1.
Computer program
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A computer program is a collection of instructions that performs a specific task when executed by a computer. A computer requires programs to function, and typically executes the programs instructions in a processing unit. A computer program is written by a computer programmer in a programming language. From the program in its form of source code, a compiler can derive machine code—a form consisting of instructions that the computer can directly execute. Alternatively, a program may be executed with the aid of an interpreter. A part of a program that performs a well-defined task is known as an algorithm. A collection of programs, libraries and related data are referred to as software. Computer programs may be categorized along functional lines, such as software or system software. The earliest programmable machines preceded the invention of the digital computer, in 1801, Joseph-Marie Jacquard devised a loom that would weave a pattern by following a series of perforated cards. Patterns could be weaved and repeated by arranging the cards, in 1837, Charles Babbage was inspired by Jacquards loom to attempt to build the Analytical Engine. The names of the components of the device were borrowed from the textile industry. In the textile industry, yarn was brought from the store to be milled, the device would have had a store—memory to hold 1,000 numbers of 40 decimal digits each. Numbers from the store would then have then transferred to the mill. It was programmed using two sets of perforated cards—one to direct the operation and the other for the input variables, however, after more than 17,000 pounds of the British governments money, the thousands of cogged wheels and gears never fully worked together. During a nine-month period in 1842–43, Ada Lovelace translated the memoir of Italian mathematician Luigi Menabrea, the memoir covered the Analytical Engine. The translation contained Note G which completely detailed a method for calculating Bernoulli numbers using the Analytical Engine and this note is recognized by some historians as the worlds first written computer program. In 1936, Alan Turing introduced the Universal Turing machine—a theoretical device that can model every computation that can be performed on a Turing complete computing machine and it is a finite-state machine that has an infinitely long read/write tape. The machine can move the back and forth, changing its contents as it performs an algorithm
2.
Computer hardware
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Computer hardware is the collection of physical components that constitute a computer system. By contrast, software is instructions that can be stored and run by hardware, hardware is directed by the software to execute any command or instruction. A combination of hardware and software forms a usable computing system, the template for all modern computers is the Von Neumann architecture, detailed in a 1945 paper by Hungarian mathematician John von Neumann. The meaning of the term has evolved to mean a stored-program computer in which an instruction fetch and this is referred to as the Von Neumann bottleneck and often limits the performance of the system. For the third year, U. S. business-to-business channel sales increased. The impressive growth was the fastest sales increase since the end of the recession, sales growth accelerated in the second half of the year peaking in fourth quarter with a 6.9 percent increase over the fourth quarter of 2012. There are a number of different types of system in use today. The personal computer, also known as the PC, is one of the most common types of computer due to its versatility, laptops are generally very similar, although they may use lower-power or reduced size components, thus lower performance. The computer case is a plastic or metal enclosure that houses most of the components, a case can be either big or small, but the form factor of motherboard for which it is designed matters more. A power supply unit converts alternating current electric power to low-voltage DC power for the components of the computer. Laptops are capable of running from a battery, normally for a period of hours. The motherboard is the component of a computer. It is usually cooled by a heatsink and fan, or water-cooling system, most newer CPUs include an on-die Graphics Processing Unit. The clock speed of CPUs governs how fast it executes instructions, many modern computers have the option to overclock the CPU which enhances performance at the expense of greater thermal output and thus a need for improved cooling. The chipset, which includes the bridge, mediates communication between the CPU and the other components of the system, including main memory. Random-Access Memory, which stores the code and data that are being accessed by the CPU. For example, when a web browser is opened on the computer it takes up memory, RAM usually comes on DIMMs in the sizes 2GB, 4GB, and 8GB, but can be much larger. Read-Only Memory, which stores the BIOS that runs when the computer is powered on or otherwise begins execution, the BIOS includes boot firmware and power management firmware
3.
