ZIP is an archive file format that supports lossless data compression. A .ZIP file may contain one or more files or directories that may have been compressed. The .ZIP file format permits a number of compression algorithms, though DEFLATE is the most common. This format was originally created in 1989 by Phil Katz, and was first implemented in PKWARE, Inc.'s PKZIP utility, as a replacement for the previous ARC compression format by Thom Henderson. The .ZIP format is now supported by many software utilities other than PKZIP. Microsoft has included built-in .ZIP support (under the name "compressed folders") in versions of Microsoft Windows since 1998. Apple has included built-in .ZIP support in Mac OS X 10.3 (via BOMArchiveHelper, now Archive Utility) and later. Most have built in support for .ZIP in similar manners to Windows and Mac OS X.