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Nemesis (computing)
Nemesis was an operating system that was designed by the University of Cambridge, the University of Glasgow, the Swedish Institute of Computer Science and Citrix Systems. Nemesis was conceived with multimedia uses in mind. It was designed with a small lightweight kernel, using shared libraries to perform functions that most operating systems perform in the kernel. This reduces the processing that is performed in the kernel on behalf of application processes, transferring the activity to the processes themselves and facilitating accounting for resource usage. The ISAs that Nemesis supports include x86 ( Intel i486, Pentium, Pentium Pro, and Pentium II), Alpha and ARM (StrongARM SA–110). Nemesis also runs on evaluation boards (21064 and 21164). See also * Exokernel Exokernel is an operating system kernel developed by the MIT Parallel and Distributed Operating Systems group, and also a class of similar operating systems. Operating systems generally present hardware re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Cambridge
, mottoeng = Literal: From here, light and sacred draughts. Non literal: From this place, we gain enlightenment and precious knowledge. , established = , other_name = The Chancellor, Masters and Scholars of the University of Cambridge , type = Public research university , endowment = £7.121 billion (including colleges) , budget = £2.308 billion (excluding colleges) , chancellor = The Lord Sainsbury of Turville , vice_chancellor = Anthony Freeling , students = 24,450 (2020) , undergrad = 12,850 (2020) , postgrad = 11,600 (2020) , city = Cambridge , country = England , campus_type = , sporting_affiliations = The Sporting Blue , colours = Cambridge Blue , website = , logo = University of Cambridge logo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Instruction Set
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, so that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Free Software Operating Systems
Free may refer to: Concept * Freedom, having the ability to do something, without having to obey anyone/anything * Freethought, a position that beliefs should be formed only on the basis of logic, reason, and empiricism * Emancipate, to procure political rights, as for a disenfranchised group * Free will, control exercised by rational agents over their actions and decisions * Free of charge, also known as gratis. See Gratis vs libre. Computing * Free (programming), a function that releases dynamically allocated memory for reuse * Free format, a file format which can be used without restrictions * Free software, software usable and distributable with few restrictions and no payment * Freeware, a broader class of software available at no cost Mathematics * Free object ** Free abelian group ** Free algebra ** Free group ** Free module ** Free semigroup * Free variable People * Free (surname) * Free (rapper) (born 1968), or Free Marie, American rapper and media personal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kernel (operating System)
The kernel is a computer program at the core of a computer's operating system and generally has complete control over everything in the system. It is the portion of the operating system code that is always resident in memory and facilitates interactions between hardware and software components. A full kernel controls all hardware resources (e.g. I/O, memory, cryptography) via device drivers, arbitrates conflicts between processes concerning such resources, and optimizes the utilization of common resources e.g. CPU & cache usage, file systems, and network sockets. On most systems, the kernel is one of the first programs loaded on startup (after the bootloader). It handles the rest of startup as well as memory, peripherals, and input/output (I/O) requests from software, translating them into data-processing instructions for the central processing unit. The critical code of the kernel is usually loaded into a separate area of memory, which is protected from access by application ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exokernel
Exokernel is an operating system kernel developed by the MIT Parallel and Distributed Operating Systems group, and also a class of similar operating systems. Operating systems generally present hardware resources to applications through high-level abstractions such as (virtual) file systems. The idea behind exokernels is to force as few abstractions as possible on application developers, enabling them to make as many decisions as possible about hardware abstractions. Exokernels are tiny, since functionality is limited to ensuring protection and multiplexing of resources, which is considerably simpler than conventional microkernels' implementation of message passing and monolithic kernels' implementation of high-level abstractions. Implemented abstractions are called library operating systems; they may request specific memory addresses, disk blocks, etc. The kernel only ensures that the requested resource is free, and the application is allowed to access it. This low-level hardwa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evaluation Boards
A microprocessor development board is a printed circuit board containing a microprocessor and the minimal support logic needed for an electronic engineer or any person that wants to become acquainted with the microprocessor on the board and to learn to program it. It also served users of the microprocessor as a method to prototype applications in products. Unlike a general-purpose system such as a home computer, usually a development board contains little or no hardware dedicated to a user interface. It will have some provision to accept and run a user-supplied program, such as downloading a program through a serial port to flash memory, or some form of programmable memory in a socket in earlier systems. History The reason for the existence of a development board was solely to provide a system for learning to use a new microprocessor, not for entertainment. So everything superfluous was left out to keep costs down. Even an enclosure was not supplied, nor a power supply. This is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
StrongARM
