Good evening ladies and gentlemen … and computer users.

I'm Eric Lindsay. For a decade before I retired, I was the network and computing support at the School of Mathematical Sciences in the University of Technology, Sydney.

I will be talking about the past, the present, and the future of three areas. These are computers, internet, and the next big thing. I want to explain why digital electronics keeps getting faster, cheaper, lighter, smaller, and more powerful, and when this will have to stop.  Also, I want to briefly mention errors in early models. 

Talk about early computer history. Punch cards. Eniac
Despite everything, Eniac used decimal numbers. It also used patch cords to set up each program. It used decade switches to set numbers. Later computers used punch cards for both program and data. They also used binary arithmetic.

The notes I have seen on doing presentations say to get the audience involved, so I am going to put a problem on the board. I hope some of our school teachers in particular with participate. This means you, Kevin.

What is the date today?    Whiteboard  XXVI X MMX
Now I want you to multiply the first two numbers and add the result to the last.
There is a reason Europe changed from Roman numbers to Arabic numerals around the 9th Century. Easier arithmetic.  Whiteboard 26 x 10 + 2010 = 2270
Positional numbers. Two times ten.

Clive, can I have the lights at 3/10th off?
Electric lights are mostly either on or off. So are the switches in computers. So using numbers based on 0 and 1 makes sense for computers. We call these binary digits, or bit for short.
Positional binary numbers.   Whiteboard Do up to 1111. 

MITS Altair. Notice front panel switches and lights. No keyboard, no display. It did not take long for computers to have ways to connect to a television, or a printer, and have a way to accept keyboard input. This limited set of connectors did not really change for decades.

A whole set of identical integrated circuits are built on silicon wafers. Early wafers were an inch in diameter. Sizes increased over the years to 2, 3, 4, 6, 8 and 12 inches. If you imagine making a pizza, it takes little more preparation time and effort, and no more cooking time, to make a 12 inch pizza instead of a 6 inch one. Everyone gets more to eat. You get more chips from large silicon wafers, so each chip tends to be a little cheaper.