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VAX MACRO
VAX MACRO is the computer assembly language implementing the VAX instruction set architecture for the OpenVMS operating system, originally released by Digital Equipment Corporation (DEC) in 1977. The syntax, directives, macro language, and lexical substitution operators of VAX MACRO formerly appeared in MACRO-11, the assembler for the PDP-11 series of computers. The ''MACRO-32'' assembler supported the VAX processors developed and manufactured by DEC. It ran under the VMS operating system and produced object files suitable for the VMS linker. The MACRO-32 assembler and linker were bundled with the operating system. To port VMS to the DEC Alpha, VAX MACRO was implemented for the Alpha architecture. Since the Alpha used a different instruction set than the VAX, MACRO-32 was implemented as a compiler, compiling VAX assembly language into Alpha instructions. The Alpha AXP chips have their own native instruction set architecture, the OpenVMS assembler for Alpha assembly code is na ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-structured Programming
Non-structured programming is the historically earliest programming paradigm capable of creating Turing-complete algorithms. It is often contrasted with the structured programming paradigm, in particular with the use of unstructured control flow using goto statements or equivalent. The distinction was particularly stressed by the publication of the influential "Go To Statement Considered Harmful" open letter in 1968 by Dutch computer scientist Edsger W. Dijkstra, who coined the term "structured programming". Unstructured programming has been heavily criticized for producing hardly-readable ("spaghetti") code. There are both high- and low-level programming languages that use non-structured programming. Some languages commonly cited as being non-structured include JOSS, FOCAL, TELCOMP, assembly languages, MS-DOS batch files, and early versions of BASIC, Fortran, COBOL, and MUMPS. Features and typical concepts Basic concepts A program in a non-structured language uses unst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operating System
An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also include accounting software for cost allocation of processor time, mass storage, printing, and other resources. For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware, although the application code is usually executed directly by the hardware and frequently makes system calls to an OS function or is interrupted by it. Operating systems are found on many devices that contain a computer from cellular phones and video game consoles to web servers and supercomputers. The dominant general-purpose personal computer operating system is Microsoft Windows with a market share of around 74.99%. macOS by Apple Inc. is in second place (14.84%), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Assembly Languages
In computer programming, assembly language (or assembler language, or symbolic machine code), often referred to simply as Assembly and commonly abbreviated as ASM or asm, is any low-level programming language with a very strong correspondence between the instructions in the language and the architecture's machine code instructions. Assembly language usually has one statement per machine instruction (1:1), but constants, comments, assembler directives, symbolic labels of, e.g., memory locations, registers, and macros are generally also supported. The first assembly code in which a language is used to represent machine code instructions is found in Kathleen and Andrew Donald Booth's 1947 work, ''Coding for A.R.C.''. Assembly code is converted into executable machine code by a utility program referred to as an '' assembler''. The term "assembler" is generally attributed to Wilkes, Wheeler and Gill in their 1951 book ''The Preparation of Programs for an Electronic Dig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X86-64
x86-64 (also known as x64, x86_64, AMD64, and Intel 64) is a 64-bit version of the x86 instruction set, first released in 1999. It introduced two new modes of operation, 64-bit mode and compatibility mode, along with a new 4-level paging mode. With 64-bit mode and the new paging mode, it supports vastly larger amounts of virtual memory and physical memory than was possible on its 32-bit predecessors, allowing programs to store larger amounts of data in memory. x86-64 also expands general-purpose registers to 64-bit, and expands the number of them from 8 (some of which had limited or fixed functionality, e.g. for stack management) to 16 (fully general), and provides numerous other enhancements. Floating-point arithmetic is supported via mandatory SSE2-like instructions, and x87/MMX style registers are generally not used (but still available even in 64-bit mode); instead, a set of 16 vector registers, 128 bits each, is used. (Each register can store one or two double-p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Itanium
Itanium ( ) is a discontinued family of 64-bit Intel microprocessors that implement the Intel Itanium architecture (formerly called IA-64). Launched in June 2001, Intel marketed the processors for enterprise servers and high-performance computing systems. The Itanium architecture originated at Hewlett-Packard (HP), and was later jointly developed by HP and Intel. Itanium-based systems were produced by HP/Hewlett Packard Enterprise (HPE) (the HPE Integrity Servers line) and several other manufacturers. In 2008, Itanium was the fourth-most deployed microprocessor architecture for enterprise-class systems, behind x86-64, Power ISA, and SPARC. In February 2017, Intel released the final generation, Kittson, to test customers, and in May began shipping in volume. It was used exclusively in mission-critical servers from Hewlett Packard Enterprise. In 2019, Intel announced that new orders for Itanium would be accepted until January 30, 2020, and shipments would cease by July 29, 20 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compiler
In computing, a compiler is a computer program that translates computer code written in one programming language (the ''source'' language) into another language (the ''target'' language). The name "compiler" is primarily used for programs that translate source code from a high-level programming language to a low-level programming language (e.g. assembly language, object code, or machine code) to create an executable program. Compilers: Principles, Techniques, and Tools by Alfred V. Aho, Ravi Sethi, Jeffrey D. Ullman - Second Edition, 2007 There are many different types of compilers which produce output in different useful forms. A ''cross-compiler'' produces code for a different CPU or operating system than the one on which the cross-compiler itself runs. A ''bootstrap compiler'' is often a temporary compiler, used for compiling a more permanent or better optimised compiler for a language. Related software include, a program that translates from a low-level language t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DEC Alpha
