1.
Software
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Computer software, or simply software, is that part of a computer system that consists of data or computer instructions, in contrast to the physical hardware from which the system is built. In computer science and software engineering, computer software is all information processed by computer systems, programs, computer software includes computer programs, libraries and related non-executable data, such as online documentation or digital media. Computer hardware and software require each other and neither can be used on its own. At the lowest level, executable code consists of machine language instructions specific to an individual processor—typically a central processing unit, a machine language consists of groups of binary values signifying processor instructions that change the state of the computer from its preceding state. For example, an instruction may change the value stored in a storage location in the computer—an effect that is not directly observable to the user. An instruction may also cause something to appear on a display of the computer system—a state change which should be visible to the user. The processor carries out the instructions in the order they are provided, unless it is instructed to jump to a different instruction, the majority of software is written in high-level programming languages that are easier and more efficient for programmers, meaning closer to a natural language. High-level languages are translated into machine language using a compiler or an interpreter or a combination of the two, an outline for what would have been the first piece of software was written by Ada Lovelace in the 19th century, for the planned Analytical Engine. However, neither the Analytical Engine nor any software for it were ever created, the first theory about software—prior to creation of computers as we know them today—was proposed by Alan Turing in his 1935 essay Computable numbers with an application to the Entscheidungsproblem. This eventually led to the creation of the academic fields of computer science and software engineering. Computer science is more theoretical, whereas software engineering focuses on practical concerns. However, prior to 1946, software as we now understand it—programs stored in the memory of stored-program digital computers—did not yet exist, the first electronic computing devices were instead rewired in order to reprogram them. On virtually all platforms, software can be grouped into a few broad categories. There are many different types of software, because the range of tasks that can be performed with a modern computer is so large—see list of software. System software includes, Operating systems, which are collections of software that manage resources and provides common services for other software that runs on top of them. Supervisory programs, boot loaders, shells and window systems are parts of operating systems. In practice, an operating system bundled with additional software so that a user can potentially do some work with a computer that only has an operating system. Device drivers, which operate or control a particular type of device that is attached to a computer, utilities, which are computer programs designed to assist users in the maintenance and care of their computers
2.
Telecommunication
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Telecommunication is the transmission of signs, signals, messages, writings, images and sounds or intelligence of any nature by wire, radio, optical or other electromagnetic systems. Telecommunication occurs when the exchange of information between communication participants includes the use of technology and it is transmitted either electrically over physical media, such as cables, or via electromagnetic radiation. Such transmission paths are divided into communication channels which afford the advantages of multiplexing. The term is used in its plural form, telecommunications. Early means of communicating over a distance included visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, other examples of pre-modern long-distance communication included audio messages such as coded drumbeats, lung-blown horns, and loud whistles. Zworykin, John Logie Baird and Philo Farnsworth, the word telecommunication is a compound of the Greek prefix tele, meaning distant, far off, or afar, and the Latin communicare, meaning to share. Its modern use is adapted from the French, because its use was recorded in 1904 by the French engineer. Communication was first used as an English word in the late 14th century, in the Middle Ages, chains of beacons were commonly used on hilltops as a means of relaying a signal. Beacon chains suffered the drawback that they could pass a single bit of information. One notable instance of their use was during the Spanish Armada, in 1792, Claude Chappe, a French engineer, built the first fixed visual telegraphy system between Lille and Paris. However semaphore suffered from the need for skilled operators and expensive towers at intervals of ten to thirty kilometres, as a result of competition from the electrical telegraph, the last commercial line was abandoned in 1880. Homing pigeons have occasionally used throughout history by different cultures. Pigeon post is thought to have Persians roots and was used by the Romans to aid their military, frontinus said that Julius Caesar used pigeons as messengers in his conquest of Gaul. The Greeks also conveyed the names of the victors at the Olympic Games to various cities using homing pigeons, in the early 19th century, the Dutch government used the system in Java and Sumatra. And in 1849, Paul Julius Reuter started a service to fly stock prices between Aachen and Brussels, a service that operated for a year until the gap in the telegraph link was closed. Sir Charles Wheatstone and Sir William Fothergill Cooke invented the telegraph in 1837. Also, the first commercial electrical telegraph is purported to have constructed by Wheatstone and Cooke. Both inventors viewed their device as an improvement to the electromagnetic telegraph not as a new device, samuel Morse independently developed a version of the electrical telegraph that he unsuccessfully demonstrated on 2 September 1837
3.
High frequency
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High frequency is the ITU designation for the range of radio frequency electromagnetic waves between 3 and 30 MHz. It is also known as the band or decameter wave as its wavelengths range from one to ten decameters. Frequencies immediately below HF are denoted medium frequency, while the band of higher frequencies is known as the very high frequency band. The HF band is a part of the shortwave band of frequencies. The band is used by shortwave broadcasting stations, aviation communication, government time stations, weather stations, amateur radio and citizens band services. By this method HF radio waves can travel beyond the horizon, around the curve of the Earth and it depends on the angle of incidence of the waves, it is lowest when the waves are directed straight upwards, and is higher with less acute angles. This means that at longer distances, where the waves graze the ionosphere at a blunt angle. The lowest usable frequency depends on the absorption in the layer of the ionosphere. This absorption is stronger at low frequencies and is stronger with increased solar activity. When all factors are at their optimum, worldwide communication is possible on HF, at many other times it is possible to make contact across and between continents or oceans. At worst, when a band is dead, no communication beyond the limited groundwave paths is possible no matter what powers, on such an open band, interference originating over a wide area affects many potential users. These issues are significant to military, safety and amateur radio users of the HF bands, other standards development such as STANAG5066 provides for error free data communications through the use of ARQ protocols. Noise, especially man-made interference from devices, tends to have a great effect on the HF bands. In recent years, concerns have risen among certain users of the HF spectrum over broadband over power lines Internet access and this is due to the frequencies on which BPL operates and the tendency for the BPL signal to leak from power lines. Some BPL providers have installed notch filters to block out certain portions of the spectrum, other electronic devices including plasma televisions can also have a detrimental effect on the HF spectrum. In aviation, HF communication systems are required for all trans-oceanic flights and these systems incorporate frequencies down to 2 MHz to include the 2182 kHz international distress and calling channel. The upper section of HF shares many characteristics with the part of VHF. The parts of this section not allocated to radio are used for local communications
4.
