allowing for inflation. I don't think anyone
foresaw this extraordinary increase in hard drive capacity.
The Sun workstation had an additional piece of hardware that could
be used as a sound card, though it was actually a general scientific
data collector. It contained a so-called DSP (Digital Signal
Processor) chip, that for certain purposes was much faster than the
main processor. DSP chips are still used in specialised
applications, including sound cards.
After that the World Wide Web appeared, via the Mosaic
browser. The IBM PC and clones gradually become dominant; at
work they were connected to a central server, and were more likely
to run Linux than Windows. I also used a PC at home; I
changed to the Macintosh in 2006.
A computing-related development that came at work shortly before I retired
was the establishment of an "access grid room", essentially a
well-equipped and well-connected video conferencing room allowing
the sharing of specialised mathematics courses between
universities. Another development late in my working life, and
one related to Sutter's comments, was the building of super-computer
class machines by hooking together a network of 100 or more
PCs. Smaller versions of these clusters were within the
reach of individual University departments or research
centres. I didn't have an excuse to seek access to them.
The electronic computer was born a little before I was, but stored
program machines did not arrive until after I was born, the earliest
electronic computers not being stored-program. The transistor
was also born shortly after I was, so the twin revolutions of
computing as we know it and of micro-electronics have taken place in
my lifetime.
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