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Flash File Systems
A flash file system is a file system designed for storing files on flash memory–based storage devices. While flash file systems are closely related to file systems in general, they are optimized for the nature and characteristics of flash memory (such as to avoid write amplification), and for use in particular operating systems. Overview While a block device layer can emulate a disk drive so that a general-purpose file system can be used on a flash-based storage device, this is suboptimal for several reasons: * Erasing blocks: flash memory blocks have to be explicitly erased before they can be written to. The time taken to erase blocks can be significant, thus it is beneficial to erase unused blocks while the device is idle. * Random access: general-purpose file systems are optimized to avoid disk seeks whenever possible, due to the high cost of seeking. Flash memory devices impose no seek latency. * Wear leveling: flash memory devices tend to wear out when a single bloc ...
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APFS
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, tvOS 10.2, watchOS 3.2, and all versions of iPadOS. It aims to fix core problems of HFS+ (also called Mac OS Extended), APFS's predecessor which had been in use since 1998. APFS is optimized for solid-state drive storage and supports encryption, snapshots, and improved handling of metadata integrity. 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 specification for software encryption was d ...
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UBIFS
UBIFS (UBI File System, more fully Unsorted Block Image File System) is a flash file system for unmanaged flash memory devices. UBIFS works on top of an UBI (unsorted block image) layer, which is itself on top of a memory technology device (MTD) layer. The file system is developed by Nokia engineers with help of the University of Szeged, Hungary. Development began in earnest in 2007, with the first stable release made to Linux kernel 2.6.27 in October 2008. Two major differences between UBIFS and JFFS2 are that UBIFS supports write caching, and UBIFS errs on the pessimistic side of free space calculation. UBIFS tends to perform better than JFFS2 for large NAND flash memory devices. This is a consequence of the UBIFS design goals: faster mounting, quicker access to large files, and improved write speeds. UBIFS also preserves or improves upon JFFS2's on-the-fly compression, recoverability and power fail tolerance. UBIFS's on-the-fly data compression allows zlib ( deflate alg ...
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Linux
Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, packaged as a Linux distribution (distro), which includes the kernel and supporting system software and library (computing), libraries—most of which are provided by third parties—to create a complete operating system, designed as a clone of Unix and released under the copyleft GPL license. List of Linux distributions, Thousands of Linux distributions exist, many based directly or indirectly on other distributions; popular Linux distributions include Debian, Fedora Linux, Linux Mint, Arch Linux, and Ubuntu, while commercial distributions include Red Hat Enterprise Linux, SUSE Linux Enterprise, and ChromeOS. Linux distributions are frequently used in server platforms. Many Linux distributions use the word "Linux" in their name, but the Free ...
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JFFS
The Journaling Flash File System (or JFFS) is a log-structured file system for use on NOR flash memory devices on the Linux operating system. It has been superseded by JFFS2. Design Flash memory (specifically NOR flash) must be erased prior to writing. The erase process has several limitations: * Erasing is very slow (typically 1–100 ms per erase block, which is 103–105 times slower than reading data from the same region). * It is only possible to erase flash in large segments (usually 64 KiB or more), whereas it can be read or written in smaller blocks (often 512 bytes). * Flash memory can only be erased a limited number of times (typically 103–106) before it becomes worn out. These constraints combine to produce a profound asymmetry between patterns of read and write access to flash memory. In contrast, magnetic hard disk drives offer nearly symmetrical read and write access: read speed and write speed are nearly identical (as both are constrained by the rate at ...
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Intel
Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California, and Delaware General Corporation Law, incorporated in Delaware. Intel designs, manufactures, and sells computer components such as central processing units (CPUs) and related products for business and consumer markets. It is one of the world's List of largest semiconductor chip manufacturers, largest semiconductor chip manufacturers by revenue, and ranked in the Fortune 500, ''Fortune'' 500 list of the List of largest companies in the United States by revenue, largest United States corporations by revenue for nearly a decade, from 2007 to 2016 Fiscal year, fiscal years, until it was removed from the ranking in 2018. In 2020, it was reinstated and ranked 45th, being the List of Fortune 500 computer software and information companies, 7th-largest technology company in the ranking. It was one of the first companies listed on Nasdaq. Intel supplies List of I ...
