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Monday, 6 March 2017

Alt-0247 and Rule: the Ed Sheeran Prize for Computer Science Education

Perhaps there should be a new category at the next Brits, the award for the year’s most outstanding contribution to computer science education, the first winner to be Ed Sheeran for his new album ÷ (pronounced Divide). This follows up his previous albums (or LPs as I still call them) + (Plus) and × (Multiply).

In trying to search for the new album, my daughter was frustrated by the lack of a ÷ key on her computer. She was about to go through the tedious procedure of using the ‘Insert Symbol’ menu in Microsoft Word to create one, which she could then copy and paste into the search box, when I said “Just type Alt-0247”, and the stargate opened into a whole new world of understanding. Ed Sheeran’s title had brilliantly illustrated the concept that everything you do on a computer has an underlying numerical representation.

The concept is ASCII – the American Standard Code for Information Exchange. I found it extremely useful in the early nineteen-eighties in working with Tandy TRS-80 and BBC computers, when I had the dubious honour of being the author of an educational computer program called Munchymaths.

ASCII had been developed twenty years earlier by IBM’s Bob Bemer and the American National Standards Institute (ANSI) as a standard way to represent characters in computers. It allows computers to communicate with each other.

In ASCII, the divide (or obelus) symbol is represented by the number 247, and can be produced by typing Alt-0247 on the number keypad.

To do it, hold down the Alt key while typing 0247 on the number pad, (number lock must be switched on), and the ÷ symbol appears when you release the Alt key. Some of us know this, and some of us don’t. It’s the Great Alt-0247.

Here are some other well known phrases or sayings in ASCII format:

  • To be, or not to be; that is the Alt-63
  • We hold these truths to be self-evident, that all men are created Alt-61
  • Alt-62 love hath no man than this
  • To see the World in a Grain of Sand, And a Heaven in a Wild Flower, Hold Alt-8734 in the palm of your hand, And Eternity in an hour

Apologies if some or all of these symbols do not work or render as intended on your device. They appear correctly in the most used fonts in Windows 10 on Microsoft computers, but different devices, software and font selections use different codes. There are now several versions of the extended ASCII table to provide for the enormous number of characters computers are called upon to represent, such as  ê   €  Œ   ¶  and so on. The infinity symbol ∞ is particularly troublesome. Unfortunately, ASCII is not as standard as it could or should be.

Furthermore, ASCII is only an intermediate representation to make things easier for us stupid humans to understand. Underneath ASCII there are lower-level concepts such as octal, hexadecimal and binary, but let’s not go there now.

Ed Sheeran, however, is always going to be spoilt for choice for new album titles.

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