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CMS EXEC
CMS EXEC, or EXEC, is an interpreted, command procedure control, computer scripting language used by the CMS EXEC Processor supplied with the IBM Virtual Machine/Conversational Monitor System ( VM/CMS) operating system. EXEC was written in 1966 by Stuart Madnick at MIT on the model of CTSS RUNCOM. He originally called this processor COMMAND, and it was later renamed EXEC. CMS EXEC has been superseded by EXEC 2 and REXX. All three — CMS EXEC, EXEC 2 and REXX — continue to be supported by the IBM CMS product. The EXEC language *EXEC processes lines up to 130 characters long when entered from a terminal, or 72 characters when read from a file. *A ''label'' consisting of a dash followed by up to seven alphanumeric characters can prefix a CMS command or an EXEC control statement. *The interpreter parses commands into blank-delimited '' tokens'' of up to eight characters each. *Variables consist of an ampersand followed by up to seven alphanumeric characters. Variables ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scripting Language
A scripting language or script language is a programming language that is used to manipulate, customize, and automate the facilities of an existing system. Scripting languages are usually interpreted at runtime rather than compiled. A scripting language's primitives are usually elementary tasks or API calls, and the scripting language allows them to be combined into more programs. Environments that can be automated through scripting include application software, text editors, web pages, operating system shells, embedded systems, and computer games. A scripting language can be viewed as a domain-specific language for a particular environment; in the case of scripting an application, it is also known as an extension language. Scripting languages are also sometimes referred to as very high-level programming languages, as they sometimes operate at a high level of abstraction, or as control languages, particularly for job control languages on mainframes. The term ''scriptin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alphanumeric
Alphanumericals or alphanumeric characters are a combination of alphabetical and numerical characters. More specifically, they are the collection of Latin letters and Arabic digits. An alphanumeric code is an identifier made of alphanumeric characters. Merriam-Webster suggests that the term "alphanumeric" may often additionally refer to other symbols, such as punctuation and mathematical symbols. In the POSIX/C locale, there are either 36 (A–Z and 0–9, case insensitive) or 62 (A–Z, a–z and 0–9, case-sensitive) alphanumeric characters. Subsets of alphanumeric used in human interfaces When a string of mixed alphabets and numerals is presented for human interpretation, ambiguities arise. The most obvious is the similarity of the letters I, O and Q to the numbers 1 and 0. Therefore, depending on the application, various subsets of the alphanumeric were adopted to avoid misinterpretation by humans. In passenger aircraft, aircraft seat maps and seats were designated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Terminal
A computer terminal is an electronic or electromechanical hardware device that can be used for entering data into, and transcribing data from, a computer or a computing system. The teletype was an example of an early-day hard-copy terminal and predated the use of a computer screen by decades. Early terminals were inexpensive devices but very slow compared to punched cards or paper tape for input, yet as the technology improved and video displays were introduced, terminals pushed these older forms of interaction from the industry. A related development was time-sharing systems, which evolved in parallel and made up for any inefficiencies in the user's typing ability with the ability to support multiple users on the same machine, each at their own terminal or terminals. The function of a terminal is typically confined to transcription and input of data; a device with significant local, programmable data-processing capability may be called a "smart terminal" or fat client. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equals Sign
The equals sign ( British English, Unicode) or equal sign (American English), also known as the equality sign, is the mathematical symbol , which is used to indicate equality in some well-defined sense. In an equation, it is placed between two expressions that have the same value, or for which one studies the conditions under which they have the same value. In Unicode and ASCII, it has the code point U+003D. It was invented in 1557 by Robert Recorde. History The etymology of the word "equal" is from the Latin word "''æqualis",'' as meaning "uniform", "identical", or "equal", from ''aequus'' ("level", "even", or "just"). The symbol, now universally accepted in mathematics for equality, was first recorded by Welsh mathematician Robert Recorde in '' The Whetstone of Witte'' (1557). The original form of the symbol was much wider than the present form. In his book Recorde explains his design of the "Gemowe lines" (meaning ''twin'' lines, from the Latin '' gemellus'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asterisk
The asterisk ( ), from Late Latin , from Ancient Greek , ''asteriskos'', "little star", is a typographical symbol. It is so called because it resembles a conventional image of a heraldic star. Computer scientists and mathematicians often vocalize it as star (as, for example, in ''the A* search algorithm'' or '' C*-algebra''). In English, an asterisk is usually five- or six-pointed in sans-serif typefaces, six-pointed in serif typefaces, and six- or eight-pointed when handwritten. Its most common use is to call out a footnote. It is also often used to censor offensive words. In computer science, the asterisk is commonly used as a wildcard character, or to denote pointers, repetition, or multiplication. History The asterisk has already been used as a symbol in ice age cave paintings. There is also a two thousand-year-old character used by Aristarchus of Samothrace called the , , which he used when proofreading Homeric poetry to mark lines that were duplicated. Origen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ampersand
