1.
Software developer
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A software developer is a person concerned with facets of the software development process, including the research, design, programming, and testing of computer software. Other job titles which are used with similar meanings are programmer, software analyst. According to developer Eric Sink, the differences between system design, software development, and programming are more apparent, even more so that developers become systems architects, those who design the multi-leveled architecture or component interactions of a large software system. In a large company, there may be employees whose sole responsibility consists of one of the phases above. In smaller development environments, a few people or even an individual might handle the complete process. The word software was coined as a prank as early as 1953, before this time, computers were programmed either by customers, or the few commercial computer vendors of the time, such as UNIVAC and IBM. The first company founded to provide products and services was Computer Usage Company in 1955. The software industry expanded in the early 1960s, almost immediately after computers were first sold in mass-produced quantities, universities, government, and business customers created a demand for software. Many of these programs were written in-house by full-time staff programmers, some were distributed freely between users of a particular machine for no charge. Others were done on a basis, and other firms such as Computer Sciences Corporation started to grow. The computer/hardware makers started bundling operating systems, systems software and programming environments with their machines, new software was built for microcomputers, so other manufacturers including IBM, followed DECs example quickly, resulting in the IBM AS/400 amongst others. The industry expanded greatly with the rise of the computer in the mid-1970s. In the following years, it created a growing market for games, applications. DOS, Microsofts first operating system product, was the dominant operating system at the time, by 2014 the role of cloud developer had been defined, in this context, one definition of a developer in general was published, Developers make software for the world to use. The job of a developer is to crank out code -- fresh code for new products, code fixes for maintenance, code for business logic, bus factor Software Developer description from the US Department of Labor
2.
Ken Thompson
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Kenneth Lane Ken Thompson, commonly referred to as ken in hacker circles, is an American pioneer of computer science. Having worked at Bell Labs for most of his career, Thompson designed and implemented the original Unix operating system. He also invented the B programming language, the predecessor to the C programming language. Since 2006, Thompson has worked at Google, where he co-invented the Go programming language, Thompson was born in New Orleans. When asked how he learned to program, Thompson stated, I was always fascinated with logic and even in grade school Id work on problems in binary. Thompson was hired by Bell Labs in 1966, in the 1960s at Bell Labs, Thompson and Dennis Ritchie worked on the Multics operating system. While writing Multics, Thompson created the Bon programming language, and he also created a video game called Space Travel. Later on Bell Labs withdrew from the MULTICS project, in order to go on playing the game, Thompson found an old PDP-7 machine and rewrote Space Travel on it. In 1970, Brian Kernighan suggested the name Unix, in a somewhat treacherous pun on the name Multics, after initial work on Unix, Thompson decided that Unix needed a system programming language and created B, a precursor to Ritchies C. In the 1960s, Thompson also began work on regular expressions, Thompson had developed the CTSS version of the editor QED, which included regular expressions for searching text. QED and Thompsons later editor ed contributed greatly to the popularity of regular expressions. Almost all programs that work with regular expressions today use some variant of Thompsons notation and he also invented Thompsons construction algorithm used for converting regular expression into nondeterministic finite automaton in order to make expression matching faster. Then there was a rewrite in a language that would come to be called C. He worked mostly on the language and on the I/O system and that was for the PDP-11, which was serendipitous, because that was the computer that took over the academic community. Feedback from Thompsons Unix development was instrumental in the development of the C programming language. Thompson would later say that the C language grew up one of the rewritings of the system and, as such. In 1975, Thompson took a sabbatical from Bell Labs and went to his alma mater, there, he helped to install Version 6 Unix on a PDP-11/70. Unix at Berkeley would later become maintained as its own system, along with Joseph Condon, Thompson created the hardware and software for Belle, a world champion chess computer
3.
Dennis Ritchie
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Dennis MacAlistair Ritchie was an American computer scientist. He created the C programming language and, with long-time colleague Ken Thompson, Ritchie and Thompson received the Turing Award from the ACM in 1983, the Hamming Medal from the IEEE in 1990 and the National Medal of Technology from President Bill Clinton in 1999. Ritchie was the head of Lucent Technologies System Software Research Department when he retired in 2007 and he was the R in K&R C, and commonly known by his username dmr. Dennis Ritchie was born in Bronxville, New York and his father was Alistair E. Ritchie, a longtime Bell Labs scientist and co-author of The Design of Switching Circuits on switching circuit theory. As a child, Dennis moved with his family to Summit, New Jersey and he graduated from Harvard University with degrees in physics and applied mathematics. However, Ritchie never officially received his PhD degree, during the 1960s, Ritchie and Ken Thompson worked on the Multics operating system at Bell Labs. However, Bell Labs pulled out of the project in 1969, Thompson then found an old PDP-7 machine and developed his own application programs and operating system from scratch, aided by Ritchie and others. In 1970, Brian Kernighan suggested the name Unix, a pun on the name Multics, to supplement assembly language with a system-level programming language, Thompson created B. Later, B was replaced by C, created by Ritchie, during the 1970s, Ritchie collaborated with James Reeds and Robert Morris on a ciphertext-only attack on the M-209 US cipher machine that could solve messages of at least 2000–2500 letters. Ritchie relates that, after discussions with the NSA, the decided not to publish it. Ritchie was also involved with the development of the Plan 9 and Inferno operating systems, and they were so influential on Research Unix that Doug McIlroy later wrote, The names of Ritchie and Thompson may safely be assumed to be attached to almost everything not otherwise attributed. Ritchie liked to emphasize that he was just one member of a group and he suggested that many of the improvements he introduced simply looked like a good thing to do, and that anyone else in the same place at the same time might have done the same thing. But Bjarne Stroustrup who designed C++ said If Dennis had decided to spend that decade on esoteric math, nowadays, the C language is widely used today in application, operating system, and embedded system development, and its influence is seen in most modern programming languages. Unix has also been influential, establishing computing concepts and principles that have been widely adopted, in the same interview, he stated that he viewed both Unix and Linux as the continuation of ideas that were started by Ken and me and many others, many years ago. In 1983, Ritchie and Thompson received the Turing Award for their development of operating systems theory. Ritchies Turing Award lecture was titled Reflections on Software Research, in 1997, both Ritchie and Thompson were made Fellows of the Computer History Museum, for co-creation of the UNIX operating system, and for development of the C programming language. In 2011, Ritchie, along with Thompson, was awarded the Japan Prize for Information, Ritchie was found dead on October 12,2011, at the age of 70 at his home in Berkeley Heights, New Jersey, where he lived alone. First news of his death came from his colleague, Rob Pike
4.
Brian Kernighan
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Brian Wilson Kernighan is a Canadian computer scientist who worked at Bell Labs alongside Unix creators Ken Thompson and Dennis Ritchie and contributed to the development of Unix. He is also coauthor of the AWK and AMPL programming languages, the K of K&R C and the K in AWK both stand for Kernighan. Since 2000 Brian Kernighan has been a Professor at the Computer Science Department of Princeton University, born in Toronto, Kernighan attended the University of Toronto between 1960 and 1964, earning his Bachelors degree in engineering physics. He received his PhD in electrical engineering from Princeton University in 1969 for research supervised by Peter Weiner, Kernighan has held a professorship in the department of computer science at Princeton since 2000. Each fall he teaches a course called Computers in Our World, kernighans name became widely known through co-authorship of the first book on the C programming language with Dennis Ritchie. Kernighan affirmed that he had no part in the design of the C language and he authored many Unix programs, including ditroff. In collaboration with Shen Lin he devised well-known heuristics for two NP-complete optimization problems, graph partitioning and the travelling salesman problem, in a display of authorial equity, the former is usually called the Kernighan–Lin algorithm, while the latter is known as the Lin–Kernighan heuristic. Kernighan was the editor for Prentice Hall International. His Software Tools series spread the essence of C/Unix thinking with makeovers for BASIC, FORTRAN, and Pascal and he has said that if stranded on an island with only one programming language it would have to be C. Kernighan coined the term Unix and helped popularize Thompsons Unix philosophy, Kernighan is also known as a coiner of the expression What You See Is All You Get, which is a sarcastic variant of the original What You See Is What You Get. Kernighans term is used to indicate that WYSIWYG systems might throw away information in a document that could be useful in other contexts, kernighans original 1978 implementation of Hello, World. Was sold at The Algorithm Auction, the world’s first auction of computer algorithms, in 1996, Kernighan taught CS50 which is the Harvard University introductory course in Computer Science. His students on CS50 include David J. Malan who now runs the course, an Interview with Brian Kernighan — By Mihai Budiu, for PC Report Romania, August 2000 Transcript of an interview with Brian Kernighan. Archived from the original on 2009-04-28, archived from the original on 2009-05-28
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Douglas McIlroy
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Malcolm Douglas McIlroy is a mathematician, engineer, and programmer. As of 2007 he is an Adjunct Professor of Computer Science at Dartmouth College, McIlroy is best known for having originally developed Unix pipelines, software componentry and several Unix tools, such as spell, diff, sort, join, graph, speak, and tr. His seminal work on software componentization makes him a pioneer of component-based software engineering and he taught at MIT from 1954 to 1958. McIlroy joined Bell Laboratories in 1958, from 1965 to 1986 was head of its Computing Techniques Research Department, from 1967 to 1968, McIlroy also served as a visiting lecturer at Oxford University. In 1997, McIlroy retired from Bell Labs, and took a position as an Adjunct Professor in the Dartmouth College Computer Science Department, McIlroy is a member of the National Academy of Engineering, and has won both the USENIX Lifetime Achievement Award and its Software Tools award. He also served on the committee of CSNET. Those types are not abstract, they are as real as int, as a programmer, it is your job to put yourself out of business. What you do today can be automated tomorrow, keep it simple, make it general, and make it intelligible. The real hero of programming is the one who writes negative code
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Bell Labs
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Nokia Bell Labs is an American research and scientific development company, owned by Finnish company Nokia. Its headquarters are located in Murray Hill, New Jersey, in addition to laboratories around the rest of the United States. The historic laboratory originated in the late 19th century as the Volta Laboratory, Bell Labs was also at one time a division of the American Telephone & Telegraph Company, half-owned through its Western Electric manufacturing subsidiary. Eight Nobel Prizes have been awarded for work completed at Bell Laboratories, in 1880, the French government awarded Alexander Graham Bell the Volta Prize of 50,000 francs, approximately US$10,000 at that time for the invention of the telephone. Bell used the award to fund the Volta Laboratory in Washington, D. C. in collaboration with Sumner Tainter, the laboratory is also variously known as the Volta Bureau, the Bell Carriage House, the Bell Laboratory and the Volta Laboratory. The laboratory focused on the analysis, recording, and transmission of sound, Bell used his considerable profits from the laboratory for further research and education to permit the diffusion of knowledge relating to the deaf. This resulted in the founding of the Volta Bureau c,1887, located at Bells fathers house at 1527 35th Street in Washington, D. C. where its carriage house became their headquarters in 1889. In 1893, Bell constructed a new building, close by at 1537 35th St. specifically to house the lab, the building was declared a National Historic Landmark in 1972. In 1884, the American Bell Telephone Company created the Mechanical Department from the Electrical, the first president of research was Frank B. Jewett, who stayed there until 1940, ownership of Bell Laboratories was evenly split between AT&T and the Western Electric Company. Its principal work was to plan, design, and support the equipment that Western Electric built for Bell System operating companies and this included everything from telephones, telephone exchange switches, and transmission equipment. Bell Labs also carried out consulting work for the Bell Telephone Company, a few workers were assigned to basic research, and this attracted much attention, especially since they produced several Nobel Prize winners. Until the 1940s, the principal locations were in and around the Bell Labs Building in New York City. Of these, Murray Hill and Crawford Hill remain in existence, the largest grouping of people in the company was in Illinois, at Naperville-Lisle, in the Chicago area, which had the largest concentration of employees prior to 2001. Since 2001, many of the locations have been scaled down or closed. The Holmdel site, a 1.9 million square foot structure set on 473 acres, was closed in 2007, the mirrored-glass building was designed by Eero Saarinen. In August 2013, Somerset Development bought the building, intending to redevelop it into a commercial and residential project. The prospects of success are clouded by the difficulty of readapting Saarinens design and by the current glut of aging, eight Nobel Prizes have been awarded for work completed at Bell Laboratories
7.