Radio
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When radio waves strike an electrical conductor, the oscillating fields induce an alternating current in the conductor. The information in the waves can be extracted and transformed back into its original form, Radio systems need a transmitter to modulate some property of the energy produced to impress a signal on it, for example using amplitude modulation or angle modulation. Radio systems also need an antenna to convert electric currents into radio waves, an antenna can be used for both transmitting and receiving. The electrical resonance of tuned circuits in radios allow individual stations to be selected, the electromagnetic wave is intercepted by a tuned receiving antenna. Radio frequencies occupy the range from a 3 kHz to 300 GHz, a radio communication system sends signals by radio. The term radio is derived from the Latin word radius, meaning spoke of a wheel, beam of light, however, this invention would not be widely adopted. The switch to radio in place of wireless took place slowly and unevenly in the English-speaking world, the United States Navy would also play a role. Although its translation of the 1906 Berlin Convention used the terms wireless telegraph and wireless telegram, the term started to become preferred by the general public in the 1920s with the introduction of broadcasting. Radio systems used for communication have the following elements, with more than 100 years of development, each process is implemented by a wide range of methods, specialised for different communications purposes. Each system contains a transmitter, This consists of a source of electrical energy, the transmitter contains a system to modulate some property of the energy produced to impress a signal on it. This modulation might be as simple as turning the energy on and off, or altering more subtle such as amplitude, frequency, phase. Amplitude modulation of a carrier wave works by varying the strength of the signal in proportion to the information being sent. For example, changes in the strength can be used to reflect the sounds to be reproduced by a speaker. It was the used for the first audio radio transmissions. Frequency modulation varies the frequency of the carrier, the instantaneous frequency of the carrier is directly proportional to the instantaneous value of the input signal. FM has the capture effect whereby a receiver only receives the strongest signal, Digital data can be sent by shifting the carriers frequency among a set of discrete values, a technique known as frequency-shift keying. FM is commonly used at Very high frequency radio frequencies for high-fidelity broadcasts of music, analog TV sound is also broadcast using FM. Angle modulation alters the phase of the carrier wave to transmit a signal
5.
Automatic link establishment
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Automatic Link Establishment, commonly known as ALE, is the worldwide de facto standard for digitally initiating and sustaining HF radio communications. A standalone ALE radio combines an HF SSB radio transceiver with an internal microprocessor and it is programmed with a unique ALE address, similar to a phone number. It decodes calls and soundings sent by other stations and uses the bit rate to store a quality score for that frequency. To reach a station, the caller enters the ALE Address. On many ALE radios this is similar to dialing a phone number, the ALE controller selects the best available idle channel for that destination address. After confirming the channel is indeed idle, it sends a brief selective calling signal identifying the intended recipient. When the distant scanning station detects ALE activity, it stops scanning, the two stations ALE controllers automatically handshake to confirm that a link of sufficient quality has been established, then notify the operators that the link is up. If the callee fails to respond or the handshaking fails, the originating ALE node usually selects another frequency either at random or by making a guess of varying sophistication. Upon successful linking, the station generally emits an audible alarm and shows a visual alert to the operator. It also indicates the callsign or other identifying information of the linked station, the operator then un-mutes the radio and answers the call then can talk in a regular conversation or negotiates a data link using voice or the ALE built-in short text message format. Alternatively, digital data can be exchanged via a built-in or external modem depending on needs, for the average user of ALE, after learning how to work the basic functions of the HF transceiver, it became similar to operating a cellular mobile phone. An ALE radio system enables connection for voice conversation, alerting, data exchange, texting, instant messaging, email, file transfer, image, geo-position tracking, or telemetry. With a radio operator initiating a call, the process takes a few minutes for the ALE to pick an HF frequency that is optimum for both sides of the communication link. It signals the operators audibly and visually on both ends, so they can begin communicating with each other immediately, in this respect, the longstanding need in HF radio for repetitive calling on pre-determined time schedules or tedious monitoring static is eliminated. It is useful as a tool for finding optimum channels to communicate between stations in real-time, in modern HF communications, ALE has largely replaced HF prediction charts, propagation beacons, chirp sounders, propagation prediction software, and traditional radio operator educated guesswork. High Frequency Internet Protocol or HFIP may be used with ALE for internet access via HF, the essence of ALE techniques is the use of automatic channel selection, scanning receivers, selective calling, handshaking, and robust burst modems. An ALE node decodes all received ALE signals heard on the channel it monitors and it utilizes the fact that all ALE messages utilize Forward error correction redundancy. By noting how much error-correction occurred in each received and decoded message and this information is coupled with the ALE address of the sending node and the channel the message was received on, and stored in the nodes Link Quality Analysis memory
6.
