1.
Data compression
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In signal processing, data compression, source coding, or bit-rate reduction involves encoding information using fewer bits than the original representation. Compression can be lossy or lossless. Lossless compression reduces bits by identifying and eliminating statistical redundancy, no information is lost in lossless compression. Lossy compression reduces bits by removing unnecessary or less important information, the process of reducing the size of a data file is referred to as data compression. In the context of data transmission, it is called coding in opposition to channel coding. Compression is useful because it reduces resources required to store and transmit data, computational resources are consumed in the compression process and, usually, in the reversal of the process. Data compression is subject to a space–time complexity trade-off, Lossless data compression algorithms usually exploit statistical redundancy to represent data without losing any information, so that the process is reversible. Lossless compression is possible because most real-world data exhibits statistical redundancy, for example, an image may have areas of color that do not change over several pixels, instead of coding red pixel, red pixel. The data may be encoded as 279 red pixels and this is a basic example of run-length encoding, there are many schemes to reduce file size by eliminating redundancy. The Lempel–Ziv compression methods are among the most popular algorithms for lossless storage, DEFLATE is a variation on LZ optimized for decompression speed and compression ratio, but compression can be slow. DEFLATE is used in PKZIP, Gzip, and PNG, LZW is used in GIF images. LZ methods use a table-based compression model where table entries are substituted for repeated strings of data, for most LZ methods, this table is generated dynamically from earlier data in the input. The table itself is often Huffman encoded, current LZ-based coding schemes that perform well are Brotli and LZX. LZX is used in Microsofts CAB format, the best modern lossless compressors use probabilistic models, such as prediction by partial matching. The Burrows–Wheeler transform can also be viewed as a form of statistical modelling. The basic task of grammar-based codes is constructing a context-free grammar deriving a single string, sequitur and Re-Pair are practical grammar compression algorithms for which software is publicly available. In a further refinement of the use of probabilistic modelling. Arithmetic coding is a more modern coding technique that uses the mathematical calculations of a machine to produce a string of encoded bits from a series of input data symbols
2.
DOS
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None of these systems were officially named DOS, and indeed DOS is a general term for disk operating system. MS-DOS dominated the IBM PC compatible market between 1981 and 1995, and Microsoft Windows, still ran on top of it until about 2001, dozens of other operating systems also use the acronym DOS, including DOS/360 from 1966. Others are Apple DOS, Apple ProDOS, Atari DOS, Commodore DOS, TRSDOS, see List of DOS operating systems § Other operating systems. IBM PC DOS and its predecessor, 86-DOS, resembled Digital Researchs CP/M—the dominant disk operating system for 8-bit Intel 8080, DOS instead ran on Intel 8086 16-bit processors. Starting with MS-DOS1.28 and PC DOS2.0 the operating system incorporated various features inspired by Xenix, when IBM introduced the IBM PC, built with the Intel 8088 microprocessor, they needed an operating system. Seeking an 8088-compatible build of CP/M, IBM initially approached Microsoft CEO Bill Gates, IBM was sent to Digital Research, and a meeting was set up. However, the negotiations for the use of CP/M broke down, Digital Research wished to sell CP/M on a royalty basis, while IBM sought a single license. Digital Research founder Gary Kildall refused, and IBM withdrew, Gates in turn approached Seattle Computer Products. There, programmer Tim Paterson had developed a variant of CP/M-80, the system was initially named QDOS, before being made commercially available as 86-DOS. Microsoft purchased 86-DOS, allegedly for $50,000 and this became Microsoft Disk Operating System, MS-DOS, introduced in 1981. Within a year Microsoft licensed MS-DOS to over 70 other companies, Microsoft later required the use of the MS-DOS name, with the exception of the IBM variant. IBM continued to develop their version, PC DOS, for the IBM PC, Digital Research became aware that an operating system similar to CP/M was being sold by IBM, and threatened legal action. IBM responded by offering an agreement, they would give PC consumers a choice of PC DOS or CP/M-86, side-by-side, CP/M cost almost $200 more than PC DOS, and sales were low. CP/M faded, with MS-DOS and PC DOS becoming the operating system for PCs. Microsoft originally sold MS-DOS only to original equipment manufacturers, one major reason for this was that not all early PCs were 100% IBM PC compatible. DOS was structured such that there was a separation between the specific device driver code and the DOS kernel. Microsoft provided an OEM Adaptation Kit which allowed OEMs to customize the device driver code to their particular system, by the early 1990s, most PCs adhered to IBM PC standards so Microsoft began selling MS-DOS in retail with MS-DOS5.0. In the mid-1980s Microsoft developed a version of DOS
3.
Microsoft Windows
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Microsoft Windows is a metafamily of graphical operating systems developed, marketed, and sold by Microsoft. It consists of families of operating systems, each of which cater to a certain sector of the computing industry with the OS typically associated with IBM PC compatible architecture. Active Windows families include Windows NT, Windows Embedded and Windows Phone, defunct Windows families include Windows 9x, Windows 10 Mobile is an active product, unrelated to the defunct family Windows Mobile. Microsoft introduced an operating environment named Windows on November 20,1985, Microsoft Windows came to dominate the worlds personal computer market with over 90% market share, overtaking Mac OS, which had been introduced in 1984. Apple came to see Windows as an encroachment on their innovation in GUI development as implemented on products such as the Lisa. On PCs, Windows is still the most popular operating system, however, in 2014, Microsoft admitted losing the majority of the overall operating system market to Android, because of the massive growth in sales of Android smartphones. In 2014, the number of Windows devices sold was less than 25% that of Android devices sold and this comparison however may not be fully relevant, as the two operating systems traditionally target different platforms. As of September 2016, the most recent version of Windows for PCs, tablets, smartphones, the most recent versions for server computers is Windows Server 2016. A specialized version of Windows runs on the Xbox One game console, Microsoft, the developer of Windows, has registered several trademarks each of which denote a family of Windows operating systems that target a specific sector of the computing industry. It now consists of three operating system subfamilies that are released almost at the time and share the same kernel. Windows, The operating system for personal computers, tablets. The latest version is Windows 10, the main competitor of this family is macOS by Apple Inc. for personal computers and Android for mobile devices. Windows Server, The operating system for server computers, the latest version is Windows Server 2016. Unlike its clients sibling, it has adopted a strong naming scheme, the main competitor of this family is Linux. Windows PE, A lightweight version of its Windows sibling meant to operate as an operating system, used for installing Windows on bare-metal computers. The latest version is Windows PE10.0.10586.0, Windows Embedded, Initially, Microsoft developed Windows CE as a general-purpose operating system for every device that was too resource-limited to be called a full-fledged computer. The following Windows families are no longer being developed, Windows 9x, Microsoft now caters to the consumers market with Windows NT. Windows Mobile, The predecessor to Windows Phone, it was a mobile operating system
4.
