- #Arc file extractor archive
- #Arc file extractor software
- #Arc file extractor code
- #Arc file extractor zip
- #Arc file extractor download
Other formats called ARC (or something similar) are listed at ARC.
#Arc file extractor archive
An archive comment, if present, is in the record preceding the special record. The special record somehow indicates whether an archive comment and/or file comments are present. The last 4 bytes of the file contain the offset of the special record. This is preceded by a sequence of 32-byte records, each containing a comment, except for one that has a special purpose. Information based on reverse engineering: An ARC file with comments ends with an 8-byte trailer that begins with the signature 'P' 'K' 0xaa 0x55.
#Arc file extractor software
The PKARC/PKPAK software supports comments, apparently using a custom ARC format extension that appears after the end-of-archive marker. It does not support Trimmed decompression. Some format identification tools identify files beginning this way as "ARC+" format.ĪRC v6.02 understands archive info items, though it's unclear if it ever creates them. By default, it uses Trimmed compression, and the files it creates begin with an archive info item ("compression method" 20). The ARC v7 software is named "ARC Plus" or "ARC+Plus". No known use in ARC, but see Hyper archive. Created by the "z" option introduced in ARC v6. PAK extensions: Refer to PAK (ARC extension)#Compression methods. This is probably the most common compression method.
#Arc file extractor code
There is a header byte giving the maximum LZW code size, but only 12 bits is generally supported. Source code comment says "inadvertent release of a developmental copy forces us to leave in". Unfortunately, there are several different compression methods named "crunched" or "Crunched". The usual compression methods are in the range 1 through 9. The compression method byte identifies a member's compression method, and/or other information about the type of member. (For files beginning with 0x1b, see ArcMac.) It is common for ARC files to have padding or other data after the end-of-archive marker.Įach member begins with a 0x1a byte, then a byte indicating the compression method used for that member file. Others include the FreeArc format and the Internet Archive ARC format, as well as a Commodore ARC that's similar in concept but not compatible to any of the other ARCs.Īn ARC file consists of a sequence of zero or more archive members, followed by an end-of-archive marker: the bytes 0x1a 0x00. There are, unfortunately, also several other incompatible file formats that have been used over the years with an "ARC" designation or file extension, so it's possible that a data set that is purportedly of type "ARC" is not actually of this format. The fact that archives from an early period of BBSing are often in this format encourages bad puns referring to those who trawl such old archives as "Raiders of the lost ARC."
#Arc file extractor zip
Nevertheless, the fallout from the suit led to rapid adoption of the competing ZIP format, introduced by Katz in 1989, and ARC files are no longer commonly encountered. Goliath" case of a faceless corporation bullying a "little guy", though in fact both companies were small, home-based operations. The lawsuit was widely regarded by the BBS community as being a "David vs. However, the ARC format suffered an equally rapid decline in its popularity after the company that published the ARC utility (called System Enhancement Associates or SEA, run by Thom Henderson who was very active in FidoNet) brought a successful trademark and copyright suit against rival Phil Katz, whose PKARC and PKXARC utilities were compatible with the ARC file format.
#Arc file extractor download
Combining the two functions in one utility simplified the process of preparing files for download and extracting them at the other end, leading to a rapid rise in popularity for the utility (also called ARC) and format both. ARC was for a time (1985-89) the leading file archiving and file compression format in the BBS world, replacing the formats used by earlier utilities which generally only did one of the two functions (either combining multiple files in one file for convenient download, or shortening the file length to take less download time and disk space).
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