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LZFSE
LZFSE (Lempel–Ziv Finite State Entropy) is an open source lossless data compression algorithm created by Apple Inc. It was released with a simpler algorithm called LZVN. Overview The name is an acronym for Lempel–Ziv and finite-state entropy (implementation of asymmetric numeral systems). LZFSE was introduced by Apple at its Worldwide Developer Conference 2015. It shipped with that year's iOS 9 and OS X 10.11 releases. Apple claims that LZFSE compresses with a ratio comparable to that of zlib ( DEFLATE) and decompresses two to three times faster while using fewer resources, therefore offering higher energy efficiency than zlib. It was aimed for scenarios where decompression speed and rate should be prioritised equally. Part of this energy efficiency was achieved by optimising the algorithm for modern micro-architectures, specifically focusing on arm64. Third-party benchmarking confirms that LZFSE decompresses faster than zlib, but also suggests that many other modern co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Finite-state Entropy
Asymmetric numeral systems (ANS)J. Duda, K. Tahboub, N. J. Gadil, E. J. Delp''The use of asymmetric numeral systems as an accurate replacement for Huffman coding'' Picture Coding Symposium, 2015.J. Duda''Asymmetric numeral systems: entropy coding combining speed of Huffman coding with compression rate of arithmetic coding'' arXiv:1311.2540, 2013. is a family of entropy encoding methods introduced by Jarosław (Jarek) Duda from Jagiellonian University, used in data compression since 2014 due to improved performance compared to previous methods. ANS combines the compression ratio of arithmetic coding (which uses a nearly accurate probability distribution), with a processing cost similar to that of Huffman coding. In the tabled ANS (tANS) variant, this is achieved by constructing a finite-state machine to operate on a large alphabet without using multiplication. Among others, ANS is used in the Facebook Zstandard compressor [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asymmetric Numeral System
Asymmetric numeral systems (ANS)J. Duda, K. Tahboub, N. J. Gadil, E. J. Delp''The use of asymmetric numeral systems as an accurate replacement for Huffman coding'' Picture Coding Symposium, 2015.J. Duda''Asymmetric numeral systems: entropy coding combining speed of Huffman coding with compression rate of arithmetic coding'' arXiv:1311.2540, 2013. is a family of entropy encoding methods introduced by Jarosław (Jarek) Duda from Jagiellonian University, used in data compression since 2014 due to improved performance compared to previous methods. ANS combines the compression ratio of arithmetic coding (which uses a nearly accurate probability distribution), with a processing cost similar to that of Huffman coding. In the tabled ANS (tANS) variant, this is achieved by constructing a finite-state machine to operate on a large alphabet without using multiplication. Among others, ANS is used in the Facebook Zstandard compressor [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apple Disk Image
Apple Disk Image is a disk image format commonly used by the macOS operating system. When opened, an Apple Disk Image is mounted as a volume within the Finder. An Apple Disk Image can be structured according to one of several proprietary disk image formats, including the Universal Disk Image Format (UDIF) from Mac OS X and the New Disk Image Format (NDIF) from Mac OS 9. An Apple disk image file's name usually has ".dmg" as its extension. A disk image is a compressed copy of the contents of a disk or folder. Disk images have .dmg at the end of their names. To see the contents of a disk image, you must first open the disk image so it appears on the desktop or in a Finder window. Features Apple Disk Image files are published with a MIME type of ''application/x-apple-diskimage''. Different file systems can be contained inside these disk images, and there is also support for creating hybrid optical media images that contain multiple file systems. Some of the file systems suppo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lossless Compression Algorithms
Lossless compression is a class of data compression that allows the original data to be perfectly reconstructed from the compressed data with no loss of information. Lossless compression is possible because most real-world data exhibits statistical redundancy. By contrast, lossy compression permits reconstruction only of an approximation of the original data, though usually with greatly improved compression rates (and therefore reduced media sizes). By operation of the pigeonhole principle, no lossless compression algorithm can efficiently compress all possible data. For this reason, many different algorithms exist that are designed either with a specific type of input data in mind or with specific assumptions about what kinds of redundancy the uncompressed data are likely to contain. Therefore, compression ratios tend to be stronger on human- and machine-readable documents and code in comparison to entropic binary data (random bytes). Lossless data compression is used in many ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zstandard
Zstandard, commonly known by the name of its reference implementation zstd, is a lossless data compression algorithm developed by Yann Collet at Facebook. ''Zstd'' is the reference implementation in C. Version 1 of this implementation was released as open-source software on 31 August 2016. Features Zstandard was designed to give a compression ratio comparable to that of the DEFLATE algorithm (developed in 1991 and used in the original ZIP and gzip programs), but faster, especially for decompression. It is tunable with compression levels ranging from negative 7 (fastest) to 22 (slowest in compression speed, but best compression ratio). The zstd package includes parallel (multi-threaded) implementations of both compression and decompression. Starting from version 1.3.2 (October 2017), zstd optionally implements very long range search and deduplication (, 128 MiB window) similar to rzip or lrzip. Compression speed can vary by a factor of 20 or more between the fastest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lossless Data Compression
