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.
Eric Schmidt
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Eric Emerson Schmidt is an American software engineer, a businessman, and the Executive Chairman of Alphabet, Inc. In 2016, Forbes ranked Schmidt as the 100th-richest person in the world, as an intern at Bell Labs, Schmidt did a complete re-write of Lex, a software program to generate lexical analysers for the UNIX computer operating system. From 1997 to 2001, he was Chief Executive Officer of Novell, from 2001 to 2011, Schmidt served as the CEO of Google. He has served on other boards in academia and industry, including the Boards of Trustees for Carnegie Mellon University, Pennsylvania. Eric Emerson Schmidt was born in Falls Church, Virginia, and grew up in Falls Church and Blacksburg, treasury Department during the Nixon Administration. Schmidt graduated from Yorktown High School in the Yorktown neighborhood of Arlington County, Virginia, in 1972 and he then attended Princeton University, where he started as an architecture major but then switched and earned a B. S. degree in electrical engineering in 1976. From 1976 to 1980, Schmidt stayed at the International House Berkeley, in 1979, at the University of California, Berkeley, Schmidt then earned an M. S. degree for designing and implementing a network linking the campus computer center with the CS and EECS departments. There, he earned a Ph. D. degree in 1982 in EECS, with a dissertation about the problems of managing distributed software development. Early in his career, Schmidt held a series of positions with IT companies including Byzromotti Design, Bell Labs, Zilog. During his summers at Bell Labs, he and Mike Lesk wrote Lex and it is an important tool for compiler construction. In 1983, Schmidt joined Sun Microsystems as its first software manager, during his time at Sun, he was the target of two notable April Fools Day pranks. In the first, his office was taken apart and rebuilt on a platform in the middle of a pond, the next year, a working Volkswagen Beetle was taken apart and re-assembled in his office. In April 1997, Schmidt became the CEO and chairman of the board of Novell, in 2001, he departed after the acquisition of Cambridge Technology Partners. Google founders Larry Page and Sergey Brin interviewed Schmidt, impressed by him, they recruited Schmidt to run their company in 2001 under the guidance of venture capitalists John Doerr and Michael Moritz. In March 2001, Schmidt joined Googles board of directors as chairman, at Google, Schmidt shared responsibility for Googles daily operations with founders Page and Brin. Upon being hired at Google, Eric Schmidt was paid a salary of $250,000 and an annual performance bonus. He was granted 14,331,703 shares of Class B common stock at $0.30 per share and 426,892 shares of Series C preferred stock at price of $2.34. In 2004, Schmidt and the Google founders agreed to a salary of US $1 with other compensation of $557,465 in 2006, $508,763 in 2008
3.
Unix
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Among these is Apples macOS, which is the Unix version with the largest installed base as of 2014. Many Unix-like operating systems have arisen over the years, of which Linux is the most popular, Unix was originally meant to be a convenient platform for programmers developing software to be run on it and on other systems, rather than for non-programmer users. The system grew larger as the system started spreading in academic circles, as users added their own tools to the system. Unix was designed to be portable, multi-tasking and multi-user in a time-sharing configuration and these concepts are collectively known as the Unix philosophy. By the early 1980s users began seeing Unix as a universal operating system. Under Unix, the system consists of many utilities along with the master control program. To mediate such access, the kernel has special rights, reflected in the division between user space and kernel space, the microkernel concept was introduced in an effort to reverse the trend towards larger kernels and return to a system in which most tasks were completed by smaller utilities. In an era when a standard computer consisted of a disk for storage and a data terminal for input and output. However, modern systems include networking and other new devices, as graphical user interfaces developed, the file model proved inadequate to the task of handling asynchronous events such as those generated by a mouse. In the 1980s, non-blocking I/O and the set of inter-process communication mechanisms were augmented with Unix domain sockets, shared memory, message queues, and semaphores. In microkernel implementations, functions such as network protocols could be moved out of the kernel, Multics introduced many innovations, but had many problems. Frustrated by the size and complexity of Multics but not by the aims and their last researchers to leave Multics, Ken Thompson, Dennis Ritchie, M. D. McIlroy, and J. F. Ossanna, decided to redo the work on a much smaller scale. The name Unics, a pun on Multics, was suggested for the project in 1970. Peter H. Salus credits Peter Neumann with the pun, while Brian Kernighan claims the coining for himself, in 1972, Unix was rewritten in the C programming language. Bell Labs produced several versions of Unix that are referred to as Research Unix. In 1975, the first source license for UNIX was sold to faculty at the University of Illinois Department of Computer Science, UIUC graduate student Greg Chesson was instrumental in negotiating the terms of this license. During the late 1970s and early 1980s, the influence of Unix in academic circles led to adoption of Unix by commercial startups, including Sequent, HP-UX, Solaris, AIX. In the late 1980s, AT&T Unix System Laboratories and Sun Microsystems developed System V Release 4, in the 1990s, Unix-like systems grew in popularity as Linux and BSD distributions were developed through collaboration by a worldwide network of programmers
4.
