Sams Teach Yourself CGI in 24 Hours, Second Edition

Content Types

All computer systems have a system that enables them to know what to do with files. On Windows systems, the three letter extension tells the system the file type and often what to do with it. Files with the .EXE extension are executable files, the .DOC extension indicates that a file is a Word document, and .HTM tells the system that the file is an HTML document. Similarly, Macintosh classic systems store the file type and file creator in the resource fork.

It probably doesn’t surprise you that every operating system has a method of specifying file types, and the method is different in each system. MS-DOS file extensions don’t mean anything on the Macintosh, and Macintosh resource forks can’t be transferred to computers running ...