The StrongARM is a family of computer microprocessors developed by Digital Equipment Corporation and manufactured in the late 1990s which implemented the ARM v4 instruction set architecture. It was later acquired by Intel in 1997 from DEC's own Digital Semiconductor division as part of a settlement of a lawsuit between the two companies over plagiarism. Intel then continued to manufacture it before replacing it with the StrongARM-derived ARM-based follow-up architecture called XScale in the early 2000s. History According to Allen Baum, the StrongARM traces its history to attempts to make a low-power version of the DEC Alpha, which DEC's engineers quickly concluded was not possible. They then became interested in designs dedicated to low-power applications which led them to the ARM family. One of the only major users of the ARM for performance-related products at that time was Apple, whose Newton device was based on the ARM platform. DEC approached Apple wondering if they migh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentium II
The Pentium II brand refers to Intel's sixth-generation microarchitecture (" P6") and x86-compatible microprocessors introduced on May 7, 1997. Containing 7.5 million transistors (27.4 million in the case of the mobile Dixon with 256 KB L2 cache), the Pentium II featured an improved version of the first ''P6''-generation core of the Pentium Pro, which contained 5.5 million transistors. However, its L2 cache subsystem was a downgrade when compared to the Pentium Pros. It is a single-core microprocessor. In 1998, Intel stratified the Pentium II family by releasing the Pentium II-based Celeron line of processors for low-end workstations and the Pentium II Xeon line for servers and high-end workstations. The Celeron was characterized by a reduced or omitted (in some cases present but disabled) on-die full-speed L2 cache and a 66 MT/s FSB. The Xeon was characterized by a range of full-speed L2 cache (from 512 KB to 2048 KB), a 100 MT/s FSB, a different physical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentium Pro
The Pentium Pro is a sixth-generation x86 microprocessor developed and manufactured by Intel and introduced on November 1, 1995. It introduced the P6 microarchitecture (sometimes termed i686) and was originally intended to replace the original Pentium in a full range of applications. While the Pentium and Pentium MMX had 3.1 and 4.5 million transistors, respectively, the Pentium Pro contained 5.5 million transistors. Later, it was reduced to a more narrow role as a server and high-end desktop processor and was used in supercomputers like ASCI Red, the first computer to reach the trillion ''floating point operations per second'' (teraFLOPS) performance mark. The Pentium Pro was capable of both dual- and quad-processor configurations. It only came in one form factor, the relatively large rectangular Socket 8. The Pentium Pro was succeeded by the Pentium II Xeon in 1998. Microarchitecture The lead architect of Pentium Pro was Fred Pollack who was specialized in supe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentium (original)
The Pentium (also referred to as P5, its microarchitecture, or i586) is a fifth generation, 32-bit x86 microprocessor that was introduced by Intel on March 22, 1993, as the very first CPU in the Pentium brand. It was instruction set compatible with the 80486 but was a new and very different microarchitecture design from previous iterations. The P5 Pentium was the first superscalar x86 microarchitecture and the world's first superscalar microprocessor to be in mass productionmeaning it generally executes at least 2 instructions per clock mainly because of a design-first dual integer pipeline design previously thought impossible to implement on a CISC microarchitecture. Additional features include a faster floating-point unit, wider data bus, separate code and data caches, and many other techniques and features to enhance performance and support security, encryption, and multiprocessing, for workstations and servers when compared to the next best previous industry standard proce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intel I486
The Intel 486, officially named i486 and also known as 80486, is a microprocessor. It is a higher-performance follow-up to the Intel 386. The i486 was introduced in 1989. It represents the fourth generation of binary compatible CPUs following the 8086 of 1978, the Intel 80286 of 1982, and 1985's i386. It was the first tightly- pipelined x86 design as well as the first x86 chip to include more than one million transistors. It offered a large on-chip cache and an integrated floating-point unit. A typical 50 MHz i486 executes around 40 million instructions per second (MIPS), reaching 50 MIPS peak performance. It is approximately twice as fast as the i386 or i286 per clock cycle. The i486's improved performance is thanks to its five-stage pipeline with all stages bound to a single cycle. The enhanced FPU unit on the chip was significantly faster than the i387 FPU per cycle. The intel 80387 FPU ("i387") was a separate, optional math coprocessor that was installed i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Library (computing)
In computer science, a library is a collection of non-volatile memory, non-volatile resources used by computer programs, often for software development. These may include configuration data, documentation, help data, message templates, Code reuse, pre-written code and subroutines, Class (computer science), classes, Value (computer science), values or Data type, type specifications. In OS/360 and successors, IBM's OS/360 and its successors they are referred to as Data set (IBM mainframe)#Partitioned datasets, partitioned data sets. A library is also a collection of implementations of behavior, written in terms of a language, that has a well-defined interface (computing), interface by which the behavior is invoked. For instance, people who want to write a higher-level program can use a library to make system calls instead of implementing those system calls over and over again. In addition, the behavior is provided for reuse by multiple independent programs. A program invokes the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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