PKZIP
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PKZIP is a file archiving computer program, notable for introducing the popular ZIP file format. PKZIP was first introduced for MS-DOS on the IBM-PC compatible platform in 1989, since then versions have been released for a number of other architectures and operating systems. PKZIP was originally written by Phil Katz and marketed by his company PKWARE, Inc, by the 1970s, file archiving programs were distributed as standard utilities with operating systems. They include the Unix utilities ar, shar, and tar and these utilities were designed to gather a number of separate files into a single archive file for easier copying and distribution. These archives could optionally be passed through a stream compressor utility, such as compress, other archivers also appeared during the 1980s, including ARC by System Enhancement Associates, Inc. Rahul Dhesis ZOO, Dean W. Coopers DWC, LHarc by Haruhiko Okomura and Haruyasu Yoshizaki, the development of PKZIP was first announced in the file SOFTDEV. DOC from within the PKPAK3.61 package, stating it would develop a new and yet unnamed compression program. The announcement had been following the lawsuit between SEA and PKWARE, Inc. Although SEA won the suit, it lost the compression war, led by BBS sysops who refused to accept or offer files compressed as. ARC files, users began recompressing any old archives that were currently stored in. ARC format into. ZIP files. The first version was released in 1989, as a DOS command-line tool, PKZIP0.8 initial version PKZIP0.9 supported reducing algorithm with four compression settings and shrinking. In addition to PKZIP and PKUNZIP, it also included ZIP2EXE, PKZIP0.92, In addition to bug fixes, PKZIP included an option to automatically choose the best compression method for each file. New tools included with PKZIP include PKZipFix, PKZIP1.01 added Implode compression, while reduced files can only be extracted from ZIP archive. Imploding was chosen based on the characteristics of the file being compressed, New utility included Thomas Atkinsons REZIP conversion utility. PKZIPs default compression behavior was changed from fastest to best, PKZIP1.02 includes new utility BIOSFIX. COM, which preserved the entire 80386 register set during any mode switches via INT 15H. OS/2 version added ZIP2EXE and 2 self-extracting archive headers, PKZIP1.10, New features included authenticity verification, mini PKSFX self-extracting module, integrating self-extracting module into ZIP2EXE, ability to save & restore volume labels. Imploding was up to 5X faster and compression ratio was improved over 1.02, EAX register was always saved on 80386 or above CPU. Removed tools included BIOSFIX, REZIP, MAKESFX, in 1993, PKWARE released PKZIP2.0. This new version dispensed with the miscellaneous compression methods of PKZIP1. x, PKZIP2. x also supported spanning archives to multiple disk, which simply split the files into multiple pieces, and using volume label on each drive to differentiate each other. A new Authenticity Verification signature format was used, registered version included PKUNZJR, PK Safe ANSI, PKCFG utilities
5.
Bulletin board system
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A bulletin board system, or BBS, is a computer server running software that allows users to connect to the system using a terminal program. Many BBSes also offer on-line games, in users can compete with each other. Bulletin board systems were in many ways a precursor to the form of the World Wide Web, social networks. Low-cost, high-performance modems drove the use of services and BBSes through the early 1990s. Infoworld estimated there were 60,000 BBSes serving 17 million users in the United States alone in 1994, over the next year, many of the leading BBS software providers went bankrupt and tens of thousands of BBSes disappeared. Today, BBSing survives largely as a hobby in most parts of the world. Most BBSes are now accessible over Telnet and typically offer free email accounts, FTP services, IRC, some offer access through packet switched networks, or packet radio connections. A precursor to the bulletin board system was Community Memory, started in August 1973 in Berkeley. Useful microcomputers did not exist at that time, and modems were both expensive and slow, Community Memory therefore ran on a mainframe computer and was accessed through terminals located in several San Francisco Bay Area neighborhoods. The poor quality of the original modem connecting the terminals to the mainframe prompted a user to invent the Pennywhistle modem, Community Memory allowed the user to type messages into a computer terminal after inserting a coin, and offered a pure bulletin board experience with public messages only. It did offer the ability to tag messages with keywords, which the user could use in searches, the system acted primarily in the form of a buy and sell system with the tags taking the place of the more traditional classifications. But users found ways to express themselves outside these bounds, unfortunately, the system was expensive to operate, and when their host machine became unavailable and a new one could not be found, the system closed in January 1975. Similar functionality was available to most mainframe users, which might be considered a sort of ultra-local BBS when used in this fashion. Commercial systems, expressly intended to offer features to the public, became available in the late 1970s. Early modems were very simple devices using acoustic couplers to handle telephone operation. The user would first pick up the phone, dial a number, disconnecting at the end of a call required the user to pick up the handset and return it to the phone. With the introduction of microcomputers with expansion slots, like the S-100 bus machines and Apple II, it possible for the modem to communicate instructions. A number of modems of this sort were available by the late 1970s
6.