String (computer science)
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In computer programming, a string is traditionally a sequence of characters, either as a literal constant or as some kind of variable. The latter may allow its elements to be mutated and the length changed, a string is generally understood as a data type and is often implemented as an array of bytes that stores a sequence of elements, typically characters, using some character encoding. A string may also more general arrays or other sequence data types and structures. When a string appears literally in source code, it is known as a literal or an anonymous string. In formal languages, which are used in logic and theoretical computer science. Let Σ be a non-empty finite set of symbols, called the alphabet, no assumption is made about the nature of the symbols. A string over Σ is any sequence of symbols from Σ. For example, if Σ =, then 01011 is a string over Σ, the length of a string s is the number of symbols in s and can be any non-negative integer, it is often denoted as |s|. The empty string is the string over Σ of length 0. The set of all strings over Σ of length n is denoted Σn, for example, if Σ =, then Σ2 =. Note that Σ0 = for any alphabet Σ, the set of all strings over Σ of any length is the Kleene closure of Σ and is denoted Σ*. In terms of Σn, Σ ∗ = ⋃ n ∈ N ∪ Σ n For example, if Σ =, although the set Σ* itself is countably infinite, each element of Σ* is a string of finite length. A set of strings over Σ is called a language over Σ. For example, if Σ =, the set of strings with an number of zeros, is a formal language over Σ. Concatenation is an important binary operation on Σ*, for any two strings s and t in Σ*, their concatenation is defined as the sequence of symbols in s followed by the sequence of characters in t, and is denoted st. For example, if Σ =, s = bear, and t = hug, then st = bearhug, String concatenation is an associative, but non-commutative operation. The empty string ε serves as the identity element, for any string s, therefore, the set Σ* and the concatenation operation form a monoid, the free monoid generated by Σ. In addition, the length function defines a monoid homomorphism from Σ* to the non-negative integers, a string s is said to be a substring or factor of t if there exist strings u and v such that t = usv
7.
Computer
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A computer is a device that can be instructed to carry out an arbitrary set of arithmetic or logical operations automatically. The ability of computers to follow a sequence of operations, called a program, such computers are used as control systems for a very wide variety of industrial and consumer devices. The Internet is run on computers and it millions of other computers. Since ancient times, simple manual devices like the abacus aided people in doing calculations, early in the Industrial Revolution, some mechanical devices were built to automate long tedious tasks, such as guiding patterns for looms. More sophisticated electrical machines did specialized analog calculations in the early 20th century, the first digital electronic calculating machines were developed during World War II. The speed, power, and versatility of computers has increased continuously and dramatically since then, conventionally, a modern computer consists of at least one processing element, typically a central processing unit, and some form of memory. The processing element carries out arithmetic and logical operations, and a sequencing, peripheral devices include input devices, output devices, and input/output devices that perform both functions. Peripheral devices allow information to be retrieved from an external source and this usage of the term referred to a person who carried out calculations or computations. The word continued with the same meaning until the middle of the 20th century, from the end of the 19th century the word began to take on its more familiar meaning, a machine that carries out computations. The Online Etymology Dictionary gives the first attested use of computer in the 1640s, one who calculates, the Online Etymology Dictionary states that the use of the term to mean calculating machine is from 1897. The Online Etymology Dictionary indicates that the use of the term. 1945 under this name, theoretical from 1937, as Turing machine, devices have been used to aid computation for thousands of years, mostly using one-to-one correspondence with fingers. The earliest counting device was probably a form of tally stick, later record keeping aids throughout the Fertile Crescent included calculi which represented counts of items, probably livestock or grains, sealed in hollow unbaked clay containers. The use of counting rods is one example, the abacus was initially used for arithmetic tasks. The Roman abacus was developed from used in Babylonia as early as 2400 BC. Since then, many forms of reckoning boards or tables have been invented. In a medieval European counting house, a checkered cloth would be placed on a table, the Antikythera mechanism is believed to be the earliest mechanical analog computer, according to Derek J. de Solla Price. It was designed to calculate astronomical positions and it was discovered in 1901 in the Antikythera wreck off the Greek island of Antikythera, between Kythera and Crete, and has been dated to circa 100 BC
8.
Recursion
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Recursion occurs when a thing is defined in terms of itself or of its type. Recursion is used in a variety of disciplines ranging from linguistics to logic, the most common application of recursion is in mathematics and computer science, where a function being defined is applied within its own definition. While this apparently defines a number of instances, it is often done in such a way that no loop or infinite chain of references can occur. The ancestors of ones ancestors are also ones ancestors, the Fibonacci sequence is a classic example of recursion, Fib =0 as base case 1, Fib =1 as base case 2, For all integers n >1, Fib, = Fib + Fib. Many mathematical axioms are based upon recursive rules, for example, the formal definition of the natural numbers by the Peano axioms can be described as,0 is a natural number, and each natural number has a successor, which is also a natural number. By this base case and recursive rule, one can generate the set of all natural numbers, recursively defined mathematical objects include functions, sets, and especially fractals. There are various more tongue-in-cheek definitions of recursion, see recursive humor, Recursion is the process a procedure goes through when one of the steps of the procedure involves invoking the procedure itself. A procedure that goes through recursion is said to be recursive, to understand recursion, one must recognize the distinction between a procedure and the running of a procedure. A procedure is a set of steps based on a set of rules, the running of a procedure involves actually following the rules and performing the steps. An analogy, a procedure is like a recipe, running a procedure is like actually preparing the meal. Recursion is related to, but not the same as, a reference within the specification of a procedure to the execution of some other procedure. For instance, a recipe might refer to cooking vegetables, which is another procedure that in turn requires heating water, for this reason recursive definitions are very rare in everyday situations. An example could be the procedure to find a way through a maze. Proceed forward until reaching either an exit or a branching point, If the point reached is an exit, terminate. Otherwise try each branch in turn, using the procedure recursively, if every trial fails by reaching only dead ends, return on the path led to this branching point. Whether this actually defines a terminating procedure depends on the nature of the maze, in any case, executing the procedure requires carefully recording all currently explored branching points, and which of their branches have already been exhaustively tried. This can be understood in terms of a definition of a syntactic category. A sentence can have a structure in which what follows the verb is another sentence, Dorothy thinks witches are dangerous, so a sentence can be defined recursively as something with a structure that includes a noun phrase, a verb, and optionally another sentence
9.