Video game console
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A video game console is an electronic, digital or computer device that outputs a video signal or visual image to display a video game that one or more people can play. The term video game console is used to distinguish a console machine primarily designed for consumers to use for playing video games. An arcade machine consists of a video game computer, display, game controller, a home computer is a personal computer designed for home use for a variety of purposes, such as bookkeeping, accessing the Internet and playing video games. There are various types of game consoles, including home video game consoles, handheld game consoles, microconsoles. Although Ralph Baer had built working game consoles by 1966, it was nearly a decade before the Pong game made them commonplace in regular peoples living rooms. Through evolution over the 1990s and 2000s, game consoles have expanded to additional functions such as CD players, DVD players, Blu-ray disc players, web browsers, set-top boxes. The first video appeared in the 1960s. They were played on massive computers connected to vector displays, not analog televisions, Ralph H. Baer conceived the idea of a home video game in 1951. In the late 1960s, while working for Sanders Associates, Baer created a series of game console designs. In 1972, Magnavox released the Magnavox Odyssey, the first home game console which could be connected to a TV set. Magnavox replaced the switch design with separate cartridges for each game, by autumn 1975, Magnavox, bowing to the popularity of Pong, cancelled the Odyssey and released a scaled-down version that played only Pong and hockey, the Odyssey 100. A second, higher end console, the Odyssey 200, was released with the 100 and added on-screen scoring, up to four players, almost simultaneously released with Ataris own home Pong console through Sears, these consoles jump-started the consumer market. All three of the new consoles used simpler designs than the original Odyssey did with no board game pieces or extra cartridges, in the years that followed, the market saw many companies rushing similar consoles to market. Most of the consoles from this era were dedicated consoles playing only the games came with the console. These video game consoles were often just called video games, because there was reason to distinguish the two yet. While a few companies like Atari, Magnavox, and newcomer Coleco pushed the envelope, Fairchild released the Fairchild Video Entertainment System in 1976. The VES, however, contained a programmable microprocessor so its cartridges only needed a single ROM chip to store microprocessor instructions, RCA and Atari soon released their own cartridge-based consoles, the RCA Studio II and the Atari 2600, respectively. The first handheld console with interchangeable cartridges was the Microvision designed by Smith Engineering
4.
Software
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Computer software, or simply software, is that part of a computer system that consists of data or computer instructions, in contrast to the physical hardware from which the system is built. In computer science and software engineering, computer software is all information processed by computer systems, programs, computer software includes computer programs, libraries and related non-executable data, such as online documentation or digital media. Computer hardware and software require each other and neither can be used on its own. At the lowest level, executable code consists of machine language instructions specific to an individual processor—typically a central processing unit, a machine language consists of groups of binary values signifying processor instructions that change the state of the computer from its preceding state. For example, an instruction may change the value stored in a storage location in the computer—an effect that is not directly observable to the user. An instruction may also cause something to appear on a display of the computer system—a state change which should be visible to the user. The processor carries out the instructions in the order they are provided, unless it is instructed to jump to a different instruction, the majority of software is written in high-level programming languages that are easier and more efficient for programmers, meaning closer to a natural language. High-level languages are translated into machine language using a compiler or an interpreter or a combination of the two, an outline for what would have been the first piece of software was written by Ada Lovelace in the 19th century, for the planned Analytical Engine. However, neither the Analytical Engine nor any software for it were ever created, the first theory about software—prior to creation of computers as we know them today—was proposed by Alan Turing in his 1935 essay Computable numbers with an application to the Entscheidungsproblem. This eventually led to the creation of the academic fields of computer science and software engineering. Computer science is more theoretical, whereas software engineering focuses on practical concerns. However, prior to 1946, software as we now understand it—programs stored in the memory of stored-program digital computers—did not yet exist, the first electronic computing devices were instead rewired in order to reprogram them. On virtually all platforms, software can be grouped into a few broad categories. There are many different types of software, because the range of tasks that can be performed with a modern computer is so large—see list of software. System software includes, Operating systems, which are collections of software that manage resources and provides common services for other software that runs on top of them. Supervisory programs, boot loaders, shells and window systems are parts of operating systems. In practice, an operating system bundled with additional software so that a user can potentially do some work with a computer that only has an operating system. Device drivers, which operate or control a particular type of device that is attached to a computer, utilities, which are computer programs designed to assist users in the maintenance and care of their computers
5.
