|
F2fs
F2FS (Flash-Friendly File System) is a flash file system initially developed by Samsung Electronics for the Linux kernel. The motive for F2FS was to build a file system that, from the start, takes into account the characteristics of NAND flash memory-based storage devices (such as solid-state disks, eMMC, and SD cards), which are widely used in computer systems ranging from mobile devices to servers. F2FS was designed on a basis of a log-structured file system approach, which is adapted to newer forms of storage. Jaegeuk Kim, the principal F2FS author, has stated that it remedies some known issues of the older log-structured file systems, such as the snowball effect of wandering trees and high cleaning overhead. In addition, since a NAND-based storage device shows different characteristics according to its internal geometry or flash memory management scheme (such as the Flash Translation Layer or FTL), it supports various parameters not only for configuring on-disk layout, but ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flash File System
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 blo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solid-state Disk
A solid-state drive (SSD) is a solid-state storage device that uses integrated circuit assemblies to store data persistently, typically using flash memory, and functioning as secondary storage in the hierarchy of computer storage. It is also sometimes called a semiconductor storage device, a solid-state device or a solid-state disk, even though SSDs lack the physical spinning disks and movable read–write heads used in hard disk drives (HDDs) and floppy disks. SSD also has rich internal parallelism for data processing. In comparison to hard disk drives and similar electromechanical media which use moving parts, SSDs are typically more resistant to physical shock, run silently, and have higher input/output rates and lower latency. SSDs store data in semiconductor cells. cells can contain between 1 and 4 bits of data. SSD storage devices vary in their properties according to the number of bits stored in each cell, with single-bit cells ("Single Level Cells" or "SLC") ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secure Digital
Secure Digital, officially abbreviated as SD, is a proprietary format, proprietary non-volatile memory, non-volatile Flash memory, flash memory card format developed by the SD Association, SD Association (SDA) for use in portable devices. The standard was introduced in August 1999 by joint efforts between SanDisk, Panasonic (Matsushita) and Toshiba as an improvement over MultiMediaCard, MultiMediaCards (MMCs), and has become the industry standard. The three companies formed SD-3C, LLC, a company that licenses and enforces intellectual property rights associated with SD memory cards and SD host and ancillary products. The companies also formed the SD Association (SDA), a non-profit organization, in January 2000 to promote and create SD Card standards. SDA today has about 1,000 member companies. The SDA uses several trademarked logos owned and licensed by SD-3C to enforce compliance with its specifications and assure users of compatibility. History 1999–2003: Creation In 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Samsung Electronics
Samsung Electronics Co., Ltd. (, sometimes shortened to SEC and stylized as SΛMSUNG) is a South Korean multinational corporation, multinational electronics corporation headquartered in Yeongtong-gu, Suwon, South Korea. It is the pinnacle of the Samsung chaebol, accounting for 70% of the group's revenue in 2012. Samsung Electronics has played a key role in the group's corporate governance due to circular ownership. Samsung Electronics has Assembly line, assembly plants and sales networks in 74 countries and employs around 290,000 people. It is majority-owned by foreign investors. Samsung Electronics is the world's List of largest technology companies by revenue, second-largest technology company by revenue, and its market capitalization stood at US$520.65 billion, the 12th largest in the world. Samsung is a major manufacturer of Electronic component, Electronic Components such as lithium-ion batteries, semiconductors, image sensors, camera modules, and Display device, d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atomic Operations
In concurrent programming, an operation (or set of operations) is linearizable if it consists of an ordered list of invocation and response events (event), that may be extended by adding response events such that: # The extended list can be re-expressed as a sequential history (is serializable). # That sequential history is a subset of the original unextended list. Informally, this means that the unmodified list of events is linearizable if and only if its invocations were serializable, but some of the responses of the serial schedule have yet to return. In a concurrent system, processes can access a shared object at the same time. Because multiple processes are accessing a single object, there may arise a situation in which while one process is accessing the object, another process changes its contents. Making a system linearizable is one solution to this problem. In a linearizable system, although operations overlap on a shared object, each operation appears to take place i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trim (computing)
A trim command (known as TRIM in the ATA command set, and UNMAP in the SCSI command set) allows an operating system to inform a solid-state drive (SSD) which blocks of data are no longer considered to be 'in use' and therefore can be erased internally. Trim was introduced soon after SSDs were introduced. Because low-level operation of SSDs differs significantly from hard drives, the typical way in which operating systems handle operations like deletes and formats resulted in unanticipated progressive performance degradation of write operations on SSDs. Trimming enables the SSD to more efficiently handle garbage collection, which would otherwise slow future write operations to the involved blocks.Shimpi, Anand Lal. (18 March 2009). p. 10. TRIM is an ATA command (Advanced Technology Attachment Command) that allows an OS to inform SSD about the blocks of data no longer in use. The SSD then deletes such blocks of data to make a way for newer blocks of data. TRIM is basically used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Defragmentation
