![]() ![]() Update : Hadrien Dorio ported hwzip to the Zig programming language. In the process he found an overflow bug in the compression ratio computation in zip_callback() and some incorrect uses of the CHECK macro in the unit tests. Those bugs have been fixed in hwzip-2.1.zip. Update : I wrote a follow-up article about the legacy Zip compression methods: Shrink, Reduce, and Implode. Update : In hwzip-1.4.zip, the distance2dist table was split into two smaller tables, reducing the binary size by 32 KB. It also ensures that Deflate blocks always emit at least two non-zero dist codeword lengths, for compatibility with old zlib versions. Update : In hwzip-1.3.zip, the minimum Lempel–Ziv back reference length was increased from three to four bytes, and the hash was changed from a three-byte rolling hash to a four-byte multiplicative hash. OPEN AND COMPRESS WITH QUEUE BETTERZIP UPDATE This made Deflate compression more than twice as fast as the previous version. Table of Contentsīack in the eighties and early nineties, before the Internet became widely available, home computer enthusiasts used dial-up modems to connect to Bulletin Board Systems (BBSes) over the telephone network.Ī BBS is an interactive computer system that typically allows users to send messages, play games, and share files.Īll that was needed to go online was a computer, a modem, and the phone number of a good BBS-something that could be found in lists published by computer magazines, and on other BBSes. ![]() One important tool for making file sharing easier was the archiver. An archiver stores one or more files into a single file, an archive, allowing the files to be stored or transferred as a single unit, and ideally also compresses them to save storage space and transfer time. One such archiver that was popular with the BBS scene was Arc, written by Thom Henderson of System Enhancement Associates (SEA), a small company he had founded with his brother-in-law. In the late eighties, a programmer named Phil Katz released his own Arc program, PKArc. It was compatible with SEA's Arc, but faster due to routines written in assembly, and it had a new compression method added by Katz. The program became popular, and Katz quit his job and founded PKWare to focus on developing it. According to legend, much of the work took place at his mother Hildegard's kitchen table in Glendale, Wisconsin. Photo of Phil Katz from an article in the Milwaukee Sentinel on 19 September 1994. ![]() SEA, however, were not thrilled by Katz's initiative. They sued for trademark violation and copyright infringement. The dispute and the surrounding debate in the BBS and PC world became known as the Arc Wars. In the end, the case was settled to SEA's advantage. Moving on from Arc, in 1989 Katz created a new archive format which he named Zip and dedicated to the public domain: OPEN AND COMPRESS WITH QUEUE BETTERZIP ARCHIVE The file format of the files created by these programs, which file format is original with the first release of this software, is hereby dedicated to the public domain. OPEN AND COMPRESS WITH QUEUE BETTERZIP CODE.OPEN AND COMPRESS WITH QUEUE BETTERZIP ARCHIVE.OPEN AND COMPRESS WITH QUEUE BETTERZIP UPDATE.OPEN AND COMPRESS WITH QUEUE BETTERZIP ZIP FILE. ![]()
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