Linux Kernel Documentation Index
Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which includes the kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name "GNU/Linux" to emphasize the importance of GNU software, causing some controversy. Popular Linux distributions include Debian, Fedora Linux, and Ubuntu, the latter of which itself consists of many different distributions and modifications, including Lubuntu and Xubuntu. Commercial distributions include Red Hat Enterprise Linux and SUSE Linux Enterprise. Desktop Linux distributions include a windowing system such as X11 or Wayland, and a desktop environment such as GNOME or KDE Plasma. Distributions intended for servers ma ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Tux (mascot)
Tux is a penguin character and the official brand character of the Linux kernel. Originally created as an entry to a Linux logo competition, Tux is the most commonly used icon for Linux, although different Comparison of Linux distributions, Linux distributions depict Tux in various styles. The character is used in many other Linux programs and as a general symbol of Linux. History Origins The concept of the Linux brand character being a penguin came from Linus Torvalds, the creator of Linux. According to Jeff Ayers, Linus Torvalds had a "fixation for flightless, fat waterfowl" and Torvalds claims to have contracted "penguinitis" after being nibbled by a little penguin on a visit to the National Zoo & Aquarium, Canberra, Australia, joking that the disease "makes you stay awake at nights just thinking about penguins and feeling great love towards them". Linus spoke at the 1994 AUUG Conference (5-9 Sept, Melbourne) as part of a "World Tour" to Belgium, Australia, Singapore and el ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Qualcomm Hexagon
Hexagon is the brand name for a family of digital signal processor (DSP) products by Qualcomm. Hexagon is also known as QDSP6, standing for “sixth generation digital signal processor.” According to Qualcomm, the Hexagon architecture is designed to deliver performance with low power over a variety of applications. Each version of Hexagon has an instruction set and a micro-architecture. These two features are intimately related. Hexagon is used in Qualcomm Snapdragon chips, for example in smartphones, cars, wearable devices and other mobile devices and is also used in components of cellular phone networks. Instruction set architecture Computing devices have instruction sets, which are their lowest, most primitive languages. Common instructions are those which cause two numbers to be added, multiplied or combined in other ways, as well as instructions that direct the processor where to look in memory for its next instruction. There are many other types of instructions. Ass ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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SPARC
SPARC (Scalable Processor Architecture) is a reduced instruction set computer (RISC) instruction set architecture originally developed by Sun Microsystems. Its design was strongly influenced by the experimental Berkeley RISC system developed in the early 1980s. First developed in 1986 and released in 1987, SPARC was one of the most successful early commercial RISC systems, and its success led to the introduction of similar RISC designs from many vendors through the 1980s and 1990s. The first implementation of the original 32-bit architecture (SPARC V7) was used in Sun's Sun-4 computer workstation and server systems, replacing their earlier Sun-3 systems based on the Motorola 68000 series of processors. SPARC V8 added a number of improvements that were part of the SuperSPARC series of processors released in 1992. SPARC V9, released in 1993, introduced a 64-bit architecture and was first released in Sun's UltraSPARC processors in 1995. Later, SPARC processors were used in symm ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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SuperH
SuperH (or SH) is a 32-bit reduced instruction set computing (RISC) instruction set architecture (ISA) developed by Hitachi and currently produced by Renesas. It is implemented by microcontrollers and microprocessors for embedded systems. At the time of introduction, SuperH was notable for having fixed-length 16-bit instructions in spite of its 32-bit architecture. This was a novel approach; at the time, RISC processors always used an instruction size that was the same as the internal data width, typically 32 bits. Using smaller instructions had consequences: the register file was smaller and instructions were generally two-operand format. But for the market the SuperH was aimed at, this was a small price to pay for the improved memory and processor cache efficiency. Later versions of the design, starting with SH-5, included both 16- and 32-bit instructions, with the 16-bit versions mapping onto the 32-bit version inside the CPU. This allowed the machine code to continue using ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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S390
The IBM System/390 is a discontinued mainframe product family implementing the ESA/390, the fifth generation of the System/360 instruction set architecture. The first computers to use the ESA/390 were the Enterprise System/9000 (ES/9000) family, which were introduced in 1990. These were followed by the 9672, Multiprise, and Integrated Server families of System/390 in 1994–1999, using CMOS microprocessors. The ESA/390 succeeded the ESA/370 used in the Enhanced 3090 and 4381 "E" models, and the System/370 architecture last used in the IBM 9370 low-end mainframe. The ESA/390 was succeeded by the 64-bit z/Architecture in 2000. History On February 15, 1988, IBM announced Enterprise Systems Architecture/370 (ESA/370) for 3090 enhanced ("E") models and for 4381 model groups 91E and 92E. In additional to the primary and secondary addressing modes that System/370 Extended Architecture (S/370-XA) supports, ESA has an access register mode in which each use of general regist ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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RISC-V
