Can someone explain the point of ISO / Image files?

[zaphox]

I have never been able to work out why ISO files and images are so popular.

As I understand it their primary purpose, or rather their main benefit, is that they can contain multiple files and retain the exact data structure from the source, without hiding or deleting "special" files such as boot information... thus making them useful for rolling out an O/S image across many computers. Fine.

But why do I keep seeing files such as videos stuffed into an ISO? You then need a special program to open it, and afaik ISOs aren't compressed either, so surely a zip or rar would be better.

I assume I'm missing something somewhere since they're so popular so if anyone would care to enlighten me I'd be grateful.

[Blaineoliver]

You can burn an iso to a disc quite easily, meaning that its easier for people wanting to reburn videos theyve either copied or downloaded.

[aidanjt]

ISO9660 defines a universal standard for the on disc data structure for CDs and DVDs. Keeping this format on hard disk makes it simple to both burn, and mount the format as if you really inserted a CD. If you just pull the contents onto the hard drive, you'd have to recreate the ISO file before burning it to disc for further copies. You'd also lose metadata such as tracks, boot code, and so on, so forth.

You can use programmes such as Daemon Tools for mounting ISO files on a virtual CD/DVD drive. And something like ImgBurn to write ISOs to disc.

Also, video, audio, and picture files should never be zip'ed/rar'ed or any other kind of forced compression, it's a waste of CPU time to 'decompress' them, you risk serious corruption, and you rarely, if ever, achieve any kind of useful compression. On the contrary, usually forced compression results in zero to negative compression ratios.

[directhex]

An ISO file is a disk image, a file containing data as would be on a CD - imagine having a .fat32 file containing a FAT32 partition or a .ext3 file containing an EXT3 partition, .iso is the same thing for an ISO9660 partition.

As a result, an ISO file is easy to dump onto a disk, for archiving.

Assuming hard disks are terribly expensive and DVDs are convenient and easy.

[synaesthesia]

And the way the files are stored is different to, for example a .zip. A zip file (just by comparison) is a compressed collection of files as they stand. An ISO (or any other CD/DVD image format) however is an image of the disc by sector, not by files, thus retaining properties you can't preserve any other way - bootable discs, multi-format discs both being good examples.

[GoNz0]

you can open an iso with winrar

[Giraffe]

Can also do it from context menu with Universal Extractor

http://www.legroom.net/software/uniextract

[mehmeh]

Can see the point, much prefer an ISO over a stupid split RAR archive. What gets me is the use of mulitple formats, (thank god for Deamon Tools!). You must be downloading from some odd sources if Video and Audio files are coming as a ISO lol.

[zaphox]

ahh ok, I see. Thanks for all the great feedback.