Open-source model
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Open-source software may be developed in a collaborative public manner. According to scientists who studied it, open-source software is a prominent example of open collaboration, a 2008 report by the Standish Group states that adoption of open-source software models has resulted in savings of about $60 billion per year to consumers. In the early days of computing, programmers and developers shared software in order to learn from each other, eventually the open source notion moved to the way side of commercialization of software in the years 1970-1980. In 1997, Eric Raymond published The Cathedral and the Bazaar and this source code subsequently became the basis behind SeaMonkey, Mozilla Firefox, Thunderbird and KompoZer. Netscapes act prompted Raymond and others to look into how to bring the Free Software Foundations free software ideas, the new term they chose was open source, which was soon adopted by Bruce Perens, publisher Tim OReilly, Linus Torvalds, and others. The Open Source Initiative was founded in February 1998 to encourage use of the new term, a Microsoft executive publicly stated in 2001 that open source is an intellectual property destroyer. I cant imagine something that could be worse than this for the software business, IBM, Oracle, Google and State Farm are just a few of the companies with a serious public stake in todays competitive open-source market. There has been a significant shift in the corporate philosophy concerning the development of FOSS, the free software movement was launched in 1983. In 1998, a group of individuals advocated that the free software should be replaced by open-source software as an expression which is less ambiguous. Software developers may want to publish their software with an open-source license, the Open Source Definition, notably, presents an open-source philosophy, and further defines the terms of usage, modification and redistribution of open-source software. Software licenses grant rights to users which would otherwise be reserved by law to the copyright holder. Several open-source software licenses have qualified within the boundaries of the Open Source Definition, the open source label came out of a strategy session held on April 7,1998 in Palo Alto in reaction to Netscapes January 1998 announcement of a source code release for Navigator. They used the opportunity before the release of Navigators source code to clarify a potential confusion caused by the ambiguity of the free in English. Many people claimed that the birth of the Internet, since 1969, started the open source movement, the Free Software Foundation, started in 1985, intended the word free to mean freedom to distribute and not freedom from cost. Since a great deal of free software already was free of charge, such software became associated with zero cost. The Open Source Initiative was formed in February 1998 by Eric Raymond and they sought to bring a higher profile to the practical benefits of freely available source code, and they wanted to bring major software businesses and other high-tech industries into open source. Perens attempted to open source as a service mark for the OSI. The Open Source Initiatives definition is recognized by governments internationally as the standard or de facto definition, OSI uses The Open Source Definition to determine whether it considers a software license open source
5.
Regular expression
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A regular expression, regex or regexp is, in theoretical computer science and formal language theory, a sequence of characters that define a search pattern. Usually this pattern is used by string searching algorithms for find or find. The concept arose in the 1950s when the American mathematician Stephen Cole Kleene formalized the description of a regular language, the concept came into common use with Unix text-processing utilities. Today, different syntaxes for writing regular expressions exist, one being the POSIX standard and another, widely used, being the Perl syntax. Regular expressions are used in engines, search and replace dialogs of word processors and text editors, in text processing utilities such as sed and AWK. Many programming languages provide regex capabilities, built-in, or via libraries, the phrase regular expressions is often used to mean the specific, standard textual syntax for representing patterns that matching text need to conform to. Each character in an expression is understood to be a metacharacter. For example, in the regex a, a is a literal character which matches just a and. is a meta character which matches every character except a newline. Therefore, this regex would match for example a or ax or a0, together, metacharacters and literal characters can be used to identify textual material of a given pattern, or process a number of instances of it. Pattern-matches can vary from a precise equality to a general similarity. Is a very general pattern, is general and a is a precise pattern. Wildcards could also achieve this, but are limited in what they can pattern. The usual context of wildcard characters is in globbing similar names in a list of files, for example, the regex ^+|+$ matches excess whitespace at the beginning or end of a line. An advanced regex used to match any numeral is ^. $, see the Examples section for more examples. A regex processor translates a regular expression in the above syntax into a representation which can be executed and matched against a string representing the text being searched in. The picture shows the NFA scheme N obtained from the regular expression s*, where s denotes a simpler regular expression in turn, Regular expressions originated in 1956, when mathematician Stephen Cole Kleene described regular languages using his mathematical notation called regular sets. These arose in theoretical science, in the subfields of automata theory. Other early implementations of pattern matching include the SNOBOL language, which did not use regular expressions, Regular expressions entered popular use from 1968 in two uses, pattern matching in a text editor and lexical analysis in a compiler
6.
