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Btrfs
Btrfs (pronounced as "better F S", "butter F S", "b-tree F S", or simply by spelling it out) is a computer storage format that combines a file system based on the copy-on-write (COW) principle with a logical volume manager (not to be confused with Linux's LVM), developed together. It was initially designed at Oracle Corporation in 2007 for use in Linux, and since November 2013, the file system's on-disk format has been declared stable in the Linux kernel. According to Oracle, Btrfs "is not a true acronym". Btrfs is intended to address the lack of pooling, snapshots, checksums, and integral multi-device spanning in Linux file systems. Chris Mason, the principal Btrfs author, stated that its goal was "to let inuxscale for the storage that will be available. Scaling is not just about addressing the storage but also means being able to administer and to manage it with a clean interface that lets people see what's being used and makes it more reliable". History The core dat ... [...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] |
Fusion-io
Fusion-io, Inc. was a computer hardware and software systems company (acquired by SanDisk Corporation in 2014) based in Cottonwood Heights, Utah, that designed and manufactured products using flash memory technology. The Fusion was marketed for applications such as databases, virtualization, cloud computing, big data. Their product was considered around 2011 to be one of the fastest storage devices on the market. History The company was founded in December 2005 as Canvas Technologies in Nevada. Co-founders were David Flynn and Rick White. The company was based in Cottonwood Heights, Utah, near Salt Lake City. In June 2006, the company name was changed to Fusion Multisystems, Incorporated. A product with the brand name was demonstrated and announced in September 2007. In March 2008, Fusion-io raised $19 million in a series A round of funding from a group of investors led by New Enterprise Associates. David Flynn was chief technology officer, while Don Basile was chief e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snapshot (computer Storage)
In computer systems, a snapshot is the state of a system at a particular point in time. The term was coined as an analogy to that in photography. It can refer to an actual copy of the state of a system or to a capability provided by certain systems. Rationale A full backup of a large data set may take a long time to complete. On multi-tasking or multi-user systems, there may be writes to that data while it is being backed up. This prevents the backup from being atomic and introduces a version skew that may result in data corruption. For example, if a user moves a file into a directory that has already been backed up, then that file would be completely missing on the backup media, since the backup operation had already taken place before the addition of the file. Version skew may also cause corruption with files which change their size or contents underfoot while being read. One approach to safely backing up live data is to temporarily disable write access to data during th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ReactOS
ReactOS is a free and open-source operating system for amd64/i686 personal computers intended to be binary-compatible with computer programs and device drivers made for Windows Server 2003 and later versions of Windows. ReactOS has been noted as a potential open-source drop-in replacement for Windows and for its information on undocumented Windows APIs. ReactOS has been in development since 1996. , it is still considered feature-incomplete alpha software, and is therefore recommended by the developers only for evaluation and testing purposes. However, many Windows applications are currently working, such as Adobe Reader 9.3, GIMP 2.6, and LibreOffice 5.4.Tests for 0.4.14 on reactos.org (February 2022) ReactOS is primarily written in [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extended File Attributes
Extended file attributes are file system features that enable users to associate computer files with metadata not interpreted by the filesystem, whereas regular attributes have a purpose strictly defined by the filesystem (such as permissions or records of creation and modification times). Unlike forks, which can usually be as large as the maximum file size, extended attributes are usually limited in size to a value significantly smaller than the maximum file size. Typical uses include storing the author of a document, the character encoding of a plain-text document, or a checksum, cryptographic hash or digital certificate, and discretionary access control information. In Unix-like systems, extended attributes are usually abbreviated as xattr. Implementations AIX In AIX, the JFS2 v2 filesystem supports extended attributes, which are accessible using the command. The , , , , and APIs support fetching, setting, listing, getting information about, and removing extended attribu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Logical Volume Manager (Linux)
In Linux, Logical Volume Manager (LVM) is a device mapper framework that provides logical volume management for the Linux kernel. Most modern Linux distributions are LVM-aware to the point of being able to have their root file systems on a logical volume. Heinz Mauelshagen wrote the original LVM code in 1998, when he was working at Sistina Software, taking its primary design guidelines from the HP-UX's volume manager. Uses LVM is used for the following purposes: * Creating single logical volumes of multiple physical volumes or entire hard disks (somewhat similar to RAID 0, but more similar to JBOD), allowing for dynamic volume resizing. * Managing large hard disk farms by allowing disks to be added and replaced without downtime or service disruption, in combination with hot swapping. * On small systems (like a desktop), instead of having to estimate at installation time how big a partition might need to be, LVM allows filesystems to be easily resized as needed. * Perfor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Logical Volume Management
