543:. They reserved blocks of disc data space for partitions and used the allocated blocks more economically, by dynamically assigning blocks of a partition to a file as needed. To achieve this, the file system had to keep track of which blocks were used or unused by data files in a catalog or file allocation table. Though this made better use of the disc data space, it resulted in fragmentation of files across the disc, and a concomitant performance overhead due additional seek time to read the data. Modern file systems reorganize fragmented files dynamically to optimize file access times. Further developments in file systems resulted in
679:, rely on massively parallel distributed data processing across many commodity computers on a high bandwidth network. In such systems, the data is distributed across multiple computers and therefore any particular computer in the system must be represented in the key of the data, either directly, or indirectly. This enables the differentiation between two identical sets of data, each being processed on a different computer at the same time.
38:
449:(or links or paths) from the start of the structure, in which data values are stored. Therefore, the data key consists of the key to the structure plus the offset (or links or paths) into the structure. When such a structure is repeated, storing variations of the data values and the data keys within the same repeating structure, the result can be considered to resemble a
471:, such that nodes are linked to each other in a cascade of parent-child relationships. Values and potentially more complex data-structures are linked to the nodes. Thus the nodal hierarchy provides the key for addressing the data structures associated with the nodes. This representation can be thought of as an
406:
or memory. This is as opposed to data storage, where the CPU must direct the transfer of data between the storage device (disk, tape...) and memory. RAM is an array of linear contiguous locations that a processor may read or write by providing an address for the read or write operation. The processor
386:
Keys in data provide the context for values. Regardless of the structure of data, there is always a key component present. Keys in data and data-structures are essential for giving meaning to data values. Without a key that is directly or indirectly associated with a value, or collection of values in
453:, in which each element of the repeating structure is considered to be a column and each repetition of the structure is considered as a row of the table. In such an organization of data, the data key is usually a value in one (or a composite of the values in several) of the columns.
539:. In those systems, the files could be filled up, running out of data space before all the data had been written to them. Thus much unused data space was reserved unproductively to ensure adequate free space for each file. Later file-systems introduced
497:. All the values for subsets of the key appear together. When passing sequentially through groups of the data with the same key, or a subset of the key changes, this is referred to in data processing circles as a break, or a
203:
Data relating to physical events or processes will have a temporal component. This temporal component may be implied. This is the case when a device such as a temperature logger receives data from a temperature
619:
It is only after instantiation that an object of a specified class exists. After an object's reference is cleared, the object also ceases to exist. The memory locations where the object's data was stored are
567:
to reduce the time taken to retrieve a subset of the original data. In order to do this, the key of the subset of data to be retrieved must be known before retrieval begins. The most popular indexes are the
212:. So the device records the date, time and temperature together. When the data logger communicates temperatures, it must also report the date and time as metadata for each temperature reading.
846:
387:
a structure, the values become meaningless and cease to be data. That is to say, there has to be a key component linked to a value component in order for it to be considered data.
215:
Fundamentally, computers follow a sequence of instructions they are given in the form of data. A set of instructions to perform a given task (or tasks) is called a
241:
stored at a specific location. Therefore, it is possible for computer programs to operate on other computer programs, by manipulating their programmatic data.
869:
576:
key indexing methods. Indexing is overhead for filing and retrieving data. There are other ways of organizing indexes, e.g. sorting the keys and using a
221:. A program is data in the form of coded instructions to control the operation of a computer or other machine. In the nominal case, the program, as
264:. However, executable files may also contain data used by the program which is built into the program. In particular, some executable files have a
842:
789:
527:
of a predetermined size. In this case, the seek location on the media, is the data key and the blocks are the data values. Early used
161:
or SQL databases, and can generally be represented as abstract key/value pairs. Data can be organized in many different types of
563:
are a way to copy out keys and location addresses from data structures in files, tables and data sets, then organize them using
621:
557:
Retrieving a small subset of data from a much larger set may imply inefficiently searching through the data sequentially.
751:
330:
stored in another file. In this example, the document would be considered data. If the word processor also features a
200:
helps translate data to information. Metadata is data about the data. Metadata may be implied, specified or given.
275:, for example, is a program. The input data to an interpreter is itself a program, just not one expressed in native
407:
may operate on any location in memory at any time in any order. In RAM the smallest element of data is the binary
873:
467:
view of repeating data structures is only one of many possibilities. Repeating data structures can be organised
913:
268:, which nominally contains constants and initial values for variables, both of which can be considered data.
819:
600:
612:
608:
590:
111:
110:. Data sourced from an analog device, such as a temperature sensor, may be converted to digital using an
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of disc drives i.e. where a logical drive can be defined as partitions from a number of physical drives.
