1.
Unix-like
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A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Unix-like application is one that behaves like the corresponding Unix command or shell, there is no standard for defining the term, and some difference of opinion is possible as to the degree to which a given operating system or application is Unix-like. The Open Group owns the UNIX trademark and administers the Single UNIX Specification and they do not approve of the construction Unix-like, and consider it a misuse of their trademark. Other parties frequently treat Unix as a genericized trademark, in 2007, Wayne R. Gray sued to dispute the status of UNIX as a trademark, but lost his case, and lost again on appeal, with the court upholding the trademark and its ownership. Unix-like systems started to appear in the late 1970s and early 1980s, many proprietary versions, such as Idris, UNOS, Coherent, and UniFlex, aimed to provide businesses with the functionality available to academic users of UNIX. These largely displaced the proprietary clones, growing incompatibility among these systems led to the creation of interoperability standards, including POSIX and the Single UNIX Specification. Various free, low-cost, and unrestricted substitutes for UNIX emerged in the 1980s and 1990s, including 4. 4BSD, Linux, some of these have in turn been the basis for commercial Unix-like systems, such as BSD/OS and OS X. The various BSD variants are notable in that they are in fact descendants of UNIX, however, the BSD code base has evolved since then, replacing all of the AT&T code. Since the BSD variants are not certified as compliant with the Single UNIX Specification, dennis Ritchie, one of the original creators of Unix, expressed his opinion that Unix-like systems such as Linux are de facto Unix systems. Eric S. Raymond and Rob Landley have suggested there are three kinds of Unix-like systems, Genetic UNIX Those systems with a historical connection to the AT&T codebase. Most commercial UNIX systems fall into this category, so do the BSD systems, which are descendants of work done at the University of California, Berkeley in the late 1970s and early 1980s. Some of these systems have no original AT&T code but can trace their ancestry to AT&T designs. Trademark or branded UNIX These systems—largely commercial in nature—have been determined by the Open Group to meet the Single UNIX Specification and are allowed to carry the UNIX name, many ancient UNIX systems no longer meet this definition. Around 2001, Linux was given the opportunity to get a certification including free help from the POSIX chair Andrew Josey for the price of one dollar. Some non-Unix-like operating systems provide a Unix-like compatibility layer, with degrees of Unix-like functionality. IBM z/OSs UNIX System Services is sufficiently complete to be certified as trademark UNIX, cygwin and MSYS both provide a GNU environment on top of the Microsoft Windows user API, sufficient for most common open source software to be compiled and run. Subsystem for Unix-based Applications provides Unix-like functionality as a Windows NT subsystem, Windows Subsystem for Linux provides a Linux-compatible kernel interface developed by Microsoft and containing no Linux code, with Ubuntu user-mode binaries running on top of it
2.
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
3.
Cray
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Cray Inc. is an American supercomputer manufacturer headquartered in Seattle, Washington. It also manufactures systems for storage and analytics. Several Cray supercomputer systems are listed in the TOP500, which ranks the most powerful supercomputers in the world, the number of Cray systems on the list varies from year to year. Cray manufactures its products in Chippewa Falls, Wisconsin, where its founder, Seymour Cray, was born, the company also has offices in St. Paul, Minnesota, and numerous other sales, service, engineering, and R&D locations around the world. The companys predecessor, Cray Research, Inc. was founded in 1972 by computer designer Seymour Cray, Seymour Cray went on to form the spin-off Cray Computer Corporation, in 1989, which went bankrupt in 1995, while Cray Research was bought by SGI the next year. Cray Inc. was formed in 2000 when Tera Computer Company purchased the Cray Research Inc. business from SGI, Seymour Cray began working in the computing field in 1950 when he joined Engineering Research Associates in Saint Paul, Minnesota. There, he helped to create the ERA1103, ERA eventually became part of UNIVAC, and began to be phased out. He left the company in 1960, a few years after former ERA employees set up Control Data Corporation and he initially worked out of the CDC headquarters in Minneapolis, but grew upset by constant interruptions by managers. He eventually set up a lab at his town in Chippewa Falls, Wisconsin. Cray had a string of successes at CDC, including the CDC6600, copying the previous arrangement, Cray kept the research and development facilities in Chippewa Falls, and the business headquarters in Minneapolis. The companys first product, the Cray-1 supercomputer, was a success because it was faster than all other computers at the time. The first system was sold within a month for US$8.8 million, Seymour Cray continued working, this time on the Cray-2, though it only ended up being marginally faster than the Cray X-MP, developed by another team at the company. Cray soon left the CEO position to become an independent contractor, however, the changing political climate resulted in poor sales prospects. Ultimately, only one Cray-3 was delivered, and a number of designs were never completed. The company filed for bankruptcy in 1995, cCCs remains then began Crays final corporation, SRC Computers, Inc. which still exists. Cray Research continued development along a line of computers, originally with lead designer Steve Chen. The uncertainty of the Cray-2 project gave rise to a number of Cray-object-code compatible Crayette firms, Scientific Computer Systems, American Supercomputer, Supertek, most sites with a Cray installation were considered a member of the exclusive club of Cray operators. Cray computers were considered quite prestigious because Crays were extremely expensive machines, new vendors introduced small supercomputers, known as minisupercomputers during the late 1980s and early 1990s, which out-competed low-end Cray machines in the market
4.