CP/M
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Initially confined to single-tasking on 8-bit processors and no more than 64 kilobytes of memory, later versions of CP/M added multi-user variations and were migrated to 16-bit processors. The combination of CP/M and S-100 bus computers was loosely patterned on the MITS Altair and this computer platform was widely used in business through the late 1970s and into the mid-1980s. CP/M increased the size for both hardware and software by greatly reducing the amount of programming required to install an application on a new manufacturers computer. An important driver of innovation was the advent of low-cost microcomputers running CP/M, as independent programmers and hackers bought them. CP/M was displaced by MS-DOS soon after the 1981 introduction of the IBM PC, manufacturers of CP/M-compatible systems customized portions of the operating system for their own combination of installed memory, disk drives, and console devices. CP/M would also run on based on the Zilog Z80 processor since the Z80 was compatible with 8080 code. CP/M used the 7-bit ASCII set, the other 128 characters made possible by the 8-bit byte were not standardized. For example, one Kaypro used them for Greek characters, WordStar used the 8th bit as an end-of-word marker. The BIOS and BDOS were memory-resident, while the CCP was memory-resident unless overwritten by an application, a number of transient commands for standard utilities were also provided. The transient commands resided in files with the extension. COM on disk, the BIOS directly controlled hardware components other than the CPU and main memory. It contained functions such as input and output and the reading and writing of disk sectors. The BDOS implemented the CP/M file system and some input/output abstractions on top of the BIOS, the CCP took user commands and either executed them directly or loaded and started an executable file of the given name. Third-party applications for CP/M were also essentially transient commands, the BDOS, CCP and standard transient commands were the same in all installations of a particular revision of CP/M, but the BIOS portion was always adapted to the particular hardware. Adding memory to a computer, for example, meant that the CP/M system had to be reinstalled with an updated BIOS capable of addressing the additional memory, a utility was provided to patch the supplied BIOS, BDOS and CCP to allow them to be run from higher memory. Once installed, the system was stored in reserved areas at the beginning of any disk which would be used to boot the system. On start-up, the bootloader would load the system from the disk in drive A. By modern standards CP/M was primitive, owing to the constraints on program size. With version 1.0 there was no provision for detecting a changed disk, if a user changed disks without manually rereading the disk directory the system would write on the new disk using the old disks directory information, ruining the data stored on the disk
10.
DOS
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None of these systems were officially named DOS, and indeed DOS is a general term for disk operating system. MS-DOS dominated the IBM PC compatible market between 1981 and 1995, and Microsoft Windows, still ran on top of it until about 2001, dozens of other operating systems also use the acronym DOS, including DOS/360 from 1966. Others are Apple DOS, Apple ProDOS, Atari DOS, Commodore DOS, TRSDOS, see List of DOS operating systems § Other operating systems. IBM PC DOS and its predecessor, 86-DOS, resembled Digital Researchs CP/M—the dominant disk operating system for 8-bit Intel 8080, DOS instead ran on Intel 8086 16-bit processors. Starting with MS-DOS1.28 and PC DOS2.0 the operating system incorporated various features inspired by Xenix, when IBM introduced the IBM PC, built with the Intel 8088 microprocessor, they needed an operating system. Seeking an 8088-compatible build of CP/M, IBM initially approached Microsoft CEO Bill Gates, IBM was sent to Digital Research, and a meeting was set up. However, the negotiations for the use of CP/M broke down, Digital Research wished to sell CP/M on a royalty basis, while IBM sought a single license. Digital Research founder Gary Kildall refused, and IBM withdrew, Gates in turn approached Seattle Computer Products. There, programmer Tim Paterson had developed a variant of CP/M-80, the system was initially named QDOS, before being made commercially available as 86-DOS. Microsoft purchased 86-DOS, allegedly for $50,000 and this became Microsoft Disk Operating System, MS-DOS, introduced in 1981. Within a year Microsoft licensed MS-DOS to over 70 other companies, Microsoft later required the use of the MS-DOS name, with the exception of the IBM variant. IBM continued to develop their version, PC DOS, for the IBM PC, Digital Research became aware that an operating system similar to CP/M was being sold by IBM, and threatened legal action. IBM responded by offering an agreement, they would give PC consumers a choice of PC DOS or CP/M-86, side-by-side, CP/M cost almost $200 more than PC DOS, and sales were low. CP/M faded, with MS-DOS and PC DOS becoming the operating system for PCs. Microsoft originally sold MS-DOS only to original equipment manufacturers, one major reason for this was that not all early PCs were 100% IBM PC compatible. DOS was structured such that there was a separation between the specific device driver code and the DOS kernel. Microsoft provided an OEM Adaptation Kit which allowed OEMs to customize the device driver code to their particular system, by the early 1990s, most PCs adhered to IBM PC standards so Microsoft began selling MS-DOS in retail with MS-DOS5.0. In the mid-1980s Microsoft developed a version of DOS
11.