Alpha (original name Alpha AXP) is a 64-bit reduced instruction set computer (RISC) instruction set architecture (ISA) developed by Digital Equipment Corporation (DEC). Alpha was designed to replace 32-bit VAX complex instruction set computers (CISC) and to be a highly competitive RISC processor for Unix workstations and similar markets. Alpha is implemented in a series of microprocessors originally developed and fabricated by DEC. These microprocessors are most prominently used in a variety of DEC workstations and servers, which eventually formed the basis for almost all of their mid-to-upper-scale lineup. Several third-party vendors also produced Alpha systems, including PC form factor motherboards. Operating systems that support Alpha included OpenVMS (formerly named OpenVMS AXP), Tru64 UNIX (formerly named DEC OSF/1 AXP and Digital UNIX), Windows NT (discontinued after NT 4.0; and prerelease Windows 2000 RC2), Linux ( Debian, SUSE, Gentoo and Red Hat), BSD UNIX ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linker (computing)
In computing, a linker or link editor is a computer system program that takes one or more object files (generated by a compiler or an assembler) and combines them into a single executable file, library file, or another "object" file. A simpler version that writes its output directly to memory is called the ''loader'', though loading is typically considered a separate process. Overview Computer programs typically are composed of several parts or modules; these parts/modules do not need to be contained within a single object file, and in such cases refer to each other by means of symbols as addresses into other modules, which are mapped into memory addresses when linked for execution. While the process of linking is meant to ultimately combine these independent parts, there are many good reasons to develop those separately at the source-level. Among these reasons are the ease of organizing several smaller pieces over a monolithic whole and the ability to better define ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PDP-11
The PDP-11 is a series of 16-bit minicomputers sold by Digital Equipment Corporation (DEC) from 1970 into the 1990s, one of a set of products in the Programmed Data Processor (PDP) series. In total, around 600,000 PDP-11s of all models were sold, making it one of DEC's most successful product lines. The PDP-11 is considered by some experts to be the most popular minicomputer. The PDP-11 included a number of innovative features in its instruction set and additional general-purpose registers that made it much easier to program than earlier models in the PDP series. Further, the innovative Unibus system allowed external devices to be easily interfaced to the system using direct memory access, opening the system to a wide variety of peripherals. The PDP-11 replaced the PDP-8 in many real-time computing applications, although both product lines lived in parallel for more than 10 years. The ease of programming of the PDP-11 made it very popular for general-purpose computing uses a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Imperative Programming
In computer science, imperative programming is a programming paradigm of software that uses statements that change a program's state. In much the same way that the imperative mood in natural languages expresses commands, an imperative program consists of commands for the computer to perform. Imperative programming focuses on describing ''how'' a program operates step by step, rather than on high-level descriptions of its expected results. The term is often used in contrast to declarative programming, which focuses on ''what'' the program should accomplish without specifying all the details of ''how'' the program should achieve the result. Imperative and procedural programming Procedural programming is a type of imperative programming in which the program is built from one or more procedures (also termed subroutines or functions). The terms are often used as synonyms, but the use of procedures has a dramatic effect on how imperative programs appear and how they are construct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Instruction Set Architecture
In computer science, an instruction set architecture (ISA), also called computer architecture, is an abstract model of a computer. A device that executes instructions described by that ISA, such as a central processing unit (CPU), is called an ''implementation''. In general, an ISA defines the supported instructions, data types, registers, the hardware support for managing main memory, fundamental features (such as the memory consistency, addressing modes, virtual memory), and the input/output model of a family of implementations of the ISA. An ISA specifies the behavior of machine code running on implementations of that ISA in a fashion that does not depend on the characteristics of that implementation, providing binary compatibility between implementations. This enables multiple implementations of an ISA that differ in characteristics such as performance, physical size, and monetary cost (among other things), but that are capable of running the same machine code, s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MACRO-11
MACRO-11 is an assembly language with macro facilities, designed for PDP-11 minicomputer family from Digital Equipment Corporation (DEC). It is the successor to Program Assembler Loader ( PAL-11R), an earlier version of the PDP-11 assembly language without macro facilities. MACRO-11 was supported on all DEC PDP-11 operating systems. PDP-11 Unix systems also include an assembler (named '' as''), structurally similar to MACRO-11, but with different syntax and fewer features. The MACRO-11 assembler (and programs created by it) could also run under the RSX-11 compatibility mode of OpenVMS on VAX. Programming example A complete " Hello, world!" program in PDP-11 macro assembler, to run under RT-11 RT-11 (Real-time 11) is a discontinued small, low-end, single-user real-time operating system for the full line of Digital Equipment Corporation PDP-11 16-bit computers. RT-11 was first implemented in 1970. It was widely used for real-time computin ...: .TITLE HELLO WORLD ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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