Macintosh Type/Creator Codes: Improving identification of files from MacOS Classic

Working with Macintosh files from the 1980 to early 2000’s can be challenging as they are often on difficult to access disks, unique encoding, have resource forks, and often don’t use extensions. Identification of files from a Macintosh formatted disk can be accomplished with identification methods such as PRONOM, but what if those standard methods come up empty or are misleading? This paper investigates a method of identification which can provide better results compared to existing methods. The Macintosh operating system used special extended attribute codes to not only identify the file type, but also the original creating application. Called Type / Creator codes, these extended attributes are often lost or hidden to the user during preservation activities but can provide important information for long term preservation. These codes along with resource forks can provide necessary information for emulation and migration activities.