Hitory of computers

Databases Edit

Main article: Database

Database Management Systems (DMS) emerged in the 1960s to address the problem of storing and retrieving large amounts of data accurately and quickly. An early such systems was IBM's Information Management System (IMS),[24] which is still widely deployed more than 50 years later.[25] IMS stores data hierarchically,[24] but in the 1970s Ted Codd proposed an alternative relational storage model based on set theory and predicate logic and the familiar concepts of tables, rows and columns. In 1981, the first commercially available relational database management system (RDBMS) was released by Oracle.[26]

All DMS consist of components, they allow the data they store to be accessed simultaneously by many users while maintaining its integrity.[27] All databases are common in one point that the structure of the data they contain is defined and stored separately from the data itself, in a database schema.[24]

In recent years, the extensible markup language (XML) has become a popular format for data representation. Although XML data can be stored in normal file systems, it is commonly held in relational databases to take advantage of their "robust implementation verified by years of both theoretical and practical effort".[28] As an evolution of the Standard Generalized Markup Language (SGML), XML's text-based structure offers the advantage of being both machine and human-readable.[29]

Data retrieval Edit

The relational database model introduced a programming-language independent Structured Query Language (SQL), based on relational algebra.

The terms "data" and "information" are not synonymous. Anything stored is data, but it only becomes information when it is organized and presented meaningfully.[30]:1–9 Most of the world's digital data is unstructured, and stored in a variety of different physical formats[31][b] even within a single organization. Data warehouses began to be developed in the 1980s to integrate these disparate stores. They typically contain data extracted from various sources, including external sources such as the Internet, organized in such a way as to facilitate decision support systems (DSS).[32]:4–6

Data transmission Edit

Data transmission has three aspects: transmission, propagation, and reception.[33] It can be broadly categorized as broadcasting, in which information is transmitted unidirectionally downstream, or telecommunications, with bidirectional upstream and downstream channels.[22]

XML has been increasingly employed as a means of data interchange since the early 2000s,[34] particularly for machine-oriented interactions such as those involved in web-oriented protocols such as SOAP,[29] describing "data-in-transit rather than ... data-at-rest".[34]

Data manipulation Edit

Hilbert and Lopez identify the exponential pace of technological change (a kind of Moore's law): machines' application-specific capacity to compute information per capita roughly doubled every 14 months between 1986 and 2007; the per capita capacity of the world's general-purpose computers doubled every 18 months during the same two decades; the global telecommunication capacity per capita doubled every 34 months; the world's storage capacity per capita required roughly 40 months to double (every 3 years); and per capita broadcast information has doubled every 12.3 years.[22]

Massive amounts of data are stored worldwide every day, but unless it can be analysed and presented effectively it essentially resides in what have been called data tombs: "data archives that are seldom visited".[35] To address that issue, the field of data mining – "the process of discovering interesting patterns and knowledge from large amounts of data"[36] – emerged in the late 1980s.[37] Hilbert and Lopez identify the exponential pace of technological change (a kind of Moore's law): machines' application-specific capacity to compute information per capita roughly doubled every 14 months between 1986 and 2007; the per capita capacity of the world's general-purpose computers doubled every 18 months during the same two decades; the global telecommunication capacity per capita doubled every 34 months; the world's storage capacity per capita required roughly 40 months to double (every 3 years); and per capita broadcast information has doubled every 12.3 years.[22]

Colossus kabi dastlabki elektron kompyuterlar zımbalama lentasidan foydalangan, uzun qog'ozli lenta ustida ma'lumotlar ketma-ket teshiklar bo'lgan, endi texnologiya eskirgan. [14] Zamonaviy kompyuterlarda qo'llaniladigan elektron ma'lumotlarni saqlash Ikkinchi Jahon Urushidan boshlab, radar signallaridan tartibsizlikni olib tashlash uchun kechikish liniyasi xotirasining bir shakli ishlab chiqilgan bo'lib, uning birinchi amaliy qo'llanilishi simobni kechiktirish liniyasi bo'lgan. [15] Dastlabki tasodifiy kiradigan raqamli saqlash moslamasi Uilyams naychasi bo'lib, u standart katod nurlari trubkasiga asoslangan edi [16], lekin unda saqlangan ma'lumotlar va kechikish liniyasi xotirasi o'zgaruvchan bo'lib, uni doimiy ravishda yangilab turish kerak edi va shu bilan bir marta yo'qoldi quvvat o'chirildi. Uchib ketmaydigan kompyuterlarni saqlashning dastlabki shakli 1932 yilda ixtiro qilingan va dunyodagi birinchi tijorat maqsadlarida ishlatiladigan elektron kompyuter Ferranti Mark 1da ishlatilgan [17] magnit baraban edi. [18]

