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CAP Computer
The Cambridge CAP computer was the first successful experimental computer that demonstrated the use of security capabilities, both in hardware and software.Levy, p.96 It was developed at the University of Cambridge Computer Laboratory in the 1970s. Unlike most research machines of the time, it was also a useful service machine. The sign currently on the front of the machine reads: The CAP project on memory protection ran from 1970 to 1977. It was based on capabilities implemented in hardware, under M. Wilkes and R. Needham with D. Wheeler responsible for the implementation. R. Needham was awarded a BCS Technical Award in 1978 for the ''CAP (Capability Protection) Project''. Design The CAP was designed such that any access to a memory segment or hardware required that the current process held the necessary capabilities. The 32-bit processor featured microprogramming control, two 256-entry caches, a 32-entry write buffer and the capability unit itself, which had 64 regi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CAP Computer (general View) - Cambridge University
A cap is a flat headgear, usually with a visor. Caps have crowns that fit very close to the head. They made their first appearance as early as 3200 BC. Caps typically have a visor, or no brim at all. They are popular in casual and informal settings, and are seen in sports and fashion. They are typically designed for warmth, and often incorporate a visor to block sunlight from the eyes. They come in many shapes, sizes, and are of different brands. Baseball caps are one of the most common types of cap. Types * Ascot cap * Ayam * Baggy green * Balmoral * Beanie (North America) * Bearskin * Beret * Biretta * Busby * Canterbury cap * Cap and bells * Cap of maintenance * Casquette * Caubeen * Caul * Coif * Combination cap (also known as a service cap) * Coppola * Cricket cap * Deerstalker * Do-rag * Dutch cap * Dixie cup, an enlisted sailor's cap, also worn by first-year midshipmen at Annapolis * Fez * Flat cap (also known as a Kerry cap in Ireland (slang of Paddy cap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BCPL
BCPL ("Basic Combined Programming Language") is a procedural, imperative, and structured programming language. Originally intended for writing compilers for other languages, BCPL is no longer in common use. However, its influence is still felt because a stripped down and syntactically changed version of BCPL, called B, was the language on which the C programming language was based. BCPL introduced several features of many modern programming languages, including using curly braces to delimit code blocks. BCPL was first implemented by Martin Richards of the University of Cambridge in 1967. Design BCPL was designed so that small and simple compilers could be written for it; reputedly some compilers could be run in 16 kilobytes. Further, the original compiler, itself written in BCPL, was easily portable. BCPL was thus a popular choice for bootstrapping a system. A major reason for the compiler's portability lay in its structure. It was split into two parts: the front end p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capability Systems
A capability is the ability to execute a specified course of action or to achieve certain outcomes. As it applies to human capital, capability represents performing or achieving certain actions/outcomes in terms of the intersection of capacity and ability. Capability may also refer to: Engineering * Capability (systems engineering), the ability to execute a specified course of action * Capability management, integrative management function in the defense sector Computing * Capability-based addressing, scheme used by some computers to control access to memory * Capability-based security, concept in the design of secure computing systems Economics * Capability Maturity Model, a development model * Capability Maturity Model Integration, a process improvement training and appraisal program * Dynamic capabilities, theory in organizational sciences * Capability management in business, capacity, materials, and expertise an organization needs in order to perform core functions * Ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computers Designed In The United Kingdom
A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations (computation) automatically. Modern digital electronic computers can perform generic sets of operations known as programs. These programs enable computers to perform a wide range of tasks. A computer system is a nominally complete computer that includes the hardware, operating system (main software), and peripheral equipment needed and used for full operation. This term may also refer to a group of computers that are linked and function together, such as a computer network or computer cluster. A broad range of industrial and consumer products use computers as control systems. Simple special-purpose devices like microwave ovens and remote controls are included, as are factory devices like industrial robots and computer-aided design, as well as general-purpose devices like personal computers and mobile devices like smartphones. Computers power the Internet, which links bil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flex Machine
The Flex Computer System was developed by Michael Foster and Ian Currie of Royal Signals and Radar Establishment (RSRE) in Malvern, England, during the late 1970s and 1980s. It used a tagged storage scheme to implement a capability architecture, and was designed for the safe and efficient implementation of strongly typed procedures. The hardware was custom and microprogrammable, with an operating system, (modular) compiler, editor, garbage collector and filing system all written in ALGOL 68RS. There were (at least) two incarnations of Flex, implemented using hardware with writable microcode. The first was supplied by Logica to an RSRE design, and the second used an ICL PERQ. The microcode alone was responsible for storage allocation, deallocation and garbage collection. This immediately precluded a whole class of errors arising from the misuse (deliberate or accidental) of pointers. A notable feature of Flex was the tagged, write-once filestore. This allowed arbitrary code ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM System/38
