ZIP file format

Type of format	Data compression
First released	February 14 1989
Designed by	Phil Katz, Gary Conway
Developer	PKWARE, Inc
Filename extension	.zip
Open Format?	Yes
Free Format?	Yes
Magic Number	50 4b 03 04 "PK♥♦" 50 4b 05 06 "PK♣♠" (empty) 50 4b 07 08 "PK•◘" (spanned)

ZIP is a popular file compression/ archive format that supports lossless data compression. 

The .ZIP file format was designed and created by Phil Katz of PKWARE and Gary Conway of Infinity Design Concepts in 1989 and was first implemented in PKWARE, Inc.'s PKZIP utility, as a replacement for the previous ARC compression format by Thom Henderson. A Zip file is typically used for compressing multiple files into one compressed folder. The ZIP file format permits a number of compression algorithms, though DEFLATE is the most common.

It is uncommon for BD-J applications to use ZIP files, the only BD title to use ZIP (so far) is Warner Bros.'s Inception (2010 Edt.) that uses ZIP files to store Java manifest, text, CSV, XML, and PNG mosaic texts for the Blu-ray's interactive "Extraction Mode".

Limits

The minimum size of a "standard" .ZIP file is 22 bytes. Such an empty zip file contains only an End of Central Directory Record (EOCD):
[0x50,0x4B,0x05,0x06,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00]

The maximum size for both the archive file and the individual files inside it is 4,294,967,295 bytes (2³²−1 bytes, or 4 GB minus 1 byte) for standard ZIP. In context of BD-J, the only file size a developer has to worry about is below 45.5 MB of the graphics memory and 4 MB of the data cache.

Links

• Wikipedia Article
• Archive Team's Article

Specifications

• APPNOTEs - The format documentation from PKWARE is traditionally in a file named APPNOTE.TXT.
  • APPNOTE from PKWARE (latest version of formal spec)
  • APPNOTE Archives from PKWARE (selected versions all the way back to 1.0)
  • Documentation from Info-ZIP (Includes Info-ZIP variants on APPNOTE.TXT dated from 1996 to 2004, specifications used as the basis for various open-source tools)
  • LoC archive
  • An early version of APPNOTE (apparently from PKZIP v1.10)
  • APPNOTE.ZIP - Possibly the first v2.x APPNOTE
  • APPNOTE v6.1.0, from archive.org
  • Bundled with PKZIP software through v1.93 - refer to the #Software section below.
• IANA registration for application/zip in July 1993 (corresponds to version 2 of APPNOTE.TXT)
• ISO/IEC 21320-1: Document Container File (see also fdd000361)
• Archive format info, including ZIP (from 1989, when ZIP was newly released)
• ZIP file header format (among other archive types)
• TorrentZip
• Info-ZIP's "extra fields" documentation

Author(s) : Æ Firestone