Human-Computer Interaction 3e ­ Dix, Finlay, Abowd, Beale

online!    how many computers?

see see page 60. Exercise: how many computers?

The exercise on page 60 reads:

In a group or class do a quick survey:

• How many computers do you have in your home?
• How many computers do you normally carry with you in your pockets or bags?

Collate the answers and see who the techno-freaks are!

Discuss your answers.

If you haven't already worked this out, these were slightly trick questions!

You can see Alan answer this in this video, or read below.

Let's start with:

How many computers do you have in your home?

Did you answer two or three, perhaps a laptop, desktop and maybe an iPad?

Or maybe you are a bit of a geek and had more: several desktop computers, games machines, multiple laptops of various ages? maybe even some retro home computers from the 1980s?

However, do you have a television, HiFi, microwave oven, washnig machines, central heating controller?

Each of these has one or more computers within it - literally computers are all around you.

Here are some in Alan's house:

On recent trains deployed on the British West Coast rail network there are over 200 computers in each carriage - from the obvious ones in the over-seat displays saying which seats have been booked and the electronic doors, to those behind the scenes in the braking system, air conditioning, and lights.

However, now it is not just computers in appliances and embedded in the environment, we also carry many computers around our bodies:

How many computers do you normally carry with you in your pockets or bags?

Alan has emptied his bum bag and this is what he found:

Let's start with some obvious ones:

• USB memory stick
• iPhone (for email, internet, Twitter)
• cheap mobile phone (which is easier to make real phone calls with!)
• digital camera

That's four, but then there are a few less obvious ones:

• chips in credit cards and store cards, and even those that are not chipped, have magnetic stripes or bar codes linking them to the digital world
• intelligent LEDs ... very techie! These are Firefly units, carried around to demo to people rather than be used day-to-day (but one day all lighting may be like this!)
• passport - no idea where the chip is in it, but it is there somewhere (see the little symbol on the cover that says it is an electronic passport), presumably embedded in the cardboard cover
• car keys - the metal key bit is not compterised, but the alarm fob will use some sort of cryptographic code to control the alarm in the car

So, even discounting the intellgent LEDs carried for demo purposes, that is seven different kinds of computer device.

Look in your pockets. You may also have an MP3 player, an entry card for your office, perhaps a bus or train pass with RFID, maybe even eCash.

Our world really is suffused with computation.

text and photos- Alan Dix © 2012