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
8.
C (programming language)
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C was originally developed by Dennis Ritchie between 1969 and 1973 at Bell Labs, and used to re-implement the Unix operating system. C has been standardized by the American National Standards Institute since 1989, C is an imperative procedural language. Therefore, C was useful for applications that had formerly been coded in assembly language. Despite its low-level capabilities, the language was designed to encourage cross-platform programming, a standards-compliant and portably written C program can be compiled for a very wide variety of computer platforms and operating systems with few changes to its source code. The language has become available on a wide range of platforms. In C, all code is contained within subroutines, which are called functions. Function parameters are passed by value. Pass-by-reference is simulated in C by explicitly passing pointer values, C program source text is free-format, using the semicolon as a statement terminator and curly braces for grouping blocks of statements. The C language also exhibits the characteristics, There is a small, fixed number of keywords, including a full set of flow of control primitives, for, if/else, while, switch. User-defined names are not distinguished from keywords by any kind of sigil, There are a large number of arithmetical and logical operators, such as +, +=, ++, &, ~, etc. More than one assignment may be performed in a single statement, function return values can be ignored when not needed. Typing is static, but weakly enforced, all data has a type, C has no define keyword, instead, a statement beginning with the name of a type is taken as a declaration. There is no function keyword, instead, a function is indicated by the parentheses of an argument list, user-defined and compound types are possible. Heterogeneous aggregate data types allow related data elements to be accessed and assigned as a unit, array indexing is a secondary notation, defined in terms of pointer arithmetic. Unlike structs, arrays are not first-class objects, they cannot be assigned or compared using single built-in operators, There is no array keyword, in use or definition, instead, square brackets indicate arrays syntactically, for example month. Enumerated types are possible with the enum keyword and they are not tagged, and are freely interconvertible with integers. Strings are not a data type, but are conventionally implemented as null-terminated arrays of characters. Low-level access to memory is possible by converting machine addresses to typed pointers
9.
Assembly language
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Each assembly language is specific to a particular computer architecture. In contrast, most high-level programming languages are generally portable across multiple architectures, Assembly language may also be called symbolic machine code. Assembly language is converted into machine code by a utility program referred to as an assembler. The conversion process is referred to as assembly, or assembling the source code, Assembly time is the computational step where an assembler is run. Assembly language uses a mnemonic to represent each low-level machine instruction or opcode, typically also each architectural register, flag, depending on the architecture, these elements may also be combined for specific instructions or addressing modes using offsets or other data as well as fixed addresses. Many assemblers offer additional mechanisms to facilitate development, to control the assembly process. A macro assembler includes a facility so that assembly language text can be represented by a name. A cross assembler is an assembler that is run on a computer or operating system of a different type from the system on which the code is to run. Cross-assembling facilitates the development of programs for systems that do not have the resources to support software development, a microassembler is a program that helps prepare a microprogram, called firmware, to control the low level operation of a computer. A meta-assembler is a used in some circles for a program that accepts the syntactic and semantic description of an assembly language. An assembler program creates object code by translating combinations of mnemonics and syntax for operations and this representation typically includes an operation code as well as other control bits and data. The assembler also calculates constant expressions and resolves symbolic names for memory locations, the use of symbolic references is a key feature of assemblers, saving tedious calculations and manual address updates after program modifications. Most assemblers also include facilities for performing textual substitution – e. g. to generate common short sequences of instructions as inline. Some assemblers may also be able to some simple types of instruction set-specific optimizations. One concrete example of this may be the ubiquitous x86 assemblers from various vendors, most of them are able to perform jump-instruction replacements in any number of passes, on request. Like early programming languages such as Fortran, Algol, Cobol and Lisp, assemblers have been available since the 1950s, however, assemblers came first as they are far simpler to write than compilers for high-level languages. There may be several assemblers with different syntax for a particular CPU or instruction set architecture, despite different appearances, different syntactic forms generally generate the same numeric machine code, see further below. A single assembler may also have different modes in order to support variations in syntactic forms as well as their exact semantic interpretations, there are two types of assemblers based on how many passes through the source are needed to produce the executable program
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Berkeley Software Distribution
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Berkeley Software Distribution is a Unix operating system derivative developed and distributed by the Computer Systems Research Group of the University of California, Berkeley, from 1977 to 1995. Today the term BSD is often used non-specifically to refer to any of the BSD descendants which together form a branch of the family of Unix-like operating systems, operating systems derived from the original BSD code remain actively developed and widely used. Historically, BSD has been considered a branch of Unix, Berkeley Unix, because it shared the initial codebase, in the 1980s, BSD was widely adopted by vendors of workstation-class systems in the form of proprietary Unix variants such as DEC ULTRIX and Sun Microsystems SunOS. This can be attributed to the ease with which it could be licensed, FreeBSD, OpenBSD, NetBSD, Darwin, and PC-BSD. The earliest distributions of Unix from Bell Labs in the 1970s included the source code to the system, allowing researchers at universities to modify. A larger PDP-11/70 was installed at Berkeley the following year, using money from the Ingres database project, also in 1975, Ken Thompson took a sabbatical from Bell Labs and came to Berkeley as a visiting professor. He helped to install Version 6 Unix and started working on a Pascal implementation for the system, graduate students Chuck Haley and Bill Joy improved Thompsons Pascal and implemented an improved text editor, ex. Other universities became interested in the software at Berkeley, and so in 1977 Joy started compiling the first Berkeley Software Distribution, 1BSD was an add-on to Version 6 Unix rather than a complete operating system in its own right. Some thirty copies were sent out, some 75 copies of 2BSD were sent out by Bill Joy. 2. 9BSD from 1983 included code from 4. 1cBSD, the most recent release,2. 11BSD, was first issued in 1992. As of 2008, maintenance updates from volunteers are still continuing, a VAX computer was installed at Berkeley in 1978, but the port of Unix to the VAX architecture, UNIX/32V, did not take advantage of the VAXs virtual memory capabilities. 3BSD was also alternatively called Virtual VAX/UNIX or VMUNIX, and BSD kernel images were normally called /vmunix until 4. 4BSD, 4BSD offered a number of enhancements over 3BSD, notably job control in the previously released csh, delivermail, reliable signals, and the Curses programming library. In a 1985 review of BSD releases, John Quarterman et al, many installations inside the Bell System ran 4. 1BSD. 4. 1BSD was a response to criticisms of BSDs performance relative to the dominant VAX operating system, the 4. 1BSD kernel was systematically tuned up by Bill Joy until it could perform as well as VMS on several benchmarks. Back at Bell Labs,4. 1cBSD became the basis of the 8th Edition of Research Unix, to guide the design of 4. The committee met from April 1981 to June 1983, apart from the Fast File System, several features from outside contributors were accepted, including disk quotas and job control. Sun Microsystems provided testing on its Motorola 68000 machines prior to release, the official 4. 2BSD release came in August 1983. On a lighter note, it marked the debut of BSDs daemon mascot in a drawing by John Lasseter that appeared on the cover of the printed manuals distributed by USENIX
11.
Illumos
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Illumos is a free and open-source Unix operating system. It derives from OpenSolaris, which in turn derives from SVR4 UNIX, illumos comprises a kernel, device drivers, system libraries, and utility software for system administration. This core is now the base for many different open-sourced OpenSolaris distributions, the maintainers write illumos in lowercase since some computer fonts do not clearly distinguish a lowercase L from an uppercase i. The name is derived from the Latin illuminare meaning to enlighten, the original plan explicitly stated that illumos would not be a distribution or a fork. However, after Oracle announced discontinuing OpenSolaris, plans were made to fork the final version of the Solaris ON kernel allowing illumos to evolve into a kernel of its own. As of 2010, efforts focused on libc, the NFS lock manager, the illumos Foundation has been incorporated in the State of California as a 5016 trade association, with founding board members Jason Hoffman, Evan Powell, and Garrett DAmore. As of August 2012 the foundation was in the process of formalizing its by-laws, at OpenStorage Summit 2010, the new logo for illumos was revealed, with official type and branding to follow over. It was originally dependent on OpenSolaris OS/Net, but a fork was made after Oracle silently decided to close the development of Solaris, ZFS, a combined file system and logical volume manager providing a high data integrity for very large storage capacities. Solaris Containers, a low overhead implementation of operating-system-level virtualization technology for x86, dTrace, a comprehensive dynamic tracing framework for troubleshooting kernel and application problems on production systems in real time Kernel-based Virtual Machine, a virtualization infrastructure. KVM supports native virtualization on processors with hardware virtualization extensions, Solaris Distributions, at illumos. org DilOS, with Debian package manager and virtualization support, available for x86-64 and SPARC. Dyson, derived from Debian using libc, and SMF init system, napp-it, ready to use and comfortable ZFS storageserver with a free Web-GUI that includes all functions for a sophisticated NAS or SAN appliance. NexentaStor, distribution optimized for virtualization, storage area networks, network-attached storage, omniOS, a self-hosting, minimalist Illumos-based release suitable for production deployment. OpenIndiana, a distribution that is a continuation and fork in the spirit of the OpenSolaris operating system, openSXCE, distribution for developers and system administrators for IA-32/x86-64 x86 platforms and SPARC. SmartOS, a distribution for cloud computing with Kernel-based Virtual Machine integration, tribblix, retro style distribution with modern components, available for x86-64 and SPARC. XStreamOS, a distribution for infrastructure, cloud, and web development, v9os, a server-only, IPS-based minimal SPARC distribution. Official website OS/Net consolidation, source code community developed and maintained
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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
13.