RISC-V (pronounced "risk-five" where five refers to the number of generations of RISC architecture that were developed at the University of California, Berkeley since 1981) is an open standard instruction set architecture (ISA) based on established RISC principles. Unlike most other ISA designs, RISC-V is provided under open source licenses that do not require fees to use. A number of companies are offering or have announced RISC-V hardware, open source operating systems with RISC-V support are available, and the instruction set is supported in several popular software toolchains. As a RISC architecture, the RISC-V ISA is a load–store architecture. Its floating-point instructions use IEEE 754 floating-point. Notable features of the RISC-V ISA include instruction bit field locations chosen to simplify the use of multiplexers in a CPU, a design that is architecturally neutral, and most-significant bits of immediate values placed at a fixed location to speed sign extension. ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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PowerPC
PowerPC (with the backronym Performance Optimization With Enhanced RISC – Performance Computing, sometimes abbreviated as PPC) is a reduced instruction set computer (RISC) instruction set architecture (ISA) created by the 1991 Apple Inc., Apple–IBM–Motorola alliance, known as AIM alliance, AIM. PowerPC, as an evolving instruction set, has been named Power ISA since 2006, while the old name lives on as a trademark for some implementations of Power Architecture–based processors. PowerPC was the cornerstone of AIM's PReP and Common Hardware Reference Platform (CHRP) initiatives in the 1990s. Originally intended for personal computers, the architecture is well known for being used by Apple's Power Macintosh, PowerBook, iMac, iBook, eMac, Mac Mini, and Xserve lines from 1994 until 2005, when Mac transition to Intel processors, Apple migrated to Intel's x86. It has since become a niche in personal computers, but remains popular for embedded system, embedded and high-performanc ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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PA-RISC
PA-RISC is an instruction set architecture (ISA) developed by Hewlett-Packard. As the name implies, it is a reduced instruction set computer (RISC) architecture, where the PA stands for Precision Architecture. The design is also referred to as HP/PA for Hewlett Packard Precision Architecture. The architecture was introduced on 26 February 1986, when the HP 3000 Series 930 and HP 9000 Model 840 computers were launched featuring the first implementation, the TS1. PA-RISC has been succeeded by the Itanium (originally IA-64) ISA, jointly developed by HP and Intel. HP stopped selling PA-RISC-based HP 9000 systems at the end of 2008 but supported servers running PA-RISC chips until 2013. History In the late 1980s, HP was building four series of computers, all based on CISC CPUs. One line was the IBM PC compatible Intel i286-based Vectra Series, started in 1986. All others were non-Intel systems. One of them was the HP Series 300 of Motorola 68000-based workstations, another Serie ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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OpenRISC
OpenRISC is a project to develop a series of open-source hardware based central processing units (CPUs) on established reduced instruction set computer (RISC) principles. It includes an instruction set architecture (ISA) using an open-source license. It is the original flagship project of the OpenCores community. The first (and only) architectural description is for the OpenRISC 1000 ("OR1k"), describing a family of 32-bit and 64-bit processors with optional floating-point arithmetic and vector processing support. The OpenRISC 1200 implementation of this specification was designed by Damjan Lampret in 2000, written in the Verilog hardware description language (HDL). The later mor1kx implementation, which has some advantages compared to the OR 1200, was designed by Julius Baxter and is also written in Verilog. Additionally software simulators exist, which implement the OR1k specification. The hardware design was released under the GNU Lesser General Public License (LGPL), while t ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Nios II
Nios II is a 32-bit embedded processor architecture designed specifically for the Altera family of field-programmable gate array (FPGA) integrated circuits. Nios II incorporates many enhancements over the original Nios architecture, making it more suitable for a wider range of embedded computing applications, from digital signal processing (DSP) to system-control. Nios II is a successor to Altera's first configurable 16-bit embedded processor Nios, introduced in 2000. Key features Like the original Nios, the Nios II architecture is a RISC soft-core architecture which is implemented entirely in the programmable logic and memory blocks of Altera FPGAs. Unlike its predecessor it is a full 32-bit design: * 32 general-purpose 32-bit registers, * Full 32-bit instruction set, data path, and address space, * Single-instruction 32 × 32 multiply and divide producing a 32-bit result. The soft-core nature of the Nios II processor lets the system designer specify and generate a custom Ni ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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MIPS Architecture
MIPS (Microprocessor without Interlocked Pipelined Stages) is a family of reduced instruction set computer (RISC) instruction set architectures (ISA)Price, Charles (September 1995). ''MIPS IV Instruction Set'' (Revision 3.2), MIPS Technologies, Inc. developed by MIPS Computer Systems, now MIPS Technologies, based in the United States. There are multiple versions of MIPS: including MIPS I, II, III, IV, and V; as well as five releases of MIPS32/64 (for 32- and 64-bit implementations, respectively). The early MIPS architectures were 32-bit; 64-bit versions were developed later. As of April 2017, the current version of MIPS is MIPS32/64 Release 6. MIPS32/64 primarily differs from MIPS I–V by defining the privileged kernel mode System Control Coprocessor in addition to the user mode architecture. The MIPS architecture has several optional extensions. MIPS-3D which is a simple set of floating-point SIMD instructions dedicated to common 3D tasks, MDMX (MaDMaX) which is a more exten ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |