(AIO), also known as #-in-1
contain more than one application on the disc. Typically, this would simply be different editions of the same version. AIOs are normally created by warez
groups in order to save time to download and upload software, while giving a large collection of editions at the same time. However, software companies may release AIOs themselves to high-paying customers.
How they work
Most All-in-Ones exploit a hack to the ISO 9660 file system
. This hack allows them to store a file only once as data, but reference it with many filenames and paths; this is also known as hardlinks
. The reason this works so effectively is that multiple editions of software commonly only change between a small group of files, so the AIO might be only a few kilobytes or megabytes larger than one copy of a certain edition of the software, but will not be as large as copying them individually. Some modified versions of the program mkisofs
are able to automatically find multiple copies of files using the -duplicates-once option.