Advances in Data Storage Technology

Advances in info Storage technical schoolnology Contents I. Introduction3 II. Purpose of entrepot4 III. Hierarchy of reposition6 A. Primary retention6 B. lowly transshipment center7 C. ordinal inject7 D. off- imbibe hold onho physical exertion8 IV. Characteristics of repositing9 A. irritability9 B. Mutability9 C. Accessibility10 D. Addressability10 E. Capacity11 F. murder11 G. Energy use11 V. primaeval store technologies12 A. Semiconductor12 B. magnetised12 C. visual13 D. Paper14 E. Uncommon14 VI. think technologies17 A. mesh connectivity17 B. Robotic remembering17 References19 I. INTRODUCTION computing device entropy storehouse, often c eached retention or stock, refers to filly reck unrivaledr comp peerlessnts and transcription media that c erstal digital data employ for computing for some interval of time. computer data experimental conditioninal provides one of the fondness functions of the modern figurer, that of info retention. It is one of th e fundamental components of entirely modern data processors, and coupled with a exchange bear on unit (CPU, a processor), implements the basic computer model utilise since the 1940s. In contemporary usage, remembering norm tout ensembley refers to a strain of semiconductor retention kn sustain as random- advance computer property ( dash) and sometimes discordent forms of troubled that temporary terminal.Similarly, retentivity today more(prenominal)(prenominal) comm single refers to mass fund visual discs, forms of magnetic retentiveness like saturated dish antenna drives, and early(a) compositors cases slower than RAM, however of a more permanent nature. Historically, depot and storage were respectively called main retrospection and thirdhand storage (or auxiliary storage). adjunct storage (or auxiliary memory units) was in addition utilise to represent memory which was not outright attackible by the CPU ( indirect or ordinal storage). The terms i nternal memory and external memory atomic come up 18 also apply. II. Purpose of storageMany different forms of storage, based on various natural phenomena, confirm been invented. So far, no practical universal storage average exists, and all forms of storage make believe some draw plunk fors. Therefore a computer organization usually contains several kinds of storage, each with an individual purpose. A digital computer represents data using the binary numeral governing body. Text, numbers, pictures, audio, and nearly any some otherwise form of discipline derriere be converted into a th order of bits, or binary digits, each of which has a value of 1 or 0. The nigh common unit of storage is the byte, equal to 8 bits.A opus of instruction can be handled by any computer whose storage space is swelled enough to accommodate the binary representation of the gather of selective information, or simply data. For example, using eight million bits, or astir(predicate) one me gabyte, a typical computer could store a brief novel. Traditionally the most important part of every computer is the central processing unit (CPU, or simply a processor), because it actually inclines on data, performs any calculations, and controls all the other components. Without a significant amount of memory, a computer would merely be able to perform fixed processs and immediately output the result.It would have to be reconfigured to change its behavior. This is acceptable for devices much(prenominal) as desk calculators or simple digital signal processors. Von Neumann machines differ in that they have a memory in which they store their operating(a) book of instructions and data. such computers ar more versatile in that they do not need to have their hardw atomic number 18 reconfigured for each new program, nevertheless can simply be reprogrammed with new in-memory instructions they also list to be simpler to design, in that a relatively simple processor whitethorn ke ep state amongst successive computations to build up involved procedural results.Most modern computers argon von Neumann machines. In practice, almost all computers use a variety of memory types, organized in a storage hierarchy around the CPU, as a trade-off between performance and cost. Generally, the lower a storage is in the hierarchy, the lesser its bandwidth and the greater its nettle latency is from the CPU. This traditional division of storage to primary, secondary, 3rd and off-line storage is also guided by cost per bit. III. Hierarchy of storage A. Primary storage Primary storage (or main memory or internal memory), often referred to simply as memory, is the only one directly accessible to the CPU.The CPU continuously immortalises instructions stored there and executes them as required. some(prenominal) data actively operated on is also stored there in undifferentiated manner. Historically, early computers employ delay lines, Williamss tubes, or rotating magnetic drums as primary storage. By 1954, those unreliable methods were mostly replaced by magnetic core memory. Core memory remained dominant until the 1970s, when advances in integrated circuit applied science allowed semiconductor memory to become economically competitive. This led to modern random-access memory (RAM).It is pocketable-sized, light, but quite expensive at the same time. (The finicky types of RAM use for primary storage be also volatile, i. e. they lose the information when not agented). As the RAM types utilise for primary storage are volatile (cleared at start up), a computer containing only much(prenominal) storage would not have a source to ingest instructions from, in order to start the computer. Hence, non-volatile primary storage containing a small startup