PKZIP

Xiver is an archiver.

You can think of it as unzip, PKZIP, that kind of stuff.

It's a GUI.

And then after that, we will, um...

Deflate.

The format was defined by PKWare for PKZIP one nine three A in October of 1991.

Then it shows up in the Info-Zip tools, then GeoNewZip, then ZLib wraps it in a library with a stable interface.

The formal spec for the wrapper is RFC 1950, May 1996, authored by L. Peter Deutsch and Gailli.

And the answer is, more than anyone wants to pay.

There was a comment on Hacker News a few years back that put it better than I can.

The algorithm is showing its age, RFC 1950 is twenty-five years old, and deflate goes back to thirty-three-year-old PKZIP, but we still use Zlib nearly everywhere, not least because it just works, no matter what language or hardware you're on.

No matter what language or hardware you're on is doing an enormous amount of work in that sentence.