In the maintenance of file systems, defragmentation is a process that reduces the degree of fragmentation. It does this by physically organizing the contents of the mass storage device used to store files into the smallest number of contiguous regions (fragments, ''extents''). It also attempts to create larger regions of free space using compaction to impede the return of fragmentation. Some defragmentation utilities try to keep smaller files within a single directory together, as they are often accessed in sequence. Defragmentation is advantageous and relevant to file systems on electromechanical disk drives (hard disk drives, floppy disk drives and optical disk media). The movement of the hard drive's read/write heads over different areas of the disk when accessing fragmented files is slower, compared to accessing the entire contents of a non-fragmented file sequentially without moving the read/write heads to seek other fragments. Causes of fragmentation Fragmentatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fsck
The system utility fsck (''file system consistency check'') is a tool for checking the consistency of a file system in Unix and Unix-like operating systems, such as Linux, macOS, and FreeBSD. A similar command, CHKDSK, exists in Microsoft Windows and its predecessor, MS-DOS. Pronunciation There is no agreed pronunciation. It can be pronounced "F-S-C-K", "F-S-check", "fizz-check", "F-sack", "fisk", "fishcake", "fizik", "F-sick", "F-sock", "F-sek", "feshk", the sibilant "fsk", "fix", "farsk" or "fusk". Use Generally, fsck is run either automatically at boot time, or manually by the system administrator. The command works directly on data structures stored on disk, which are internal and specific to the particular file system in use - so an fsck command tailored to the file system is generally required. The exact behaviors of various fsck implementations vary, but they typically follow a common order of internal operations and provide a common command-line interface to the user. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filesystem-level Encryption
Filesystem-level encryption, often called file-based encryption, FBE, or file/folder encryption, is a form of disk encryption where individual files or directories are encrypted by the file system itself. This is in contrast to the full disk encryption where the entire partition or disk, in which the file system resides, is encrypted. Types of filesystem-level encryption include: * the use of a 'stackable' cryptographic filesystem layered on top of the main file system * a single ''general-purpose'' file system with encryption The advantages of filesystem-level encryption include: * flexible file-based key management, so that each file can be and usually is encrypted with a separate encryption key * individual management of encrypted files e.g. incremental backups of the individual changed files even in encrypted form, rather than backup of the entire encrypted volume * access control can be enforced through the use of public-key cryptography, and * the fact that cryptographic ke ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wandering Trees
{{Disambig ...
Wandering may refer to: * Wandering (dementia) * ''Wandering'', a 2021 EP by JO1 * Wandering, Western Australia, a town located in the Wheatbelt region of Western Australia * Shire of Wandering, a local government area in the Wheatbelt region of Western Australia See also * * * Wander (other) * Wanderer (other) * Jitter * Joyride (crime) * Meander (other) * Vagabond (other) * Vagrant (other) A vagrant is a person who lives without a home or regular employment and wanders from place to place. Vagrant or vagrancy may also refer to: Biology Concepts * Vagrancy (biology), the state of roaming or growing far outside of ones species' usu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inode
The inode (index node) is a data structure in a Unix-style file system that describes a file-system object such as a file or a directory. Each inode stores the attributes and disk block locations of the object's data. File-system object attributes may include metadata (times of last change, access, modification), as well as owner and permission data. A directory is a list of inodes with their assigned names. The list includes an entry for itself, its parent, and each of its children. Etymology There has been uncertainty on the Linux kernel mailing list about the reason for the "i" in "inode". In 2002, the question was brought to Unix pioneer Dennis Ritchie, who replied: A 1978 paper by Ritchie and Ken Thompson bolsters the notion of "index" being the etymological origin of inodes. They wrote: Additionally, Maurice J. Bach wrote that an inode "is a contraction of the term index node and is commonly used in literature on the UNIX system". Details A file system relies on dat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nexus 9
The Nexus 9 (codenamed Volantis or Flounder) is a tablet computer co-developed by Google and HTC that runs the Android operating system. It is the fourth tablet in the Google Nexus series, a family of Android consumer devices marketed by Google and built by an OEM partner. The device is available in two storage sizes, 16 GB for US$399 and 32 GB for US$479. Along with the Nexus 6 mobile phone and Nexus Player digital media device, the Nexus 9 launched with 5.0 Lollipop, which offered several new features, notably a modified visual appearance, and the complete replacement of the Dalvik virtual machine with ART. Google has included an additional step to "Enable OEM unlock" before users can unlock the Nexus 9 bootloader. Release The Nexus 9 was announced on 15 October 2014, with pre-orders available on 17 October and was released on 3 November 2014. A 4G LTE version was released in the US on 12 December 2014. Specifications Hardware The Nexus 9 tablet features an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