Research Unix
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The term Research Unix first appeared in the Bell System Technical Journal to distinguish it from other versions internal to Bell Labs whose code-base had diverged from the primary CSRC version. However, that term was little-used until Version 8 Unix, but has been applied to earlier versions as well. Prior to V8, the system was most commonly called simply UNIX or the UNIX Time-Sharing System. AT&T licensed Version 5 to educational institutions, and Version 6 also to commercial sites, schools paid $200 and others $20,000, discouraging most commercial use, but Version 6 was the most widely used version into the 1980s. So, the first Research Unix would be the First Edition, another common way of referring to them is Version x Unix, where x is the manual edition. All modern editions of Unix—excepting Unix-like implementations such as Coherent, Minix, starting with the 8th Edition, versions of Research Unix had a close relationship to BSD. This began by using 4. 1cBSD as the basis for the 8th Edition. 1c and this continued with 9th and 10th. The ordinary user command-set was, I guess, a bit more BSD-flavored than SysVish, Version 3, Version 4 and Version 5 should not be confused with the UNIX3.0, UNIX4.0 and UNIX5.0 releases by the AT&T UNIX Support Group. After Version 10, Unix development at Bell Labs was stopped in favor of a system, Plan 9 from Bell Labs. In 2002, Caldera International released V7 Unix as FOSS under a permissive BSD-like software license, in 2017, Unix Heritage Society and Alcatel-Lucent USA Inc. List of new features in Research Unix 9th Edition
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Kernel (operating system)
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The kernel is a computer program that is the core of a computers operating system, with complete control over everything in the system. It is the first program loaded on start-up and it handles the rest of start-up as well as input/output requests from software, translating them into data-processing instructions for the central processing unit. It handles memory and peripherals like keyboards, monitors, printers, the critical code of the kernel is usually loaded into a protected area of memory, which prevents it from being overwritten by applications or other, more minor parts of the operating system. The kernel performs its tasks, such as running processes and handling interrupts, in contrast, everything a user does is in user space, writing text in a text editor, running programs in a GUI, etc. This separation prevents user data and kernel data from interfering with other and causing instability. The kernels interface is an abstraction layer. When a process makes requests of the kernel, it is called a system call, Kernel designs differ in how they manage these system calls and resources. A monolithic kernel runs all the operating instructions in the same address space. A microkernel runs most processes in space, for modularity. The kernel takes responsibility for deciding at any time which of the running programs should be allocated to the processor or processors. Random-access memory Random-access memory is used to both program instructions and data. Typically, both need to be present in memory in order for a program to execute, often multiple programs will want access to memory, frequently demanding more memory than the computer has available. The kernel is responsible for deciding which memory each process can use, input/output devices I/O devices include such peripherals as keyboards, mice, disk drives, printers, network adapters, and display devices. The kernel allocates requests from applications to perform I/O to an appropriate device, key aspects necessary in resource management are the definition of an execution domain and the protection mechanism used to mediate the accesses to the resources within a domain. Kernels also usually provide methods for synchronization and communication between processes called inter-process communication, finally, a kernel must provide running programs with a method to make requests to access these facilities. The kernel has full access to the memory and must allow processes to safely access this memory as they require it. Often the first step in doing this is virtual addressing, usually achieved by paging and/or segmentation, virtual addressing allows the kernel to make a given physical address appear to be another address, the virtual address. This allows every program to behave as if it is the one running
15.
Monolithic kernel
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A monolithic kernel is an operating system architecture where the entire operating system is working in kernel space and is alone in supervisor mode. The monolithic model differs from other operating system architectures in that it defines a high-level virtual interface over computer hardware. A set of primitives or system calls implement all operating system such as process management, concurrency. Device drivers can be added to the kernel as modules and this modularity of the operating system is at the binary level and not at the architecture level. Modular monolithic operating systems are not to be confused with the level of modularity inherent in Server-Client operating systems which use microkernels. Practically speaking, dynamically loading modules is simply a more flexible way of handling the operating system image at runtime — as opposed to rebooting with a different operating system image, the modules allow easy extension of the operating systems capabilities as required. Dynamically loadable modules incur a small overhead when compared to building the module into the system image. Namely, an unloaded module need not be stored in random access memory
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Microkernel
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In computer science, a microkernel is the near-minimum amount of software that can provide the mechanisms needed to implement an operating system. These mechanisms include low-level address space management, thread management, If the hardware provides multiple rings or CPU modes, the microkernel may be the only software executing at the most privileged level, which is generally referred to as supervisor or kernel mode. Traditional operating system functions, such as drivers, protocol stacks. In terms of the code size, as a general rule microkernels tend to be smaller than monolithic kernels. The MINIX3 microkernel, for example, has approximately 12,000 lines of code, in 1967, Regnecentralen was installing a RC4000 prototype in a Polish fertilizer plant in Puławy. The computer used a small operating system tailored for the needs of the plant. Brinch Hansen and his team became concerned with the lack of generality and reusability of the RC4000 system and they feared that each installation would require a different operating system so they started to investigate novel and more general ways of creating software for the RC4000. In 1969, their effort resulted in the completion of the RC4000 Multiprogramming System and its nucleus provided inter-process communication based on message-passing for up to 23 unprivileged processes, out of which 8 at a time were protected from one another. Besides these elementary mechanisms, it had no strategy for program execution. This strategy was to be implemented by a hierarchy of running programs in which parent processes had complete control over child processes, microkernels were first developed in the 1980s as a response to changes in the computer world, and to several challenges adapting existing mono-kernels to these new systems. New device drivers, protocol stacks, file systems and other systems were being developed all the time. This code was located in the monolithic kernel, and thus required considerable work. This would not only allow these services to be easily worked on. Moreover, it would allow entirely new operating systems to be built up on a common core, microkernels were a very hot topic in the 1980s when the first usable local area networks were being introduced. The same mechanisms that allowed the kernel to be distributed into user space also allowed the system to be distributed across network links. The first microkernels, notably Mach, proved to have disappointing performance, however, during this time the speed of computers grew greatly in relation to networking systems, and the disadvantages in performance came to overwhelm the advantages in development terms. As of 2012, the Mach-based GNU Hurd is also functional and included in testing versions of Arch Linux, although major work on microkernels had largely ended, experimenters continued development. Microkernels are closely related to exokernels, early operating system kernels were rather small, partly because computer memory was limited
17.
Hybrid kernel
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A hybrid kernel is an operating system kernel architecture that attempts to combine aspects and benefits of microkernel and monolithic kernel architectures used in computer operating systems. The traditional kernel categories are monolithic kernels and microkernels, the hybrid category is controversial, due to the similarity of hybrid kernels and ordinary monolithic kernels, the term has been dismissed by Linus Torvalds as simple marketing. The idea behind a hybrid kernel is to have a structure similar to that of a microkernel. In contrast to a microkernel, all operating system services in a hybrid kernel are still in kernel space, so there are none of the reliability benefits of having services in user space, as with a microkernel.1, and Xbox One. Conversely, the reason NT is not a system is because most of the system components run in the same address space as the kernel. The subsystems are not written to a particular OS personality, the primary operating system personality on Windows is the Windows API, which is always present. The emulation subsystem which implements the Windows personality is called the Client/Server Runtime Subsystem, on versions of NT prior to 4.0, this subsystem process also contained the window manager, graphics device interface and graphics device drivers. For performance reasons, however, in version 4.0 and later, as of 2007, one other operating system personality, UNIX, is offered as an optionally installed system component on certain versions of Windows Vista and Windows Server 2003 R2. The associated subsystem process is the Subsystem for UNIX-Based Applications, which was part of a Windows add-on called Windows Services for UNIX. An OS/2 subsystem was supported in versions of Windows NT. The POSIX subsystem was supplanted by the UNIX subsystem, hence the identical executable name, in August 2016, Microsoft unveiled the latest Windows subsystem called the Linux Subsystem for Windows. This subsystem, available only on 64-bit Windows 10 version 1607 and this was intended so that developers could run their tools on Windows without having to emulate them, and thus requires developer mode to be enabled in Windows Settings. It is designed only to run applications, although a reddit user has discovered a way to run GUI applications or even an entire desktop environment with it. Certain applications that rely on the Linux kernel itself will not be able to run because it does not include the Linux kernel. Applications that run on NT are written to one of the OS personalities, an OS personality is implemented via a set of user-mode DLLs, which are mapped into application processes address spaces as required, together with an emulation subsystem server process. XNU is the kernel that Apple Inc. acquired and developed for use in the OS X and iOS operating systems and released as free, XNU is an acronym for X is Not Unix. XNU runs on ARM as part of iOS, IA-32, archived from the original on March 15,2006
18.
