The difference between a .dmg file & a .cdr file (using Disk Utility) ?

HI Pat,

From Wikipedia: A file with the extension .dmg (an abbreviation for disk image) uses a disk image format commonly found on Mac OS X. The format allows secure password protection as well as file compression and hence serves both security and file distribution functions. Its most common function is the distribution of software over the Internet. When opened, DMG files are "mounted" as a drive within the Finder.

From: Wikipedia .cdr and ISO

ISO image
Filename extension .iso
Uniform Type Identifier public.iso-image
Type of format Disk image
Standard(s) ISO 9660
An ISO image is an archive file (a.k.a. disk image) of an optical disc using a conventional ISO (International Organization for Standardization) format that is supported by many software vendors. ISO image files typically have a file extension of .ISO but Mac OS X ISO images often have the extension .CDR. The name "ISO" is taken from the ISO 9660 file system used with CD-ROM media, but an ISO image can also contain UDF file system because UDF is backward-compatible to ISO 9660.


Carolyn 🙂

Message was edited by: Carolyn Samit