What is hardware? What is software?

Hardware is anything you can kick: all of the real, physical bits of a computer system. The screen's hardware, the keyboard is hardware, and all the bits inside the main box and the box itself—they're all hardware. Even if you have a furry mouse: it may be soft, but it's not software.

Software, on the other hand, is a lot more slippery. It comprises instructions followed by the computer—software is any bit of a computer system that only exists as data.

All programs are software, and all software is, in some sense, a program. Applications like text editors and web browsers are classic examples of software. But most of the workings of a mobile phone are software too; and so are video recorders' (infamously awkward) interfaces.

All of those esoteric things I wrote about before that are actually computers all run software; there are at least as many different types of software as there are kinds of computer.

So all of my documents are software, right?

Not really. Your documents are… well, documents—they just happen to be written in an electronic binary form that a computer can read and a human can't (without the help of a computer).

Let's say you have a document that reads something like:

A fox and a dog jumped about a bit together …or something—I wasn't really paying attention.

That's definitely a document: it's just a wodge of text. A program, however, would look more like:

PRINT "A fox and a dog jumped about a bit together …or something—I wasn't really paying attention."

See that PRINT? That's an instruction—and that makes it software, because it's telling the computer what to do.

Programs are like a list of verbs for the computer—things to do; whereas documents are just things—nouns.

If you show an idiot a car (a noun), they won't know what to do with it until you say “drive!” (a verb). Similarly, if you give a computer a document, it'll just stare at you blankly, maybe beep a bit, until you tell it what to do with the document.

That's what software does—it tells the computer what to do.

What is a computer?

It's a little less obvious than it seems, actually. A computer is any machine that deals with information. That's a pretty broad definition, and it includes things like calculators, TVs, digital music players, mobile phones and even cars.

Each of these is specialised—it's only designed to do one specific thing: manipulate numbers; show moving pictures with sound; play music; talk to other people; and... deal with car stuff..., respectively. (What does an in-car computer do, anyway?)

Usually, though, when someone talks about a “computer” they mean a personal computer.

So what’s a personal computer, then?

Unlike the computers inside calculators and videos and things, a PC is a generic computer—it's designed to be able to do lots of different things: you can draw pictures with a PC, read prose, play games, record sound, play video, calculate pi, cure cancer...

A computer is the whole system: it's made up of lots of different parts, each with its own function. The central processing unit (CPU) is the main brain—it does most of the thinking; the memory (or “RAM”) stores the things the CPU is thinking about at the moment; there's also usually a long-term storage device, typically a hard disc, which holds everything that needs to be kept (so, all your stuff); there'll be a means for you to talk to the computer, typically a keyboard and mouse; and a means for the computer to talk to you, typically a screen (or “monitor”) and some speakers. (I'll go into more detail about each of these later.)

Convergence

Recently (in the 2000s), things that weren't generic computers have started to become more generic—everything's converging towards being a computer. For example, mobile phones used to only be able to make phone calls and send text messages; now they can also store notes, play music and video, browse the web, and transfer all kinds of information to many other devices.

The computing power of small portable devices is fast approaching the level that a full-blown desktop PC might have had not too long ago. My computer's about ten years old; apart from their smaller screens, many modern “smartphones” have very similar technical specifications to it.

It's this abundance of computing power that's allowed specialised devices to become more generic and more capable; and so a lot more things can nowadays be usefully considered a “computer”.