Plan 9 from Bell Labs
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Plan 9 from Bell Labs is a distributed operating system, originally developed by the Computing Sciences Research Center at Bell Labs between the mid-1980s and 2002. It takes some of the principles of Unix, developed in the research group. In Plan 9, virtually all computing resources, including files, network connections, a unified network protocol called 9P ties a network of computers running Plan 9 together, allowing them to share all resources so represented. The name Plan 9 from Bell Labs is a reference to the Ed Wood 1959 cult science fiction Z-movie Plan 9 from Outer Space, also, Glenda, the Plan 9 Bunny, is presumably a reference to Woods film Glen or Glenda. The system continues to be used and developed by operating system researchers, Plan 9 from Bell Labs was originally developed, starting mid-1980s, by members of the Computing Science Research Center at Bell Labs, the same group that originally developed Unix and C. The Plan 9 team was led by Rob Pike, Ken Thompson, Dave Presotto and Phil Winterbottom. Over the years, many developers have contributed to the project including Brian Kernighan, Tom Duff, Doug McIlroy, Bjarne Stroustrup. Plan 9 replaced Unix as Bell Labss primary platform for operating systems research and it explored several changes to the original Unix model that facilitate the use and programming of the system, notably in distributed multi-user environments. After several years of development and internal use, Bell Labs shipped the system to universities in 1992. Three years later, in 1995, Plan 9 was made available for parties by AT&T via the book publisher Harcourt Brace. By early 1996, the Plan 9 project had been put on the burner by AT&T in favor of Inferno. In the late 1990s, Bell Labs new owner Lucent Technologies dropped commercial support for the project and in 2000, a fourth release under a new free software license occurred in 2002. A user and development community, including current and former Bell Labs personnel, the development source tree is accessible over the 9P and HTTP protocols and is used to update existing installations. In addition to the components of the OS included in the ISOs, Bell Labs also hosts a repository of externally developed applications. Plan 9 is a operating system, designed to make a network of heterogeneous. In a typical Plan 9 installation, users work at running the window system rio. Permanent data storage is provided by additional network hosts acting as file servers and its designers state that, he foundations of the system are built on two ideas, a per-process name space and a simple message-oriented file system protocol. The potential complexity of this setup is controlled by a set of locations for common resources
7.
Command-line interface
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A program which handles the interface is called a command language interpreter or shell. The interface is implemented with a command line shell, which is a program that accepts commands as text input. Command-line interfaces to computer operating systems are widely used by casual computer users. Alternatives to the line include, but are not limited to text user interface menus, keyboard shortcuts. Examples of this include the Windows versions 1,2,3,3.1, and 3.11, DosShell, and Mouse Systems PowerPanel. Command-line interfaces are preferred by more advanced computer users, as they often provide a more concise. Programs with command-line interfaces are generally easier to automate via scripting, a program that implements such a text interface is often called a command-line interpreter, command processor or shell. Under most operating systems, it is possible to replace the shell program with alternatives, examples include 4DOS for DOS, 4OS2 for OS/2. For example, the default Windows GUI is a program named EXPLORER. EXE. These programs are shells, but not CLIs, application programs may also have command line interfaces. When a program is launched from an OS command line shell, interactive command line sessions, After launch, a program may provide an operator with an independent means to enter commands in the form of text. OS inter-process communication, Most operating systems support means of inter-process communication, Command lines from client processes may be redirected to a CLI program by one of these methods. Some applications support only a CLI, presenting a CLI prompt to the user, Some examples of CLI-only applications are, DEBUG Diskpart Ed Edlin Fdisk Ping Some computer programs support both a CLI and a GUI. In some cases, a GUI is simply a wrapper around a separate CLI executable file, in other cases, a program may provide a CLI as an optional alternative to its GUI. CLIs and GUIs often support different functionality, for example, all features of MATLAB, a numerical analysis computer program, are available via the CLI, whereas the MATLAB GUI exposes only a subset of features. The early Sierra games, like the first three Kings Quest games, used commands from a command line to move the character around in the graphic window. Early computer systems often used teleprinter machines as the means of interaction with a human operator, the computer became one end of the human-to-human teleprinter model. So instead of a human communicating with another human over a teleprinter, in time, the actual mechanical teleprinter was replaced by a glass tty, and then by a smart terminal
8.
