Comfort for Application Developers from Tom de Marco

Thanks to a tweet from @flowchainsensei, I've just been enjoying an excellent article by Tom de Marco. It's well worth a read; I took away two key thoughts.

1. Developing software is much harder than developing hardware
2. Software developers spend much of their life feeling bad about late delivery when it's usually not their fault.

To put his core conclusion another way, most software projects are a waste of effort. They have such low marginal utility that they are doomed never to show a return for the organisation that funds them. If we just didn't do them the world would be better off.

Of course, we'd need to find work for the ex-developers.  Maybe they could learn to teach. We could certainly use a few more skilled IT teachers.

I2C on the Beagleboard xM

It's really easy driving I2C™ devices from the Beagleboard. I'm using the Trainer-xM from tincantools; that takes care of shifting voltage levels from the 1.8v used by the Beagleboard to the 5v levels that my I2C boards expect.

There are a few I2C coding examples on the web; since my BB image includes python and geany, I've written the I2C code in Python and can edit and test it on the board. Much faster than an edit-compile-upload-test cycle.

Here's the code:

import i2c, time

extender = i2c.I2C_device(0x20)
extender.begin_transmission()
extender.send(chr(0))
time.sleep(5)
for count in range(0, 16):
    extender.send(chr(count))
    time.sleep(0.5)
extender.end_transmission()

See it running.

From little Acorns do great Raspberries grow

I recently re-discovered an old friend: the great-great-grandfather of the ARM-based Raspberry Pi . It's the original Acorn micro-computer (ca. 1979). Acorn went to on make a succession of machines, including the BBC Micro and the Archimedes.

The Archimedes was based on a proprietary RISC chip which is the grandfather of today's ARM chips. The Raspberry Pi is part-funded by Dave Braben, who wrote Elite (arguably the most famous BBC micro game). Broadcom, who are make the Pi's ARM chip, have strong historic links with Acorn.

I'll try the micro out in a day or two; I still have the (fairly minimal) original documentation, and there is more information on Wikipedia. The micro was arguably one of the best investments made by Cocking and Drury; my colleague Jonathan Barman used it to learn assembler, and went on to master 370 Assembler, through which he landed us a major contract with a national brewery.