Warez scene
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The Scene is meant to be hidden from the public, only being shared with those within the community. However, as files were commonly leaked outside the community and their popularity grew, some individuals from The Scene began leaking files and uploading them to filehosts, torrents, the Scene has no central leadership, location, or other organizational conventionals. The groups themselves create a ruleset for each Scene category that then becomes the active rules for encoding material and these rulesets include a rigid set of requirements that warez groups must follow in releasing and managing material. The groups must follow these rules when uploading material, and if the release has an error or breaks a rule. Groups are in constant competition to get releases up as fast as possible, first appearing around the time of BBSes, The Scene is composed primarily of people dealing with and distributing media content for which special skills and advanced software are required. The warez scene started emerging in the 1970s, used by predecessors of software cracking and their work was made available on privately run bulletin board systems. The first BBSes were located in the U. S. but similar boards started appearing in Canada, the United Kingdom, Australia, at the time, setting up a machine capable of distributing data was not trivial and required a certain amount of technical skill. The reason it was usually done was for technical challenge, the BBSes typically hosted several megabytes of material. The best boards had multiple phone lines and up to one hundred megabytes of storage space, releases were mostly games and later software. The groups would promote their abilities with ever more sophisticated and advanced software, graphical art, the subcommunities, which were doing nothing illegal, eventually branched off. The programs containing the promotional material evolved to become separate programs distributed through The Scene and were nicknamed Intros. The demoscene grew especially strong in Scandinavia, where annual gatherings are hosted, when releasing material, groups must first encode properly so as not to be nuked, which shows up as a cautionary flag to potential users. After encoding, they upload the files to a topsite that is a FTP server where all the files originate, when the upload is complete, they execute a command that causes the name and category of the release to be announced in the topsites IRC channel. New releases are also announced 0sec on various public websites and this is called a pre release. Once this is done, all releases for the same material are nuked as duplicates. However, if there is an error or the file breaking the ruleset for the category. Other groups then encode the same material and release it with a PROPER tag in the filename, the same group may re-encode the file, with the new release marked as REPACK. This FTP server and IRC are hidden and closed to the public, each release in The Scene consists of a folder containing the material, plus an NFO and SFV file
7.
Floppy disk
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Floppy disks are read and written by a floppy disk drive. Floppy disks, initially as 8-inch media and later in 5¼-inch and 3½-inch sizes, were a form of data storage and exchange from the mid-1970s into the mid-2000s. These formats are usually handled by older equipment and these disks and associated drives were produced and improved upon by IBM and other companies such as Memorex, Shugart Associates, and Burroughs Corporation. The term floppy disk appeared in print as early as 1970, in 1976, Shugart Associates introduced the first 5¼-inch FDD. By 1978 there were more than 10 manufacturers producing such FDDs, there were competing floppy disk formats, with hard- and soft-sector versions and encoding schemes such as FM, MFM and GCR. The 5¼-inch format displaced the 8-inch one for most applications, the most common capacity of the 5¼-inch format in DOS-based PCs was 360 kB and in 1984 IBM introduced the 1.2 MB dual-sided floppy disk along with its PC-AT model. IBM started using the 720 kB double-density 3½-inch microfloppy disk on its Convertible laptop computer in 1986 and these disk drives could be added to older PC models. In 1988 IBM introduced a drive for 2.88 MB DSED diskettes in its top-of-the-line PS/2 models, throughout the early 1980s, limitations of the 5¼-inch format became clear. Originally designed to be practical than the 8-inch format, it was itself too large, as the quality of recording media grew. A number of solutions were developed, with drives at 2-, 2½-, 3-, 3½-, the large market share of the 5¼-inch format made it difficult for these new formats to gain significant market share. A variant on the Sony design, introduced in 1982 by a number of manufacturers, was then rapidly adopted. By the end of the 1980s, 5¼-inch disks had been superseded by 3½-inch disks, by the mid-1990s, 5¼-inch drives had virtually disappeared, as the 3½-inch disk became the predominant floppy disk. Floppy disks became ubiquitous during the 1980s and 1990s in their use with computers to distribute software, transfer data. Before hard disks became affordable to the population, floppy disks were often used to store a computers operating system. Most home computers from that period have a primary OS and BASIC stored as ROM, by the early 1990s, the increasing software size meant large packages like Windows or Adobe Photoshop required a dozen disks or more. In 1996, there were a five billion standard floppy disks in use. Then, distribution of packages was gradually replaced by CD-ROMs, DVDs. External USB-based floppy disk drives are available, many modern systems provide firmware support for booting from such drives
8.
7-Zip
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7-Zip is an open-source file archiver, an application used primarily to compress files. 7-Zip uses its own 7z archive format, but can read, the program can be used from a command-line interface as the command p7zip, as a graphical user interface, or with a window-based shell integration. 7-Zip began in 1999 and is developed by Igor Pavlov, most of the source code is under the GNU LGPL license. The unRAR code is under the GNU LGPL with an unRAR restriction, by default, 7-Zip creates 7z-format archives with a. 7z file extension. Each archive can contain multiple directories and files, as a container format, security or size reduction are achieved using a stacked combination of filters. These can consist of pre-processors, compression algorithms, and encryption filters, the core 7z compression uses a variety of algorithms, the most common of which are bzip2, PPMd, LZMA2, and LZMA. Developed by Pavlov, LZMA is a new system, making its debut as part of the 7z format. LZMA uses an LZ-based sliding dictionary of up to 4 GB in size, the native 7z file format is open and modular. All filenames are stored as Unicode, the 7z file format specification is distributed with the programs source code, in the doc subdirectory. 7-Zip supports a number of compression and non-compression archive formats, including ZIP, Gzip, bzip2, xz, tar. 7-Zip supports the ZIPX format for unpacking only and it has had this support since at least version 9.20, which was released in late 2010. 7-Zip can open some MSI files, allowing access to the meta-files within along with the main contents, some Microsoft CAB and NSIS installer formats can be opened. Similarly, some Microsoft executable programs that are self-extracting archives or otherwise contain archived content may be opened as archives. When compressing ZIP or gzip files, 7-Zip uses its own DEFLATE encoder, which may achieve higher compression, the 7-Zip deflate encoder implementation is available separately as part of the AdvanceCOMP suite of tools. The decompression engine for RAR archives was developed using source code of the unRAR program, 7-Zip v15.06 and later support the RAR5 file format. It can also unpack a few types of backup created by Android stock recovery image, 7-Zip comes with a file manager along with the standard archiver tools. The file manager, by default, displays hidden files because it not follow Windows Explorers policies. The tabs show name, modification time, original and compressed sizes, attributes, when going up one directory on the root, all drives, removable or internal appear
9.
Zipeg
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Zipeg is an open source free software that extracts files from compressed archives like ZIP, RAR, 7z and others, some of which are rarely used types. Zipeg works under Mac OS X and Windows and it is best known for its file preview ability. It is incapable of compressing files, although it is able to extract compressed ones, Zipeg is built on top of the 7-Zip backend. Its UI is implemented in Java and is open source, Zipeg automatically detects filenames in national alphabets and correctly translates them to Unicode. Zipeg reads Exif thumbnails from JPEG digital photographs and uses them for tool tip style preview, zip Data compression Zipeg review from c|net Zipeg review by Macworld Zipeg main site http, //www. zipeg. com/ Zipeg source code http, //zipeg. googlecode. com/
10.
