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Virtualization Software
In computing, virtualization (abbreviated v12n) is a series of technologies that allows dividing of physical computing resources into a series of virtual machines, operating systems, processes or containers. Virtualization began in the 1960s with IBM CP/CMS. The control program CP provided each user with a simulated stand-alone System/360 computer. In hardware virtualization, the ''host machine'' is the machine that is used by the virtualization and the ''guest machine'' is the virtual machine. The words ''host'' and ''guest'' are used to distinguish the software that runs on the physical machine from the software that runs on the virtual machine. The software or firmware that creates a virtual machine on the host hardware is called a ''hypervisor'' or ''virtual machine monitor''. Hardware virtualization is not the same as hardware emulation. Hardware-assisted virtualization facilitates building a virtual machine monitor and allows guest OSes to be run in isolation. Desktop v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
QEMU 6
The Quick Emulator (QEMU) is a free and open-source emulator that uses dynamic binary translation to emulate a computer's Central processing unit, processor; that is, it translates the emulated binary codes to an equivalent binary format which is executed by the machine. It provides a variety of hardware and device models for the virtual machine, enabling it to run different guest operating systems. QEMU can be used with a Kernel-based Virtual Machine (KVM) to emulate hardware at near-native speeds. Additionally, it supports User space and kernel space, user-level processes, allowing applications compiled for one processor architecture to run on another. QEMU supports the emulation of x86, ARM architecture family, ARM, PowerPC, RISC-V, and QEMU#Emulated hardware platforms, other architectures. Licensing QEMU is free software developed by Fabrice Bellard. Different components of QEMU are licensed under the GNU General Public License (GPL), BSD license, GNU Lesser General Public ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VM (operating System)
VM (often: VM/CMS) is a family of IBM virtual machine operating systems used on IBM mainframes System/370, System/390, zSeries, System z and compatible systems, including the Hercules (emulator), Hercules emulator for personal computers. Design The heart of the VM architecture is the ''Control Program'' or hypervisor abbreviated CP, VM-CP and sometimes, ambiguously, VM. It runs on the physical hardware, and creates the virtual machine environment. VM-CP provides full virtualization of the physical machine – including all I/O and other privileged operations. It performs the system's resource-sharing, including device management, dispatching, virtual storage management, and other traditional operating system tasks. Each VM user is provided with a separate virtual machine having its own address space, virtual devices, etc., and which is capable of running any software that could be run on a stand-alone machine. A given VM mainframe typically runs hundreds or thousands of virt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comparison Of Platform Virtualization Software
Platform virtualization software, specifically emulators and hypervisors, are software packages that emulate the whole physical computer machine, often providing multiple virtual machines on one physical platform. The table below compares basic information about platform virtualization hypervisors. General Features * Providing any virtual environment usually requires some overhead of some type or another. Native usually means that the virtualization technique does not do any CPU level virtualization (like Bochs), which executes code more slowly than when it is directly executed by a CPU. Some other products such as VMware and Virtual PC use similar approaches to Bochs and QEMU, however they use a number of advanced techniques to shortcut most of the calls directly to the CPU (similar to the process that JIT compiler uses) to bring the speed to near native in most cases. However, some products such as coLinux, Xen, z/VM (in real mode) do not suffer the cost of CPU-level s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Network World
International Data Group (IDG, Inc.) is an American market intelligence and demand generation company focused on the technology industry. IDG, Inc.'s mission is centered around supporting the technology industry through research, data, marketing technology, and insights that help create and sustain relationships between businesses. IDG, Inc. is wholly owned by Blackstone and is led by Genevieve Juillard, who was appointed CEO of the company in 2023. Juillard serves on IDG, Inc.'s leadership team along with IDC President Crawford Del Prete and IDG, Inc.'s Chief Financial Officer Tiziana Figliolia. IDG, Inc. is headquartered in Needham, Massachusetts and is the parent company of both International Data Corporation (IDC) and Foundry (formerly IDG Communications). History International Data Group was initially founded as International Data Corporation (IDC) in 1964 by Patrick Joseph McGovern, shortly after he had graduated from the Massachusetts Institute of Technology (MIT) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Privilege (computing)
In computing, privilege is defined as the delegation of authority to perform security-relevant functions on a computer system. A privilege allows a user to perform an action with security consequences. Examples of various privileges include the ability to create a new user, install software, or change kernel functions. Users who have been delegated extra levels of control are called privileged. Users who lack most privileges are defined as unprivileged, regular, or normal users. Theory Privileges can either be automatic, granted, or applied for. An automatic privilege exists when there is no requirement to have permission to perform an action. For example, on systems where people are required to log into a system to use it, logging out will not require a privilege. Systems that do not implement file protection - such as MS-DOS - essentially give unlimited privilege to perform any action on a file. A granted privilege exists as a result of presenting some credential to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trap (computing)
