ZIP is an archive file format that supports lossless data compression AZIP file may contain one or more files or directories that may have been compressed. TheZIP 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. TheZIP format is now supported by many software utilities other than PKZIP. Microsoft has included built-inZIP support in versions of Microsoft Windows since 1998. Apple has included built-inZIP support in MacOSX 10.3 and later. Most free operating systems have built in support forZIP in similar manners to Windows and Mac OS X.