User interface
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The user interface, in the industrial design field of human–computer interaction, is the space where interactions between humans and machines occur. Examples of this concept of user interfaces include the interactive aspects of computer operating systems, hand tools, heavy machinery operator controls. The design considerations applicable when creating user interfaces are related to or involve such disciplines as ergonomics and psychology. Generally, the goal of user interface design is to produce a user interface makes it easy, efficient. This generally means that the needs to provide minimal input to achieve the desired output. Other terms for user interface are man–machine interface and when the machine in question is a computer human–computer interface, the user interface or human–machine interface is the part of the machine that handles the human–machine interaction. Membrane switches, rubber keypads and touchscreens are examples of the part of the Human Machine Interface which we can see. In complex systems, the interface is typically computerized. The term human–computer interface refers to this kind of system, in the context of computing the term typically extends as well to the software dedicated to control the physical elements used for human-computer interaction. The engineering of the interfaces is enhanced by considering ergonomics. The corresponding disciplines are human factors engineering and usability engineering, which is part of systems engineering, tools used for incorporating human factors in the interface design are developed based on knowledge of computer science, such as computer graphics, operating systems, programming languages. Nowadays, we use the graphical user interface for human–machine interface on computers. There is a difference between a user interface and an interface or a human–machine interface. A human-machine interface is typically local to one machine or piece of equipment, an operator interface is the interface method by which multiple equipment that are linked by a host control system is accessed or controlled. The system may expose several user interfaces to serve different kinds of users, for example, a computerized library database might provide two user interfaces, one for library patrons and the other for library personnel. The user interface of a system, a vehicle or an industrial installation is sometimes referred to as the human–machine interface. HMI is a modification of the original term MMI, in practice, the abbreviation MMI is still frequently used although some may claim that MMI stands for something different now. Another abbreviation is HCI, but is commonly used for human–computer interaction
19.
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
20.
Graphical user interface
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GUIs were introduced in reaction to the perceived steep learning curve of command-line interfaces, which require commands to be typed on a computer keyboard. The actions in a GUI are usually performed through direct manipulation of the graphical elements, beyond computers, GUIs are used in many handheld mobile devices such as MP3 players, portable media players, gaming devices, smartphones and smaller household, office and industrial controls. Designing the visual composition and temporal behavior of a GUI is an important part of application programming in the area of human–computer interaction. Its goal is to enhance the efficiency and ease of use for the logical design of a stored program. Methods of user-centered design are used to ensure that the language introduced in the design is well-tailored to the tasks. The visible graphical interface features of an application are sometimes referred to as chrome or GUI, typically, users interact with information by manipulating visual widgets that allow for interactions appropriate to the kind of data they hold. The widgets of an interface are selected to support the actions necessary to achieve the goals of users. A model–view–controller allows a structure in which the interface is independent from and indirectly linked to application functions. This allows users to select or design a different skin at will, good user interface design relates to users more, and to system architecture less. Large widgets, such as windows, usually provide a frame or container for the main presentation content such as a web page, smaller ones usually act as a user-input tool. A GUI may be designed for the requirements of a market as application-specific graphical user interfaces. By the 1990s, cell phones and handheld game systems also employed application specific touchscreen GUIs, newer automobiles use GUIs in their navigation systems and multimedia centers, or navigation multimedia center combinations. Sample graphical desktop environments A GUI uses a combination of technologies and devices to provide a platform that users can interact with, a series of elements conforming a visual language have evolved to represent information stored in computers. This makes it easier for people with few computer skills to work with, the most common combination of such elements in GUIs is the windows, icons, menus, pointer paradigm, especially in personal computers. The WIMP style of interaction uses a virtual device to represent the position of a pointing device, most often a mouse. Available commands are compiled together in menus, and actions are performed making gestures with the pointing device, a window manager facilitates the interactions between windows, applications, and the windowing system. The windowing system handles hardware devices such as pointing devices, graphics hardware, window managers and other software combine to simulate the desktop environment with varying degrees of realism. Smaller mobile devices such as personal assistants and smartphones typically use the WIMP elements with different unifying metaphors, due to constraints in space
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X Window System
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The X Window System is a windowing system for bitmap displays, common on UNIX-like computer operating systems. X provides the framework for a GUI environment, drawing and moving windows on the display device and interacting with a mouse. X does not mandate the user interface – this is handled by individual programs, as such, the visual styling of X-based environments varies greatly, different programs may present radically different interfaces. X originated at the Massachusetts Institute of Technology in 1984, the protocol has been version 11 since September 1987. The X. Org Foundation leads the X project, with the current reference implementation, X. Org Server, available as free and open source software under the MIT License, X is an architecture-independent system for remote graphical user interfaces and input device capabilities. Each person using a terminal has the ability to interact with the display with any type of user input device. X provides the framework, or primitives, for building such GUI environments, drawing and moving windows on the display and interacting with a mouse. X does not mandate the user interface, individual client programs handle this, programs may use Xs graphical abilities with no user interface. As such, the styling of X-based environments varies greatly. Unlike most earlier display protocols, X was specifically designed to be used over network connections rather than on an integral or attached display device. X features network transparency, which means an X program running on a computer somewhere on a network can display its user interface on an X server running on other computer on the network. The fact that the server is applied to the software in front of the user is often surprising to users accustomed to their programs being clients to services on remote computers. Xs network protocol is based on X command primitives and this approach allows both 2D and 3D operations by an X client application which might be running on a different computer to still be fully accelerated on the X servers display. X provides no support for audio, several projects exist to fill this niche. X uses a model, an X server communicates with various client programs. The server accepts requests for graphical output and sends back user input, a client and server can even communicate securely over the Internet by tunneling the connection over an encrypted network session. An X client itself may emulate an X server by providing services to other clients. This is known as X nesting, open-source clients such as Xnest and Xephyr support such X nesting
22.
Software license
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A software license is a legal instrument governing the use or redistribution of software. Under United States copyright law all software is copyright protected, in code as also object code form. The only exception is software in the public domain, most distributed software can be categorized according to its license type. Two common categories for software under copyright law, and therefore with licenses which grant the licensee specific rights, are proprietary software and free, unlicensed software outside the copyright protection is either public domain software or software which is non-distributed, non-licensed and handled as internal business trade secret. Contrary to popular belief, distributed unlicensed software is copyright protected. Examples for this are unauthorized software leaks or software projects which are placed on public software repositories like GitHub without specified license. As voluntarily handing software into the domain is problematic in some international law domains, there are also licenses granting PD-like rights. Therefore, the owner of a copy of software is legally entitled to use that copy of software. Hence, if the end-user of software is the owner of the respective copy, as many proprietary licenses only enumerate the rights that the user already has under 17 U. S. C. §117, and yet proclaim to take away from the user. Proprietary software licenses often proclaim to give software publishers more control over the way their software is used by keeping ownership of each copy of software with the software publisher. The form of the relationship if it is a lease or a purchase, for example UMG v. Augusto or Vernor v. Autodesk. The ownership of goods, like software applications and video games, is challenged by licensed. The Swiss based company UsedSoft innovated the resale of business software and this feature of proprietary software licenses means that certain rights regarding the software are reserved by the software publisher. Therefore, it is typical of EULAs to include terms which define the uses of the software, the most significant effect of this form of licensing is that, if ownership of the software remains with the software publisher, then the end-user must accept the software license. In other words, without acceptance of the license, the end-user may not use the software at all, one example of such a proprietary software license is the license for Microsoft Windows. The most common licensing models are per single user or per user in the appropriate volume discount level, Licensing per concurrent/floating user also occurs, where all users in a network have access to the program, but only a specific number at the same time. Another license model is licensing per dongle which allows the owner of the dongle to use the program on any computer, Licensing per server, CPU or points, regardless the number of users, is common practice as well as site or company licenses
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Free software
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The right to study and modify software entails availability of the software source code to its users. This right is conditional on the person actually having a copy of the software. Richard Stallman used the existing term free software when he launched the GNU Project—a collaborative effort to create a freedom-respecting operating system—and the Free Software Foundation. The FSFs Free Software Definition states that users of software are free because they do not need to ask for permission to use the software. Free software thus differs from proprietary software, such as Microsoft Office, Google Docs, Sheets, and Slides or iWork from Apple, which users cannot study, change, freeware, which is a category of freedom-restricting proprietary software that does not require payment for use. For computer programs that are covered by law, software freedom is achieved with a software license. Software that is not covered by law, such as software in the public domain, is free if the source code is in the public domain. Proprietary software, including freeware, use restrictive software licences or EULAs, Users are thus prevented from changing the software, and this results in the user relying on the publisher to provide updates, help, and support. This situation is called vendor lock-in, Users often may not reverse engineer, modify, or redistribute proprietary software. Other legal and technical aspects, such as patents and digital rights management may restrict users in exercising their rights. Free software may be developed collaboratively by volunteer computer programmers or by corporations, as part of a commercial, from the 1950s up until the early 1970s, it was normal for computer users to have the software freedoms associated with free software, which was typically public domain software. Software was commonly shared by individuals who used computers and by manufacturers who welcomed the fact that people were making software that made their hardware useful. Organizations of users and suppliers, for example, SHARE, were formed to exchange of software. As software was written in an interpreted language such as BASIC. Software was also shared and distributed as printed source code in computer magazines and books, in United States vs. IBM, filed January 17,1969, the government charged that bundled software was anti-competitive. While some software might always be free, there would henceforth be an amount of software produced primarily for sale. In the 1970s and early 1980s, the industry began using technical measures to prevent computer users from being able to study or adapt the software as they saw fit. In 1980, copyright law was extended to computer programs, Software development for the GNU operating system began in January 1984, and the Free Software Foundation was founded in October 1985
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Open-source software
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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
25.
Computer multitasking
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In computing, multitasking is a concept of performing multiple tasks over a certain period of time by executing them concurrently. As a result, a computer executes segments of multiple tasks in a manner, while the tasks share common processing resources such as central processing units. Multitasking does not necessarily mean that multiple tasks are executing at exactly the same time, even on multiprocessor or multicore computers, which have multiple CPUs/cores so more than one task can be executed at once, multitasking allows many more tasks to be run than there are CPUs. In the case of a computer with a single CPU, only one task is said to be running at any point in time, multitasking solves the problem by scheduling which task may be the one running at any given time, and when another waiting task gets a turn. The act of reassigning a CPU from one task to one is called a context switch. Multiprogramming systems are designed to maximize CPU usage, in time-sharing systems, the running task is required to relinquish the CPU, either voluntarily or by an external event such as a hardware interrupt. Time sharing systems are designed to allow programs to execute apparently simultaneously. In real-time systems, some waiting tasks are guaranteed to be given the CPU when an event occurs. Real time systems are designed to control devices such as industrial robots. The term multitasking has become a term, as the same word is used in many other languages such as German, Italian, Dutch, Danish. In the early days of computing, CPU time was expensive, when the computer ran a program that needed access to a peripheral, the central processing unit would have to stop executing program instructions while the peripheral processed the data. The first computer using a system was the British Leo III owned by J. Lyons. During batch processing, several different programs were loaded in the memory. When the first program reached an instruction waiting for a peripheral, the context of program was stored away. The process continued until all programs finished running, multiprogramming doesnt give any guarantee that a program will run in a timely manner. Indeed, the very first program may very well run for hours without needing access to a peripheral. As there were no users waiting at a terminal, this was no problem, users handed in a deck of punched cards to an operator. Multiprogramming greatly reduced wait times when multiple batches were being processed, the expression time sharing usually designated computers shared by interactive users at terminals, such as IBMs TSO, and VM/CMS
26.