In digital computers, an interrupt (sometimes referred to as a trap) is a request for the processor to ''interrupt'' currently executing code (when permitted), so that the event can be processed in a timely manner. If the request is accepted, the processor will suspend its current activities, save its state, and execute a function called an ''interrupt handler'' (or an ''interrupt service routine'', ISR) to deal with the event. This interruption is often temporary, allowing the software to resume normal activities after the interrupt handler finishes, although the interrupt could instead indicate a fatal error. Interrupts are commonly used by hardware devices to indicate electronic or physical state changes that require time-sensitive attention. Interrupts are also commonly used to implement computer multitasking and system calls, especially in real-time computing. Systems that use interrupts in these ways are said to be interrupt-driven. History Hardware interrupts were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypervisor
A hypervisor, also known as a virtual machine monitor (VMM) or virtualizer, is a type of computer software, firmware or hardware that creates and runs virtual machines. A computer on which a hypervisor runs one or more virtual machines is called a ''host machine'', and each virtual machine is called a ''guest machine''. The hypervisor presents the guest operating systems with a virtual operating platform and manages the execution of the guest operating systems. Unlike an emulator, the guest executes most instructions on the native hardware. Multiple instances of a variety of operating systems may share the virtualized hardware resources: for example, Linux, Windows, and macOS instances can all run on a single physical x86 machine. This contrasts with operating-system–level virtualization, where all instances (usually called ''containers'') must share a single kernel, though the guest operating systems can differ in user space, such as different Linux distributions with the sam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Popek And Goldberg Virtualization Requirements
The Popek and Goldberg virtualization requirements are a set of conditions sufficient for a computer architecture to support system virtualization efficiently. They were introduced by Gerald J. Popek and Robert P. Goldberg in their 1974 article "Formal Requirements for Virtualizable Third Generation Architectures". Even though the requirements are derived under simplifying assumptions, they still represent a convenient way of determining whether a computer architecture supports efficient virtualization and provide guidelines for the design of virtualized computer architectures. VMM definition System virtual machines are capable of virtualizing a full set of hardware resources, including a processor (or processors), memory and storage resources and peripheral devices. A virtual machine monitor (VMM, also called hypervisor) is the piece of software that provides the abstraction of a virtual machine. There are three properties of interest when analyzing the environment created by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cloud Computing
Cloud computing is "a paradigm for enabling network access to a scalable and elastic pool of shareable physical or virtual resources with self-service provisioning and administration on-demand," according to International Organization for Standardization, ISO. Essential characteristics In 2011, the National Institute of Standards and Technology (NIST) identified five "essential characteristics" for cloud systems. Below are the exact definitions according to NIST: * On-demand self-service: "A consumer can unilaterally provision computing capabilities, such as server time and network storage, as needed automatically without requiring human interaction with each service provider." * Broad network access: "Capabilities are available over the network and accessed through standard mechanisms that promote use by heterogeneous thin or thick client platforms (e.g., mobile phones, tablets, laptops, and workstations)." * Pooling (resource management), Resource pooling: " The provider' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microcomputer
A microcomputer is a small, relatively inexpensive computer having a central processing unit (CPU) made out of a microprocessor. The computer also includes memory and input/output (I/O) circuitry together mounted on a printed circuit board (PCB). Microcomputers became popular in the 1970s and 1980s with the advent of increasingly powerful microprocessors. The predecessors to these computers, mainframes and minicomputers, were comparatively much larger and more expensive (though indeed present-day mainframes such as the IBM System z machines use one or more custom microprocessors as their CPUs). Many microcomputers (when equipped with a keyboard and screen for input and output) are also personal computers (in the generic sense). An early use of the term "personal computer" in 1962 predates microprocessor-based designs. ''(See "Personal Computer: Computers at Companies" reference below)''. A "microcomputer" used as an embedded control system may have no human-readable input and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distributed Computing
Distributed computing is a field of computer science that studies distributed systems, defined as computer systems whose inter-communicating components are located on different networked computers. The components of a distributed system communicate and coordinate their actions by passing messages to one another in order to achieve a common goal. Three significant challenges of distributed systems are: maintaining concurrency of components, overcoming the lack of a global clock, and managing the independent failure of components. When a component of one system fails, the entire system does not fail. Examples of distributed systems vary from SOA-based systems to microservices to massively multiplayer online games to peer-to-peer applications. Distributed systems cost significantly more than monolithic architectures, primarily due to increased needs for additional hardware, servers, gateways, firewalls, new subnets, proxies, and so on. Also, distributed systems are prone to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minicomputer
A minicomputer, or colloquially mini, is a type of general-purpose computer mostly developed from the mid-1960s, built significantly smaller and sold at a much lower price than mainframe computers . By 21st century-standards however, a mini is an exceptionally large machine. Minicomputers in the traditional technical sense covered here are only small relative to generally even earlier and much bigger machines. The class formed a distinct group with its own software architectures and operating systems. Minis were designed for control, instrumentation, human interaction, and communication switching, as distinct from calculation and record keeping. Many were sold indirectly to original equipment manufacturers (OEMs) for final end-use application. During the two-decade lifetime of the minicomputer class (1965–1985), almost 100 minicomputer vendor companies formed. Only a half-dozen remained by the mid-1980s. When single-chip CPU microprocessors appeared in the 1970s, the defi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