Finite-state machine
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A finite-state machine or finite-state automaton, finite automaton, or simply a state machine, is a mathematical model of computation. It is a machine that can be in exactly one of a finite number of states at any given time. The FSM can change from one state to another in response to external inputs. A FSM is defined by a list of its states, its state. The behavior of machines can be observed in many devices in modern society that perform a predetermined sequence of actions depending on a sequence of events with which they are presented. The finite state machine has less power than some other models of computation such as the Turing machine. The computational power distinction means there are tasks that a Turing machine can do. This is because a FSMs memory is limited by the number of states it has, FSMs are studied in the more general field of automata theory. An example of a mechanism that can be modeled by a machine is a turnstile. A turnstile, used to access to subways and amusement park rides, is a gate with three rotating arms at waist height, one across the entryway. Initially the arms are locked, blocking the entry, preventing patrons from passing through, depositing a coin or token in a slot on the turnstile unlocks the arms, allowing a single customer to push through. After the customer passes through, the arms are locked again until another coin is inserted, considered as a state machine, the turnstile has two possible states, Locked and Unlocked. There are two inputs that affect its state, putting a coin in the slot and pushing the arm. In the locked state, pushing on the arm has no effect, no matter how many times the input push is given, putting a coin in – that is, giving the machine a coin input – shifts the state from Locked to Unlocked. In the unlocked state, putting additional coins in has no effect, however, a customer pushing through the arms, giving a push input, shifts the state back to Locked. Each state is represented by a node, edges show the transitions from one state to another. Each arrow is labeled with the input that triggers that transition, an input that doesnt cause a change of state is represented by a circular arrow returning to the original state. The arrow into the Locked node from the dot indicates it is the initial state
9.
O'Reilly Media
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OReilly Media is an American media company established by Tim OReilly that publishes books and Web sites and produces conferences on computer technology topics. Their distinctive brand features a woodcut of an animal on many of their book covers, the company began in 1978 as a private consulting firm doing technical writing, based in the Cambridge, Massachusetts area. In 1984, it began to retain publishing rights on manuals created for Unix vendors, a few 70-page Nutshell Handbooks were well-received, but the focus remained on the consulting business until 1988. After a conference displaying OReillys preliminary Xlib manuals attracted significant attention, in 1992, OReilly Media published one of the first popular books about the Internet, Ed Krols Whole Internet Users Guide and Catalog. OReilly Media also created the first web portal, the Global Network Navigator in 1993, it was sold to AOL in 1995, GNN was the first site on the World Wide Web to feature paid advertising. The firm is now recognized for the conferences and summits it organizes. In 1997, OReilly launched The Perl Conference to raise the profile of the Perl programming language, many of the companys other software bestsellers were also on topics that were off the radar of the commercial software industry. In 1998, OReilly invited many of the leaders of projects to a meeting. Originally called the summit, the meeting became known as the Open Source Summit. The OReilly Open Source Convention is now one of OReillys flagship events, other key events include the Strata Conference on big data, the Velocity Conference on Web Performance and Operations, and FOO Camp. Past events of note include the OReilly Emerging Technology Conference and the Web 2.0 Summit, overall, OReilly describes its business not as publishing or conferences, but as changing the world by spreading the knowledge of innovators. In 2001, O’Reilly launched Safari Books Online, a subscription based service providing access to ebooks as a joint venture with the Pearson Technology Group. In 2013, O’Reilly acquired Pearson’s interest in the joint venture, in 2003, after the dot com bust, O’Reilly’s corporate goal was to reignite enthusiasm in the computer industry. Dale Dougherty, an executive at O’Reilly, coined the phrase Web 2.0 during a brainstorming session and this then became the name for the Web 2.0 Summit run by OReilly Media and TechWeb. In May 2006 CMP Media learned of an event called the Web 2.0 Half day conference. Concerned over their obligation to take reasonable means to enforce their trade and service marks CMP sent a cease and this attempt to restrict through legal mechanisms the use of the term was criticized by some. In 2004, the named the Maker Movement with the launch of Make. Today, the flagship Maker Faire in San Mateo, CA, other Faires around the world collectively draw millions
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