WinRAR
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WinRAR is a trialware file archiver utility for Windows. It can create and view archives in RAR or ZIP file formats, to enable the user to test the integrity of archives, WinRAR embeds CRC32 or BLAKE2 checksums for each file in each archive. WinRAR supports creating encrypted, multi-part and self-extracting archives, WinRAR and the RAR file format have evolved over time. Support for the archive format RAR5, using the same RAR file extension as earlier versions, was added in v5, WinRAR versions before 5.0 do not support RAR5 archives. AES encryption, when used, was increased from 128- to 256-bit, maximum path length for files in RAR and ZIP archives is increased to 2048 characters. The RAR5 file format removed comments for each file, authenticity verification, RAR5 also changed the file name for split volumes from archivename. rNN to archivename. partNN. rar. Packing of RAR or ZIP archives, unpacking of ACE, ARJ, BZIP2, CAB, EXE, GZ, ISO, JAR, LHA, RAR, TAR, UUE, XZ, Z, ZIP, ZIPX, 7z,001 archives. Checksum verification for ACE, ARJ, BZIP2, CAB, GZ, BZIP2, RAR, XZ, ZIP, when creating RAR archives, Support for maximum file size of 16 EiB minus 1. Compression dictionary from 1 MiB to 1 GiB, optional 256-bit BLAKE2 file hash can replace default 32-bit CRC32 file checksum. Optional encryption using AES with a 256-bit key, optional data redundancy is provided in the form of Reed-Solomon recovery records and recovery volumes, allowing reconstruction of damaged archives. Optional Quick Open Record to open RAR files faster, Ability to create multi-volume archives Ability to create self-extracting files. The self-extractor can execute commands, such as running a specified program automatically after self-extraction, Support for advanced NTFS file system options, such as NTFS hard and symbolic links. Support for maximum path length up to 2048 characters, optional file time stamp preservation, creation, last access, high precision modification times. The software is distributed as try before you buy, it may be used without charge for 40 days, in China, a completely free-to-use personal edition has been provided officially since 2015. It was widely reported that WinRAR v5. exe labelled as self-extracting archive, then you can trick them into running your smuggled JavaScript. Command line RAR and UNRAR were first released in autumn 1993, early development version WinRAR1. 54b was released in 1995 as 16-bit Windows 3. x application. Version 2.00 was released on September 6,1996, since version 3.00, the new RAR3 archive format is implemented. The new compressed archives cannot be managed by old versions of WinRAR, since version 3.41, WinRAR adds support for Linux. Z archives like GZIP and BZIP2
11.
JAR (software)
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JAR is a tool for creating compressed file archives that use. j as their file extension. It was invented by Robert K. Jung and was meant to be a successor to ARJ and it can achieve very good compression, but is not in wide use. JAR should not be confused with the. jar file extension used for Java Archive files, ARJ, an archiver by the same author ARJ Software Inc
12.
Free software
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The right to study and modify software entails availability of the software source code to its users. This right is conditional on the person actually having a copy of the software. Richard Stallman used the existing term free software when he launched the GNU Project—a collaborative effort to create a freedom-respecting operating system—and the Free Software Foundation. The FSFs Free Software Definition states that users of software are free because they do not need to ask for permission to use the software. Free software thus differs from proprietary software, such as Microsoft Office, Google Docs, Sheets, and Slides or iWork from Apple, which users cannot study, change, freeware, which is a category of freedom-restricting proprietary software that does not require payment for use. For computer programs that are covered by law, software freedom is achieved with a software license. Software that is not covered by law, such as software in the public domain, is free if the source code is in the public domain. Proprietary software, including freeware, use restrictive software licences or EULAs, Users are thus prevented from changing the software, and this results in the user relying on the publisher to provide updates, help, and support. This situation is called vendor lock-in, Users often may not reverse engineer, modify, or redistribute proprietary software. Other legal and technical aspects, such as patents and digital rights management may restrict users in exercising their rights. Free software may be developed collaboratively by volunteer computer programmers or by corporations, as part of a commercial, from the 1950s up until the early 1970s, it was normal for computer users to have the software freedoms associated with free software, which was typically public domain software. Software was commonly shared by individuals who used computers and by manufacturers who welcomed the fact that people were making software that made their hardware useful. Organizations of users and suppliers, for example, SHARE, were formed to exchange of software. As software was written in an interpreted language such as BASIC. Software was also shared and distributed as printed source code in computer magazines and books, in United States vs. IBM, filed January 17,1969, the government charged that bundled software was anti-competitive. While some software might always be free, there would henceforth be an amount of software produced primarily for sale. In the 1970s and early 1980s, the industry began using technical measures to prevent computer users from being able to study or adapt the software as they saw fit. In 1980, copyright law was extended to computer programs, Software development for the GNU operating system began in January 1984, and the Free Software Foundation was founded in October 1985
13.
Archive Manager
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Archive Manager is the archive manager of the GNOME desktop environment. Archive Manager can, Create and modify archives, view the content of an archive. View a file contained in the archive, backend programs are needed to use Archive Manager as a frontend. This can be set however using gconf-editor, Comparison of archive formats Comparison of file archivers Official website Manuals Source code
14.
Ark (software)
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Ark is a file archiver and compressor developed by KDE and included in the KDE Applications software bundle. It supports various common archive and compression formats including zip, 7z, rar, lha, Ark uses libarchive and karchive to support tar-based archives, and is also a frontend for several command-line archivers. Ark can be integrated into Konqueror, through KParts technology, after installing it, files can be added or extracted in/from the archives using Konquerors context menus. Support for editing files in archive with external programs, files can also be deleted from the archive. Archive creation with drag and drop from file manager, comparison of file archivers KDE Utilities / Ark
15.
