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Info-ZIP is an open source version of Phil Katz's "deflate" and "inflate" routines used in his popular file compression program, PKZIP. The free code released by the Info-ZIP project spawned a horde of PKZIP imitators (WinZip, Power Archiver, Turbozip, PowerZip and many more), establishing the PKZIP file format as a de facto industry standard.

The first version of what would become Info-ZIP was published by Samuel Smith in March 1989, complete with the source code in both Pascal and C forms. In September he released 2.0, including support for the new "implode" method that had been added to PKZIP 1.01. A port to Unix was released by Carl Mascott and John Cowan in December.

In March 1990 a number of interested parties set up a mail list on a disused DEC-20 mainframe at the White Sands Missile Range, agreeing to form a group to clean up the code and make it officially public. In May the first version of this code was released, as Info-ZIP 3.0.

In 1994 and 1995 Info-ZIP turned a corner, and effectively became the defacto ZIP program. A huge number of ports were released that year, including numerous minicomputers, mainframes and practically every microcomputer ever developed. All the while the software had continued to add support for newer compression systems being added to PKZIP, eventually this happened so quickly that there was no reason to use PKZIP. It was also in 1995 that the principal maintainers start to work heavily on the PNG format, and changes to Info-ZIP slowed.