program (BIOS) is used to bootstrap the computer, that is, to choose a big program from non-volatile secondary storage to RAM and start to execute it.A non-volatile applied science used for this purpos e is called ROM (Read-only memory). Recently, primary storage and secondary storage in some uses refer to what was historically called, respectively, secondary storage and tertiary storage. B. utility(prenominal) storage Secondary storage (or external memory) differs from primary storage in that it is not directly accessible by the CPU. The computer usually uses its input/output channels to access secondary storage and transfers the sought after data using intermediate area in primary storage. Secondary storage does not lose the data when the device is powered razeit is non-volatile.Consequently, modern computer systems typically have two orders of magnitude more secondary storage than primary storage and data is kept for a longstanding time there. In modern computers, hard disk drives are usually used as secondary storage. Rotating optical storage devices, such as CD and videodisc drives, have longer access times. nigh other examples of secondary storage technologies are inst ant memory (e. g. USB flash drives or keys), floppy disks, magnetic tape, paper tape, punched cards, standalone RAM disks, and Iomega Zip drives. C. Tertiary storage Tertiary storage or tertiary memory provides a third level of storage.Typically it involves a robotic mechanism which will mount (insert) and get out removable mass storage media into storage device according to the systems demands this data is often copied to secondary storage before use. It is primarily used for archival of rarely accessed information since it is much slower than secondary storage (e. g. 560 seconds vs. 1-10 milliseconds). This is primarily useful for extraordinarily long data stores, accessed without human race agents. Typical examples include tape libraries and optical jukeboxes. D. Off-line storageOff-line storage is computer data storage on a medium or a device that is not under the control of a processing unit. The medium is recorded, usually in a secondary or tertiary storage device, and wh erefore physically removed or disconnected. It essential be inserted or connected by a human operator before a computer can access it again. Unlike tertiary storage, it cannot be accessed without human interaction. In modern personal computers, most secondary and tertiary storage media are also used for off-line storage. optical discs and flash memory devices are most popular, and to much lesser cessation removable hard disk drives.In enterprise uses, magnetic tape is predominant. honest-to-goodness examples are floppy disks, Zip disks, or punched cards. IV. Characteristics of storage Storage technologies at all levels of the storage hierarchy can be differentiated by evaluating certain core diagnostics as well as measuring characteristics unique(predicate) to a particular slaying. These core characteristics are volatility, mutability, accessibility, and addressability. For any particular implementation of any storage technology, the characteristics worth measuring are conten tedness and performance. A. VolatilityNon-volatile memory will retain the stored information even if it is not invariably supplied with electric power. It is suitable for long-term storage of information. Nowadays used for most of secondary, tertiary, and off-line storage. In 1950s and 1960s, it was also used for primary storage, in the form of magnetic core memory. Volatile memory requires constant power to maintain the stored information. The fastest memory technologies of today are volatile ones (not a universal rule). Since primary storage is required to be very fast, it predominantly uses volatile memory.B. Mutability Read/ pull through storage or chatoyant storage allows information to be overwritten at any time. A computer without some amount of read/ indite storage for primary storage purposes would be useless for many tasks. Modern computers typically use read/write storage also for secondary storage. Read only storage retains the information stored at the time of manufa cture, and write once storage (Write one time Read Many) allows the information to be written only once at some point after manufacture. These are called immutable storage.Immutable storage is used for tertiary and off-line storage. Examples include CD-ROM and CD-R. C. Accessibility Random access any location in storage can be accessed at any moment in approximately the same amount of time. Such characteristic is well suited for primary and secondary storage. Sequential access the accessing of pieces of information will be in a serial order, one after the other therefore the time to access a particular piece of information depends upon which piece of information was last accessed. Such characteristic is typical of off-line storage. D. AddressabilityLocation-addressable each individually accessible unit of information in storage is selected with its numerical memory address. In modern computers, location-addressable storage usually limits to primary storage, accessed internally by c omputer programs, since location-addressability is very efficient, but burdensome for humans. The underlying device is still location-addressable, but the operating system of a computer provides the file system abstraction to make the operation more understandable. In modern computers, secondary, tertiary and off-line storage use file systems. E.Capacity Raw capacity the total amount of stored information that a storage device or medium can hold. It is expressed as a quantity of bits or bytes (e. g. 10. 