Programming language
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A programming language is a formal computer language designed to communicate instructions to a machine, particularly a computer. Programming languages can be used to programs to control the behavior of a machine or to express algorithms. From the early 1800s, programs were used to direct the behavior of such as Jacquard looms. Thousands of different programming languages have created, mainly in the computer field. Many programming languages require computation to be specified in an imperative form while other languages use forms of program specification such as the declarative form. The description of a language is usually split into the two components of syntax and semantics. Some languages are defined by a document while other languages have a dominant implementation that is treated as a reference. Some languages have both, with the language defined by a standard and extensions taken from the dominant implementation being common. A programming language is a notation for writing programs, which are specifications of a computation or algorithm, some, but not all, authors restrict the term programming language to those languages that can express all possible algorithms. For example, PostScript programs are created by another program to control a computer printer or display. More generally, a language may describe computation on some, possibly abstract. It is generally accepted that a specification for a programming language includes a description, possibly idealized. In most practical contexts, a programming language involves a computer, consequently, abstractions Programming languages usually contain abstractions for defining and manipulating data structures or controlling the flow of execution. Expressive power The theory of computation classifies languages by the computations they are capable of expressing, all Turing complete languages can implement the same set of algorithms. ANSI/ISO SQL-92 and Charity are examples of languages that are not Turing complete, markup languages like XML, HTML, or troff, which define structured data, are not usually considered programming languages. Programming languages may, however, share the syntax with markup languages if a computational semantics is defined, XSLT, for example, is a Turing complete XML dialect. Moreover, LaTeX, which is used for structuring documents. The term computer language is used interchangeably with programming language
6.
Computing platform
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Computing platform means in general sense, where any piece of software is executed. It may be the hardware or the system, even a web browser or other application. The term computing platform can refer to different abstraction levels, including a hardware architecture, an operating system. In total it can be said to be the stage on which programs can run. For example, an OS may be a platform that abstracts the underlying differences in hardware, platforms may also include, Hardware alone, in the case of small embedded systems. Embedded systems can access hardware directly, without an OS, this is referred to as running on bare metal, a browser in the case of web-based software. The browser itself runs on a platform, but this is not relevant to software running within the browser. An application, such as a spreadsheet or word processor, which hosts software written in a scripting language. This can be extended to writing fully-fledged applications with the Microsoft Office suite as a platform, software frameworks that provide ready-made functionality. Cloud computing and Platform as a Service, the social networking sites Twitter and facebook are also considered development platforms. A virtual machine such as the Java virtual machine, applications are compiled into a format similar to machine code, known as bytecode, which is then executed by the VM. A virtualized version of a system, including virtualized hardware, OS, software. These allow, for instance, a typical Windows program to run on what is physically a Mac, some architectures have multiple layers, with each layer acting as a platform to the one above it. In general, a component only has to be adapted to the layer immediately beneath it, however, the JVM, the layer beneath the application, does have to be built separately for each OS
7.
Operating system
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An operating system is system software that manages computer hardware and software resources and provides common services for computer programs. All computer programs, excluding firmware, require a system to function. Operating systems are found on many devices that contain a computer – from cellular phones, the dominant desktop operating system is Microsoft Windows with a market share of around 83. 3%. MacOS by Apple Inc. is in place, and the varieties of Linux is in third position. Linux distributions are dominant in the server and supercomputing sectors, other specialized classes of operating systems, such as embedded and real-time systems, exist for many applications. A single-tasking system can run one program at a time. Multi-tasking may be characterized in preemptive and co-operative types, in preemptive multitasking, the operating system slices the CPU time and dedicates a slot to each of the programs. Unix-like operating systems, e. g. Solaris, Linux, cooperative multitasking is achieved by relying on each process to provide time to the other processes in a defined manner. 16-bit versions of Microsoft Windows used cooperative multi-tasking, 32-bit versions of both Windows NT and Win9x, used preemptive multi-tasking. Single-user operating systems have no facilities to distinguish users, but may allow multiple programs to run in tandem, a distributed operating system manages a group of distinct computers and makes them appear to be a single computer. The development of networked computers that could be linked and communicate with each other gave rise to distributed computing, distributed computations are carried out on more than one machine. When computers in a work in cooperation, they form a distributed system. The technique is used both in virtualization and cloud computing management, and is common in large server warehouses, embedded operating systems are designed to be used in embedded computer systems. They are designed to operate on small machines like PDAs with less autonomy and they are able to operate with a limited number of resources. They are very compact and extremely efficient by design, Windows CE and Minix 3 are some examples of embedded operating systems. A real-time operating system is a system that guarantees to process events or data by a specific moment in time. A real-time operating system may be single- or multi-tasking, but when multitasking, early computers were built to perform a series of single tasks, like a calculator. Basic operating system features were developed in the 1950s, such as resident monitor functions that could run different programs in succession to speed up processing
8.