Haiku Applications
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Haiku is a free and open-source operating system compatible with the now discontinued BeOS. Haiku comes with a set of small yet essential applications. Core applications are a part of Haiku, as they serve many different purposes. Haiku also has some 3rd party applications to supplement the core applications, the applications are usually executed by double clicking on the icon. ActivityMonitor is a monitor, making it possible for users to analyse the performance. They can view such as the memory being used, cached memory. ActivityMonitor presents the information in form, which makes it easy for the users to understand their computer performance. Haiku CharacterMap is a Character Map utility that shows the UTF-8 Code of every character a font supports, the font size can be changed and the user can drag any character into the StyledEdit application or the character can be copied and pasted where needed. CodyCam is a photo and video program that makes it possible for the user to take pictures at a specified interval from a connected webcam or any other video-in device. Users can specify the name, the image and video format, the capture interval. DeskCalc is a simple Calculator that can perform different tasks related to mathematics and it has a simple interface and on the front screen it has some functions or buttons which can perform addition, subtraction, multiplication and division but it is not restricted to these only. DeskCalc can also perform tasks related to trigonometry, the type of the calculator can also be changed into scientific, radical or any other type to use it for different purposes. DiskProbe is a Hex editor to view and alter data of a file or on a device on a byte-level, at the start, a file has to be chosen by the user to edit it further in the application. The main view shows a block of data and its size can be changed, diskUsage is a Disk space analyser application that provides graphical information to the user showing the disk space being consumed. Scan button has to be clicked once the user executes the application in order to start the scanning process, the application provides a pie chart showing the volume of space being used. Users can understand the graph and can utilise that data in different ways. Every segment of the circle represents a folder and when the cursor is taken one of them. The user can choose to re-scan the folder if they want to and they can also open it with another application or can fetch further information about the memory consumed
16.
KGB Archiver
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KGB Archiver is a file archiver and data compression utility based on the PAQ6 compression algorithm. Written in Microsoft Visual C++ by Tomasz Pawlak, KGB Archiver is designed to achieve a high compression ratio. As a consequence, the program is relatively memory- and CPU-intensive, KGB Archiver is free and open-source software released under the terms of the GNU General Public License. Version 2 beta 2 is available for Microsoft Windows and a version of KGB Archiver 1.0 is available for Unix-like operating systems. KGB Archiver is one of the few applications that works with the PAQ algorithm for making its KGB files and it has ten levels of compression, from very weak to maximal. However, at higher levels, the time required to compress a file increases significantly. The official website is now offline, the minimum requirements for running KGB Archiver are,1.5 GHz processor 256 MB RAM Supports native. kgb files and. RAR Comparison of file archivers KGB Archiver on SourceForge. net
17.
PAQ
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PAQ is a series of lossless data compression archivers that have gone through collaborative development to top rankings on several benchmarks measuring compression ratio. Specialized versions of PAQ have won the Hutter Prize and the Calgary Challenge, PAQ is free software distributed under the GNU General Public License. PAQ uses a context mixing algorithm, unlike PPM, a context doesnt need to be contiguous. All PAQ versions predict and compress one bit at a time, once the next-bit probability is determined, it is encoded by arithmetic coding. There are three methods for combining predictions, depending on the version, In PAQ1 through PAQ3, each prediction is represented as a pair of bit counts and these counts are combined by weighted summation, with greater weights given to longer contexts. In PAQ4 through PAQ6, the predictions are combined as before, in PAQ7 and later, each model outputs a probability rather than a pair of counts. The probabilities are combined using a neural network. PAQ1SSE and later versions postprocess the prediction using secondary symbol estimation, the combined prediction and a small context are used to look up a new prediction in a table. After the bit is encoded, the entry is adjusted to reduce the prediction error. SSE stages can be pipelined with different contexts or computed in parallel with the outputs averaged and it is always possible to find an x such that the length of x is at most one byte longer than the Shannon limit, −log2P bits. The length of s is stored in the archive header, the arithmetic coder in PAQ is implemented by maintaining for each prediction a lower and upper bound on x, initially. After each prediction, the current range is split into two parts in proportion to P and P, the probability that the bit of s will be a 0 or 1 respectively. The next bit is encoded by selecting the corresponding subrange to be the new range. The number x is decompressed back to string s by making a series of bit predictions. The range is split as with compression, the portion containing x becomes the new range, and the corresponding bit is appended to s. In PAQ, the lower and upper bounds of the range are represented in 3 parts, the most significant base-256 digits are identical, so they can be written as the leading bytes of x. The next 4 bytes are kept in memory, such that the byte is different. The trailing bits are assumed to be all zeros for the lower bound, Compression is terminated by writing one more byte from the lower bound
18.
PeaZip
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PeaZip is a free and open-source file manager and file archiver for Microsoft Windows, Linux and BSD made by Giorgio Tani. It supports its native PEA archive format and other mainstream formats, PeaZip is mainly written in Free Pascal, using Lazarus. PeaZip is released under the terms of the GNU Lesser General Public License, PeaZip allows users to run extracting and archiving operations automatically using command-line generated exporting the job defined in the GUI front-end. It can also create, edit and restore an archives layout for speeding up archiving or backup operations definition, in addition, the programs user interface can be customized. PeaZip is available for IA-32 and x86-64 as natively standalone, portable application and as installable package for Microsoft Windows, Linux and it is available also as PortableApps package. Along with more popular and general-purpose archive formats like 7z, Tar, PeaZip supports the PAQ and LPAQ formats. PeaZip supports encryption with AES 256-bit cipher in 7z, and ZIP archive formats, in PeaZips native PEA format, and in FreeArcs ARC format, supported ciphers are AES 256-bit, Blowfish, Twofish 256 and Serpent 256. The graphical frontends progress bar is less reliable than the native consoles progress indicator for the various backend utilities, PeaZip does not support editing files inside archives It also does not support adding files to subfolders in an already created archive. Adding files to archives always adds them to the root directory, PEA, an acronym for Pack Encrypt Authenticate, is an archive file format. It is a general purpose archiving format featuring compression and multiple volume output and it was developed in conjunction with the PeaZip file archiver. PeaZip and Universal Extractor support the PEA archive format. DLL2.6.0, FreeArcs ARC Prior to release 5. From release 5.3 on, PeaZip no longer has ad-supported bundle, PeaZip Portable and PeaZip for Linux packages never featured an ad-supported bundle. net
19.