The ampersand, also known as the and sign, is the logogram , representing the conjunction "and". It originated as a ligature of the letters ''et''—Latin for "and". Etymology Traditionally in English, when spelling aloud, any letter that could also be used as a word in itself ("A", "I", and, " O") was prefixed with the Latin expression ('by itself'), as in "per se A". It was also common practice to add the sign at the end of the alphabet as if it were the 27th letter, pronounced as the Latin ''et'' or later in English as ''and''. As a result, the recitation of the alphabet would end in "X, Y, Z, ''and per se and''". This last phrase was routinely slurred to "ampersand" and the term had entered common English usage by 1837. It has been falsely claimed that André-Marie Ampère used the symbol in his widely read publications and that people began calling the new shape "Ampère's and". History The ampersand can be traced back to the 1st century A.D. and the old Roman ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Token (parser)
In computer science, lexical analysis, lexing or tokenization is the process of converting a sequence of characters (such as in a computer program or web page) into a sequence of ''lexical tokens'' ( strings with an assigned and thus identified meaning). A program that performs lexical analysis may be termed a ''lexer'', ''tokenizer'', or ''scanner'', although ''scanner'' is also a term for the first stage of a lexer. A lexer is generally combined with a parser, which together analyze the syntax of programming languages, web pages, and so forth. Applications A lexer forms the first phase of a compiler frontend in modern processing. Analysis generally occurs in one pass. In older languages such as ALGOL, the initial stage was instead line reconstruction, which performed unstropping and removed whitespace and comments (and had scannerless parsers, with no separate lexer). These steps are now done as part of the lexer. Lexers and parsers are most often used for compilers, b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyphen
The hyphen is a punctuation mark used to join words and to separate syllables of a single word. The use of hyphens is called hyphenation. ''Son-in-law'' is an example of a hyphenated word. The hyphen is sometimes confused with dashes ( figure dash , en dash , em dash , horizontal bar ), which are longer and have different uses, or with the minus sign , which is also longer and more vertically centred in some typefaces. Although hyphens are not to be confused with en dashes, there are some overlaps in usage (in which either a hyphen or an en dash may be acceptable, depending on user preference, as discussed below). In addition, the hyphen often substitutes for the en dash elsewhere in informal writing. As an orthographic concept, the hyphen is a single entity. In terms of character encoding and display, it is represented by any of several characters and glyphs, including the Unicode hyphen (shown at the top of the infobox on this page), the hyphen-minus, the soft ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virtual Machine
In computing, a virtual machine (VM) is the virtualization/ emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized hardware, software, or a combination. Virtual machines differ and are organized by their function, shown here: * ''System virtual machines'' (also termed full virtualization VMs) provide a substitute for a real machine. They provide functionality needed to execute entire operating systems. A hypervisor uses native execution to share and manage hardware, allowing for multiple environments which are isolated from one another, yet exist on the same physical machine. Modern hypervisors use hardware-assisted virtualization, virtualization-specific hardware, primarily from the host CPUs. * Process virtual machines are designed to execute computer programs in a platform-independent environment. Some virtual machine emulators, such as QEMU and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
REXX
Rexx (Restructured Extended Executor) is a programming language that can be interpreted or compiled. It was developed at IBM by Mike Cowlishaw. It is a structured, high-level programming language designed for ease of learning and reading. Proprietary and open source Rexx interpreters exist for a wide range of computing platforms; compilers exist for IBM mainframe computers. Rexx is a full language that can be used as a scripting, macro language, and application development language. It is often used for processing data and text and generating reports; these similarities with Perl mean that Rexx works well in Common Gateway Interface (CGI) programming and it is indeed used for this purpose. Rexx is the primary scripting language in some operating systems, e.g. OS/2, MVS, VM, AmigaOS, and is also used as an internal macro language in some other software, such as SPF/PC, KEDIT, THE and the ZOC terminal emulator. Additionally, the Rexx language can be used for scripting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EXEC 2
EXEC 2 is an interpreted, command procedure control, computer scripting language used by the EXEC 2 Processor originally supplied with the CMS component of the IBM Virtual Machine/System Product (VM/SP) operating system. Relation to EXEC EXEC 2 is mostly compatible with CMS EXEC but EXEC 2 scripts must begin with an &TRACE statement. Some EXEC statements and predefined variables do not exist in EXEC 2, although in some cases there are analogs. There are some minor differences in some statements and predefined functions. EXEC 2 has the following enhancements: * There is no 8-byte restriction on token length. * Statements can be up to 255 characters long. * EXEC 2 can issue commands to subcommand environments as well as CMS and CP. * EXEC 2 has additional built-in functions. * EXEC 2 has user-defined functions. * EXEC 2 commands may include subroutines and functions. * EXEC 2 has extra debugging facilities. * CMS programs can manipulate EXEC 2 variables. Some statemts of EXEC a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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