The System/38 is a discontinued minicomputer and midrange computer manufactured and sold by IBM. The system was announced in 1978. The System/38 has 48-bit addressing, which was unique for the time, and a novel integrated database system. It was oriented toward a multi-user system environment. At the time, the typical system handled from a dozen to several dozen terminals. Although the System/38 failed to displace the systems it was intended to replace, its architecture served as the basis of the much more successful IBM AS/400. History The System/38 was introduced on October 24, 1978 and delivered in 1980. Developed under the code-name "Pacific", it was made commercially available in August 1979. The system offered a number of innovative features, and was designed by a number of engineers including Frank Soltis and Glenn Henry. The architecture shared many similarities with the design of the failed IBM Future Systems project, including the single-level store, the use of micro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SPITBOL
SPITBOL (Speedy Implementation of SNOBOL) is a compiled implementation of the SNOBOL4 programming language. Originally targeted for the IBM System/360 and System/370 family of computers, it has now been ported to most major microprocessors including the SPARC. It was created by Robert Dewar and Ken Belcher, who were then at the Illinois Institute of Technology. Prior to the development of SPITBOL, SNOBOL4 was thought to be slow, memory-intensive, and impossible to compile due to its dynamic nature. While delayed binding prevents everything from being determined at compile time, SPITBOL adopts various strategies for making decisions as early as possible. Recent versions of the SPITBOL compiler are available. Since 2001 the source code for the original SPITBOL 360 compiler has been made available under the GNU General Public License. MACRO SPITBOL is an implementation of SPITBOL written in the 1970s by Robert Dewar and Anthony P. McCann. MACRO SPITBOL is coded in MINIMAL, an assemb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Process (computing)
In computing, a process is the instance of a computer program that is being executed by one or many threads. There are many different process models, some of which are light weight, but almost all processes (even entire virtual machines) are rooted in an operating system (OS) process which comprises the program code, assigned system resources, physical and logical access permissions, and data structures to initiate, control and coordinate execution activity. Depending on the OS, a process may be made up of multiple threads of execution that execute instructions concurrently. While a computer program is a passive collection of instructions typically stored in a file on disk, a process is the execution of those instructions after being loaded from the disk into memory. Several processes may be associated with the same program; for example, opening up several instances of the same program often results in more than one process being executed. Multitasking is a method to allow ... [...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 to a h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
File System
In computing, file system or filesystem (often abbreviated to fs) is a method and data structure that the operating system uses to control how data is stored and retrieved. Without a file system, data placed in a storage medium would be one large body of data with no way to tell where one piece of data stopped and the next began, or where any piece of data was located when it was time to retrieve it. By separating the data into pieces and giving each piece a name, the data are easily isolated and identified. Taking its name from the way a paper-based data management system is named, each group of data is called a "file". The structure and logic rules used to manage the groups of data and their names is called a "file system." There are many kinds of file systems, each with unique structure and logic, properties of speed, flexibility, security, size and more. Some file systems have been designed to be used for specific applications. For example, the ISO 9660 file system is designe ... [...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%), and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ALGOL 68C
ALGOL 68C is an imperative computer programming language, a dialect of ALGOL 68, that was developed by Stephen R. Bourne and Michael Guy to program the Cambridge Algebra System (CAMAL). The initial compiler was written in the Princeton Syntax Compiler (PSYCO, by Edgar T. Irons) that was implemented by J. H. Mathewman at Cambridge. ALGOL 68C was later used for the CHAOS OS for the capability-based security CAP computer at University of Cambridge in 1971. Other early contributors were Andrew D. Birrell and Ian Walker. Subsequent work was done on the compiler after Bourne left Cambridge University in 1975. Garbage collection was added, and the code base is still running on an emulated OS/MVT using Hercules. The ALGOL 68C compiler generated output in ''ZCODE'', a register-based intermediate language, which could then be either interpreted or compiled to a native executable. This ability to interpret or compile ZCODE encouraged the porting of ALGOL 68C to many different computi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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