4 megabytes). Memory storage niggardness the compactness of stored information. It is the storage capacity of a medium divided with a unit of length, area or volume (e. g. 1. 2 megabytes per square inch). F. Performance Latency the time it takes to access a particular location in storage. The relevant unit of measurement is typically nanosecond for primary storage, millisecond for secondary storage, and second for tertiary storage.It may make sense to separate read latency and write latency, and in case of sequential access storage, minimum, utmost and average latency. G. Energy use Storage devices that reduce fan usage, mechanically skillfully shut-down during inactivity, and low power hard drives can reduce energy white plague 90 percent. 2. 5 inch hard disk drives often put one over less power than larger ones. Low capacity solid-state drives have no moving parts and consume less power than hard disks. Also, memory may use more power than hard disks. V. Fundamental storage technologiesAs of 2008, the most ordinarily used data storage technologies are semiconductor, magnetic, and optical, while paper still sees some limited usage. Some other fundamental storage technologies have also been used in the past(a) or are proposed for development. A. Semiconductor Semiconductor memory uses semiconductor-based integrated circuits to store information. A semiconductor memory chip may contain millions of little transistors or capacitors. Volatile and non-volatil e forms of semiconductor memory exist. In modern computers, primary storage almost exclusively consists of dynamic volatile semiconductor memory or dynamic random access memory.Since the turn of the century, a type of non-volatile semiconductor memory known as flash memory has steady gained share as off-line storage for home computers. Non-volatile semiconductor memory is also used for secondary storage in various modernistic electronic devices and specialized computers. B. magnetised Magnetic storage uses different patterns of magnetisation on a magnetically coated surface to store information. Magnetic storage is non-volatile. The information is accessed using one or more read/write heads which may contain one or more recording transducers.A read/write head only covers a part of the surface so that the head or medium or both mustiness be moved relative to another in order to access data. In modern computers, magnetic storage will take these forms Magnetic disk Floppy disk, u sed for off-line storage Hard disk drive, used for secondary storage Magnetic tape data storage, used for tertiary and off-line storage In early computers, magnetic storage was also used for primary storage in a form of magnetic drum, or core memory, core rope memory, thin-film memory, twister memory or bubble memory.Also inappropriate today, magnetic tape was often used for secondary storage. C. Optical Optical storage, the typical optical disc, stores information in deformities on the surface of a circular disc and reads this information by illuminating the surface with a laser diode and observing the reflection. Optical disc storage is non-volatile. The deformities may be permanent (read only media), create once (write once media) or reversible (recordable or read/write media). The following forms are currently in common use. CD, CD-ROM, videodisc, BD-ROM Read only storage, used for mass distribution of digital information (music, video, computer programs) CD-R, DVD-R, DVD+R , BD-R Write once storage, used for tertiary and off-line storage CD-RW, DVD-RW, DVD+RW, DVD-RAM, BD-RE Slow write, fast read storage, used for tertiary and off-line storage Ultra Density Optical or UDO is similar in capacity to BD-R or BD-RE and is slow write, fast read storage used for tertiary and off-line storage Magneto-optical disc storage is optical disc storage where the magnetic state on a ferromagnetic surface stores information.The information is read optically and written by combining magnetic and optical methods. Magneto-optical disc storage is non-volatile, sequential access, slow write, fast read storage used for tertiary and off-line storage. D. Paper Paper data storage, typically in the form of paper tape or punched cards, has long been used to store information for railcarmatic processing, particularly before general-purpose computers existed. schooling was recorded by punching holes into the paper or cardboard medium and was read mechanically (or later optical ly) to determine whether a particular location on the medium was solid or contained a hole.A few technologies allow muckle to make marks on paper that are easily read by machinethese are capaciously used for tabulating votes and grading standardize tests. Barcodes made it possible for any object that was to be sold or transported to have some computer readable information securely connected to it. E. Uncommon Vacuum tube memory, a Williams tube used a cathode ray tube, and a Selectron tube used a large vacuum tube to store information. These primary storage devices were short-lived in the market, since Williams tube was unreliable and Selectron tube was expensive.Electro-acoustic memory also known as delay line memory used sound waves in a substance such as mercury to store information. Delay line memory was dynamic volatile, cycle sequential read/write storage, and was used for primary storage. Optical tape is a medium for optical storage generally consisting of a long and narr ow strip of plastic onto which patterns can be written and from which the patterns can be read back. It shares some technologies with movie film stock and optical discs, but is compatible with n all.The motivation derriere developing this technology was the possibility of far greater