166:
131:
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532:
446:
182:
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127:
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238:
256:. Typically, programs are stored in special file types, different from those used for other data.
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577:
272:
234:
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elements consist of an address and a byte/word of data storage. Digital data are often stored in
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1024:
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at run time, the creation of references to in-memory data-structures of objects that have been
154:
103:
66:
24:
402:(RAM) holds data that the CPU has direct access to. A CPU may only manipulate data within its
564:
472:
424:
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354:
230:
222:
20:
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142:
in the form of digital electrical or optical signals. Data pass in and out of computers via
1154:
662:
524:
399:
343:
334:, then the dictionary (word list) for the spell checker would also be considered data. The
327:
208:. When the temperature is received it is assumed that the data has a temporal reference of
107:
523:. These devices typically seek to a location on the magnetic media and then read or write
8:
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1079:
1007:
512:
464:
450:
186:
906:
411:. The capabilities and limitations of accessing RAM are processor specific. In general
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308:
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139:
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Data can be represented in computers in multiple ways, as per the following examples:
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441:, abstract and logical keys codes can be stored in association with values to form a
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Quantities, characters, or symbols on which operations are performed by a computer
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501:. It particularly facilitates the aggregation of data values on subsets of a key.
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similarly involves programs manipulating other programs as data. Programs like
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representation. In modern (post-1960) computer systems, all data is digital.
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Modern scalable and high-performance data persistence technologies, such as
519:, persistent data storage was traditionally achieved by writing the data to
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program from one file, and then use the running program to open and edit a
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The total amount of digital data in 2007 was estimated to be 281 billion
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Various types of data which can be visualized through a computer device
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0). Each location can store usually 8 or 32 bits depending on the
279:. In many cases, the interpreted program will be a human-readable
37:
811:
338:
used by the spell checker to suggest corrections would be either
237:(CPU), are also data. At its most essential, a single datum is a
118:, characters, or symbols on which operations are performed by a
569:
205:
58:
730:
233:
manipulated by the program, but not actually executed by the
843:"Study: amount of digital info > global storage capacity"
593:
uses two basic concepts for understanding data and software:
695:
624:
and are reclassified as unused memory available for reuse.
604:, which is an example of a hierarchical data structure; and
437:
Data keys need not be a direct hardware address in memory.
245:
31:
646:
521:
external block devices like magnetic tape and disk drives
480:
408:
872:. International Data Corporation via EMC. Archived from
271:
The line between program and data can become blurry. An
891:
669:
457:
531:
data file-systems or disc operating systems reserved
106:. Data moving to or from a computer, in most cases,
173:. Data structures can store data of many different
138:, electronic, or mechanical recording media, and
1187:
382:Data keys and values, structures and persistence
786:The Oxford pocket dictionary of current english
867:
584:
907:
83:system of ones (1) and zeros (0), instead of
870:"The diverse and exploding digital universe"
641:for persistent data storage. Databases use
493:Data has some inherent features when it is
311:and such use other programs as their data.
260:contain programs; all other files are also
914:
900:
840:
65:is a single symbol of data. Data requires
487:
102:. Data within a computer, in most cases,
36:
30:For broader coverage of this topic, see
1188:
79:is data that is represented using the
53:(treated as singular, plural, or as a
895:
792:from the original on 28 November 2011
505:
445:. Data structures have predetermined
361:as distinguished from human-readable
868:Gantz, John F.; et al. (2008).
822:from the original on 5 February 2018
670:Parallel distributed data processing
475:. Modern computer operating system
458:Organised recurring data structures
342:data or text in some interpretable
13:
849:from the original on 13 March 2008
192:
14:
1207:
225:by the computer, will consist of
57:) is any sequence of one or more
627:
598:The taxonomic rank-structure of
665:completeness, when saving data.
551:
861:
834:
804:
774:
744:
653:systems, communicating over a
283:, which is manipulated with a
1:
737:
535:blocks on the disc drive for
90:Data exists in three states:
841:Paul, Ryan (12 March 2008).
7:
683:
591:Object-oriented programming
585:Abstraction and indirection
415:is arranged as an array of
248:in a file, they have to be
112:analog-to-digital converter
10:
1212:
479:are a common example; and
29:
18:
929:
661:logging system to ensure
647:structured query language
511:Until the advent of bulk
318:might first instruct the
921:
726:State (computer science)
565:inverted tree structures
419:beginning at address 0 (
578:binary search algorithm
431:
357:) are sometimes called
349:In an alternate usage,
235:central processing unit
488:Sorted or ordered data
393:
104:moves as parallel data
42:
25:Datum (disambiguation)
637:introduced a further
425:computer architecture
40:
21:Data (disambiguation)
1095:Protection (privacy)
818:. 24 December 2015.