Tar (computing)
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In computing, tar is a computer software utility for collecting many files into one archive file, often referred to as a tarball, for distribution or backup purposes. The name is derived from ape chive, as it was developed to write data to sequential I/O devices with no file system of their own. The archive data sets created by tar contain various file system parameters, such as name, time stamps, ownership, file access permissions, the command line utility was first introduced in the seventh edition of unix in January 1979, replacing the tp program. The file structure to store information was later standardized in POSIX. 1-1988 and later POSIX. 1-2001. Many historic tape drives read and write variable-length data blocks, leaving significant wasted space on the tape between blocks, some tape drives only support fixed-length data blocks. Also, when writing to any medium such as a filesystem or network, therefore, the tar command writes data in blocks of many 512 byte records. The user can specify a blocking factor, which is the number of records per block, a tar archive consists of a series of file objects, hence the popular term tarball, referencing how a tarball collects objects of all kinds that stick to its surface. Each file object includes any data, and is preceded by a 512-byte header record. The file data is written unaltered except that its length is rounded up to a multiple of 512 bytes. The original tar implementation did not care about the contents of the padding bytes, and left the buffer data unaltered, the end of an archive is marked by at least two consecutive zero-filled records. The final block of an archive is padded out to length with zeros. The file header record contains metadata about a file, to ensure portability across different architectures with different byte orderings, the information in the header record is encoded in ASCII. Thus if all the files in an archive are ASCII text files, the fields defined by the original Unix tar format are listed in the table below. The link indicator/file type table includes some modern extensions, when a field is unused it is filled with NUL bytes. The header uses 257 bytes, then is padded with NUL bytes to make it fill a 512 byte record, there is no magic number in the header, for file identification. Numeric values are encoded in octal numbers using ASCII digits, with leading zeroes, for historical reasons, a final NUL or space character should also be used. Thus although there are 12 bytes reserved for storing the file size and this gives a maximum file size of 8 gigabytes on archived files. To overcome this limitation, star in 2001 introduced a base-256 coding that is indicated by setting the bit of the leftmost byte of a numeric field
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Xarchiver
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Xarchiver is a front-end to various command line archiving tools for Linux and BSD operating systems, designed to be independent of the desktop environment. It is the default archiving application of Xfce and LXDE and it uses the GTK+2 toolkit to provide the program interface, therefore it is capable of running on any system where GTK+2 support exists. A large number of applications also use the toolkit, so support is widespread among other Linux distributions irrespective of their specific desktop solution. Supported formats at this time with an installed program are 7z, ARJ, bzip2, gzip, LHA, lzma, lzop, RAR, RPM, DEB, tar. Xarchiver uses the Direct Save Protocol XDS for drag and drop file saving, the program acts as a front-end for various commonly installed libraries dealing with the supported compression formats. Xarchiver cant create archives whose archiver is not installed, currently, the Xfce master branch of Xarchiver is being continued at GitHub. Comparison of file archivers Official website Continuation at GitHub Xarchiver on SourceForge. net Xarchiver
21.
Filzip
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Filzip is a freeware file archiver program for the Microsoft Windows platform. It was written by Philipp Engel, while free, the author does request donations to help the cost of development and reward him for his work. As of April 2015, no new version has been released since version 3.0.6, Filzip has been presumed unmaintained the software development. The program has been localized to more than twenty languages, Filzip supports seven different archive formats, allowing the user to add and extract files from the archives. These include ZIP, BH, CAB, JAR, LHA, TAR, a handful of other formats are supported for extraction only, including ACE, ARC, ARJ, RAR, and ZOO. Files within most formats can be viewed without explicitly unpacking them, ZIP files may be spanned, that is, written to any number of files with a fixed maximum size so that they can be placed on removable media. The program has integration, and can create self-extracting executable archives for redistribution without licensing fees, CNET rated it 4/5 stars and wrote, Easy program operation sets this freeware file compression tool apart from the crowded genre. Comparison of file archivers Comparison of archive formats List of archive formats ZIP Official website File compression review including Filzip Review of Filzip at DonationCoder. com
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StuffIt Expander
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StuffIt Expander is a proprietary, freeware, closed source, decompression software utility developed by Allume Systems. It runs on the classic Mac OS, macOS, Microsoft Windows, as of November 2010, the latest Macintosh version is 2011, which requires Mac OS X v10.5 or later. Version 2010 runs on Mac OS X v10.4, version 10.0.2 runs on Mac OS X v10.3, the latest version for Mac OS9 is 7.0.3. As of September 2011, the Linux version is no longer available for download from the official page, StuffIt has been a target of criticism and dissatisfaction from Mac users in the past as the file format changes frequently, notably during the introduction of StuffIt version 5.0. Expander 5.0 contained many bugs, and its format was not readable by the earlier version 4.5. The latest stand-alone version for Windows is 2009, contrary to the version 12.0, which was only able to decompress the newer. sitx archives, version 2009 claims to be able to decompress over 30 formats, some listed below. The executables require both, the. NET v2.0 framework and MSVC2008 runtimes, the previous stand-alone version able to decompress. sit and other classic Mac OS-specific archives was 7.02, distributed with StuffIt v7.0. x for Windows. From versions 7.5. x to 11 the Expander capabilities were actually performed by the StuffIt Standard Edition, to start StuffIt in Expander mode the following command line switches were used, -expand -uiexpander. Note that the registration reminder dialogue box is not shown in this case, there is also a command line DOS application called UNSTUFF v1.1 that allows decompression of. sit files. x StuffIt v1.5.1 to 8.0
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TUGZip
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TUGZip is a freeware file archiver for Microsoft Windows. It handles a variety of archive formats, including some of the commonly used ones like zip, rar, gzip, bzip2, sqx. It can also view disk image files like BIN, C2D, IMG, ISO, tugZip repairs corrupted ZIP archives and can encrypt files with 6 different algorithms. Since the release of TUGZip 3.5.0.0, development has been suspended due to lack of time from Kindahls side
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ZipGenius
