The short version: Why can't I burn common ISO files on to regular CDs?
The longer version:
I have a stack of CD-Rs, with discs from two different brands. I also have two ISO files with Ubuntu 10.04 and 08.04.
Since CDs and the ISOs are both, as far as I'm aware, old and well established standards, I would expect this to "just work".
However, with both brands of discs, neither images can be burned to the discs, as CDBurnerXP claims the discs fit only 689.64 MB while the ISO sizes are 699.95/694.42 MB.
If I made the ISOs myself, this could easily be be written off as a mistake on my part, but since we're talking about files that are probably downloaded by the hundredthousands or millions, I'm assuming this should work.
In reponse to the comment, these are my assumptions:
- CDs are (nearly) always of the same size, 700mb. (They used to be 650, and there are rare exceptions of 800MB, but neither are common today).
- Canonical creates ISOs that aim to reach the broadest possible audience, so they create 700mb ISOs.
- The ISO files from assumption 2, should be burnable onto discs in assumption 1.
Yet I find myself with a very small difference between disc size and file size, that I can't explain, mostly because my 700mb discs can't actually fit a 700mb file.