Due to the Mac OS forked file structure, transferring Mac OS files to non-Macintosh computers is problematic. MacBinary was developed as a means of preserving this structure without sacrificing portability. It combines the data and resource forks and the Finder information of a file into a single document. This document is then suitable for transport via FTP, the World Wide Web, and electronic mail. You can also store the document on computers that run different operating systems, such as Unix or Windows. It is similar to BinHex, but MacBinary produces binary files as opposed to ASCII text. Thus, MacBinary files take up less disk space than BinHex files, but older applications and servers are more likely to corrupt them.

The first incarnation of MacBinary was released in 1985. The standard was originally specified by Dennis Brothers (author of the terminal program MacTEP and later an Apple employee), Yves Lempereur, et al., following which Lempereur added support for MacBinary into BinHex 5.0. Two years later it was updated to MacBinary II, to accommodate changes in Mac OS. MacBinary II remained compatible with subsequent updates of the operating system; however, changes introduced to the Finder in Mac OS 8.5 have necessitated MacBinary III, the third release.

Files encoded with MacBinary, regardless of the version, usually have .bin appended to the ends of their filenames. E-mail programs such as Eudora can extract and decode MacBinary mail messages. Most dedicated FTP programs, such as Fetch and Transmit, decode MacBinary files they download.

For Mac OS X, the MacBinary format has been largely superseded by the .dmg disk image format which appears in the Finder as a mounted volume after it has been double-clicked.

External Links

• Home of the MacBinary Format