Microsoft Windows
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Microsoft Windows is a metafamily of graphical operating systems developed, marketed, and sold by Microsoft. It consists of families of operating systems, each of which cater to a certain sector of the computing industry with the OS typically associated with IBM PC compatible architecture. Active Windows families include Windows NT, Windows Embedded and Windows Phone, defunct Windows families include Windows 9x, Windows 10 Mobile is an active product, unrelated to the defunct family Windows Mobile. Microsoft introduced an operating environment named Windows on November 20,1985, Microsoft Windows came to dominate the worlds personal computer market with over 90% market share, overtaking Mac OS, which had been introduced in 1984. Apple came to see Windows as an encroachment on their innovation in GUI development as implemented on products such as the Lisa. On PCs, Windows is still the most popular operating system, however, in 2014, Microsoft admitted losing the majority of the overall operating system market to Android, because of the massive growth in sales of Android smartphones. In 2014, the number of Windows devices sold was less than 25% that of Android devices sold and this comparison however may not be fully relevant, as the two operating systems traditionally target different platforms. As of September 2016, the most recent version of Windows for PCs, tablets, smartphones, the most recent versions for server computers is Windows Server 2016. A specialized version of Windows runs on the Xbox One game console, Microsoft, the developer of Windows, has registered several trademarks each of which denote a family of Windows operating systems that target a specific sector of the computing industry. It now consists of three operating system subfamilies that are released almost at the time and share the same kernel. Windows, The operating system for personal computers, tablets. The latest version is Windows 10, the main competitor of this family is macOS by Apple Inc. for personal computers and Android for mobile devices. Windows Server, The operating system for server computers, the latest version is Windows Server 2016. Unlike its clients sibling, it has adopted a strong naming scheme, the main competitor of this family is Linux. Windows PE, A lightweight version of its Windows sibling meant to operate as an operating system, used for installing Windows on bare-metal computers. The latest version is Windows PE10.0.10586.0, Windows Embedded, Initially, Microsoft developed Windows CE as a general-purpose operating system for every device that was too resource-limited to be called a full-fledged computer. The following Windows families are no longer being developed, Windows 9x, Microsoft now caters to the consumers market with Windows NT. Windows Mobile, The predecessor to Windows Phone, it was a mobile operating system
12.
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
13.
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
14.
Asterisk
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An asterisk is a typographical symbol or glyph. It is so called because it resembles a conventional image of a star, computer scientists and mathematicians often vocalize it as star. In English, an asterisk is usually five-pointed in sans-serif typefaces, six-pointed in serif typefaces and it can be used as censorship. It is also used on the Internet to correct ones spelling, the asterisk is derived from the need of the printers of family trees in feudal times for a symbol to indicate date of birth. The original shape was seven-armed, each arm like a shooting from the center. In computer science, the asterisk is used as a wildcard character, or to denote pointers, repetition. Origin Adamantius is known to have used the asteriskos to mark missing Hebrew lines from his Hexapla. The asterisk evolved in shape over time, but its meaning as a used to correct defects remained. In the Middle Ages, the asterisk was used to emphasize a part of text. However, an asterisk was not always used, one hypothesis to the origin of the asterisk is that it stems from the five thousand year old Sumerian character dingir,
15.
Question mark
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The question mark is a punctuation mark that indicates an interrogative clause or phrase in many languages. The question mark is not used for indirect questions, the question mark glyph is also often used in place of missing or unknown data. In Unicode, it is encoded at U+003F, lynne Truss attributes an early form of the modern question mark in western language to Alcuin of York. Truss describes the punctus interrogativus of the late 8th century as and this earliest question mark was a decoration of one of these dots, with the lightning flash perhaps meant to denote intonation, and perhaps associated with early musical notation like neumes. It has also suggested that the glyph derives from the Latin quaestiō, meaning question. The lowercase q was written above the o, and this mark was transformed into the modern symbol. According to a 2011 discovery by a Cambridge manuscript expert, Syriac was the first language to use a mark to indicate an interrogative sentence. The Syriac question mark has the form of a double dot. In English, the question mark typically occurs at the end of a sentence, however, the question mark may also occur at the end of a clause or phrase, where it replaces the comma, Is it good in form. Or, Showing off for him, for all of them, what did he have to be hubrid about. —but from mood and nervousness. This is quite common in Spanish, where the use of bracketing question marks explicitly indicates the scope of interrogation, en el caso de que no puedas ir con ellos, ¿quieres ir con nosotros. In Spanish, since the edition of the Ortografía of the Royal Academy in 1754. An interrogative sentence, clause, or phrase begins with a question mark ⟨¿⟩ and ends with the question mark ⟨. ⟩, as in, Ella me pregunta «¿qué hora es. » – She asks me. The one exception is when the mark is matched with an exclamation mark, as in. – Who do you think you are, nonetheless, even here the Academy recommends matching punctuation, ¡¿Quién te has creído que eres. Other languages of Spain, Catalan and Galician also uses the opening question mark though usually only in long sentences or in cases which would otherwise be ambiguous. Basque only use one question mark, in Armenian the question mark takes the form of an open circle and is placed over the last vowel of the question word. It is defined in Unicode at U+055E ՞ ARMENIAN QUESTION MARK, the Greek question mark appeared around the same time as the Latin one, in the 8th century
16.
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
17.