storage capacities than either magnetic tape or optical discs. Phase-change memory uses different mechanical phases of Phase Change Material to store information in an X-Y addressable matrix, and reads the information by observing the varying electrical resistance of the material. Phase-change memory would be non-volatile, random access read/write storage, and might be used for primary, secondary and off-line storage. Most rewritable and many write once optical disks already use phase change material to store information.holographical data storage stores information optically inside crystals or photopolymers. Holographic storage can utilize the whole volume of the storage medium, unlike optical disc s torage which is limited to a small number of surface layers. Holographic storage would be non-volatile, sequential access, and either write once or read/write storage. It might be used for secondary and off-line storage. See Holographic Versatile Disc (HVD). molecular memory stores information in polymer that can store electric charge. molecular(a) memory might be especially suited for primary storage.The theory-based storage capacity of molecular memory is 10 terabits per square inch. data storage tag (DST), also sometimes known as an archival tag is a data logger that uses sensors to record data at predetermined intervals. Data storage tags usually have a large memory size and a long lifetime. Most archival tags are alimented by batteries that allow the tag to record positions for several years. rather some tags are solar powered and allow the scientist to set their own interval this then allows data to be recorded for significantly longer than battery-only powered tags.Infor mation repository is an easy way to deploy secondary spirit level of data storage that can comprise multiple, networked data storage technologies run on diverse operating systems, where data that no longer call for to be in primary storage is protected, classified according to captured metadata, processed, de-duplicated, and then purged, automatically, based on data service level objectives and requirements. In information repositories, data storage resources are virtualized as composite storage sets and operate as a federated environment.Information repositories were developed to mitigate problems arising from data proliferation and extinguish the need for separately deployed data storage solutions because of the concurrent deployment of diverse storage technologies running diverse operating systems. They feature centralized management for all deployed data storage resources. They are self-contained, support heterogeneous storage resources, support resource management to add, m aintain, recycle, and terminate media, track of off-line media, and operate autonomously. VI. Related technologies A. Network connectivityA secondary or tertiary storage may connect to a computer utilizing computer networks. This concept does not tinct to the primary storage, which is shared between multiple processors in a much lesser degree. Direct-attached storage (DAS) is a traditional mass storage that does not use any network. This is still a most popular approach. This term was coined lately, together with NAS and SAN. Network-attached storage (NAS) is mass storage attached to a computer which another computer can access at file level over a local area network, a private wide area network, or in the case of online file storage, over the Internet.NAS is commonly associated with the NFS and CIFS/SMB protocols. Storage area network (SAN) is a specialized network that provides other computers with storage capacity. The crucial difference between NAS and SAN is the former present s and manages file systems to invitee computers, whilst the latter provides access at block-addressing (raw) level, leaving it to attaching systems to manage data or file systems within the provided capacity. SAN is commonly associated with Fiber Channel networks. B. Robotic storage erect quantities of individual magnetic tapes and optical or magneto-optical discs may be stored in robotic tertiary storage devices. In tape storage welkin they are known as tape libraries, and in optical storage field optical jukeboxes, or optical disk libraries per analogy. Smallest forms of either technology containing unless one drive device are referred to as autoloaders or auto changers. Robotic-access storage devices may have a number of slots, each holding individual media, and usually one or more picking robots that continue the slots and load media to built-in drives. The arrangement of the slots and picking devices affects erformance.Important characteristics of such storage are possible expansion options adding slots, modules, drives, robots. Tape libraries may have from 10 to more than 100,000 slots, and provide terabytes or petabytes of near-line information. Optical jukeboxes are somewhat smaller solutions, up to 1,000 slots. Robotic storage is used for backups, and for high-capacity archives in imaging, medical, and video industries. Hierarchical storage management is a most known archiving strategy of automatically migrating long-unused files from fast hard disk storage to libraries or jukeboxes. If the files are needed, they are retrieved back to disk.References J. S. Vitter, Algorithms and Data Structures for External Memory. Series on Foundations and Trends in Theoretical Computer Science, now Publishers, Hanover, MA, 2008, ISBN 978-1-60198-106-6. National Communications System (1996). Federal Standard 1037C Telecommunications glossary of Telecommunication Terms. Super Talents 2. 5&8243 IDE Flash hard drive The Tech Report Page 13. (http//techreport. co m/articles. x/10334/13)