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Identiv
Identiv (originally SCM Microsystems) is a digital security and Internet of Things technology company listed on the Nasdaq stock market. Identiv provides physical and digital products using radio frequency identification (RFID) and near field communication (NFC) technologies, focusing on Internet of Things (IoT) applications. The company has customers in the government, enterprise, consumer, education, healthcare and transportation sectors. Identiv is headquartered in Fremont, California, and has additional locations in the Americas, Europe, the Middle East, and the Asia-Pacific. History Identiv was founded in 1990 in Munich, Germany as ''SCM Microsystems GmbH''. It received venture capital from Index Ventures and made its initial public offering An initial public offering (IPO) or stock launch is a public offering in which shares of a company are sold to institutional investors and usually also to retail (individual) investors. An IPO is typically underwritten by one ...
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PCMCIA
The Personal Computer Memory Card International Association (PCMCIA) was an industry consortium of computer hardware manufacturers from 1989 to 2009. Starting with the PCMCIA card in 1990 (the name later simplified to ''PC Card''), it created various standards for peripheral interfaces designed for laptop computers. History PCMCIA was based on the original initiative of the British mathematician and computer scientist Ian H. S. Cullimore, one of the founders of the Sunnyvale-based Poqet Computer Corporation, who was seeking to integrate some kind of memory card technology as storage medium into their early DOS-based palmtop PCs, when traditional floppy drives and harddisks were found to be too power-hungry and large to fit into their battery-powered handheld devices. When in July 1989, Poqet contacted Fujitsu for their existing but still non-standardized SRAM memory cards, and Intel for their flash technology, the necessity and potential of establishing a worldwide mem ...
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Write Once Read Many
Write once read many (WORM) describes a data storage device in which information, once written, cannot be modified. This write protection affords the assurance that the data cannot be tampered with once it is written to the device, excluding the possibility of data loss from human error, computer bugs, or malware. On ordinary (non-WORM) data storage devices, the number of times data can be modified is limited only by the lifespan of the device, as modification involves physical changes that may cause wear to the device. The "read many" aspect is unremarkable, as modern storage devices permit unlimited reading of data once written. Historical exceptions include time-limited discs such as Flexplay, designed for short-term rental of movies; and early non-volatile memory technologies such as magnetic-core memory and bubble memory, from which reading data also erased it. WORM prevents important data being deleted or modified, helping to preserve its authenticity. History WORM dr ...
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MS-DOS
MS-DOS ( ; acronym for Microsoft Disk Operating System, also known as Microsoft DOS) is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, its rebranding as IBM PC DOS, and a few operating systems attempting to be compatible with MS-DOS, are sometimes referred to as "DOS" (which is also the generic acronym for disk operating system). MS-DOS was the main operating system for IBM PC compatibles during the 1980s, from which point it was gradually superseded by operating systems offering a graphical user interface (GUI), in various generations of the graphical Microsoft Windows operating system. IBM licensed and re-released it in 1981 as PC DOS 1.0 for use in its PCs. Although MS-DOS and PC DOS were initially developed in parallel by Microsoft and IBM, the two products diverged after twelve years, in 1993, with recognizable differences in compatibility, syntax and capabilities. Beginning in 1988 with DR-DOS, ...
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Microsoft
Microsoft Corporation is an American multinational corporation and technology company, technology conglomerate headquartered in Redmond, Washington. Founded in 1975, the company became influential in the History of personal computers#The early 1980s and home computers, rise of personal computers through software like Windows, and the company has since expanded to Internet services, cloud computing, video gaming and other fields. Microsoft is the List of the largest software companies, largest software maker, one of the Trillion-dollar company, most valuable public U.S. companies, and one of the List of most valuable brands, most valuable brands globally. Microsoft was founded by Bill Gates and Paul Allen to develop and sell BASIC interpreters for the Altair 8800. It rose to dominate the personal computer operating system market with MS-DOS in the mid-1980s, followed by Windows. During the 41 years from 1980 to 2021 Microsoft released 9 versions of MS-DOS with a median frequen ...
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Santa Clara, California
Santa Clara ( ; Spanish language, Spanish for "Clare of Assisi, Saint Clare") is a city in Santa Clara County, California. The city's population was 127,647 at the 2020 United States census, 2020 census, making it the List of cities and towns in the San Francisco Bay Area, eighth-most populous city in the Bay Area. Located in the southern San Francisco Bay Area, Bay Area, the city was founded by the Spanish in 1777 with the establishment of Mission Santa Clara de Asís under the leadership of Junípero Serra. Santa Clara is located in the center of Silicon Valley and is home to the headquarters of companies such as Intel, Advanced Micro Devices (AMD), and Nvidia. It is also home to Santa Clara University, the oldest university in California, and Levi's Stadium, the home of the National Football League's San Francisco 49ers, and California's Great America Park. Santa Clara is bordered by San Jose, California, San Jose on almost every side, except for Sunnyvale, California, Sunnyv ...
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