PowerShell
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PowerShell is a task automation and configuration management framework from Microsoft, consisting of a command-line shell and associated scripting language built on the. NET Framework. Initially a Windows component only, PowerShell was made open-source and cross-platform on 18 August 2016, in PowerShell, administrative tasks are generally performed by cmdlets, which are specialized. NET classes implementing a particular operation. Sets of cmdlets may be combined into scripts, executables, or by instantiating regular. NET classes and these work by accessing data in different data stores, like the file system or registry, which are made available to the PowerShell runtime via PowerShell providers. PowerShell also provides a hosting API with which the PowerShell runtime can be embedded inside other applications and these applications can then use PowerShell functionality to implement certain operations, including those exposed via the graphical interface. Other Microsoft applications including Microsoft SQL Server 2008 also expose their management interface via PowerShell cmdlets, PowerShell includes its own extensive, console-based help, similar to man pages in Unix shells, via the Get-Help cmdlet. Local help contents can be retrieved from the Internet via Update-Help cmdlet, alternatively, help from the web can be acquired on a case-by-case basis via the -online switch to Get-Help. Every released version of Microsoft DOS and Microsoft Windows for personal computers has included a command-line interface tool, the shell is a command line interpreter that supports a few basic commands. For other purposes, a console application must be invoked from the shell. The shell also includes a language, which can be used to automate various tasks. In Windows Server 2003, the situation was improved, but scripting support was considered unsatisfactory. Microsoft attempted to address some of shortcomings by introducing the Windows Script Host in 1998 with Windows 98. It integrates with the Active Script engine and allows scripts to be written in languages, such as JScript and VBScript. Different versions of Windows provided various special-purpose command line interpreters with their own command sets, none of them were integrated with the command shell, nor were they interoperable. By 2002 Microsoft had started to develop a new approach to command line management, the shell and the ideas behind it were published in August 2002 in a white paper titled Monad Manifesto. Monad was to be a new extensible command shell with a design that would be capable of automating a full range of core administrative tasks. Microsoft first showed off Monad at the Professional Development Conference in Los Angeles in October 2003, a private beta program began a few months later which eventually led to a public beta program. Microsoft published the first Monad public beta release on June 17,2005, Beta 2 on September 11,2005, and Beta 3 on January 10,2006. Not much later, on April 25,2006 Microsoft formally announced that Monad had been renamed Windows PowerShell, Release Candidate 1 of PowerShell was released at the same time
18.
Square brackets
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A bracket is a tall punctuation mark typically used in matched pairs within text, to set apart or interject other text. The matched pair may be described as opening and closing, or left, forms include round, square, curly, and angle brackets, and various other pairs of symbols. Chevrons were the earliest type of bracket to appear in written English, desiderius Erasmus coined the term lunula to refer to the rounded parentheses, recalling the shape of the crescent moon. Some of the names are regional or contextual. Sometimes referred to as angle brackets, in cases as HTML markup. Occasionally known as broken brackets or brokets, ⸤ ⸥, ｢ ｣ – corner brackets ⟦ ⟧ – double square brackets, white square brackets Guillemets, ‹ › and « », are sometimes referred to as chevrons or angle brackets. The characters ‹ › and « », known as guillemets or angular quote brackets, are actually quotation mark glyphs used in several European languages, which one of each pair is the opening quote mark and which is the closing quote varies between languages. In English, typographers generally prefer to not set brackets in italics, however, in other languages like German, if brackets enclose text in italics, they are usually set in italics too. Parentheses /pəˈrɛnθᵻsiːz/ contain material that serves to clarify or is aside from the main point, a milder effect may be obtained by using a pair of commas as the delimiter, though if the sentence contains commas for other purposes, visual confusion may result. In American usage, parentheses are considered separate from other brackets. Parentheses may be used in writing to add supplementary information. They can also indicate shorthand for either singular or plural for nouns and it can also be used for gender neutral language, especially in languages with grammatical gender, e. g. he agreed with his physician. Parenthetical phrases have been used extensively in informal writing and stream of consciousness literature, examples include the southern American author William Faulkner as well as poet E. E. Cummings. Parentheses have historically been used where the dash is used in alternatives, such as parenthesis) is used to indicate an interval from a to c that is inclusive of a. That is, [5, 12) would be the set of all numbers between 5 and 12, including 5 but not 12. The numbers may come as close as they like to 12, including 11.999 and so forth, in some European countries, the notation [5, 12[ is also used for this. The endpoint adjoining the bracket is known as closed, whereas the endpoint adjoining the parenthesis is known as open, if both types of brackets are the same, the entire interval may be referred to as closed or open as appropriate. Whenever +∞ or −∞ is used as an endpoint, it is considered open
19.
SQL
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Originally based upon relational algebra and tuple relational calculus, SQL consists of a data definition language, data manipulation language, and data control language. The scope of SQL includes data insert, query, update and delete, schema creation and modification, although SQL is often described as, and to a great extent is, a declarative language, it also includes procedural elements. SQL was one of the first commercial languages for Edgar F. Codds relational model, as described in his influential 1970 paper, despite not entirely adhering to the relational model as described by Codd, it became the most widely used database language. SQL became a standard of the American National Standards Institute in 1986, since then, the standard has been revised to include a larger set of features. Despite the existence of such standards, most SQL code is not completely portable among different database systems without adjustments, SQL was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce in the early 1970s. The acronym SEQUEL was later changed to SQL because SEQUEL was a trademark of the UK-based Hawker Siddeley aircraft company, in June 1979, Relational Software, Inc. introduced the first commercially available implementation of SQL, Oracle V2 for VAX computers. SQL deviates in several ways from its foundation, the relational model. In that model, a table is a set of tuples, while in SQL, tables and query results are lists of rows, the same row may occur multiple times, and the order of rows can be employed in queries. Critics argue that SQL should be replaced with a language that strictly returns to the foundation, for example. The SQL language is subdivided into several elements, including, Clauses. Queries, which retrieve the data based on specific criteria and this is an important element of SQL. Statements, which may have a persistent effect on schemata and data, or may control transactions, program flow, connections, sessions, SQL statements also include the semicolon statement terminator. Though not required on every platform, it is defined as a part of the SQL grammar. Insignificant whitespace is ignored in SQL statements and queries, making it easier to format SQL code for readability. Other operators have at times been suggested or implemented, such as the skyline operator, SQL has the case/when/then/else/end expression, which was introduced in SQL-92. In its most general form, which is called a case in the SQL standard, it works like else if in other programming languages. If the source does not specify an ELSE expression, SQL defaults to ELSE NULL, an abbreviated syntax—called simple case in the SQL standard—mirrors switch statements, This syntax uses implicit equality comparisons, with the usual caveats for comparing with NULL. For the Oracle-SQL dialect, the latter can be shortened to an equivalent DECODE construct, The last value is the default, if none is specified, however, unlike the standards simple case, Oracles DECODE considers two NULLs equal with each other
20.
