|
Article on other languages:
|
StuffIt is a family of computer software utilities for archiving and compressing files on the Macintosh, Microsoft Windows and Linux platforms: it was originally produced for the Macintosh. The proprietary compression format used by the StuffIt utilities is also termed StuffIt.
OverviewStuffIt was originally developed in the summer of 1987 by Raymond Lau, [6] a high school student at Stuyvesant High School in New York City. It combined the fork-combining capabilities of utilities such as MacBinary with newer compression algorithms similar to those used in ZIP. Compared to existing utilities on the Mac, notably PackIt, StuffIt offered "one step" operation and compression ratios that could not be matched. By the fall of 1987 StuffIt had largely replaced PackIt in the Mac world, with many software sites even going so far as to convert over existing PackIt archives to save more space. StuffIt soon became very popular and Aladdin Systems was formed to market it (the last shareware release by Lau was version 1.5.1). They split the product line in two, offering StuffIt Classic in shareware and StuffIt Deluxe as a commercial package. Deluxe added a variety of additional functions, including additional compression methods and integration into the Mac Finder to allow files to be compressed from a "Magic Menu" without opening StuffIt itself. StuffIt was upgraded several times, but Lau had removed himself from direct development and major upgrades to the "internal machinery" were rare. As a result, the shareware utility Compact Pro stole much of StuffIt's market in the early 1990s through a combination of ease-of-use, better compression and much higher speed. In fact, Compact Pro could uncompress StuffIt archives at roughly twice the speed of StuffIt itself. A major upgrade followed in order to compete, adding the freeware StuffIt Expander in order to make the format more universally acceptable, as well as the shareware StuffIt Lite which made it easier to produce — prior to this anyone attempting to use the format needed to buy StuffIt, making Compact Pro more attractive. This move was very successful, and Compact Pro disappeared almost overnight. Several other Mac compression utilities appeared and disappeared during the 1990s, but none became a real threat to StuffIt's market. The only ones to see any widespread use were special-purpose "disk expanders" like DiskDoubler and SuperDisk!, which served a different niche. Apparently as a side-effect, StuffIt once again saw few upgrades. PC-based formats long surpassed StuffIt in terms of compression, notably newer systems like RAR and 7z. These had little impact on the Mac market, as most of these never appeared in an easy-to-use program on the Mac. With the introduction of OpenStep as the basis for what would become Mac OS X, newer Mac software lost their forks and no longer needed anything except the built-in Unix utilities like gzip and tar. Numerous programs "wrapping" these utilities were distributed, and since these files could be opened on any machine, they were considerably more practical than StuffIt in an era when most data is cross-platform. Although the writing was clearly on the wall, StuffIt did not respond to this change in the market, and when OS X was eventually released in 2001 they did not have a version supporting the new operating system. Although it was late to market, Aladdin introduced the completely new StuffIt X in September 2002 with StuffIt Deluxe 7.0 for Macintosh. It was designed to be extendable, support more compression methods, support long file names, and support Unix and Windows file attributes. StuffIt X improves over the original StuffIt format and its descendants by adding multiple compression algorithms such as PPM, and BWT to LZW-type compression. It also added a "block mode" option and several encryption options. In January 2005, JPEG compression was added as a StuffIt X compression option (see the related 'SIF Format' below). One of the advantages of the StuffIt format is the ability to choose compression algorithms best suited for a particular data set, unlike Zip which always uses deflate or bzip which always uses BWT. A drawback of Stuffit X format is that, as of December 2007, it is impossible to decompress Stuffit X files on machines not running Windows or Mac OS. Until the 2005 release of Mac OS X v10.4 "Tiger", StuffIt Expander came preloaded with the Macintosh operating system. Once the dominant archive method on the Macintosh platform, StuffIt's removal from Tiger underscores the Macintosh user base's recent move away from the format, and towards the DMG and ZIP formats. However, Apple's built-in Zip utility BOMArchiveHelper does not support encrypted ZIP archives, archives created with PKWare's Deflate64 setting, or a wide variety of other compressed, encrypted and encoded formats that users encounter, so StuffIt or another third-party utility is still handy to have. Although Mac files generally did not use filename extensions, one of StuffIt's primary uses was to allow Mac files to be stored on non-Mac systems where extensions were required. StuffIt-compressed files typically have the extension .sit, although newer Stuffit X-compressed files carry the file extension .sitx. Encrypted StuffIt archives created with the now-discontinued Private File utility will have .pf extensions. StuffIt-compressed ShrinkWrap disk images will carry .img or .image extensions. However, a Classic version of StuffIt is needed to mount the images or convert them to a newer format readable in Mac OS X. Allume Systems offers free downloads of StuffIt Expander for Mac and Windows, which expands (uncompresses) files compressed using the StuffIt and StuffIt X format, as well as many other compressed, encoded, encrypted and segmented formats. The shareware application DropStuff permits the compressing of files into the StuffIt X format. The StuffIt and StuffIt X formats remain, unlike some other file compression formats, proprietary, and Allume Systems charge license fees for its use in other programs. Given this, few alternative programs support the format. StuffIt Image Format (SIF)Early in 2005 Allume released a new JPEG compression system that regularly obtained compression in the order of 25% (meaning a compressed file size 75% of the original file size) without any further loss of image quality and with the ability to rebuild the original file, not just the original image. (ZIP-like programs typically achieve JPEG compression rates in the order of 1 to 3%. Programs that optimise JPEGs without regard for the original file, only the original image, obtain compression rates from 3 to 10% (depending on the efficiency of the original JPEG). Programs that use the rarely implemented arithmetic coding option available to the JPEG standard typically achieve rates around 12%.) Allume implemented their new technique as a StuffIt X format option in their StuffIt Deluxe product. They have also proposed a new image format known as SIF, which simply consists of a single JPEG file compressed using this new technique. CriticismsMarketing Practices Unlike many freeware applications, the free stuffit expander utility is not available for public download. The developer requires prospective users to submit a valid E-Mail address and other information which is then used to send marketing information to the user. There is no opportunity to opt out of this marketing prior to download. [1] It can be downloaded for free, without sending marketing information, from download.com [2]. Backwards Compatibility Changes to the Stuffit compression software, claimed by the developer to be upgrades, frequently render previous versions of Stuffit unable to decompress newer archives without first downloading or purchasing the new version. This incompatibility can be inconvenient for work flows where timely execution is of importance. Though users are able to create archives in a legacy format, this functionality is not clearly exposed. [3] Diminishing Relevance Given the built-in ZIP decompression utilities in OS X and ZIP's dominance in Windows, users are less and less likely to possess the software necessary to decompress a Stuffit archive. Developers are thus discouraged by their user base from using Stuffit to distribute software and other data. [4][5] StuffIt WirelessOn July 5, 2005, Smith Micro Software announced that they had bought Allume Systems and were intending to expand the new JPEG recompression technique to wireless platforms and other file formats. The initial press release and preliminary information saw the first use of the title “StuffIt Wireless.” See alsoNotes
External links
Article keywords: stuffit deluxe, free stuffit, Questions for article: lz77 プログラム |
||||||||||||||||||||||||||||||||||||||||||||
This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.
Mercedes Car
This site monitored by SitePinger.net