Once upon a time, when the world was very young, you used to be able to buy an entertainment appliance, take it home, plug it in, and then use it for the next 15 years with nary a thought.

But computers, in all their many forms, have all but completely replaced ‘dumb’ electronics, and while it’s great that your TV can now display your photographs directly from a flash memory card or via USB connection, this new age brings new complications.

If you own a PVR, or a games console, or even one of the earlier digital set-top boxes, you probably read the manual, got to the chapter on ‘firmware’, and then put it aside before it could give you the Fear.

And why not: strange and terrible things were spoken of between those pages. Connecting your TV tuner to the internet so you can download software to make it work better, what kind of crazy talk is that?

But this is the world in which we live, where every appliance that does more than make bread brown and crispy (and even a couple of those) is actually, in some way, a computer running an operating system.

What is firmware?

Some definitions first. Thanks to nearly three decades of personal computers, we’re now all familiar with the difference between hardware (the physical machinery of the PC) and software (the programs you load onto it to do stuff). But there’s another tier of ‘ware’ in the middle called firmware.

It’s called firmware because it’s not quite hard and not quite soft. It’s stored semi-permanently on chips that cannot be removed from the computer, and needs special commands and procedures to be changed or overwritten.

The firmware is where computers store their most important, most basic operating instructions. The firmware tells your desktop PC to look for Windows when you switch it on. It explains how the keyboard and mouse connect to the computer, and it sends a video signal to the display.

There are equivalent firmware jobs for your entertainment appliances too. Though in some senses, firmware on a set-top box or a PVR is more like Windows – it runs the onscreen display and makes sure when you press a button on the remote, something actually happens.

Updating firmware involves writing information to a special chip on the device’s motherboard. Unlike a hard drive or flash memory card, it’s very hard to erase the information on this chip. In fact it can only be done with a special electrical signal. So it’s not quite hard, it’s certainly not soft. It’s in between: firm.

What does it do?

The question is, why would you want to mess around with firmware? Why can’t it just be loaded on at the factory and then forgotten about?

The thing is, once devices go out into the market and real people start using them, manufacturers can observe and improve on the device. In the bad old days, if they saw their TV had a design flaw in the way you changed channels, it was a case of bad luck for the owners of the TV, and good luck for people who bought the next year’s model.

While that kind of thing still goes on, firmware updates allow users to improve their device without having to shell out cash for a new one.

PVR crashing a lot? Timer function awkward to program? Look for a firmware update: it may solve the problem. Where you see firmware updates most predominantly is on games consoles. The PlayStation 3 in particular receives regular updates, which you download via its wireless network adaptor or Ethernet port, as simple as selecting a menu item and pressing ‘X’.