Percentage
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In mathematics, a percentage is a number or ratio expressed as a fraction of 100. It is often denoted using the percent sign, %, or the abbreviations pct. pct, a percentage is a dimensionless number. For example, 45% is equal to 45⁄100,45,100, percentages are often used to express a proportionate part of a total. If 50% of the number of students in the class are male. If there are 1000 students, then 500 of them are male, an increase of $0.15 on a price of $2.50 is an increase by a fraction of 0. 15/2.50 =0.06. Expressed as a percentage, this is a 6% increase, while many percentage values are between 0 and 100, there is no mathematical restriction and percentages may take on other values. For example, it is common to refer to 111% or −35%, especially for percent changes, in Ancient Rome, long before the existence of the decimal system, computations were often made in fractions which were multiples of 1⁄100. For example, Augustus levied a tax of 1⁄100 on goods sold at auction known as centesima rerum venalium, computation with these fractions was equivalent to computing percentages. Many of these texts applied these methods to profit and loss, interest rates, by the 17th century it was standard to quote interest rates in hundredths. The term per cent is derived from the Latin per centum, the sign for per cent evolved by gradual contraction of the Italian term per cento, meaning for a hundred. The per was often abbreviated as p. and eventually disappeared entirely, the cento was contracted to two circles separated by a horizontal line, from which the modern % symbol is derived. The percent value is computed by multiplying the value of the ratio by 100. For example, to find 50 apples as a percentage of 1250 apples, first compute the ratio 50⁄1250 =0.04, and then multiply by 100 to obtain 4%. The percent value can also be found by multiplying first, so in this example the 50 would be multiplied by 100 to give 5,000, and this result would be divided by 1250 to give 4%. To calculate a percentage of a percentage, convert both percentages to fractions of 100, or to decimals, and multiply them, for example, 50% of 40% is, 50⁄100 × 40⁄100 =0.50 ×0.40 =0.20 = 20⁄100 = 20%. It is not correct to divide by 100 and use the percent sign at the same time, whenever we talk about a percentage, it is important to specify what it is relative to, i. e. what is the total that corresponds to 100%. The following problem illustrates this point, in a certain college 60% of all students are female, and 10% of all students are computer science majors. If 5% of female students are computer science majors, what percentage of computer science majors are female and we are asked to compute the ratio of female computer science majors to all computer science majors
21.
Microsoft Access
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Microsoft Access is a database management system from Microsoft that combines the relational Microsoft Jet Database Engine with a graphical user interface and software-development tools. It is a member of the Microsoft Office suite of applications, included in the Professional, Microsoft Access stores data in its own format based on the Access Jet Database Engine. It can also import or link directly to data stored in other applications, software developers, data architects and power users can use Microsoft Access to develop application software. Visual objects used in forms and reports expose their methods and properties in the VBA programming environment, Microsofts first attempt to sell a relational database product was during the mid 1980s, when Microsoft obtained the license to sell R, Base. In the late 1980s Microsoft developed its own solution codenamed Omega and it was confirmed in 1988 that a database product for Windows and OS/2 was in development. Omega was also expected to provide a front end to the Microsoft SQL Server, the application was very resource-hungry, and there were reports that it was working slowly on the 386 processors that were available at the time. It was scheduled to be released in the 1st quarter of 1990, parts of the project were later used for other Microsoft projects, Cirrus and Thunder. After Accesss premiere, the Omega project was demonstrated in 1992 to several journalists, after the Omega project was scrapped, some of its developers were assigned to the Cirrus project. Its goal was to create a competitor for applications like Paradox or dBase that would work on Windows, after Microsoft acquired FoxPro, there were rumors that the Microsoft project might get replaced with it, but the company decided to develop them in parallel. It was assumed that the project would use of Extensible Storage Engine but, in the end. The project used some of the code from both the Omega project and a version of Visual Basic. In July 1992, betas of Cirrus shipped to developers and the name Access became the name of the product. The product shipped on seven 1.44 MB diskettes, the manual shows a 1994 copyright date. Originally, the software worked well with relatively small databases but testing showed that some circumstances caused data corruption. With Office 95, Microsoft Access 7.0 became part of the Microsoft Office Professional Suite, joining Microsoft Excel, Word, since then, Microsoft has released new versions of Microsoft Access with each release of Microsoft Office. This includes Access 97, Access 2000, Access 2002, Access 2003, Access 2007, Access 2010, and Access 2013. Versions 3.0 and 3.5 of Microsoft Jet database engine had an issue which made these versions of Access unusable on a computer with more than 1 GB of memory. While Microsoft fixed this problem for Jet 3. 5/Access 97 post-release, the native Access database format has also evolved over the years
22.