Multiuser
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Multi-user software is software that allows access by multiple users of a computer. Most batch processing systems for mainframe computers may also be considered multi-user, however, the term multitasking is more common in this context. An example is a Unix server where multiple remote users have access to the Unix shell prompt at the same time, another example uses multiple X Window sessions spread across multiple terminals powered by a single machine - this is an example of the use of thin client. Similar functions were available under MP/M, Concurrent DOS, Multiuser DOS and FlexOS. The operating system provides isolation of each users processes from other users, management systems are implicitly designed to be used by multiple users, typically one system administrator or more and an end-user community. Multi-user operating systems such as Unix sometimes have a user mode or runlevel available for emergency maintenance. Multiseat Interix in a Multi-User Windows TSE Environment paper about the Unix multi-user model and MS-Windows NT TSE
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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
28.
AT&T Corporation
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Founded in 1885 as the original American Telephone and Telegraph Company, it was at times the worlds largest telephone company, the worlds largest cable television operator, and a regulated monopoly. At its peak in the 1950s and 1960s, it employed one million people, in 2005, AT&T was purchased by Baby Bell and former subsidiary SBC Communications for more than $16 billion. SBC then changed its name to AT&T Inc, AT&T started with Bell Patent Association, a legal entity established in 1874 to protect the patent rights of Alexander Graham Bell after he invented the telephone system. Originally a verbal agreement, it was formalized in writing in 1875 as Bell Telephone Company, in 1880 the management of American Bell had created what would become AT&T Long Lines. The project was the first of its kind to create a nationwide long-distance network with a commercially viable cost-structure, the project was formally incorporated in New York State as a separate company named American Telephone and Telegraph Company on March 3,1885. With this assets transfer, AT&T became the parent of both American Bell and the Bell System. AT&T was involved mainly in the business and, although it was a partner with RCA, was reluctant to see radio grow because such growth might diminish the demand for wired services. It established station WEAF in New York as what was termed a toll station, AT&T could provide no programming, but anyone who wished to broadcast a message could pay a toll to AT&T and then air the message publicly. The original studio was the size of a telephone booth, the idea, however, did not take hold, because people would pay to broadcast messages only if they were sure that someone was listening. As a result, WEAF began broadcasting entertainment material, drawing amateur talent found among its employees, throughout most of the 20th century, AT&T held a monopoly on phone service in the United States and Canada through a network of companies called the Bell System. At this time, the company was nicknamed Ma Bell, on April 30,1907, Theodore Newton Vail became President of AT&T. Vail believed in the superiority of one system and AT&T adopted the slogan One Policy, One System. This would be the philosophy for the next 70 years. Under Vail, AT&T began buying up many of the telephone companies including Western Union telegraph. Anxious to avoid action from government antitrust suits, AT&T and the government entered into an agreement known as the Kingsbury Commitment. These actions brought unwanted attention from antitrust regulators, in the Kingsbury Commitment, AT&T and the government reached an agreement that allowed AT&T to continue operating as a monopoly. While AT&T periodically faced scrutiny from regulators, this state of affairs continued until the breakup in 1984. The United States Justice Department opened the case United States v. AT&T in 1974 and this was prompted by suspicion that AT&T was using monopoly profits from its Western Electric subsidiary to subsidize the cost of its network, a violation of anti-trust law
29.
Bell System
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On December 31,1983, the system was broken up into independent companies by a U. S. Justice Department mandate. Ma Bell is also used to refer to the female voices behind recordings for the Bell System, Mary Moore, Jane Barbe. In 1877, the American Bell Telephone Company, named after Alexander Graham Bell, opened the first telephone exchange in New Haven, within a few years local exchange companies were established in every major city in the United States. In 1899, American Telephone & Telegraph acquired the assets of its parent, originally American Bell had created AT&T to provide long-distance calls between New York and Chicago and beyond. AT&T became the parent of American Bell, and thus the head of the Bell System, because regulatory and tax rules were leaner in New York than in Boston, after 1934, AT&T was regulated by the Federal Communication Commission. Receiving a U. S. patent for the invention of the telephone on March 7,1876, Alexander Graham Bell formed the Bell Telephone Company in 1877, on April 30,1907, Theodore Newton Vail returned as President of AT&T. Vail believed in the superiority of one system and AT&T adopted the slogan One Policy, One System. This would be the philosophy for the next 70 years. Under Vail, AT&T began buying up many of the telephone companies including Western Union telegraph. Anxious to avoid action from government antitrust suits, AT&T entered into an agreement known as the Kingsbury Commitment with the federal government. S. The Bell trademark pictured here was used from 1921 through 1939 by both the AT&T corporation and the regional operating corporations to co-brand themselves under a single Bell System trademark, the regional operating corporations name was placed where name of associated company appears in this template version of the trademark. Bell system telephones and related equipment were made by Western Electric, member telephone companies paid a fixed fraction of their revenues as a license fee to Bell Labs. As a result of this monopoly, by 1940 the Bell System effectively owned most telephone service in the United States, from local. This allowed Bell to prohibit their customers from connecting phones not made or sold by Bell to the system without paying fees, Northern Electric was spun off in 1956 by Western Electric, but AT&T did not spin off Bell Canada until 1975. The Bell Systems Caribbean regional operating companies were sold to the ITT Corporation, before 1956, the Bell Systems reach was truly gargantuan. The 1984 Bell System divestiture brought an end to the branded as the Bell System. The suit was settled on January 8,1982, superseding the former restrictions that AT&T and the DOJ had agreed upon in 1956. Currently, the word mark Bell, the logo, and other related trademarks, are held by each of the remaining Bell companies, namely AT&T, Verizon, CenturyLink, and Cincinnati Bell
30.
University of California, Berkeley
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The University of California, Berkeley, is a public research university located in Berkeley, California. In 1960s, UC Berkeley was particularly noted for the Free Speech Movement as well as the Anti-Vietnam War Movement led by its students. S, Department of Energy, and is home to many world-renowned research institutes and organizations including Mathematical Sciences Research Institute and Space Sciences Laboratory. Faculty member J. R. Oppenheimer, the father of the atomic bomb, Lawrence Livermore Lab also discovered or co-discovered six chemical elements. The Academic Ranking of World Universities also ranks the University of California, Berkeley, third in the world overall, in 1866, the private College of California purchased the land comprising the current Berkeley campus. Ten faculty members and almost 40 students made up the new University of California when it opened in Oakland in 1869, billings was a trustee of the College of California and suggested that the college be named in honor of the Anglo-Irish philosopher George Berkeley. In 1870, Henry Durant, the founder of the College of California, with the completion of North and South Halls in 1873, the university relocated to its Berkeley location with 167 male and 22 female students and held its first classes. In 1905, the University Farm was established near Sacramento, ultimately becoming the University of California, by the 1920s, the number of campus buildings had grown substantially, and included twenty structures designed by architect John Galen Howard. Robert Gordon Sproul served as president from 1930 to 1958, by 1942, the American Council on Education ranked UC Berkeley second only to Harvard University in the number of distinguished departments. During World War II, following Glenn Seaborgs then-secret discovery of plutonium, UC Berkeley physics professor J. Robert Oppenheimer was named scientific head of the Manhattan Project in 1942. Along with the Lawrence Berkeley National Laboratory, Berkeley is now a partner in managing two other labs, Los Alamos National Laboratory and Lawrence Livermore National Laboratory, originally, military training was compulsory for male undergraduates, and Berkeley housed an armory for that purpose. In 1917, Berkeleys ROTC program was established, and its School of Military Aeronautics trained future pilots, including Jimmy Doolittle, both Robert McNamara and Frederick C. Weyand graduated from UC Berkeleys ROTC program, earning B. A. degrees in 1937 and 1938, in 1926, future fleet admiral Chester W. Nimitz established the first Naval Reserve Officers Training Corps unit at Berkeley. The Board of Regents ended compulsory military training at Berkeley in 1962, during the McCarthy era in 1949, the Board of Regents adopted an anti-communist loyalty oath. A number of faculty members objected and were dismissed, ten years passed before they were reinstated with back pay, in 1952, the University of California became an entity separate from the Berkeley campus. Each campus was given autonomy and its own Chancellor. Then-president Sproul assumed presidency of the entire University of California system, Berkeley gained a reputation for student activism in the 1960s with the Free Speech Movement of 1964 and opposition to the Vietnam War. In the highly publicized Peoples Park protest in 1969, students and the school conflicted over use of a plot of land, then governor of California Ronald Reagan called the Berkeley campus a haven for communist sympathizers, protesters, and sex deviants. Modern students at Berkeley are less active, with a greater percentage of moderates and conservatives
31.