In computer storage, logical volume management or LVM provides a method of allocating space on mass storage, mass-storage devices that is more flexible than conventional Partition (computing), partitioning schemes to store volumes. In particular, a volume manager can concatenate, Data striping, stripe together or otherwise combine partitions (or block devices in general) into larger virtual partitions that administrators can re-size or move, potentially without interrupting system use. Volume management represents just one of many forms of Storage Virtualization, storage virtualization; its implementation takes place in a layer in the Device driver, device-driver stack of an operating system (OS) (as opposed to within storage devices or in a network). Design Most volume-manager implementations share the same basic design. They start with physical volumes (PVs), which can be either hard disks, hard disk Partition (computing), partitions, or Logical Unit Number, Logical Unit N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copy-on-write
Copy-on-write (COW), sometimes referred to as implicit sharing or shadowing, is a resource-management technique used in computer programming to efficiently implement a "duplicate" or "copy" operation on modifiable resources. If a resource is duplicated but not modified, it is not necessary to create a new resource; the resource can be shared between the copy and the original. Modifications must still create a copy, hence the technique: the copy operation is deferred until the first write. By sharing resources in this way, it is possible to significantly reduce the resource consumption of unmodified copies, while adding a small overhead to resource-modifying operations. In virtual memory management Copy-on-write finds its main use in sharing the virtual memory of operating system processes, in the implementation of the fork system call. Typically, the process does not modify any memory and immediately executes a new process, replacing the address space entirely. Thus, it would be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
File System
In computing, file system or filesystem (often abbreviated to fs) is a method and data structure that the operating system uses to control how data is stored and retrieved. Without a file system, data placed in a storage medium would be one large body of data with no way to tell where one piece of data stopped and the next began, or where any piece of data was located when it was time to retrieve it. By separating the data into pieces and giving each piece a name, the data are easily isolated and identified. Taking its name from the way a paper-based data management system is named, each group of data is called a " file". The structure and logic rules used to manage the groups of data and their names is called a "file system." There are many kinds of file systems, each with unique structure and logic, properties of speed, flexibility, security, size and more. Some file systems have been designed to be used for specific applications. For example, the ISO 9660 file system is desig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extent (file Systems)
In computing, an extent is a contiguous area of storage reserved for a file in a file system, represented as a range of block numbers, or tracks on count key data devices. A file can consist of zero or more extents; one file fragment requires one extent. The direct benefit is in storing each range compactly as two numbers, instead of canonically storing every block number in the range. Also, extent allocation results in less file fragmentation. Extent-based file systems can also eliminate most of the metadata overhead of large files that would traditionally be taken up by the block-allocation tree. But because the savings are small compared to the amount of stored data (for all file sizes in general) but make up a large portion of the metadata (for large files), the overall benefits in storage efficiency and performance are slight. In order to resist fragmentation, several extent-based file systems do allocate-on-flush. Many modern fault-tolerant file systems also do copy-o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pool (computer Science)
In computer science, a pool is a collection of resources that are kept, in memory, ready to use, rather than the memory acquired on use and the memory released afterwards. In this context, ''resources'' can refer to system resources such as file handles, which are external to a process, or internal resources such as objects. A pool client requests a resource from the pool and performs desired operations on the returned resource. When the client finishes its use of the resource, it is returned to the pool rather than released and lost. The pooling of resources can offer a significant response-time boost in situations that have high cost associated with resource acquiring, high rate of the requests for resources, and a low overall count of simultaneously used resources. Pooling is also useful when the latency is a concern, because a pool offers predictable times required to obtain resources since they have already been acquired. These benefits are mostly true for system resou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melbourne
Melbourne ( ; Boonwurrung/ Woiwurrung: ''Narrm'' or ''Naarm'') is the capital and most populous city of the Australian state of Victoria, and the second-most populous city in both Australia and Oceania. Its name generally refers to a metropolitan area known as Greater Melbourne, comprising an urban agglomeration of 31 local municipalities, although the name is also used specifically for the local municipality of City of Melbourne based around its central business area. The metropolis occupies much of the northern and eastern coastlines of Port Phillip Bay and spreads into the Mornington Peninsula, part of West Gippsland, as well as the hinterlands towards the Yarra Valley, the Dandenong and Macedon Ranges. It has a population over 5 million (19% of the population of Australia, as per 2021 census), mostly residing to the east side of the city centre, and its inhabitants are commonly referred to as "Melburnians". The area of Melbourne has been home to Aboriginal Vi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
