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Vinum Volume Manager
Vinum is a logical volume manager, also called software RAID, allowing implementations of the RAID-0, RAID-1 and RAID-5 models, both individually and in combination. The original Vinum was part of the base distribution of the FreeBSD operating system since 3.0, and also NetBSD between 2003-10-10 and 2006-02-25, as well as descendants of FreeBSD, including DragonFly BSD; in more recent versions of FreeBSD, it has been replaced with gvinum, which was first introduced around FreeBSD 6. Vinum source code is maintained in the FreeBSD and DragonFly source trees. Vinum supports RAID levels 0, 1, 5, and JBOD. Vinum was inspired by Veritas Volume Manager. Vinum is invoked as gvinum (GEOM Vinum) on FreeBSD version 5.4 and up. In modern FreeBSD, it may be considered to be a legacy volume manager; modern alternatives being GEOM and ZFS. In NetBSD, it has been removed before NetBSD 4.0 due to lack of interest and maintenance; RAIDframe was cited as providing similar functionality. In Dragon ... [...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 devices that is more flexible than conventional partitioning schemes to store volumes. In particular, a volume manager can concatenate, 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; its implementation takes place in a layer in the 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 partitions, or Logical Unit Numbers (LUNs) of an external storage device. Volume management treats each PV as being composed of a sequence of chunks called ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SCSI
Small Computer System Interface (SCSI, ) is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, electrical, optical and logical interfaces. The SCSI standard defines command sets for specific peripheral device types; the presence of "unknown" as one of these types means that in theory it can be used as an interface to almost any device, but the standard is highly pragmatic and addressed toward commercial requirements. The initial Parallel SCSI was most commonly used for hard disk drives and tape drives, but it can connect a wide range of other devices, including scanners and CD drives, although not all controllers can handle all devices. The ancestral SCSI standard, X3.131-1986, generally referred to as SCSI-1, was published by the X3T9 technical committee of the American National Standards Institute (ANSI) in 1986. SCSI-2 was published in August 1990 as X3.T9.2/86-109 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Data Storage
Computer data storage is a technology consisting of computer components and recording media that are used to retain digital data. It is a core function and fundamental component of computers. The central processing unit (CPU) of a computer is what manipulates data by performing computations. In practice, almost all computers use a storage hierarchy, which puts fast but expensive and small storage options close to the CPU and slower but less expensive and larger options further away. Generally, the fast volatile technologies (which lose data when off power) are referred to as "memory", while slower persistent technologies are referred to as "storage". Even the first computer designs, Charles Babbage's Analytical Engine and Percy Ludgate's Analytical Machine, clearly distinguished between processing and memory (Babbage stored numbers as rotations of gears, while Ludgate stored numbers as displacements of rods in shuttles). This distinction was extended in the Von Neuma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BSD Software
The Berkeley Software Distribution or Berkeley Standard Distribution (BSD) is a discontinued operating system based on Research Unix, developed and distributed by the Computer Systems Research Group (CSRG) at the University of California, Berkeley. The term "BSD" commonly refers to its open-source descendants, including FreeBSD, OpenBSD, NetBSD, and DragonFly BSD. BSD was initially called Berkeley Unix because it was based on the source code of the original Unix developed at Bell Labs. In the 1980s, BSD was widely adopted by workstation vendors in the form of proprietary Unix variants such as DEC Ultrix and Sun Microsystems SunOS due to its permissive licensing and familiarity to many technology company founders and engineers. Although these proprietary BSD derivatives were largely superseded in the 1990s by UNIX SVR4 and OSF/1, later releases provided the basis for several open-source operating systems including FreeBSD, OpenBSD, NetBSD, DragonFly BSD, Darwin, and TrueOS. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volume Manager
In computer storage, logical volume management or LVM provides a method of allocating space on mass-storage devices that is more flexible than conventional partitioning schemes to store volumes. In particular, a volume manager can concatenate, 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; its implementation takes place in a layer in the 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 partitions, or Logical Unit Numbers (LUNs) of an external storage device. Volume management treats each PV as being composed of a sequence of chunks called phy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotating Disc Computer Storage Media
Rotation, or spin, is the circular movement of an object around a '' central axis''. A two-dimensional rotating object has only one possible central axis and can rotate in either a clockwise or counterclockwise direction. A three-dimensional object has an infinite number of possible central axes and rotational directions. If the rotation axis passes internally through the body's own center of mass, then the body is said to be ''autorotating'' or ''spinning'', and the surface intersection of the axis can be called a ''pole''. A rotation around a completely external axis, e.g. the planet Earth around the Sun, is called ''revolving'' or ''orbiting'', typically when it is produced by gravity, and the ends of the rotation axis can be called the '' orbital poles''. Mathematics Mathematically, a rotation is a rigid body movement which, unlike a translation, keeps a point fixed. This definition applies to rotations within both two and three dimensions (in a plane and in space, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