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ZipGenius is a freeware file archiver developed by Matteo Riso of M. Dev Software for Microsoft Windows. It is capable of handling nearly two dozen file formats, including all the most common formats, as well as password-protect archives and it is presented in two editions, standard and suite. While the suite edition includes optional modules of the ZipGenius project, ZipGenius was first released as Mr. Zip 98 to a strict group of users, and renamed ZipGenius in March 1998. In April 1999, its first public release was made, zipGeniuss latest release is version 6.3.2.3112, containing a large number of fixes, the majority of which are bug fixes not visible at first glance. ZipGenius features include, support for TWAIN devices, file extraction to CD/DVD burner, an FTP client, ZGAlbum allows users to create slideshows with pictures, which can be loaded from a folder or imported through a TWAIN device. ZipGenius also fully integrates with Windows Explorer shell, user interface and functions have been placed in multiple locations. Program functions can be accessed either from a menu of buttons on the main toolbar and they can be customized to suit user preferences. ZipGenius 6 is capable of opening a variety of commonly used with Linux, such as RPM, TAR, TAR. GZ, TGZ, GZ. As regards data security, the archive history file is encrypted, the most recently used files list can be enabled or disabled, users can create self-locking/self-erasing archives and can choose to encrypt files with one of four algorithms. Also, CZIP files no longer depends on ZipGenius because users can create executable CZIP files which allow the user to send encrypted archives to people who do not use ZipGenius. ZipGenius is reported to be still under development and it is claimed that Matteo Riso, the main developer, is focusing on next release, whose codename is Miky2007, and that a new version of the software will be still branded as ZipGenius. ZipGenius is hosted at zipgenius. it, but in 2008 the WinInizio Software team put zipgenius. com online to offer a website for users not speaking Italian. WinInizio. it hosts also a support section — in both Italian and English. On July 1,2009, website ZipGenius. it has been totally redesigned upon the MODx web application, on July 6,2009, ZipGenius 6.1.0.1010 was released to the public. ZipGenius is able to handle the open source UPX executable compressor, if UPX. exe is in ZipGenius program folder, users will get an extra compression level while creating new ZIP archives, Brutal+UPX. Many executable files are distributed as they are after code compilation, ZipGenius supports the 7-Zip compression format, conceived by Igor Pavlov, which can compress files more than standard ZIP or RAR compression formats. ZipGenius complies with this feature, and allows users to manage those files as if they were common ZIP files, in addition, users can optimize them, OpenOffice. org does not use the maximum compression level available for. ZIP format, but ZipGenius does. When users optimize an OpenOffice. org document with ZipGenius, the gain is from 5 to 10 KB of size reduction because ZipGenius will recompress the document with the Brutal compression level, list of file archivers Comparison of file archivers Official international website ZipGenius homepage
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PowerArchiver
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PowerArchiver is a proprietary file archiver for Microsoft Windows, developed by ConeXware Inc. It supports full read-write access to several different archive formats, including ZIP, 7z, additionally, read-only support includes RAR, ACE and various disk image formats. The evaluation version of the program remains functional for 40 days, personal licenses are currently permitted free lifetime updates to all future versions of the software, while the business license is valid through two major versions. PowerArchivers first public release was made in March 1999 and it was advertised as a free archiving solution and was written in Borland Delphi. It turned into shareware in June 2001 with version 7, prior to being PowerArchiver, the software was known as EasyZip. A command line version and a Microsoft Outlook plugin is also provided, powerArchivers user interface has been translated into 15 languages. The latest release of PowerArchiver fully supports Windows 7 and provides the user an option to use the Ribbon GUI, as featured in Microsoft Office 2007, users can revert to the old-style toolbar if they wish. In 2011 Softpedia gave it five stars, praising its wide support for various compressed file types, FTP, later in 2013 Download. com gave it five stars. Data compression Comparison of file archivers PowerArchiver home page History pre-9.0, post-9.0
26.
WinAce
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WinAce is an archiving program for Windows with its own ACE compressed archive format and built-in support for other common archive formats types such as ZIP, RAR and CAB. They also offer a freeware command-line decompression program called Unace for Mac OS X, WinAce peaked in popularity around 2000, but since fallen in popularity to WinRAR and Windows built-in Zip functionality. Beginning with version 2.65, WinAce is bundled with the WhenU adware program and this bundle has been removed from the current version and has been replaced with an opt-in sponsorship deal via TrialPay. There is a version for DOS called Commandline ACE. In addition to the ACE format, it has support for other common archive format types such as ARJ, RAR, ZIP. Program distribution contains both Commandline ACE and UnACE decompressor, both programs are in versions for DOS, OS/2 and Windows, and have support for Long File Names. Despite its name, Commandline ACE contains full-fledged Norton Commander-like interface, UnACE can be run only in commandline mode. Commandline ACE can be used for manipulation, similar to that existing in Norton Commander. List of file archivers Comparison of file archivers Official WinAce site
27.
WinZip
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WinZip is a shareware file archiver and compressor for Windows, macOS, iOS and Android developed by WinZip Computing. It can create archives in Zip file format, and unpack some other file formats. Unpack BZ2, LHA, LZH, RAR, ZIP, 7Z, WinZip 1.0 was released in April 1991 as a graphical user interface front-end for PKZIP. Earlier in January 1991 Nico Mak Computing released a GUI front-end for OS/2 Presentation Manager called PMZIP and it used the OS/2 versions of the PKWARE, Inc. Originally released on CompuServe, availability of WinZip expanded across major online services, including GEnie, Prodigy, in 1993, WinZip announced the launch of its official support for customers on the Windows Utility Forum, serving over 100,000 members, providing updates and related information. By 1994, WinZip had become the official and required compression tool used by operators on CompuServe for forum file libraries. Starting from version 5.0 in 1993, the creators of WinZip incorporated compression code from the Info-ZIP project, from version 6.0 until version 9. This upgrade scheme was discontinued as of version 10.0, WinZip is available in standard and professional versions. However, the shell in Windows ME and later versions of Microsoft Windows has the ability to open and create. zip files, which reduces the need for extra compression software. On May 2,2006, Corel Corporation, best known for its WordPerfect and CorelDRAW product lines, WinZip 1.0 for Mac OS X was released in November 2010. This version is compatible with Mac OS X10.6 “Snow Leopard”, WinZip Mac Edition 2 includes support for OS X10.8 Mountain Lion. 128- and 256-bit key AES encryption in addition to the less secure PKZIP2.0 encryption method used in earlier versions, the AES implementation, using Brian Gladmans code, was FIPS-197 certified, on March 27,2003. However, Central Directory Encryption feature is not supported, support of additional compression methods, bzip2, PPMd, WavPack, LZMA, JPEG. Unicode support to ensure international characters are displayed for filenames in a Zip file, the ZIP file archive format was originally invented for MS-DOS in 1989 by Phil Katz. Seeing the need for an application with a Graphical User Interface, Nico Mak seized the opportunity. WinZip 1.0 was initial version for Windows, WinZip 2.0 added support for ARC files, support for self-extracting ZIP files, optional interface to Virus Scan software, dialog box to specify paths and filenames of external programs. WinZip 3.0 added full support for LZH files, including self-extracting LZH files, configurable support for most virus scanners, simplified options to add, WinZip 3.2 added Built-in ZIP Extraction so that PKUNZIP is not needed for most ZIP extract operations. WinZip always uses PKZIP. EXE to modify ZIP files, WinZip 4.0 added support for PKZIP2.0, including built-in ZIP extraction, support for the ARJ file format, new toolbar with descriptive pictorial buttons, added a 3-D look to all dialog boxes