Microsoft
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Its best known software products are the Microsoft Windows line of operating systems, Microsoft Office office suite, and Internet Explorer and Edge web browsers. Its flagship hardware products are the Xbox video game consoles and the Microsoft Surface tablet lineup, as of 2016, it was the worlds largest software maker by revenue, and one of the worlds most valuable companies. Microsoft was founded by Paul Allen and Bill Gates on April 4,1975, to develop and it rose to dominate the personal computer operating system market with MS-DOS in the mid-1980s, followed by Microsoft Windows. The companys 1986 initial public offering, and subsequent rise in its share price, since the 1990s, it has increasingly diversified from the operating system market and has made a number of corporate acquisitions. In May 2011, Microsoft acquired Skype Technologies for $8.5 billion, in June 2012, Microsoft entered the personal computer production market for the first time, with the launch of the Microsoft Surface, a line of tablet computers. The word Microsoft is a portmanteau of microcomputer and software, Paul Allen and Bill Gates, childhood friends with a passion for computer programming, sought to make a successful business utilizing their shared skills. In 1972 they founded their first company, named Traf-O-Data, which offered a computer that tracked and analyzed automobile traffic data. Allen went on to pursue a degree in science at Washington State University. The January 1975 issue of Popular Electronics featured Micro Instrumentation and Telemetry Systemss Altair 8800 microcomputer, Allen suggested that they could program a BASIC interpreter for the device, after a call from Gates claiming to have a working interpreter, MITS requested a demonstration. Since they didnt actually have one, Allen worked on a simulator for the Altair while Gates developed the interpreter and they officially established Microsoft on April 4,1975, with Gates as the CEO. Allen came up with the name of Micro-Soft, as recounted in a 1995 Fortune magazine article. In August 1977 the company formed an agreement with ASCII Magazine in Japan, resulting in its first international office, the company moved to a new home in Bellevue, Washington in January 1979. Microsoft entered the OS business in 1980 with its own version of Unix, however, it was MS-DOS that solidified the companys dominance. For this deal, Microsoft purchased a CP/M clone called 86-DOS from Seattle Computer Products, branding it as MS-DOS, following the release of the IBM PC in August 1981, Microsoft retained ownership of MS-DOS. Since IBM copyrighted the IBM PC BIOS, other companies had to engineer it in order for non-IBM hardware to run as IBM PC compatibles. Due to various factors, such as MS-DOSs available software selection, the company expanded into new markets with the release of the Microsoft Mouse in 1983, as well as with a publishing division named Microsoft Press. Paul Allen resigned from Microsoft in 1983 after developing Hodgkins disease, while jointly developing a new OS with IBM in 1984, OS/2, Microsoft released Microsoft Windows, a graphical extension for MS-DOS, on November 20,1985. Once Microsoft informed IBM of NT, the OS/2 partnership deteriorated, in 1990, Microsoft introduced its office suite, Microsoft Office
32.
Xenix
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Xenix is a discontinued version of the Unix operating system for various microcomputer platforms, licensed by Microsoft from AT&T Corporation in the late 1970s. The Santa Cruz Operation later acquired rights to the software. In the mid-to-late 1980s, Xenix was the most common Unix variant, Microsoft chairman Bill Gates said in 1996 that for a long time that company had the highest-volume AT&T Unix license. Bell Labs, the developer of Unix, was part of the regulated Bell System and it instead licensed the software to others. Because Microsoft was not able to license the UNIX name itself, Microsoft called Xenix a universal operating environment. The first version of Xenix was very close to the original UNIX version 7 source on the PDP-11, Microsoft said in 1981, and later versions were to incorporate its own fixes and improvements. The first port was for the Z8001 16-bit processor, the first customer ship was January 1981 for Central Data Corporation of Illinois, the first 8086 port was for the Altos Computer Systems non-PC-compatible 8600-series computers. Intel sold complete computers with Xenix under their Intel System 86 brand and this included processor boards like iSBC 86/12 and also MMU boards such as the iSBC309. The first Intel Xenix systems shipped in July 1982, seattle Computer Products also made 8086 computers bundled with Xenix, like their Gazelle II, which used the S-100 bus and was available in late 1983 or early 1984. There was also a port for IBM System 9000, SCO had initially worked on its own PDP-11 port of V7, called Dynix, but then struck an agreement with Microsoft for joint development and technology exchange on Xenix in 1982. In 1984, a port to the 68000-based Apple Lisa was jointly developed by SCO and Microsoft, the difficulty in porting to the various 8086 and Z8000-based machines, said Microsoft in its 1983 OEM directory, had been the lack of a standardized memory management unit and protection facilities. A generally available port to the unmapped Intel 8086/8088 architecture was done by The Santa Cruz Operation around 1983, SCO Xenix for the PC XT shipped sometime in 1984 and contained some enhancement from 4. 2BSD, it also supported the Micnet local area networking. The later 286 version of Xenix leveraged the integrated MMU present on this chip, the 286 Xenix was accompanied by new hardware from Xenix OEMs. For example, the Sperry PC/IT, an IBM PC AT clone, was advertised as capable of supporting eight simultaneous dumb terminal users under this version and it was followed by a System V.2 codebase in Xenix 5.0. Microsoft hopes that XENIX will become the choice for software production and exchange. Microsoft referred to its own MS-DOS as its single-user, single-tasking operating system, microsofts Chris Larson described MS-DOS2. 0s Xenix compatibility as the second most important feature. AT&T started selling System V, however, after the breakup of the Bell System, Microsoft, believing that it could not compete with Unixs developer, decided to abandon Xenix. The decision was not immediately transparent, which led to the term vaporware and it agreed with IBM to develop OS/2, and the Xenix team was assigned to that project
33.
IBM
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International Business Machines Corporation is an American multinational technology company headquartered in Armonk, New York, United States, with operations in over 170 countries. The company originated in 1911 as the Computing-Tabulating-Recording Company and was renamed International Business Machines in 1924, IBM manufactures and markets computer hardware, middleware and software, and offers hosting and consulting services in areas ranging from mainframe computers to nanotechnology. IBM is also a research organization, holding the record for most patents generated by a business for 24 consecutive years. IBM has continually shifted its business mix by exiting commoditizing markets and focusing on higher-value, also in 2014, IBM announced that it would go fabless, continuing to design semiconductors, but offloading manufacturing to GlobalFoundries. Nicknamed Big Blue, IBM is one of 30 companies included in the Dow Jones Industrial Average and one of the worlds largest employers, with nearly 380,000 employees. Known as IBMers, IBM employees have been awarded five Nobel Prizes, six Turing Awards, ten National Medals of Technology, in the 1880s, technologies emerged that would ultimately form the core of what would become International Business Machines. On June 16,1911, their four companies were amalgamated in New York State by Charles Ranlett Flint forming a fifth company, the Computing-Tabulating-Recording Company based in Endicott, New York. The five companies had 1,300 employees and offices and plants in Endicott and Binghamton, New York, Dayton, Ohio, Detroit, Michigan, Washington, D. C. and Toronto. They manufactured machinery for sale and lease, ranging from commercial scales and industrial time recorders, meat and cheese slicers, to tabulators and punched cards. Thomas J. Watson, Sr. fired from the National Cash Register Company by John Henry Patterson, called on Flint and, Watson joined CTR as General Manager then,11 months later, was made President when court cases relating to his time at NCR were resolved. Having learned Pattersons pioneering business practices, Watson proceeded to put the stamp of NCR onto CTRs companies and his favorite slogan, THINK, became a mantra for each companys employees. During Watsons first four years, revenues more than doubled to $9 million, Watson had never liked the clumsy hyphenated title of the CTR and in 1924 chose to replace it with the more expansive title International Business Machines. By 1933 most of the subsidiaries had been merged into one company, in 1937, IBMs tabulating equipment enabled organizations to process unprecedented amounts of data, its clients including the U. S. During the Second World War the company produced small arms for the American war effort, in 1949, Thomas Watson, Sr. created IBM World Trade Corporation, a subsidiary of IBM focused on foreign operations. In 1952, he stepped down after almost 40 years at the company helm, in 1957, the FORTRAN scientific programming language was developed. In 1961, IBM developed the SABRE reservation system for American Airlines, in 1963, IBM employees and computers helped NASA track the orbital flight of the Mercury astronauts. A year later it moved its headquarters from New York City to Armonk. The latter half of the 1960s saw IBM continue its support of space exploration, on April 7,1964, IBM announced the first computer system family, the IBM System/360
34.
IBM AIX
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AIX is a series of proprietary Unix operating systems developed and sold by IBM for several of its computer platforms. AIX is based on UNIX System V with 4. 3BSD-compatible extensions and it is one of five commercial operating systems that have versions certified to The Open Groups UNIX03 standard. The AIX family of operating systems debuted in 1986, became the operating system for the RS/6000 series on its launch in 1990. It is currently supported on IBM Power Systems alongside IBM i, Unix started life at AT&Ts Bell Labs research center in the early 1970s, running on DEC minicomputers. By 1976, the system was in use at various academic institutions, including Princeton. This port would later grow out to become UTS, a mainframe Unix offering by IBMs competitor Amdahl Corporation, IBMs own involvement in Unix can be dated to 1979, when it assisted Bell Labs in doing its own Unix port to the 370. In the process, IBM made modifications to the TSS/370 hypervisor to better support Unix and it took until 1985 for IBM to offer its own Unix on the S/370 platform, IX/370, which was developed by Interactive Systems Corporation and intended by IBM to compete with Amdahl UTS. AIX Version 1, introduced in 1986 for the IBM6150 RT workstation, was based on UNIX System V Releases 1 and 2, in developing AIX, IBM and Interactive Systems Corporation also incorporated source code from 4.2 and 4.3 BSD UNIX. Among other variants, IBM later produced AIX Version 3, based on System V Release 3, since 1990, AIX has served as the primary operating system for the RS/6000 series. AIX Version 4, introduced in 1994, added symmetric multiprocessing with the introduction of the first RS/6000 SMP servers and continued to evolve through the 1990s, culminating with AIX4.3.3 in 1999. Version 4.1, in a modified form, was also the standard operating system for the Apple Network Server systems sold by Apple Computer to complement the Macintosh line. IBM maintains that their license was irrevocable, and continued to sell, AIX was a component of the 2003 SCO v. IBM lawsuit, in which the SCO Group filed a lawsuit against IBM, alleging IBM contributed SCOs intellectual property to the Linux codebase. The SCO Group, who argued they were the owners of the copyrights covering the Unix operating system. In March 2010, a jury returned a finding that Novell, not the SCO Group. AIX6 was announced in May 2007, and it ran as an open beta from June 2007 until the availability of AIX6.1 on November 9,2007. Major new features in AIX6.1 included full role-based access control, workload partitions, enhanced security, AIX7.1 was announced in April 2010, and an open beta ran until general availability of AIX7.1 in September 2010. Several new features, including better scalability, enhanced clustering and management capabilities were added, AIX7.1 includes a new built-in clustering capability called Cluster Aware AIX. AIX is able to organize multiple LPARs through the communications channel to neighboring CPUs
35.