USENIX Annual Technical Conference
The USENIX Annual Technical Conference (USENIX ATC, or, canonically, USENIX) is a conference of computing professions sponsored by the USENIX association. The conference includes computing tutorials, and a single track technical session for presenting refereed research papers, SIG meetings, and BoFs. There have been several notable announcements and talks at USENIX. In 1995, James Gosling announced "Oak", which was to become the Java Programming Language. John Ousterhout first presented TCL here, and Usenet was announced here. It is considered one of the most prestigious operating systems venues and has an 'A' rating from the Australian Ranking of ICT Conferences (ERA). List of conferences * USENIX ATC 2018 — Boston, Massachusetts, July 11–13, 2018. * USENIX ATC 2017 — Santa Clara, California, July 12–14, 2017. * USENIX ATC 2016 — Denver, Colorado, June 22–24, 2016. * USENIX ATC 2015 — Santa Clara, California, July 8–10, 2015. * USENIX ATC 2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bioctl
The bio(4) pseudo-device driver and the bioctl(8) utility implement a generic RAID volume management interface in OpenBSD and NetBSD. The idea behind this software is similar to ifconfig, where a single utility from the operating system can be used to control any RAID controller using a generic interface, instead of having to rely on many proprietary and custom RAID management utilities specific for each given hardware RAID manufacturer. Features include monitoring of the health status of the arrays, controlling identification through blinking the LEDs and managing of sound alarms, and specifying hot spare disks. Additionally, the softraid configuration in OpenBSD is delegated to bioctl as well; whereas the initial creation of volumes and configuration of hardware RAID is left to card BIOS as non-essential after the operating system has already been booted. Interfacing between the kernel and userland is performed through the ioctl system call through the /dev/bio pseudo-devi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Storage Area Network
A storage area network (SAN) or storage network is a computer network which provides access to consolidated, block-level data storage. SANs are primarily used to access data storage devices, such as disk arrays and tape libraries from servers so that the devices appear to the operating system as direct-attached storage. A SAN typically is a dedicated network of storage devices not accessible through the local area network (LAN). Although a SAN provides only block-level access, file systems built on top of SANs do provide file-level access and are known as shared-disk file systems. Newer SAN configurations enable hybrid SAN and allow traditional block storage that appears as local storage but also object storage for web services through APIs. Storage architectures Storage area networks (SANs) are sometimes referred to as ''network behind the servers'' and historically developed out of a centralized data storage model, but with its own data network. A SAN is, at its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disk Array
A disk array is a disk storage system which contains multiple disk drives. It is differentiated from a disk enclosure, in that an array has cache memory and advanced functionality, like RAID, deduplication, encryption and virtualization. Components of a disk array include: * Disk array controllers * Cache in form of both volatile random-access memory and non-volatile flash memory. * Disk enclosures for both magnetic rotational hard disk drives and electronic solid-state drives. * Power supplies Typically a disk array provides increased availability, resiliency, and maintainability by using additional redundant components (controllers, power supplies, fans, etc.), often up to the point where all single points of failure (SPOFs) are eliminated from the design. Additionally, disk array components are often hot-swappable. Traditionally disk arrays were divided into categories: * Network attached storage (NAS) arrays * Storage area network (SAN) arrays: ** Modular SAN arrays ** Mon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hard Drives
A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating platters coated with magnetic material. The platters are paired with magnetic heads, usually arranged on a moving actuator arm, which read and write data to the platter surfaces. Data is accessed in a random-access manner, meaning that individual blocks of data can be stored and retrieved in any order. HDDs are a type of non-volatile storage, retaining stored data when powered off. Modern HDDs are typically in the form of a small rectangular box. Introduced by IBM in 1956, HDDs were the dominant secondary storage device for general-purpose computers beginning in the early 1960s. HDDs maintained this position into the modern era of servers and personal computers, though personal computing devices produced in large volume, like cell phones and tablets, rely o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BIOS
In computing, BIOS (, ; Basic Input/Output System, also known as the System BIOS, ROM BIOS, BIOS ROM or PC BIOS) is firmware used to provide runtime services for operating systems and programs and to perform hardware initialization during the booting process (power-on startup). The BIOS firmware comes pre-installed on an IBM PC or IBM PC compatible's system board and exists in some UEFI-based systems to maintain compatibility with operating systems that do not support UEFI native operation. The name originates from the Basic Input/Output System used in the CP/M operating system in 1975. The BIOS originally proprietary to the IBM PC has been reverse engineered by some companies (such as Phoenix Technologies) looking to create compatible systems. The interface of that original system serves as a ''de facto'' standard. The BIOS in modern PCs initializes and tests the system hardware components ( Power-on self-test), and loads a boot loader from a mass storage device whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
