Computer Awareness GK Questions with Answers – Page 5

NoSQL databases drop the fixed table and row structure so that they can hold large and irregular data and spread it over many machines, and MongoDB is the best known document store, keeping records as documents in a format close to JSON.

Clustering is unsupervised because the data carries no labels: the algorithm itself groups similar records, k-means doing so by placing k centres and moving them until each record sits with its nearest centre.

ETL names the three steps through which data enters a warehouse: it is extracted from the operational systems that produced it, transformed so that formats, units, codes and duplicates are reconciled into one consistent shape, and then loaded into the warehouse tables.

It uses historical data with statistical models and machine learning to estimate what will probably happen next, such as which loan accounts are likely to slip into default or how much electricity a city will draw next summer.

Storage units climb in powers of two, each unit being 1,024 times the one below it, so 1,024 bytes make a kilobyte, 1,024 kilobytes a megabyte, 1,024 megabytes a gigabyte, 1,024 gigabytes a terabyte and 1,024 terabytes a petabyte.

The Apriori algorithm first finds the sets of items that appear together often enough to pass a support threshold, using the rule that any subset of a frequent set must itself be frequent, and then turns those frequent sets into rules measured by confidence.

In the process called Knowledge Discovery in Databases, or KDD, the stages run from selection of the relevant data, through cleaning and preprocessing, to transformation, then data mining, and finally interpretation and evaluation of what was found.

It splits a large file into fixed-size blocks, 128 megabytes by default in current versions, scatters those blocks over the machines of the cluster and keeps more than one copy of each block so that the failure of a machine does not lose data.

Virtualisation is the technique of running several logical machines on one physical machine and belongs to the chapter on cloud computing, not to the definition of big data.

On-Line Transaction Processing is the mode in which a bank counter, a railway booking window or a payment gateway works: each transaction is processed the moment it is entered, so the response to the user is immediate, and every committed transaction is written at once, so the database always reflects…

A data warehouse is exactly that, a central store into which data from many operational systems is extracted, cleaned and loaded so that it can be analysed for decision making.

Tata Consultancy Services was set up in 1968 as a division of the Tata group to provide management consultancy and data processing, and its registered office and headquarters have remained in Mumbai, the home city of the group.

The two left a research centre in California and founded Adobe in 1982 at San Jose, naming it after a creek near Warnock's home.

Alibaba was started in 1999 by Jack Ma, a former English teacher, in his apartment in Hangzhou, the capital of Zhejiang province, and the company has kept its headquarters in that city.

Faqir Chand Kohli was the first general manager and later deputy chairman of Tata Consultancy Services, and he is credited with creating the model on which Indian software exports grew, namely training engineering graduates in programming and selling their services to clients abroad.

Google reorganised its businesses in 2015 and placed them under a new holding company named Alphabet Inc. Google continued as the subsidiary running search, advertising, Android, Chrome, Maps and YouTube, while separate ventures such as the self-driving car company and the life sciences company were made direct subsidiaries of Alphabet.

Robert Noyce, one of the inventors of the integrated circuit, and Gordon Moore, who gave the observation known as Moore's law that the number of transistors on a chip doubles about every two years, left an earlier firm and founded Intel in 1968.

Shiv Nadar and a group of colleagues left their jobs at an electronics firm and set up Hindustan Computers Limited, shortened to HCL, in 1976 to design and sell Indian-made microcomputers.

The company was registered in 1945 by M. H. Hasham Premji and made vanaspati cooking oil and laundry soap at Amalner in Maharashtra.

Infosys was started in 1981 at Pune by N. R. Narayana Murthy together with six colleagues, among them Nandan Nilekani, S. Gopalakrishnan, S. D. Shibulal, K. Dinesh, N. S. Raghavan and Ashok Arora, with a very small amount of borrowed capital.