DD, DiskDoubler Archive (.dd)

The DD Archive file format

DD files are created when using Macintosh's DiskDoubler. DiskDoubler is a file archiver for older Apple Mac operating systems. The DD files contain files that have been compressed for archive creation and space saving reasons. DiskDoubler and thus the DD file extension are now deprecated. The program has been replaced by Now Compress and Stuffit and can not be run on Mac OS X.

Technical details of DD files

The Macintosh DiskDoubler uses a compression algorithm called LZ78 to compress and archive files from a Mac computer. The program compresses files on a user's hard drive. When opened, the compressed DD files expand immediately.

More information about the DD file format

File extension	.dd
File category	Archive
Associated programs	DDExpand (Mac) SuperDoubler (Mac) Symantec Norton DiskDoubler (Mac) The Unarchiver (Mac)
Useful links	More about the DiskDoubler here
Developer	Symantec