|
Compression like a archive may save space, but you end up having to unpack the data before you can use it... I know that DMG image on Mac OS X compresses the data which is alot smaller than iso and is mountable in Mac OS X and Windows (using special software). Technically, like WanderingKnight said, the ISO format does not compress anything, it's merely stores the files in a CD image or ISO but can be compressed using third party software into a archive to make it smaller. Also, proprietary imaging software such as PowerISO can also achieve this without needing to compact the software, but burning the disc will require the amount of space when uncompressed.
With a video dvd, compressing is not practical, and you need to remaster the whole DVD in order to fit it to a 4.2 GB (actual size) disc.
|