VisiCalc
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VisiCalc was the first spreadsheet computer program for personal computers, originally released for the Apple II by VisiCorp. It is often considered the application that turned the microcomputer from a hobby for computer enthusiasts into a business tool. VisiCalc is considered the Apple IIs killer app and it sold over 700,000 copies in six years, and as many as 1 million copies over its history. Initially developed in a 6502 assembler running on the Multics time sharing system, VisiCalc was ported to numerous platforms, in order to do this, the company developed porting platforms that produced bug compatible versions. The company took the approach when the IBM PC was launched. Sales were initially brisk, with about 300,000 copies sold, VisiCalc used the A1 notation in formulas. When Lotus 1-2-3 was launched in 1983, taking advantage of the expanded memory and screen of the PC. Sales imploded so rapidly that the company was soon insolvent, Lotus Development purchased the company in 1985, and immediately ended sales of VisiCalc and the companys other products. VISICALC represented a new idea of a way to use a computer, — Ted Nelson VisiCalc traces its history to a presentation that Dan Bricklin was watching while attending Harvard Business School. The professor was creating a model on a blackboard that was ruled with lines to create a table. When the professor found an error or wanted to change a parameter, he had to erase, Bricklin realized that he could replicate the process on a computer using an electronic spreadsheet to view results of underlying formulae. Bricklin was joined by Bob Frankston, and the pair worked on VisiCalc for two months during the winter of 1978–79, forming Software Arts, Bricklin wrote that with the years of experience we had at the time we created VisiCalc, we were familiar with many row/column financial programs. However, these earlier timesharing programs were not completely interactive, nor did they run on personal computers, Frankston described VisiCalc as a magic sheet of paper that can perform calculations and recalculations, which allows the user to just solve the problem using familiar tools and concepts. Personal Software began selling it in mid-1979 for under $100, after a demonstration at the fourth West Coast Computer Faire and it required an Apple II with 32K of random-access memory, and supported saving files to magnetic tape cassette or Apples Disk II floppy disk system. VisiCalc was unusually easy to use and came with excellent documentation, ben Rosen speculated in July 1979 that VisiCalc could someday become the software tail that wags the personal computer dog. For the first 12 months it was available for the Apple II. Many bought $2000 Apples to run the software, even if they already owned computers. Apples rival Tandy Corporation used VisiCalc on its own Apple IIs, other software supported its Data Interchange Format to share data
9.