Lossless compression is a class of data compression that allows the original data to be perfectly reconstructed from the compressed data with no loss of information. Lossless compression is possible because most real-world data exhibits statistical redundancy. By contrast, lossy compression permits reconstruction only of an approximation of the original data, though usually with greatly improved compression rates (and therefore reduced media sizes). By operation of the pigeonhole principle, no lossless compression algorithm can efficiently compress all possible data. For this reason, many different algorithms exist that are designed either with a specific type of input data in mind or with specific assumptions about what kinds of redundancy the uncompressed data are likely to contain. Therefore, compression ratios tend to be stronger on human- and machine-readable documents and code in comparison to entropic binary data (random bytes). Lossless data compression is used in man ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apple File System
Apple File System (APFS) is a proprietary file system developed and deployed by Apple Inc. for macOS Sierra (10.12.4) and later, iOS 10.3 and later, tvOS 10.2 and later, watchOS 3.2 and later, and all versions of iPadOS. It aims to fix core problems of HFS+ (also called Mac OS Extended), APFS's predecessor on these operating systems. APFS is optimized for solid-state drive storage and supports encryption, snapshots, and increased data integrity, among other capabilities. History Apple File System was announced at Apple's developers conference (WWDC) in June 2016 as a replacement for HFS+, which had been in use since 1998. APFS was released for 64-bit iOS devices on March 27, 2017, with the release of iOS 10.3, and for macOS devices on September 25, 2017, with the release of macOS 10.13. Apple released a partial specification for APFS in September 2018 which supported read-only access to Apple File Systems on unencrypted, non-Fusion storage devices. The specificati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HFS Plus
HFS Plus or HFS+ (also known as Mac OS Extended or HFS Extended) is a journaling file system developed by Apple Inc. It replaced the Hierarchical File System (HFS) as the primary file system of Apple computers with the 1998 release of Mac OS 8.1. HFS+ continued as the primary Mac OS X file system until it was itself replaced with the Apple File System (APFS), released with macOS High Sierra in 2017. HFS+ is also one of the formats supported by the iPod digital music player. Compared to its predecessor HFS, also called ''Mac OS Standard'' or ''HFS Standard,'' HFS Plus supports much larger files (block addresses are 32-bit length instead of 16-bit) and using Unicode (instead of Mac OS Roman or any of several other character sets) for naming items. Like HFS, HFS Plus uses B-trees to store most volume metadata, but unlike most file systems that support hard links, HFS Plus supports hard links to directories. HFS Plus permits filenames up to 255 characters in length, and n-fork ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ARM64
AArch64 or ARM64 is the 64-bit extension of the ARM architecture family. It was first introduced with the Armv8-A architecture. Arm releases a new extension every year. ARMv8.x and ARMv9.x extensions and features Announced in October 2011, ARMv8-A represents a fundamental change to the ARM architecture. It adds an optional 64-bit architecture, named "AArch64", and the associated new "A64" instruction set. AArch64 provides user-space compatibility with the existing 32-bit architecture ("AArch32" / ARMv7-A), and instruction set ("A32"). The 16-32bit Thumb instruction set is referred to as "T32" and has no 64-bit counterpart. ARMv8-A allows 32-bit applications to be executed in a 64-bit OS, and a 32-bit OS to be under the control of a 64-bit hypervisor. ARM announced their Cortex-A53 and Cortex-A57 cores on 30 October 2012. Apple was the first to release an ARMv8-A compatible core (Cyclone) in a consumer product (iPhone 5S). AppliedMicro, using an FPGA, was the first to demo ARMv8 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LZ4 (compression Algorithm)
LZ4 is a lossless data compression algorithm that is focused on compression and decompression speed. It belongs to the LZ77 family of byte-oriented compression schemes. Features The LZ4 algorithms aims to provide a good trade-off between speed and compression ratio. Typically, it has a smaller (i.e., worse) compression ratio than the similar LZO algorithm, which in turn is worse than algorithms like DEFLATE. However, LZ4 compression speed is similar to LZO and several times faster than DEFLATE, while decompression speed is significantly faster than LZO. Design LZ4 only uses a dictionary-matching stage (LZ77), and unlike other common compression algorithms does not combine it with an entropy coding stage (e.g. Huffman coding in DEFLATE). The LZ4 algorithm represents the data as a series of sequences. Each sequence begins with a one-byte token that is broken into two 4-bit fields. The first field represents the number of literal bytes that are to be copied to the output. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OS X El Capitan
OS X El Capitan ( ) () is the twelfth major release of macOS (named OS X at the time of El Capitan's release), Apple Inc.'s desktop and server operating system for Macintosh. It focuses mainly on performance, stability, and security. Following the California location-based naming scheme introduced with OS X Mavericks, El Capitan was named after a rock formation in Yosemite National Park. El Capitan is the final version to be released under the name OS X. OS X El Capitan received far better reviews than did Yosemite. The first beta of OS X El Capitan was released to developers shortly following the WWDC keynote on June 8, 2015. The first public beta was made available on July 9, 2015. There were multiple betas released after the keynote. OS X El Capitan was released to end users on September 30, 2015, as a free upgrade through the Mac App Store. System requirements All Macintosh products that can run Mountain Lion, Mavericks, or Yosemite can run El Capitan, although not all ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haruhiko Okumura
from Toshiba, Tokyo, Japan was named Fellow of the Institute of Electrical and Electronics Engineers (IEEE) in 2016 ''for contribution to image processing and display technologies''. His public domain The public domain (PD) consists of all the creative work to which no exclusive intellectual property rights apply. Those rights may have expired, been forfeited, expressly waived, or may be inapplicable. Because those rights have expired, ... LZSS implementation from 1989 is used in many products. He also worked on an adding an arithmetic-encoding step to form LZARI, the precursor to LZH.Haruhiko OkumuraHistory of Data Compression in Japan.Archived on January 10, 2016. References Fellow Members of the IEEE Living people Year of birth missing (living people) {{Japan-engineer-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