816:OpenBSD manual pages
639:layer of abstraction
400:Random access memory
344:programming language
165:, including arrays,
155:relational databases
114:. Data representing
108:moves as serial data
19:For other uses, see
513:non-volatile memory
404:processor registers
782:"Computer program"
506:Peripheral storage
229:. The elements of
144:peripheral devices
43:
1183:
1182:
1175:Wrangling/munging
1025:Format management
651:client and server
649:protocol between
1203:
916:
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902:
893:
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876:on 11 March 2008
865:
859:
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845:. Ars Technics.
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831:
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797:
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758:. Archived from
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659:two phase commit
655:computer network
572:and the dynamic
320:operating system
305:program updaters
277:machine language
258:Executable files
47:computer science
1211:
1210:
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1155:Synchronization
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701:Data dictionary
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495:sorted on a key
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434:
396:
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353:(which are not
314:For example, a
289:Metaprogramming
195:
193:Characteristics
187:data structures
185:and even other
163:data structures
151:computer memory
96:data in transit
35:
28:
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1080:Pre-processing
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721:Database index
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633:The advent of
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545:virtualization
525:blocks of data
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469:hierarchically
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443:data structure
433:
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395:
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355:human-readable
324:word processor
309:virus scanners
244:To store data
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67:interpretation
15:
9:
6:
4:
3:
2:
1208:
1197:
1196:Computer data
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762:on 2019-06-23
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677:Apache Hadoop
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663:transactional
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628:Database data
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499:control break
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473:inverted tree
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332:spell checker
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26:
22:
1085:Preservation
1075:Philanthropy
939:Augmentation
922:
878:. Retrieved
874:the original
863:
851:. Retrieved
836:
824:. Retrieved
815:
806:
794:. Retrieved
785:
776:
764:. Retrieved
760:the original
755:
746:
618:
609:instantiated
599:
558:
552:Indexed data
528:
477:file systems
389:
385:
369:
362:
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351:binary files
348:
340:machine code
313:
270:
266:data segment
243:
227:machine code
216:
214:
209:
202:
196:
177:, including
148:
92:data at rest
89:
76:Digital data
74:
62:
50:
44:
1145:Stewardship
1035:Integration
984:Degradation
969:Compression
949:Archaeology
934:Acquisition
711:Data stream
483:is another.
421:hexadecimal
413:main memory
285:text editor
273:interpreter
254:file format
140:transmitted
100:data in use
71:information
1165:Validation
1100:Publishing
1090:Processing
1060:Management
974:Corruption
964:Collection
826:4 February
796:11 October
766:14 January
738:References
657:, using a
541:partitions
537:data files
533:contiguous
336:algorithms
322:to load a
262:data files
250:serialized
116:quantities
69:to become
1170:Warehouse
1135:Scrubbing
1115:Retention
1110:Reduction
1065:Migration
1040:Integrity
1008:Transform
959:Cleansing
812:"file(1)"
635:databases
417:locations
372:gigabytes
301:debuggers
293:compilers
287:program.
281:text file
149:Physical
55:mass noun
1190:Category
1140:Security
1130:Scraping
1105:Recovery
979:Curation
944:Analysis
880:12 March
853:13 March
847:Archived
820:Archived
790:Archived
716:Data set
691:Big data
684:See also
645:, and a
643:metadata
529:raw disk
439:Indirect
376:exabytes
328:document
223:executed
198:Metadata
132:magnetic
128:recorded
120:computer
1150:Storage
1125:Science
1120:Quality
1050:Lineage
1045:Library
1020:Farming
1003:Extract
989:Editing
622:garbage
611:from a
601:classes
560:Indexes
465:tabular
447:offsets
297:linkers
231:storage
218:program
183:strings
179:numbers
171:objects
157:, like
136:optical
59:symbols
1070:Mining
1030:Fusion
756:Lexico
752:"Data"
570:B-tree
206:sensor
169:, and
167:graphs
159:tables
124:stored
85:analog
731:Tuple
517:flash
515:like
451:table
374:(281
252:in a
246:bytes
239:value
175:types
63:datum
1160:Type
1055:Loss
1013:Load
923:Data
882:2008
855:2008
828:2018
798:2012
768:2022
696:Data
574:hash
463:The
432:Keys
364:text
359:data
316:user
126:and
122:are
98:and
51:data
32:Data
23:and
998:ELT
994:ETL
954:Big
481:XML
409:bit
394:RAM
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210:now
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