Sun Microsystems
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Sun contributed significantly to the evolution of several key computing technologies, among them Unix, RISC processors, thin client computing, and virtualized computing. Sun was founded on February 24,1982, at its height, the Sun headquarters were in Santa Clara, California, on the former west campus of the Agnews Developmental Center. On January 27,2010, Oracle Corporation acquired Sun by for US$7.4 billion, other technologies include the Java platform, MySQL, and NFS. Sun was a proponent of open systems in general and Unix in particular, the initial design for what became Suns first Unix workstation, the Sun-1, was conceived by Andy Bechtolsheim when he was a graduate student at Stanford University in Palo Alto, California. Bechtolsheim originally designed the SUN workstation for the Stanford University Network communications project as a personal CAD workstation and it was designed around the Motorola 68000 processor with an advanced memory management unit to support the Unix operating system with virtual memory support. He built the first ones from spare parts obtained from Stanfords Department of Computer Science, on February 24,1982, Vinod Khosla, Andy Bechtolsheim, and Scott McNealy, all Stanford graduate students, founded Sun Microsystems. Bill Joy of Berkeley, a developer of the Berkeley Software Distribution. The Sun name is derived from the initials of the Stanford University Network, Sun was profitable from its first quarter in July 1982. By 1983 Sun was known for producing 68000-based systems with high-quality graphics that were the only computers other than DECs VAX to run 4. 2BSD and it licensed the computer design to other manufacturers, which typically used it to build Multibus-based systems running Unix from UniSoft. Suns initial public offering was in 1986 under the stock symbol SUNW, the symbol was changed in 2007 to JAVA, Sun stated that the brand awareness associated with its Java platform better represented the companys current strategy. Suns logo, which features four interleaved copies of the sun in the form of a rotationally symmetric ambigram, was designed by professor Vaughan Pratt. The initial version of the logo was orange and had the sides oriented horizontally and vertically, but it was rotated to stand on one corner and re-colored purple. In the dot-com bubble, Sun began making more money. It also began spending more, hiring workers and building itself out. Some of this was because of demand, but much was from web start-up companies anticipating business that would never happen. Sales in Suns important hardware division went into free-fall as customers closed shop, several quarters of steep losses led to executive departures, rounds of layoffs, and other cost cutting. In December 2001, the fell to the 1998, pre-bubble level of about $100. But it kept falling, faster than many other tech companies, a year later it had dipped below $10 but bounced back to $20
36.
Solaris (operating system)
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Solaris is a Unix operating system originally developed by Sun Microsystems. It superseded their earlier SunOS in 1993, Oracle Solaris, so named as of 2010, has been owned by Oracle Corporation since the Sun acquisition by Oracle in January 2010. Solaris is known for its scalability, especially on SPARC systems, Solaris supports SPARC-based and x86-based workstations and servers from Oracle and other vendors, with efforts underway to port to additional platforms. Solaris is registered as compliant with the Single Unix Specification, historically, Solaris was developed as proprietary software. In June 2005, Sun Microsystems released most of the codebase under the CDDL license, with OpenSolaris, Sun wanted to build a developer and user community around the software. After the acquisition of Sun Microsystems in January 2010, Oracle decided to discontinue the OpenSolaris distribution, in August 2010, Oracle discontinued providing public updates to the source code of the Solaris kernel, effectively turning Solaris 11 back into a closed source proprietary operating system. Following that, in 2011 the Solaris 11 kernel source code leaked to BitTorrent, however, through the Oracle Technology Network, industry partners can still gain access to the in-development Solaris source code. Source code for the source components of Solaris 11 is available for download from Oracle. In 1987, AT&T Corporation and Sun announced that they were collaborating on a project to merge the most popular Unix variants on the market at that time, BSD, System V and this became Unix System V Release 4. On September 4,1991, Sun announced that it would replace its existing BSD-derived Unix, SunOS4 and this was identified internally as SunOS5, but a new marketing name was introduced at the same time, Solaris 2. The justification for this new overbrand was that it encompassed not only SunOS, but also the OpenWindows graphical user interface and Open Network Computing functionality. Although SunOS4.1. x micro releases were retroactively named Solaris 1 by Sun, for releases based on SunOS5, the SunOS minor version is included in the Solaris release number. For example, Solaris 2.4 incorporates SunOS5.4. After Solaris 2.6, the 2. was dropped from the name, so Solaris 7 incorporates SunOS5.7. Although SunSoft stated in its initial Solaris 2 press release their intent to support both SPARC and x86 systems, the first two Solaris 2 releases,2.0 and 2.1, were SPARC-only. An x86 version of Solaris 2.1 was released in June 1993, about 6 months after the SPARC version, as a desktop and it included the Wabi emulator to support Windows applications. At the time, Sun also offered the Interactive Unix system that it had acquired from Interactive Systems Corporation, in 1994, Sun released Solaris 2.4, supporting both SPARC and x86 systems from a unified source code base. Solaris uses a code base for the platforms it supports, SPARC
37.
Novell
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/noʊˈvɛl/ was a software and services company headquartered in Provo, Utah. It had been instrumental in making Utah Valley a focus for technology, Novell technology contributed to the emergence of local area networks, which displaced the dominant mainframe computing model and changed computing worldwide. The company began in 1979 in Orem, Utah as Novell Data Systems Inc. a hardware manufacturer producing CP/M-based systems, former Eyring Research Institute employee Dennis Fairclough was the member of the original team that started Novell Data Systems. It was co-founded by George Canova, Darin Field, and Jack Davis, victor V. Vurpillat brought the deal to Pete Musser, chairman of the board of Safeguard Scientifics, Inc. who provided the seed funding. The company initially did not do well, the microcomputer produced by the company was comparatively weak against performance by competitors. In order to compete on systems sales Novell Data Systems planned a program to more than one microcomputer to operate together. The former ERI employees Drew Major, Dale Neibaur and Kyle Powell, the Safeguard board then ordered Musser to shut Novell down. Davis left Novell Data Systems in November 1981, followed by Canova in March 1982, rubinstein and Dolin, along with Jack Messman, interviewed and hired Raymond Noorda. The required funding was obtained through an offering to Safeguard shareholders, managed by the Cleveland brokerage house, Prescott, Ball and Turben. Major, Neibaur and Powell continued to support Novell through their SuperSet Software Group, in January 1983, the companys name was shortened to Novell, Inc. and Raymond Noorda became the head of the firm. Later that same year, the company introduced its most significant product, a network interface card was developed for the IBM PC industry standard architecture bus. The server was using the first network operating system called ShareNet, later, ShareNet was ported to run on the Intel platform and renamed NetWare. The first commercial release of NetWare was version 1.5, Novell based its network protocol on Xerox Network Systems, and created its own standards from IDP and SPP, which it named Internetwork Packet Exchange and Sequenced Packet Exchange. File and print services ran on the NetWare Core Protocol over IPX, as did Routing Information Protocol, NetWare uses Novell DOS as a boot loader. Novell DOS is similar to MS-DOS and IBM PC DOS, but no license for DOS is required. Novell had already acquired Kanwal Rekhis company Excelan, which manufactured smart Ethernet cards and commercialized the Internet protocol TCP/IP, Novell did extremely well throughout the 1980s. It aggressively expanded its share by selling its expensive Ethernet cards at cost. By 1990, Novell had an almost monopolistic position in NOS for any business requiring a network, with this market leadership, Novell began to acquire and build services on top of its NetWare operating platform
38.
Apple Inc.
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Apple is an American multinational technology company headquartered in Cupertino, California that designs, develops, and sells consumer electronics, computer software, and online services. Apples consumer software includes the macOS and iOS operating systems, the media player, the Safari web browser. Its online services include the iTunes Store, the iOS App Store and Mac App Store, Apple Music, Apple was founded by Steve Jobs, Steve Wozniak, and Ronald Wayne in April 1976 to develop and sell personal computers. It was incorporated as Apple Computer, Inc. in January 1977, Apple joined the Dow Jones Industrial Average in March 2015. In November 2014, Apple became the first U. S. company to be valued at over US$700 billion in addition to being the largest publicly traded corporation in the world by market capitalization. The company employs 115,000 full-time employees as of July 2015 and it operates the online Apple Store and iTunes Store, the latter of which is the worlds largest music retailer. Consumers use more than one billion Apple products worldwide as of March 2016, Apples worldwide annual revenue totaled $233 billion for the fiscal year ending in September 2015. This revenue accounts for approximately 1. 25% of the total United States GDP.1 billion, the corporation receives significant criticism regarding the labor practices of its contractors and its environmental and business practices, including the origins of source materials. Apple was founded on April 1,1976, by Steve Jobs, Steve Wozniak, the Apple I kits were computers single-handedly designed and hand-built by Wozniak and first shown to the public at the Homebrew Computer Club. The Apple I was sold as a motherboard, which was less than what is now considered a personal computer. The Apple I went on sale in July 1976 and was market-priced at $666.66, Apple was incorporated January 3,1977, without Wayne, who sold his share of the company back to Jobs and Wozniak for $800. Multimillionaire Mike Markkula provided essential business expertise and funding of $250,000 during the incorporation of Apple, during the first five years of operations revenues grew exponentially, doubling about every four months. Between September 1977 and September 1980 yearly sales grew from $775,000 to $118m, the Apple II, also invented by Wozniak, was introduced on April 16,1977, at the first West Coast Computer Faire. It differed from its rivals, the TRS-80 and Commodore PET, because of its character cell-based color graphics. While early Apple II models used ordinary cassette tapes as storage devices, they were superseded by the introduction of a 5 1/4 inch floppy disk drive and interface called the Disk II. The Apple II was chosen to be the platform for the first killer app of the business world, VisiCalc. VisiCalc created a market for the Apple II and gave home users an additional reason to buy an Apple II. Before VisiCalc, Apple had been a distant third place competitor to Commodore, by the end of the 1970s, Apple had a staff of computer designers and a production line
39.