IBM 1956 yilda o'zining 305 RAMAC kompyuter tizimining tarkibiy qismi sifatida birinchi qattiq disk diskini taqdim etdi. [19]: 6 Hozirgi kunda aksariyat raqamli ma'lumotlar magnitlangan holda qattiq disklarda yoki CD-ROM kabi vositalarda saqlanadi. [20] : 4-5– 2002 yilgacha aksariyat ma'lumotlar analog qurilmalarda saqlanar edi, ammo o'sha yili raqamli saqlash hajmi birinchi marta analogdan oshib ketdi. 2007 yilga kelib dunyo bo'ylab saqlangan ma'lumotlarning deyarli 94% raqamli shaklda saqlangan: [21] 52% qattiq disklarda, 28% optik qurilmalarda va 11% raqamli magnit lentada. Ma'lumotlarga ko'ra, elektron qurilmalarda ma'lumotlarni saqlash bo'yicha dunyo miqyosidagi imkoniyatlar 1986 yildagi 3 eksabaytdan kam bo'lgan 2007 yildan 295 eksabaytgacha o'sgan [22], har 3 yilda taxminan ikki baravar ko'paygan. [23]

Ma'lumotlar bazalarini tahrirlash

Asosiy maqola: Ma'lumotlar bazasi

Ma'lumotlar bazasini boshqarish tizimlari (DMS) 1960 yilda katta hajmdagi ma'lumotlarni saqlash va olish muammolarini aniq va tezkor hal qilish uchun paydo bo'lgan. Bunday tizimlarning boshlanishi IBMning Axborotni boshqarish tizimi (IMS) [24] bo'lib, u 50 yildan ko'proq vaqt o'tgach ham keng tarqalgan. [25] IMS ma'lumotlarni ierarxik tarzda saqlaydi, ammo 1970-yillarda Ted Kodd to'plamlar nazariyasi va predikat mantig'iga va jadvallar, satrlar va ustunlar tanish tushunchalariga asoslangan relyatsion saqlashning muqobil modelini taklif qildi. 1981 yilda Oracle tomonidan birinchi savdo-sotiqda mavjud bo'lgan relyatsion ma'lumotlar bazasini boshqarish tizimi (RDBMS) chiqarildi. [26]

Barcha DMS-lar tarkibiy qismlardan iborat bo'lib, ular o'zlari saqlagan ma'lumotlarga bir vaqtning o'zida ko'plab foydalanuvchilar tomonidan uning yaxlitligini saqlab qolishda imkon beradi. [27] Barcha ma'lumotlar bazalari bir nuqtada keng tarqalgan bo'lib, ular tarkibidagi ma'lumotlar tuzilishi aniqlanadi va ma'lumotlar bazasidan sxemada saqlanadi. [24]

So'nggi yillarda kengaytiriladigan belgilash tili (XML) ma'lumotlarni namoyish qilish uchun mashhur formatga aylandi. XML ma'lumotlari oddiy fayl tizimlarida saqlanishi mumkin bo'lsa-da, odatda, ular "ko'p yillik nazariy va amaliy harakatlar bilan tasdiqlangan mustahkam amalga oshirish" imkoniyatidan foydalanish uchun relyatsion ma'lumotlar bazalarida saqlanadi. [28] Standart umumlashtirilgan markalash tili (SGML) evolyutsiyasi sifatida XML-ning matnga asoslangan tuzilishi ham mashinada, ham odam tomonidan tushunarli bo'lish afzalligini beradi. [29]

Ma'lumotlarni qidirishni tahrirlash

Ma'lumotlar bazasining relyatsion modeli relyatsion algebra asosida dasturlash tilida mustaqil ravishda tuzilgan so'rovlar tilini (SQL) joriy qildi.

"Ma'lumotlar" va "ma'lumot" atamalari sinonim emas. Saqlanadigan har qanday narsa ma'lumotdir, lekin u faqat tartibga solinib va ​​mazmunli taqdim etilgandan keyingina ma'lumotga aylanadi. [30]: 1-9 Dunyo raqamli ma'lumotlarining aksariyati tuzilmasiz va turli xil fizik formatlarda saqlanadi [31] [b] bitta tashkilot ichida. Ma'lumotlar omborlari 1980-yillarda ushbu xilma-xil do'konlarni birlashtirish uchun ishlab chiqila boshlandi. Ular, odatda, qarorlarni qo'llab-quvvatlash tizimlarini (DSS) osonlashtiradigan tarzda tashkil etilgan turli xil manbalardan, shu jumladan Internet kabi tashqi manbalardan olingan ma'lumotlarni o'z ichiga oladi. [32]: 4-6

