A change in the unit reading policy of file sizes in Ubuntu 10.04 is causing some confusion amongst early adopters.
Previously Ubuntu showed 1MB as 1024 (1 MiB). Now it displays 1MB to be 1000kB.
Example
An Ubuntu .iso will now read 708MB in Lucid but 675MB in Karmic.
Result
Jenny Silver notices her freshly download Ubuntu .iso is 708MB. Alarm bells ring: her CD-R has ‘700MB capacity’ written on it. Does this mean she’ll have to use a DVD-R instead?
It’s actually all okay
In reality, no. In fact when tries to burn the .iso she’ll see she has actually has 25MB free on her “700MB” disc. This is because despite file sizes in Nautilus now being displayed “correctly” various applications still use the old unit reading. Her 700MB disc is, actually, 734 MB.
There is a ‘bug’ on this that can be found @ Bug #315913
Thank to Miguel