Spreadsheet
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A spreadsheet is an interactive computer application for organization, analysis and storage of data in tabular form. Spreadsheets are developed as computerized simulations of paper accounting worksheets, the program operates on data entered in cells of a table. Each cell may contain either numeric or text data, or the results of formulas that automatically calculate, a spreadsheet may also refer to one such electronic document. Spreadsheet users can adjust any stored value and observe the effects on calculated values and this makes the spreadsheet useful for what-if analysis since many cases can be rapidly investigated without manual recalculation. Modern spreadsheet software can have multiple interacting sheets, and can display either as text and numerals. Besides performing basic arithmetic and mathematical functions, modern spreadsheets provide built-in functions for financial and statistical operations. Such calculations as net present value or standard deviation can be applied to data with a pre-programmed function in a formula. Spreadsheet programs also provide conditional expressions, functions to convert between text and numbers, and functions operate on strings of text. Spreadsheets have replaced paper-based systems throughout the business world, although they were first developed for accounting or bookkeeping tasks, they now are used extensively in any context where tabular lists are built, sorted, and shared. LANPAR, available in 1969, was the first electronic spreadsheet on mainframe and time sharing computers, LANPAR was an acronym, LANguage for Programming Arrays at Random. VisiCalc was the first electronic spreadsheet on a microcomputer, and it helped turn the Apple II computer into a popular, Lotus 1-2-3 was the leading spreadsheet when DOS was the dominant operating system. Excel now has the largest market share on the Windows and Macintosh platforms, a spreadsheet program is a standard feature of an office productivity suite, since the advent of web apps, office suites now also exist in web app form. A spreadsheet consists of a table of cells arranged into rows and columns, X locations, the columns, are normally represented by letters, A, B, C, etc. while rows are normally represented by numbers,1,2,3, etc. A single cell can be referred to by addressing its row and column and this electronic concept of cell references was first introduced in LANPAR and a variant used in VisiCalc, and known as A1 notation. Additionally, spreadsheets have the concept of a range, a group of cells, for instance, one can refer to the first ten cells in the first column with the range A1, A10. LANPAR innovated forward referencing/natural order calculation which didnt re-appear until Lotus 123, in modern spreadsheet applications, several spreadsheets, often known as worksheets or simply sheets, are gathered together to form a workbook. A workbook is physically represented by a file, containing all the data for the book, the sheets, worksheets are normally represented by tabs that flip between pages, each one containing one of the sheets, although Numbers changes this model significantly. Cells in a multi-sheet book add the name to their reference, for instance
10.
Apple II series
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Introduced at the West Coast Computer Faire on April 16,1977, the Apple II was among the first successful personal computers, it launched the Apple company into a successful business. Throughout the years, a number of models were sold, with the most popular model remaining relatively little changed into the 1990s, while primarily an 8-bit computer, by mid-run a 16-bit model was introduced. It was first sold on June 10,1977, by the end of production in 1993, somewhere between five and six million Apple II series computers had been produced. The Apple II was one of the longest running mass-produced home computer series, the Apple II became one of several recognizable and successful computers during the 1980s and early 1990s, although this was mainly limited to the USA. The original Apple II operating system was in ROM along with Integer BASIC, programs were entered, then saved and loaded on cassette tape. When the Disk II was implemented in 1978 by Steve Wozniak, the final and most popular version of this software was Apple DOS3.3. Some commercial Apple II software booted directly and did not use standard DOS formats and this discouraged the copying or modifying of the software on the disks and improved loading speed. Apple DOS was superseded by ProDOS, which supported a hierarchical filesystem, with an optional third-party Z80-based expansion card the Apple II could boot into the CP/M operating system and run WordStar, dBase II, and other CP/M software. At the height of its evolution, towards the late 1980s, by 1992, the platform had 16-bit processing capabilities, a mouse-driven graphical user interface, and graphics and sound capabilities far beyond the original. At its peak, it was an industry with its associated community of third-party developers and retailers. The Apple IIGS was sold until the end of 1992, the last II-series Apple in production, total Apple II sales for its 14-year run were about 6 million units, with the peak occurring in 1983 when 1 million were sold. The Apple II was designed to more like a home appliance than a piece of electronic equipment. The Apple II had color and high-resolution graphics modes, sound capabilities, the Apple II was targeted for the masses rather than just hobbyists and engineers, it also influenced most of the microcomputers that followed it. Unlike preceding home microcomputers, it was sold as a consumer appliance rather than as a kit. VanLOVEs Apple Handbook and The Apple Educators Guide by Gerald VanDiver, the Apple dealer network used this book to emphasize the growing software developer base in education and personal use. The Apple II series had a built into the motherboard shell. An upgrade kit was later to house the motherboard of an Apple IIGS in an Apple IIe case. The Apple II case was durable enough, according to a 1981 Apple ad, early II-series models were usually designated Apple ][ plus