Supercomputer
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A supercomputer is a computer with a high level of computing performance compared to a general-purpose computer. Performance of a supercomputer is measured in floating-point operations per second instead of instructions per second. As of 2015, there are supercomputers which can perform up to quadrillions of FLOPS and it tops the rankings in the TOP500 supercomputer list. Sunway TaihuLights emergence is also notable for its use of indigenous chips, as of June 2016, China, for the first time, had more computers on the TOP500 list than the United States. However, U. S. built computers held ten of the top 20 positions, in November 2016 the U. S. has five of the top 10, throughout their history, they have been essential in the field of cryptanalysis. The use of multi-core processors combined with centralization is an emerging trend, the history of supercomputing goes back to the 1960s, with the Atlas at the University of Manchester and a series of computers at Control Data Corporation, designed by Seymour Cray. These used innovative designs and parallelism to achieve superior computational peak performance, Cray left CDC in 1972 to form his own company, Cray Research. Four years after leaving CDC, Cray delivered the 80 MHz Cray 1 in 1976, the Cray-2 released in 1985 was an 8 processor liquid cooled computer and Fluorinert was pumped through it as it operated. It performed at 1.9 gigaflops and was the second fastest after M-13 supercomputer in Moscow. Fujitsus Numerical Wind Tunnel supercomputer used 166 vector processors to gain the top spot in 1994 with a speed of 1.7 gigaFLOPS per processor. The Hitachi SR2201 obtained a performance of 600 GFLOPS in 1996 by using 2048 processors connected via a fast three-dimensional crossbar network. The Intel Paragon could have 1000 to 4000 Intel i860 processors in various configurations, the Paragon was a MIMD machine which connected processors via a high speed two dimensional mesh, allowing processes to execute on separate nodes, communicating via the Message Passing Interface. Approaches to supercomputer architecture have taken dramatic turns since the earliest systems were introduced in the 1960s, early supercomputer architectures pioneered by Seymour Cray relied on compact innovative designs and local parallelism to achieve superior computational peak performance. However, in time the demand for increased computational power ushered in the age of massively parallel systems, supercomputers of the 21st century can use over 100,000 processors connected by fast connections. The Connection Machine CM-5 supercomputer is a parallel processing computer capable of many billions of arithmetic operations per second. Throughout the decades, the management of heat density has remained a key issue for most centralized supercomputers, the large amount of heat generated by a system may also have other effects, e. g. reducing the lifetime of other system components. There have been diverse approaches to management, from pumping Fluorinert through the system. Systems with a number of processors generally take one of two paths
5.
Computer cluster
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A computer cluster consists of a set of loosely or tightly connected computers that work together so that, in many respects, they can be viewed as a single system. Unlike grid computers, computer clusters have each set to perform the same task. The components of a cluster are usually connected to each other through fast local area networks and they have a wide range of applicability and deployment, ranging from small business clusters with a handful of nodes to some of the fastest supercomputers in the world such as IBMs Sequoia. The desire to get more computing power and better reliability by orchestrating a number of low-cost commercial off-the-shelf computers has given rise to a variety of architectures, the computer clustering approach usually connects a number of readily available computing nodes via a fast local area network. g. Via a single system image concept, Computer clustering relies on a centralized management approach which makes the nodes available as orchestrated shared servers. It is distinct from other such as peer to peer or grid computing which also use many nodes. A computer cluster may be a simple system which just connects two personal computers, or may be a very fast supercomputer. A basic approach to building a cluster is that of a Beowulf cluster which may be built with a few computers to produce a cost-effective alternative to traditional high performance computing. An early project that showed the viability of the concept was the 133-node Stone Soupercomputer, the developers used Linux, the Parallel Virtual Machine toolkit and the Message Passing Interface library to achieve high performance at a relatively low cost. Although a cluster may consist of just a few personal computers connected by a simple network, greg Pfister has stated that clusters were not invented by any specific vendor but by customers who could not fit all their work on one computer, or needed a backup. Pfister estimates the date as some time in the 1960s, the first production system designed as a cluster was the Burroughs B5700 in the mid-1960s. This allowed up to four computers, each with one or two processors, to be tightly coupled to a common disk storage subsystem in order to distribute the workload. Unlike standard multiprocessor systems, each computer could be restarted without disrupting overall operation, the first commercial loosely coupled clustering product was Datapoint Corporations Attached Resource Computer system, developed in 1977, and using ARCnet as the cluster interface. Clustering per se did not really take off until Digital Equipment Corporation released their VAXcluster product in 1984 for the VAX/VMS operating system, the ARC and VAXcluster products not only supported parallel computing, but also shared file systems and peripheral devices. The idea was to provide the advantages of parallel processing, while maintaining data reliability, two other noteworthy early commercial clusters were the Tandem Himalayan and the IBM S/390 Parallel Sysplex. Within the same frame, while computer clusters used parallelism outside the computer on a commodity network. Following the success of the CDC6600 in 1964, the Cray 1 was delivered in 1976, while early supercomputers excluded clusters and relied on shared memory, in time some of the fastest supercomputers relied on cluster architectures. Computer clusters may be configured for different purposes ranging from general purpose business needs such as web-service support, in either case, the cluster may use a high-availability approach
6.
