On the face of it, nothing could be simpler than recordable CDs. Pop a disc in a drive, copy some files to it and, hey presto, you have your own disc. The reality, however, can seem far from straightforward and CD recording carries more than its fair share of jargon.

So, if you don't know your burn speeds from your buffer under runs, or think CD-DA is a transvestite teddy boy's haircut, this will explain everything in simple terms.

Disco inferno
Ordinary CD-Roms and audio CDs are pressed in bulk from a glass master disc by an injection moulding process. Making your own discs obviously needs something a little less industrial and that's where the CD recorder drive comes in. There are two types of disc.

CD-R (CD-Recordable): once created - or 'burned', to use the vernacular - the contents of a CD-R disc are permanent, just like a CD-Rom or audio CD you buy in a shop.

CD-Rs that contain computer data can be read by any CD-Rom or DVD-Rom drive, making them ideal for backups or sharing the files on them. Audio CD-Rs can be played in an ordinary CD player, so you can create your own compilation CDs. At less than £1 a piece, blank CD-Rs are cheap too.

CD-RW (CD-Rewritable): CD-RWs are burned in a CD-RW drive but the discs can be reused, just like floppy disks. Data CD-RWs can be read by all but the most ancient CD-Rom and DVD-Rom drives, and it's the same story for audio CD-RWs. A CD-RW drive is also used to burn CD-Rs.

Both CD-R and CD-RW have the same capacity as an ordinary CD-Rom, at 650Mb of data or 74 minutes of audio. CD-Rs are also available in a slightly larger 700Mb capacity, as small 3cm discs and even as low-capacity, credit card-shaped discs.

Speed king
If you have time on your hands, any CD-RW drive will do (CD-R drives have all but disappeared so we won't mention them again) but if not, drive speed becomes an issue.

The speed at which a drive can read from and write to discs is described by three numbers, usually of the form 16 x 12 x 32 and to understand what they mean requires a quick history lesson.

The first CD-Rom drives read discs at a speed of 150Kb/s, which meant it took about 70 minutes to copy a whole 650Mb CD-Rom to a PC's hard disk. Since they were the first drives, they were called 'single-speed' drives.

Double-speed drives were twice as fast, at 300Kb/s; quad-speed drives read discs at 600Kb/s; then came 8-speed, 12-speed, 16-speed and so on.

The fastest CD-Rom drive currently available reads at 40-speed (or 6,000Kb/s) and can copy a CD to a hard disk in just under two minutes. Incidentally, 40-speed and 40x mean the same thing, it's just that one's just shorter to write. Lesson over.

Write speeds are the same as read speeds, except that they describe how fast a drive can write to a blank CD-R or CD-RW. So when a CD-RW drive is described as 16 x 12 x 32, for example, it means it can write to CD-R at 16-speed, CD-RW at 12-speed and read from CD at 32-speed.

The order of these ratings may vary but, at the moment, the highest figure is the CD read speed, the next highest the CD-R write speed, the lowest the CD-RW write speed.

CD-Rs are much quicker to burn than CD-RW because of differences in the materials they're made from but it's always quicker to read from a CD than to write to it.

The faster a drive is, the higher its cost, so it's worth thinking about whether a 32-speed drive than can write an entire CD-R in two minutes is worth paying much more for than a 16-speed drive that does it in four-and-a-half minutes. Faster drives also require blank CDs designed for high-speed use and these cost more than their slower siblings.

Old buffers
When a disc is being burned, the CD-RW drive needs a constant supply of data. If it runs out for any reason, the burning stops. Thanks to the intricacies of CD recording technology, this results in a spoilt, useless disc or, to coin a term, a 'coaster'.

Interruptions in the supply of data usually happen when the computer's hard drive is not able to supply the CD-RW fast enough. To help prevent this, most CD-RW drives have some built-in memory - a buffer - that's topped up with data while being simultaneously emptied for writing.

That way, if the data supply stops for any reason, the CD-RW drive still has data in the buffer that it can use until the supply resumes. If the data is interrupted long enough for the buffer to empty, however, a 'buffer under run' occurs. The burning stops and a coaster is produced.

Buffer under runs were the bane of CD-RW drive users but thankfully, not any more. CD recording technology now incorporates something that's known by the generic term of 'burn-proofing'.

To cut a long story short, this prevents a disc being spoilt even if the burning process is halted for any length of time. It just picks up from where it left off.

Session music
If you have a CD's worth of data to record, you can simply burn it in one go and have done with it. If you've just got a few megabytes, however, storing it on a 650Mb disc is a touch wasteful. Thankfully, there is a solution in the form of 'sessions'.

Sessions allow data to be burned onto a CD in batches and the CD can be used normally in the meantime. You need a multi-session CD-RW drive to use them but all but the oldest drives support this feature.

All CD recording software gives the choice of creating a multi-session disc, or continuing a multi-session if the disc already contains previous sessions. Some software also offers the option of leaving a session 'open' when you've finished.

An open session can't be read on any computer but, as audio CDs can only contain one session, this feature is useful if you're creating audio CDs over a period of time. For computer data though, sessions can be closed as soon as the burning is finished and most software handles this automatically.

Making tracks
Unlike a CD filled with computer files, a CD filled with music (CD-DA - CD-Digital Audio, or simply an 'audio CD') is treated differently. First, a computer - be it a PC or CD player - knows that the files contain audio data for playback purposes and second, the files can't be copied simply by dragging and dropping them.

When it comes to creating an audio CD, there's an additional point to bear in mind. All CD recording software offers two options to create an audio CD: track-at-once and disc-at-once.

Track-at-once writes each music track individually and turns off the laser beam between each one. This results in a two-second gap between each track. Disc-at-once writes all of the tracks in one go, without turning off the laser.

This means that the gaps between tracks can be any length you like or there can be no gap at all and the CD recording software should let you specify your preference.

Cost a packet
So far, we've assumed you're burning a CD using an application such as Easy CD Creator or Nero, where you compile the files you want to burn and then burn them in one or more sessions.

With packet-writing software, however, you can treat a CD-R or CD-RW just like any other type of storage disk and create your CD simply by dragging and dropping files with Windows Explorer.

Before a CD-R or CD-RW can be used for packet writing, it needs to be formatted and, depending on the speed of your drive, this can take some time. Formatting a disc for packet writing also reduces its capacity and this is significant for CD-RW. A 650Mb disc ends up with only 500Mb of useable space.

Burn it up
So there you have it: pretty much all you need to know about burning your own audio and data CDs.

Although we haven't quite covered everything there is to know about recordable CDs, with a bit of luck you will never need to learn about images, mixed-mode discs, ISO or Joliet to be able to start burning your own discs.