In computing (specifically data transmission and data storage), block is a sequence of bytes or bits, having a nominal length (a block size). Computing is usually defined like the activity of using and developing Computer technology Computer hardware and software. Computer data storage, often called storage or memory, refers to Computer components devices and recording media that retain digital A byte (pronounced "bite" baɪt is the basic unit of measurement of information storage in Computer science. A bit is a binary digit, taking a value of either 0 or 1 Binary digits are a basic unit of Information storage and communication Data thus structured is said to be blocked. The process of putting data into blocks is called blocking. Blocking is used to facilitate the handling of the data-stream by the computer program receiving the data. Blocked data is normally read a whole block at a time. Blocking is almost universally employed when storing data to 9-track magnetic tape, to rotating media such as floppy disks, hard disks, optical discs and to NAND flash memory. Magnetic tape is a medium for Magnetic recording generally consisting of a thin magnetizable coating on a long and narrow strip of Plastic. A floppy disk is an increasingly Obsolete data storage medium that is composed of a disk of thin flexible ("floppy" Magnetic storage medium encased A hard disk drive ( HDD) commonly referred to as a hard drive, hard disk, or fixed disk drive, is a Non-volatile storage device Flash memory is non-volatile computer memory that can be electrically erased and reprogrammed
Most file systems are based on a block device, which is a level of abstraction for the hardware responsible for storing and retrieving specified blocks of data, though the block size in file systems block may be multiple of the physical block size. In Computing, a file system (often also written as filesystem) is a method for storing and organizing Computer files and the data they contain to make --> Abstraction is the process or result of generalization by reducing the information Hardware is a general term that refers to the physical artifacts of a Technology. In classical file systems, a single block may only contain a part of a single file. A computer file is a block of Arbitrary Information, or resource for storing information which is available to a Computer program and is usually This leads to space inefficiency due to internal fragmentation, since file lengths are often not multiples of block size, and thus the last block of files will remain partially empty. In Computer storage, fragmentation is a phenomenon in which storage space is used inefficiently reducing storage capacity This will create slack space, which averages half a block per file. In Computer storage, fragmentation is a phenomenon in which storage space is used inefficiently reducing storage capacity Some newer file systems attempt to solve this through techniques called block suballocation and tail merging. Block suballocation is a feature of some computer File systems which allows large blocks or allocation units to be used while making efficient use of "slack" space at Block suballocation is a feature of some computer File systems which allows large blocks or allocation units to be used while making efficient use of "slack" space at
Block storage is normally abstracted by a file system or database management system for use by applications and end users. A database management system ( DBMS) is Computer software designed for the purpose of managing Databases DBMSes may use any of a variety of Data models The physical or logical volumes accessed via block I/O may be devices internal to a server, direct attached via SCSI or Fibre Channel, or distant devices accessed via a storage area network (SAN) using a protocol such as iSCSI, or AoE. Fibre Channel, or FC, is a Gigabit -speed network technology primarily used for Storage networking. In Information technology, a storage area network ( SAN) is an architecture to attach remote computer storage devices (such as Disk arrays tape libraries In computing the iSCSI (for " Internet SCSI " protocol allows clients (called initiators) to send SCSI commands ( ''CDBs'' ATA over Ethernet ( AoE) is a Network protocol developed by the Brantley Coile Company designed for simple high-performance access of SATA storage devices Database management systems often use their own block I/O for improved performance and recoverability as compared to layering the DBMS on top of a file system.
See also
- Block allocation map
- Block size (cryptography)
- Disk sector
- Cluster (file system)
- Fixed Block Architecture (FBA) versus Count-key-data (CKD)
External links
In Computer file systems a block allocation map ( BAM) is a Data structure used to track the allocated or freed disk blocks. In modern Cryptography, symmetric key Ciphers are generally divided into Stream ciphers and Block ciphers Block ciphers operate on a In the context of Computer Disk storage, a sector is a subdivision of a track (Figure 1 item A on a Magnetic disk or Optical disc In computer File systems a cluster is the unit of disk space allocation for files and directories Fixed Block Architecture ( FBA) is a disk layout in which each physical record ( block) on disk is of the same size Count Key Data (CKD is a disk data architecture Each physical disk record consists of a count area an optional key and a data record followed by an inter-record gapDapyx Software network: MP3 Explorer | Ebook Manager | Zenithic