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Bzip2
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Bzip2 is a free and open-source file compression program that uses the Burrows–Wheeler algorithm. It only compresses single files and is not a file archiver and it is developed and maintained by Julian Seward. Seward made the first public release of bzip2, version 0.15, the compressors stability and popularity grew over the next several years, and Seward released version 1.0 in late 2000. Bzip2 compresses most files more effectively than the older LZW and Deflate compression algorithms, LZMA is generally more space-efficient than bzip2 at the expense of even slower compression speed, while having much faster decompression. Bzip2 compresses data in blocks of size between 100 and 900 kB and uses the Burrows–Wheeler transform to convert frequently-recurring character sequences into strings of identical letters and it then applies move-to-front transform and Huffman coding. Bzip2s ancestor bzip used arithmetic coding instead of Huffman, the change was made because of a software patent restriction. Bzip2 performance is asymmetric, as decompression is relatively fast, as of May 2010, this functionality has not been incorporated into the main project. Like gzip, bzip2 is only a data compressor, thus the sequence AAAAAAABBBBCCCD is replaced with AAAA\3BBBB\0CCCD, where \3 and \0 represent byte values 3 and 0 respectively. Runs of symbols are always transformed after four consecutive symbols, even if the run-length is set to zero, in the worst case, it can cause an expansion of 1.25 and best case a reduction to <0.02. While the specification allows for runs of length 256–259 to be encoded. The author of bzip2 has stated that the RLE step was a mistake and was only intended to protect the original BWT implementation from pathological cases. This is the reversible block-sort that is at the core of bzip2, the block is entirely self-contained, with input and output buffers remaining the same size—in bzip2, the operating limit for this stage is 900 kB. For the block-sort, a matrix is created in which row i contains the whole of the buffer, following rotation, the rows of the matrix are sorted into alphabetic order. A 24-bit pointer is stored marking the position for when the block is untransformed. In practice, it is not necessary to construct the matrix, rather. The output buffer is the last column of the matrix, this contains the whole buffer, again, this transform does not alter the size of the processed block. Each of the symbols in use in the document is placed in an array, when a symbol is processed, it is replaced by its location in the array and that symbol is shuffled to the front of the array. The effect is that immediately recurring symbols are replaced by zero symbols, much natural data contains identical symbols that recur within a limited range
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Gzip
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Gzip is a file format and a software application used for file compression and decompression. The program was created by Jean-loup Gailly and Mark Adler as a free replacement for the compress program used in early Unix systems. Version 0.1 was first publicly released on 31 October 1992, Gzip is based on the DEFLATE algorithm, which is a combination of LZ77 and Huffman coding. DEFLATE was intended as a replacement for LZW and other patent-encumbered data compression algorithms which, at the time, limited the usability of compress, although its file format also allows for multiple such streams to be concatenated, gzip is normally used to compress just single files. Compressed archives are created by assembling collections of files into a single tar archive. The final. tar. gz or. tgz file is called a tarball. Gzip is not to be confused with the ZIP archive format, various implementations of the program have been written. The most commonly known is the GNU Projects implementation using Lempel-Ziv coding, openBSDs version of gzip is actually the compress program, to which support for the gzip format was added in OpenBSD3.4. The g in this specific version stands for gratis and these implementations originally come from NetBSD, and supports decompression of bzip2 and the Unix pack format. The tar utility included in most Linux distributions can extract. tar. gz files by passing the z option, zlib is an abstraction of the DEFLATE algorithm in library form which includes support both for the gzip file format and a lightweight stream format in its API. The zlib stream format, DEFLATE, and the file format were standardized respectively as RFC1950, RFC1951. The gzip format is used in HTTP compression, a used to speed up the sending of HTML. It is one of the three formats for HTTP compression as specified in RFC2616. This RFC also specifies a zlib format, which is equal to the gzip format except that gzip adds eleven bytes of overhead in the form of headers and trailers. Still, the format is sometimes recommended over zlib because Microsoft Internet Explorer does not implement the standard correctly. Zlib DEFLATE is used internally by the Portable Network Graphics format, since the late 1990s, bzip2, a file compression utility based on a block-sorting algorithm, has gained some popularity as a gzip replacement. It produces considerably smaller files, but at the cost of memory, comparison of file archivers Free file format List of archive formats List of Unix programs GNU Gzip home page Original gzip Home Page
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Lzip
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Like gzip and bzip2, concatenation is supported to compress multiple files, but the convention is to bundle a file that is an archive itself, such as those created by the tar or cpio Unix programs. Lzip can split the output for the creation of multivolume archives, the file that is produced by lzip is usually given. lz as its filename extension, and the data is described by the MIME type application/x-lzip. The lzip suite of programs was written in C++ and C by Antonio Diaz Diaz and is being distributed as software under the terms of version 2 or later of the GNU General Public License. Lzip is capable of creating archives with independently decompressible data sections called a multimember archive, for example, if the underlying file is a tar archive, this can allow extracting any undamaged files, even if other parts of the archive are damaged. The recovery tool can merge multiple copies of an archive where each copy may have damage in a different part of the file. 7-Zip was released in 2000, a tool employing LZMA first became available on Unix-like operating systems in 2004 when a port of the version of 7-Zip was released. Nevertheless, LZMA Utils was extended to have features and then renamed to XZ Utils. The Linux distribution Dragora GNU/Linux-Libre employs lzip for its software packages, in popular Linux distributions, lzip can usually be installed from official package repositories. GNOMEs archiving tool, Archive Manager, supports lzip files, adding dist-lzip to AM_INIT_AUTOMAKE will build lzip-ed tarballs. Lossless data compression Comparison of archive repair programs Official website Lzip format specification
