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A binary prefix is a unit prefix for multiples of units in data processing, data transmission, and digital information, principally in association with the bit and the byte, to indicate multiplication by a power of 2. As shown in the table to the right there are two sets of symbols for binary prefixes, one set established by International Electrotechnical Commission (IEC) and several other standards and trade organizations using two letter symbols, e.g. Mi indicating 1,048,576 with a second set established by semiconductor industry convention using one letter symbols, e.g., M also indicating 1,048,576.
In computing, virtual memory, or virtual storage is a memory management technique that provides an "idealized abstraction of the storage resources that are actually available on a given machine" which "creates the illusion to users of a very large (main) memory".
Virtual Storage Access Method (VSAM) is an IBM DASD file storage access method, first used in the OS/VS1, OS/VS2 Release 1 (SVS) and Release 2 (MVS) operating systems, later used throughout the Multiple Virtual Storage (MVS) architecture and now in z/OS. Originally a record-oriented filesystem, VSAM comprises four data set organizations: key-sequenced (KSDS), relative record (RRDS), entry-sequenced (ESDS) and linear (LDS). The KSDS, RRDS and ESDS organizations contain records, while the LDS organization simply contains a sequence of pages with no intrinsic record structure, for use as a memory-mapped file.
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.
NetApp, Inc. is an American hybrid cloud data services and data management company headquartered in San Jose, California. It has ranked in the Fortune 500 from 2012–2021. Founded in 1992 with an IPO in 1995, NetApp offers cloud data services for management of applications and data both online and physically.
IBM manufactured magnetic disk storage devices from 1956 to 2003, when it sold its hard disk drive business to Hitachi. Both the hard disk drive (HDD) and floppy disk drive (FDD) were invented by IBM and as such IBM's employees were responsible for many of the innovations in these products and their technologies. The basic mechanical arrangement of hard disk drives has not changed since the IBM 1301. Disk drive performance and characteristics are measured by the same standards now as they were in the 1950s. Few products in history have enjoyed such spectacular declines in cost and physical size along with equally dramatic improvements in capacity and performance.
In computing, file system or filesystem 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 is 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."
IBM Spectrum Protect is a data protection platform that gives enterprises a single point of control and administration for backup and recovery. It is the flagship product in the IBM Spectrum Protect family.
GPFS is a high-performance clustered file system software developed by IBM. It can be deployed in shared-disk or shared-nothing distributed parallel modes, or a combination of these. It is used by many of the world's largest commercial companies, as well as some of the supercomputers on the Top 500 List. For example, it is the filesystem of the Summit at Oak Ridge National Laboratory which was the #1 fastest supercomputer in the world in the November 2019 top500 list of supercomputers. Summit is a 200 Petaflops system composed of more than 9,000 POWER9 processors and 27,000 NVIDIA Volta GPUs. The storage filesystem called Alpine has 250 PB of storage using Spectrum Scale on IBM ESS storage hardware, capable of approximately 2.5TB/s of sequential I/O and 2.2TB/s of random I/O.
In computer science, storage virtualization is "the process of presenting a logical view of the physical storage resources to" a host computer system, "treating all storage media in the enterprise as a single pool of storage."
The IBM Storage product portfolio includes disk, flash, tape, NAS storage products, storage software and services. IBM's approach is to focus on data management.
A clustered file system is a file system which is shared by being simultaneously mounted on multiple servers. There are several approaches to clustering, most of which do not employ a clustered file system. Clustered file systems can provide features like location-independent addressing and redundancy which improve reliability or reduce the complexity of the other parts of the cluster. Parallel file systems are a type of clustered file system that spread data across multiple storage nodes, usually for redundancy or performance.
Btrfs is a computer storage format that combines a file system based on the copy-on-write (COW) principle with a logical volume manager, 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".
In computing, virtualization or virtualisation is the act of creating a virtual version of something at the same abstraction level, including virtual computer hardware platforms, storage devices, and computer network resources.
Hitachi Data Systems (HDS) was a provider of modular mid-range and high-end computer data storage systems, software and services. Its operations are now a part of Hitachi Vantara.
Universal Storage Platform (USP) was the brand name for an Hitachi Data Systems line of computer data storage disk arrays circa 2004 to 2010.
IBM FlashSystem is an IBM Storage enterprise system that stores data on flash memory. Unlike storage systems that use standard solid-state drives, IBM FlashSystem products incorporate custom hardware based on technology from the 2012 IBM acquisition of Texas Memory Systems.
John Mason "Jack" Harker was an inventor, mechanical engineer, and product and program manager who pioneered development of disk storage systems. Starting as a member of the original team that developed the first disk storage system, he went on to develop IBM Direct Access Storage products for the next 35 years. Over that time, Harker was twice director of the IBM San Jose Storage Laboratories, an IBM Fellow, and an IEEE Fellow. He retired from IBM in 1987 and died in 2013.
Object storage is a computer data storage that manages data as objects, as opposed to other storage architectures like file systems which manages data as a file hierarchy, and block storage which manages data as blocks within sectors and tracks. Each object typically includes the data itself, a variable amount of metadata, and a globally unique identifier. Object storage can be implemented at multiple levels, including the device level, the system level, and the interface level. In each case, object storage seeks to enable capabilities not addressed by other storage architectures, like interfaces that are directly programmable by the application, a namespace that can span multiple instances of physical hardware, and data-management functions like data replication and data distribution at object-level granularity.
References
- ↑ Rodeh, Ohad (2007). B-trees, shadowing, and clones (PDF). USENIX Linux Storage & Filesystem Workshop. Also Rodeh, Ohad (2008). "B-trees, shadowing, and clones". ACM Transactions on Storage. 3 (4): 1–27. doi:10.1145/1326542.1326544. S2CID 207166167.