Ma'lumot uzatishni tahrirlash

Ma'lumotlarni uzatish uchta jihatga ega: uzatish, tarqatish va qabul qilish. [33] U keng miqyosda yuqori va quyi oqim kanallari bilan bir yo'nalishda quyi oqim yoki telekommunikatsiya orqali uzatiladigan eshittirish sifatida tasniflanishi mumkin. [22]

XML 2000-yillarning boshidan beri ma'lumotlar almashinuvi vositasi sifatida tobora ko'proq foydalanilmoqda, [34], xususan, SOAP kabi veb-yo'naltirilgan protokollarda ishtirok etganlar kabi mashinaga yo'naltirilgan o'zaro aloqalar uchun [29], "ma'lumotlarni uzatishda emas, balki transitda" ... dam olish paytida ma'lumot ". [34]

Ma'lumotlar bilan ishlashni tahrirlash

Xilbert va Lopes texnologik o'zgarishlarning eksponensial tezligini aniqlaydilar (Mur qonunining bir turi): 1986-2007 yillar oralig'ida har 14 oyda bir kishi boshiga ma'lumotni hisoblash uchun mashinalarning qo'llaniladigan hajmi taxminan ikki baravarga oshdi; xuddi shu yigirma yil ichida dunyodagi umumiy maqsadli kompyuterlarning jon boshiga sig'imi har 18 oyda ikki baravar oshdi; jon boshiga to'g'ri keladigan global telekommunikatsiya quvvati har 34 oyda ikki baravarga oshdi; dunyoda jon boshiga saqlash hajmi taxminan 40 oyni ikki baravarga oshirish kerak (har 3 yilda); va jon boshiga tarqatiladigan ma'lumotlar har 12,3 yilda ikki baravar ko'paygan. [22]

Dunyo bo'ylab har kuni katta miqdordagi ma'lumotlar saqlanadi, ammo ularni tahlil qilish va samarali taqdim etish imkoniyati bo'lmasa, ular ma'lumotlar qabrlari deb nomlangan joyda joylashgan: "kamdan-kam hollarda tashrif buyuradigan ma'lumotlar arxivlari". [35] Ushbu muammoni hal qilish uchun ma'lumotlarni qazib olish sohasi - "katta hajmdagi ma'lumotlardan qiziqarli naqshlar va bilimlarni topish jarayoni" [36] - 1980 yillarning oxirlarida paydo bo'ldi. [37] Xilbert va Lopes texnologik o'zgarishlarning eksponensial tezligini aniqlaydilar (Mur qonunining bir turi): 1986-2007 yillar oralig'ida har 14 oyda bir kishi boshiga ma'lumotni hisoblash uchun mashinalarning qo'llaniladigan hajmi taxminan ikki baravarga oshdi; xuddi shu yigirma yil ichida dunyodagi umumiy maqsadli kompyuterlarning jon boshiga sig'imi har 18 oyda ikki baravar oshdi; jon boshiga to'g'ri keladigan global telekommunikatsiya quvvati har 34 oyda ikki baravarga oshdi; dunyoda jon boshiga saqlash hajmi taxminan 40 oyni ikki baravarga oshirish kerak (har 3 yilda); va jon boshiga tarqatiladigan ma'lumotlar har 12,3 yilda ikki baravar ko'paygan. [22]

Colossus kabisi elektron elektron kompyuterlar zimbalama lentasidan foydalanilgan, uzun qog'ozli lenta ustidagi ma'lumotlar ketma-ket teshiklar bo'lgan, endi texnologiya eskirgan. [14] Zamonaviy kompyuterlarda rejalashtirilgan elektron tekshiruv Ikkinchi Jahon Urushidan foydalanilgan, radar signallaridan tartibsizlikni olib tashlash uchun kechikish liniyasi xotirasining bir shakli ishlab chiqilgan bo'lib, uning birinchi amaliy bajarilishi simobni kechiktirish liniyasi bo'lgan. [15] Dastlabki tasodifiy kiradigan raqamlarni hisobga olish moslamasi Uilyams naychasi bo'lib, u standart katod nurlari trubkasiga qarab edi [16], lekin unda saqlangan ma'lumotlar va kechikish liniyasi xotirasi o'zgaruvchan bo'lib, uni doimiy ravishda yangilab turish kerak edi va shu bilan bir marta kuchayib quvvatni o'chirildi. Uchib ketmaydigan kompyuterlarni boshqarish dastlabki shakli 1932 yilda ixtiro qilingan va dunyodagi birinchi tijorat maqsadlarida elektron kompyuter Ferranti Mark 1da ishlatilgan [17] magnit baraban edi. [18]