One problem with DVD recorders is that the industry never really standardised on one writable DVD format. Instead, the market is split in half between plus and minus formats. There are currently five different kinds of writable DVD: DVD-R, DVD-RW, DVD+R, DVD+RW and DVD-RAM.

That might look like a bit of a mess, but it becomes clearer once you understand what the different parts of the names mean. The R stands for recordable, while RW stands for re-writable. Recordable discs can only be written to once (and if it goes wrong, you have to just throw them away), while re-writable discs can be erased and written on again and again.

The plus and the minus just represent different standards that are being used for the format: a DVD-R is pretty much the same thing as a DVD+R, except that they are incompatible with one another. The biggest advantage of plus over minus is that plus discs dont always need to be finalised, meaning that you dont have to wait for the drive to make them usable before you can play them back or remove them.

However, apart from that, the differences between the formats are really negligible they represent a political split in electronics manufacturers more than anything else. Because of this, most people buy recorders that can handle all the different formats and just buy whichever discs are cheapest, eliminating the problem altogether.

DVD-RAM is a bit of a special case, as it doesnt really fit into the range of formats you would expect. A DVD-RAM doesnt really look like a DVD, as it is a DVD inside a special case, making it resemble a large floppy disk. DVD-RAM is a more reliable format that can handle errors better than the other two re-writable formats, and will last much, much longer. Unfortunately, these discs are also about 50% more expensive than the others, and most recorders do not support them.