Regular expression
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A regular expression, regex or regexp is, in theoretical computer science and formal language theory, a sequence of characters that define a search pattern. Usually this pattern is used by string searching algorithms for find or find. The concept arose in the 1950s when the American mathematician Stephen Cole Kleene formalized the description of a regular language, the concept came into common use with Unix text-processing utilities. Today, different syntaxes for writing regular expressions exist, one being the POSIX standard and another, widely used, being the Perl syntax. Regular expressions are used in engines, search and replace dialogs of word processors and text editors, in text processing utilities such as sed and AWK. Many programming languages provide regex capabilities, built-in, or via libraries, the phrase regular expressions is often used to mean the specific, standard textual syntax for representing patterns that matching text need to conform to. Each character in an expression is understood to be a metacharacter. For example, in the regex a, a is a literal character which matches just a and. is a meta character which matches every character except a newline. Therefore, this regex would match for example a or ax or a0, together, metacharacters and literal characters can be used to identify textual material of a given pattern, or process a number of instances of it. Pattern-matches can vary from a precise equality to a general similarity. Is a very general pattern, is general and a is a precise pattern. Wildcards could also achieve this, but are limited in what they can pattern. The usual context of wildcard characters is in globbing similar names in a list of files, for example, the regex ^+|+$ matches excess whitespace at the beginning or end of a line. An advanced regex used to match any numeral is ^. $, see the Examples section for more examples. A regex processor translates a regular expression in the above syntax into a representation which can be executed and matched against a string representing the text being searched in. The picture shows the NFA scheme N obtained from the regular expression s*, where s denotes a simpler regular expression in turn, Regular expressions originated in 1956, when mathematician Stephen Cole Kleene described regular languages using his mathematical notation called regular sets. These arose in theoretical science, in the subfields of automata theory. Other early implementations of pattern matching include the SNOBOL language, which did not use regular expressions, Regular expressions entered popular use from 1968 in two uses, pattern matching in a text editor and lexical analysis in a compiler
23.
General Services Administration
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The General Services Administration is an independent agency of the United States government, established in 1949 to help manage and support the basic functioning of federal agencies. GSA employs about 12,000 federal workers and has an operating budget of roughly $26.3 billion. GSA oversees $66 billion of procurement annually and it contributes to the management of about $500 billion in U. S. federal property, divided chiefly among 8,300 owned and leased buildings and a 210,000 vehicle motor pool. GSAs business lines include the Federal Acquisition Service, the Public Buildings Service, the GSA is member of the Procurement G6, an informal group leading the use of framework agreements and e-procurement instruments in public procurement. In 1947 President Harry Truman asked former President Herbert Hoover to lead what became known as the Hoover Commission to make recommendations to reorganize the operations of the federal government, one of the recommendations of the commission was the establishment of an Office of the General Services. This proposed office would combine the responsibilities of the following organizations, General Jess Larson, Administrator of the War Assets Administration, was named GSAs first Administrator. The first job awaiting Administrator Larson and the newly formed GSA was a renovation of the White House. The structure had fallen into such a state of disrepair by 1949 that one inspector of the time said the structure was standing “purely from habit. Everything, except the four walls without a roof, was stripped down. GSA completed the renovation in 1952, GSA headquarters, located at Eighteenth and F Streets, NW, was U. S. General Services Administration Building listed on the National Register of Historic Places in 1986 as Interior Department Offices, in 1960, GSA created the Federal Telecommunications System, a government-wide intercity telephone system. In 1970, the Nixon administration created the Consumer Product Information Coordinating Center, the Federal Buildings Fund was initiated in 1974, which allowed the GSA to issue rent bills to federal agencies. In 1972, the GSA established the Automated Data and Telecommunications Service, in 1973, the GSA created the Office of Federal Management Policy. GSA’s Office of Acquisition Policy centralized procurement policy in 1978, in 1984, GSA introduced the federal government to the use of charge cards, known as the GMA SmartPay system. The National Archives and Records Administration was spun off into an independent agency in 1985, the same year, the GSA began to provide governmentwide policy oversight and guidance for federal real property management as a result of an Executive Order signed by President Ronald Reagan. In 2003, the Federal Protective Service was moved to the Department of Homeland Security, in 2005, GSA reorganized to merge the Federal Supply Service and Federal Technology Service business lines into the Federal Acquisition Service. On April 3,2009, President Barack Obama nominated Martha N. Johnson to serve as the GSA Administrator, after a 9-month delay, the United States Senate confirmed her nomination on February 4,2010. In July 1991, GSA contractors began the excavation of what is now the Ted Weiss Federal Building in New York City, when initial excavation disturbed burials, destroying skeletons and artifacts, GSA sent archaeologists to excavate—but hid their findings from the public
24.
MIL-STD-188
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MIL-STD-188 is a series of U. S. military standards relating to telecommunications. S. Department of Defense looked to develop a series of standards that would alleviate the problem, … systems developed for use by U. S. forces are considered to be for joint use. The MIL-STD-188 standards were created to address telecommunication design parameters based on proven technologies, to ensure interoperability, DISA made these standards mandatory for use in all new DoD systems and equipment, or major upgrades. The mandatory use of standards will aid significantly in achieving standardization and result in improvements in availability, maintainability, reliability. This, in turn, will enhance lifecycle configuration management and logistic support with subsequent reductions in life cycle costs, in line with a decision by the Joint Chiefs of Staff, these standards are published in the MIL-STD-188 series of documents. The MIL-STD-188 series standards are encompassed by the DoD’s Joint Technical Architecture, for any DoD Agency to get a waiver to receive an item that deviates from the standards they also must apply to the JSC. Currently the DoD is placing its emphasis on the development of standards for tactical. Note, The following list of documents are those that are presently active, documents with three digit numbers followed by a letter of the alphabet indicate that they are revisions of an older version of that document. According to the DoD the MIL-STD-188-100 series contains technical standards and design objectives which are common to both the long haul and tactical communications systems, database with most MILSTD and DEFSTAN publications
This article incorporates public domain material from the General Services Administration document "Federal Standard 1037C" (in support of MIL-STD-188).
This article incorporates