MacOS
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Within the market of desktop, laptop and home computers, and by web usage, it is the second most widely used desktop OS after Microsoft Windows. Launched in 2001 as Mac OS X, the series is the latest in the family of Macintosh operating systems, Mac OS X succeeded classic Mac OS, which was introduced in 1984, and the final release of which was Mac OS9 in 1999. An initial, early version of the system, Mac OS X Server 1.0, was released in 1999, the first desktop version, Mac OS X10.0, followed in March 2001. In 2012, Apple rebranded Mac OS X to OS X. Releases were code named after big cats from the release up until OS X10.8 Mountain Lion. Beginning in 2013 with OS X10.9 Mavericks, releases have been named after landmarks in California, in 2016, Apple rebranded OS X to macOS, adopting the nomenclature that it uses for their other operating systems, iOS, watchOS, and tvOS. The latest version of macOS is macOS10.12 Sierra, macOS is based on technologies developed at NeXT between 1985 and 1997, when Apple acquired the company. The X in Mac OS X and OS X is pronounced ten, macOS shares its Unix-based core, named Darwin, and many of its frameworks with iOS, tvOS and watchOS. A heavily modified version of Mac OS X10.4 Tiger was used for the first-generation Apple TV, Apple also used to have a separate line of releases of Mac OS X designed for servers. Beginning with Mac OS X10.7 Lion, the functions were made available as a separate package on the Mac App Store. Releases of Mac OS X from 1999 to 2005 can run only on the PowerPC-based Macs from the time period, Mac OS X10.5 Leopard was released as a Universal binary, meaning the installer disc supported both Intel and PowerPC processors. In 2009, Apple released Mac OS X10.6 Snow Leopard, in 2011, Apple released Mac OS X10.7 Lion, which no longer supported 32-bit Intel processors and also did not include Rosetta. All versions of the system released since then run exclusively on 64-bit Intel CPUs, the heritage of what would become macOS had originated at NeXT, a company founded by Steve Jobs following his departure from Apple in 1985. There, the Unix-like NeXTSTEP operating system was developed, and then launched in 1989 and its graphical user interface was built on top of an object-oriented GUI toolkit using the Objective-C programming language. This led Apple to purchase NeXT in 1996, allowing NeXTSTEP, then called OPENSTEP, previous Macintosh operating systems were named using Arabic numerals, e. g. Mac OS8 and Mac OS9. The letter X in Mac OS Xs name refers to the number 10 and it is therefore correctly pronounced ten /ˈtɛn/ in this context. However, a common mispronunciation is X /ˈɛks/, consumer releases of Mac OS X included more backward compatibility. Mac OS applications could be rewritten to run natively via the Carbon API, the consumer version of Mac OS X was launched in 2001 with Mac OS X10.0. Reviews were variable, with praise for its sophisticated, glossy Aqua interface
40.
Modular design
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Modular design, or modularity in design, is a design approach that subdivides a system into smaller parts called modules or skids, that can be independently created and then used in different systems. Besides reduction in cost, and flexibility in design, modularity offers other benefits such as augmentation, examples of modular systems are cars, computers, process systems, solar panels and wind turbines, elevators and modular buildings. Earlier examples include looms, railroad signaling systems, telephone exchanges, pipe organs, computers use modularity to overcome changing customer demands and to make the manufacturing process more adaptive to change. Modular design is an attempt to combine the advantages of standardization with those of customization, a downside to modularity is that low quality modular systems are not optimized for performance. This is usually due to the cost of putting up interfaces between modules, aspects of modular design can be seen in cars or other vehicles to the extent of there being certain parts to the car that can be added or removed without altering the rest of the car. Modular design can be seen in certain buildings, modular buildings generally consist of universal parts that are manufactured in a factory and then shipped to a build site where they are assembled into a variety of arrangements. Modular buildings can be added to or reduced in size by adding or removing certain components and this can be done without altering larger portions of the building. Modular buildings can also undergo changes in functionality using the process of adding or removing components. For example, a building can be built using modular parts such as walls, frames, doors, ceilings. The interior can then be partitioned with walls and furnished with desks, computers. The new building can then be refurnished with whatever items are needed to carry out its desired functions, many misconceptions are held regarding modular buildings. In reality modular construction is a method of construction for quick turnaround. Industries that would benefit from this include healthcare, commercial, retail, military, in 1963 Motorola introduced the first rectangular color picture tube, and in 1967 introduced the modular Quasar brand. In 1964 it opened its first research and development branch outside of the United States, in 1974 Motorola sold its television business to the Japan-based Matsushita, the parent company of Panasonic. Modular design in hardware is the same as in other things. The idea is to build computers with easily replaceable parts that use standardized interfaces and this technique allows a user to upgrade certain aspects of the computer easily without having to buy another computer altogether. This idea is also being implemented in Project Ara, which provides a platform for manufactures to create modules for a smartphone which can then be customised by the end user, a computer is one of the best examples of modular design. Typical modules include power units, processors, mainboards, graphics cards, hard drives
41.
Unix philosophy
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The Unix philosophy, originated by Ken Thompson, is a set of cultural norms and philosophical approaches to minimalist, modular software development. It is based on the experience of leading developers of the Unix operating system, early Unix developers were important in bringing the concepts of modularity and reusability into software engineering practice, spawning a software tools movement. The Unix philosophy emphasizes building simple, short, clear, modular, the Unix philosophy favors composability as opposed to monolithic design. The UNIX philosophy is documented by Doug McIlroy in the The Bell System Technical Journal from 1978, to do a new job, build afresh rather than complicate old programs by adding new features. Expect the output of every program to become the input to another, as yet unknown, dont clutter output with extraneous information. Avoid stringently columnar or binary input formats, Design and build software, even operating systems, to be tried early, ideally within weeks. Dont hesitate to throw away the parts and rebuild them. Use tools in preference to unskilled help to lighten a programming task, even if you have to detour to build the tools and expect to throw some of them out after youve finished using them. Later summarized by Peter H. Salus in A Quarter-Century of Unix, This is the Unix philosophy, Write programs that do one thing, Write programs to handle text streams, because that is a universal interface. The whole philosophy of UNIX seems to out of assembler. The development of pipes in 1973 formalized the existing principle of stdin-stdout into a philosophy in Version 3 Unix, the truth about Unix, The user interface is horrid was a 1981 criticism of the design philosophy published in Datamation. Instead, what makes it effective is the approach to programming, many UNIX programs do quite trivial things in isolation, but, combined with other programs, become general and useful tools. The authors further write that their goal for this book is to communicate the UNIX programming philosophy, in October 1984, Brian Kernighan and Rob Pike published a paper called Program Design in the UNIX Environment. In this paper, they criticize the accretion of program options, the authors contrast Unix tools such as cat, with larger program suites used by other systems. The design of cat is typical of most UNIX programs, it implements one simple, other commands are used for other functions. For example, there are separate commands for file system tasks like renaming files, deleting them, other systems instead lump these into a single file system command with an internal structure and command language of its own. That approach is not necessarily worse or better, but it is certainly against the UNIX philosophy. McIlroy, then head of the Bell Labs CSRC, and inventor of the Unix pipe, summarized the Unix philosophy as follows, This is the Unix philosophy, Write programs that do one thing, Write programs to handle text streams, because that is a universal interface
42.
Unix filesystem
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In Unix and operating systems inspired by it, the file system is considered a central component of the operating system. It was also one of the first parts of the system to be designed and implemented by Ken Thompson in the first experimental version of Unix, also, the filesystem provides access to other resources through so-called device files that are entry points to terminals, printers, and mice. The rest of this article uses Unix as a name to refer to both the original Unix operating system and its many workalikes. The filesystem appears as one rooted tree of directories, the root of the entire tree is denoted /. In the original Bell Labs Unix, a setup was customary. This second disk was mounted at the empty directory named usr on the first disk, Unix directories do not contain files. Instead, they contain the names of files paired with references to so-called inodes, multiple names in the file system may refer to the same file, a feature termed a hard link. The mathematical traits of hard links make the system a limited type of directed acyclic graph, although the directories still form a tree. The original Unix file system supported three types of files, ordinary files, directories, and special files, also termed device files. The Berkeley Software Distribution and System V each added a file type to be used for communication, BSD added sockets. BSD also added symbolic links to the range of types, which are files that refer to other files. Symlinks were modeled after a feature in Multics, and differ from hard links in that they may span filesystems. Other Unix systems may support added types of files, certain conventions exist for locating some kinds of files, such as programs, system configuration files, and users home directories. These were first documented in the man page since Version 7 Unix, subsequent versions. The details of the layout have varied over time.0 Unported License
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Unix shell
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A Unix shell is a command-line interpreter or shell that provides a traditional Unix-like command line user interface. Users direct the operation of the computer by entering commands as text for a command line interpreter to execute, users typically interact with a Unix shell using a terminal emulator, however, direct operation via serial hardware connections, or networking session, are common for server systems. All Unix shells provide filename wildcarding, piping, here documents, command substitution, variables and control structures for condition-testing, the most generic sense of the term shell means any program that users employ to type commands. In Unix-like operating systems, users typically have many choices of command-line interpreters for interactive sessions, when a user logs in to the system interactively, a shell program is automatically executed for the duration of the session. The Unix shell is both a command language as well as a scripting programming language, and is used by the operating system as the facility to control the execution of the system. Shells created for operating systems often provide similar functionality. On hosts with a system, like macOS, some users may never use the shell directly. However, some vendors have replaced the traditional shell-based startup system with different approaches. The first Unix shell was the Thompson shell, sh, written by Ken Thompson at Bell Labs and distributed with Versions 1 through 6 of Unix, though not in current use, it is still available as part of some Ancient UNIX Systems. It was modeled after the Multics shell, itself modeled after the RUNCOM program Louis Pouzin showed to the Multics Team, the rc suffix on some Unix configuration files, is a remnant of the RUNCOM ancestry of Unix shells. The PWB shell or Mashey shell, sh, was a version of the Thompson shell, augmented by John Mashey and others and distributed with the Programmers Workbench UNIX. It focused on making shell programming practical, especially in large shared computing centers and it added shell variables, user-executable shell scripts, and interrupt-handling. Control structures were extended from if/goto to if/then/else/endif, switch/breaksw/endsw, as shell programming became widespread, these external commands were incorporated into the shell itself for performance. But the most widely distributed and influential of the early Unix shells were the Bourne shell, both shells have been used as the coding base and model for many derivative and work-alike shells with extended feature sets. The Bourne shell, sh, was a rewrite by Stephen Bourne at Bell Labs. The language, including the use of a keyword to mark the end of a block, was influenced by ALGOL68. Traditionally, the Bourne shell program name is sh and its path in the Unix file system hierarchy is /bin/sh, but a number of compatible work-alikes are also available with various improvements and additional features. The sh of FreeBSD, NetBSD are based on ash that has enhanced to be POSIX conformant for the occasion
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