Cray-2
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The Cray-2 is a supercomputer with four vector processors built with emitter-coupled logic and made by Cray Research starting in 1985. At 1.9 GFLOPS peak performance, it was the fastest machine in the world when it was released, the Cray-2 was replaced as the worlds fastest computer by the ETA-10G in 1990. With the successful launch of his famed Cray-1, Seymour Cray turned to the design of its successor. By 1979 he had become fed up with management interruptions in what was now a large company, and as he had done in the past, decided to resign his management post and move to form a new lab. As with his move to Chippewa Falls, Wisconsin from Control Data HQ in Minneapolis, Minnesota, Cray management understood his needs and supported his move to a new lab in Boulder. Working as an independent consultant at these new Cray Labs, he put together a team and this Lab would later close, and a decade later a new facility in Colorado Springs would open. The classic example of design is the CDC8600, which packed four CDC 7600-like machines based on ECL logic into a 1 x 1 meter cylinder. Unfortunately the density needed to achieve this cycle time led to the machines downfall, one solution to this problem, one that most computer vendors had already moved to, was to use integrated circuits instead of individual components. Each IC included a selection of components from a module pre-wired into a circuit by the construction process. If an IC did not work, another one would be tried, at the time the 8600 was being designed the simple MOSFET-based technology did not offer the speed Cray needed. Relentless improvements changed things by the mid-1970s, however, and the Cray-1 had been able to use newer ICs, in fact, the Cray-1 was actually somewhat faster than the 8600 because it packed considerably more logic into the system due to the ICs small size. Although IC design continued to improve, the size of the ICs was constrained largely by mechanical limits. In order to gain another 10-fold increase in performance over the Cray-1, the goal Cray aimed for, another design problem was the increasing performance gap between the processor and main memory. In the era of the CDC6600 memory ran at the speed as the processor. Cray solved this by adding ten smaller computers to the system, allowing them to deal with the external storage. Adding four processors simply made this problem worse and it was the foreground processors task to run the computer, handling storage and making efficient use of the multiple channels into main memory. It drove the background processors by passing in the instructions they should run via eight 16 word buffers, modern CPUs use a variation of this design as well, although the foreground processor is now referred to as the load/store unit and is not a complete machine unto its own. Main memory banks were arranged in quadrants to be accessed at the same time, the downside to this approach is that the cost of setting up the scatter/gather unit in the foreground processor was fairly high
7.
UNIX System V
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UNIX System V is one of the first commercial versions of the Unix operating system. It was originally developed by AT&T and first released in 1983, four major versions of System V were released, numbered 1,2,3, and 4. It was the source of common commercial Unix features. System V is sometimes abbreviated to SysV, as of 2012, the Unix market is divided between three System V variants, IBMs AIX, Hewlett-Packards HP-UX and Oracles Solaris. System V was the successor to 1982s UNIX System III, while AT&T sold their own hardware that ran System V, most customers instead ran a version from a reseller, based on AT&Ts reference implementation. A standards document called the System V Interface Definition outlined the default features, in the 1980s and early-1990s, System V was considered one of the two major versions of UNIX, the other being the Berkeley Software Distribution. Historically, BSD was also commonly called BSD Unix or Berkeley Unix, the dispute had several levels, some technical and some cultural. The divide was roughly between longhairs and shorthairs, programmers and technical people tended to line up with Berkeley and BSD, more business-oriented types with AT&T and System V. While HP, IBM and others chose System V as the basis for their Unix offerings, other such as Sun Microsystems. Throughout its development, though, System V was infused with features from BSD, since the early 1990s, due to standardization efforts such as POSIX and the commercial success of Linux, the division between System V and BSD has become less important. System V, known inside Bell Labs as Unix 5.0, there was never an external release of Unix 4.0, which would have been System IV. This first release of System V was developed by AT&Ts UNIX Support Group, System V also included features such as the vi editor and curses from 4.1 BSD, developed at the University of California, Berkeley, it also improved performance by adding buffer and inode caches. It also added support for communication using messages, semaphores. SVR1 ran on DEC PDP-11 and VAX minicomputers, System V Release 2 was released in April,1984. It added shell functions and the SVID, new kernel features included record and file locking, demand paging, and copy on write. The concept of the base was formalized, and the DEC VAX-11/780 was chosen for this release. The porting base is the original version of a release. Educational source licenses for SVR2 were offered by AT&T for US$800 for the first CPU, a commercial source license was offered for $43,000, with three months of support, and a $16,000 price per additional CPU
8.
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
