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Infrastructure As A Service
Infrastructure as a service (IaaS) is a cloud computing service model where a cloud services vendor provides computing resources such as storage, network, servers, and virtualization (which emulates computer hardware). This service frees users from maintaining their own data center, but they must install and maintain the operating system and application software. Iaas provides users high-level APIs to control details of underlying network infrastructure such as backup, data partitioning, scaling, security and physical computing resources. Services can be scaled on-demand by the user. According to the Internet Engineering Task Force (IETF), such infrastructure is the most basic cloud-service model. IaaS can be hosted in a public cloud (where users share hardware, storage, and network devices), a private cloud (users do not share resources), or a hybrid cloud (combination of both). Overview The US National Institute of Standards and Technology (NIST) defines infrastructure as a ... [...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] |
OpenStack
OpenStack is a free, open standard cloud computing platform. It is mostly deployed as infrastructure-as-a-service (IaaS) in both public and private clouds where virtual servers and other resources are made available to users. The software platform consists of interrelated components that control diverse, multi-vendor hardware pools of processing, storage, and networking resources throughout a data center. Users manage it either through a web-based dashboard, through command-line tools, or through RESTful web services. OpenStack began in 2010 as a joint project of Rackspace Hosting and NASA. , it was managed by the OpenStack Foundation, a non-profit corporate entity established in September 2012 to promote OpenStack software and its community. By 2018, more than 500 companies had joined the project. In 2020 the foundation announced it would be renamed the Open Infrastructure Foundation in 2021. History In July 2010, Rackspace Hosting and NASA announced an open-source ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compound Annual Growth Rate
Compound annual growth rate (CAGR) is a business, economics and investing term representing the mean annualized growth rate for compounding values over a given time period. CAGR smoothes the effect of volatility of periodic values that can render arithmetic means less meaningful. It is particularly useful to compare growth rates of various data values, such as revenue growth of companies, or of economic values, over time. Equation For annual values, CAGR is defined as: :\mathrm(t_0,t_n) = \left( \frac \right)^\frac - 1 where V(t_0) is the initial value, V(t_n) is the end value, and t_n - t_0 is the number of years. CAGR can also be used to calculate mean annualized growth rates on quarterly or monthly values. The numerator of the exponent would be the value of 4 in the case of quarterly, and 12 in the case of monthly, with the denominator being the number of corresponding periods involved. In practice, CAGR calculations are often performed in Microsoft Excel. A convenient ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cgroups
cgroups (abbreviated from control groups) is a Linux kernel feature that limits, accounts for, and isolates the resource usage (CPU, memory, disk I/O, etc.) of a collection of processes. Engineers at Google started the work on this feature in 2006 under the name "process containers". In late 2007, the nomenclature changed to "control groups" to avoid confusion caused by multiple meanings of the term "container" in the Linux kernel context, and the control groups functionality was merged into the Linux kernel mainline in kernel version 2.6.24, which was released in January 2008. Since then, developers have added many new features and controllers, such as support for kernfs in 2014, firewalling, and unified hierarchy. cgroup v2 was merged in Linux kernel 4.5 with significant changes to the interface and internal functionality. Versions There are two versions of cgroups. Cgroups was originally written by Paul Menage and Rohit Seth, and merged into the mainline Linux ker ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linux Kernel
The Linux kernel is a Free and open-source software, free and open source Unix-like kernel (operating system), kernel that is used in many computer systems worldwide. The kernel was created by Linus Torvalds in 1991 and was soon adopted as the kernel for the GNU operating system (OS) which was created to be a free software, free replacement for Unix. Since the late 1990s, it has been included in many Linux distributions, operating system distributions, many of which are called Linux. One such Linux kernel operating system is Android (operating system), Android which is used in many mobile and embedded devices. Most of the kernel code is written in C (programming language), C as supported by the GNU compiler collection (GCC) which has extensions beyond standard C. The code also contains assembly language, assembly code for architecture-specific logic such as optimizing memory use and task execution. The kernel has a Modular programming, modular design such that modules can be inte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OS-level Virtualization
OS-level virtualization is an operating system (OS) virtualization paradigm in which the kernel allows the existence of multiple isolated user space instances, including containers ( LXC, Solaris Containers, AIX WPARs, HP-UX SRP Containers, Docker, Podman), zones ( Solaris Containers), virtual private servers ( OpenVZ), partitions, virtual environments (VEs), virtual kernels (DragonFly BSD), and jails ( FreeBSD jail and chroot). Such instances may look like real computers from the point of view of programs running in them. A computer program running on an ordinary operating system can see all resources (connected devices, files and folders, network shares, CPU power, quantifiable hardware capabilities) of that computer. Programs running inside a container can only see the container's contents and devices assigned to the container. On Unix-like operating systems, this feature can be seen as an advanced implementation of the standard chroot mechanism, which changes the apparen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyper-V
Hyper-V is a native hypervisor developed by Microsoft; it can create virtual machines on x86-64 systems running Windows. It is included in Pro and Enterprise editions of Windows (since Windows 8) as an optional feature to be manually enabled. A server computer running Hyper-V can be configured to expose individual virtual machines to one or more networks. Overview Codenamed Viridian and briefly known before its release as Windows Server Virtualization, a beta version was shipped with certain x86-64 editions of Windows Server 2008. The finalized version was released on June 26, 2008 and was delivered through Windows Update. Hyper-V has since been released with every version of Windows Server starting with version 2012, superseding Microsoft Virtual Server, and starting with Windows 8, Hyper-V has been the hardware virtualization component for personal computers, superseding Windows Virtual PC. Microsoft provides Hyper-V through two channels: # Part of Windows: Hyper-V is an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VMware ESX
VMware ESXi (formerly ESX) is an enterprise-class, type-1 hypervisor developed by VMware, a subsidiary of Broadcom, for deploying and serving virtual computers. As a type-1 hypervisor, ESXi is not a software application that is installed on an operating system (OS); instead, it includes and integrates vital OS components, such as a kernel. After version 4.1 (released in 2010), VMware renamed ESX to ''ESXi''. ESXi replaces Service Console (a rudimentary operating system) with a more closely integrated OS. ESX/ESXi is the primary component in the VMware Infrastructure software suite. The name ''ESX'' originated as an abbreviation of Elastic Sky X. In September 2004, the replacement for ESX was internally called ''VMvisor'', but later changed to ESXi (as the "i" in ESXi stood for "integrated"). Architecture ESX runs on bare metal (without running an operating system) unlike other VMware products. It includes its own kernel. In the historic VMware ESX, a Linux kernel was star ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kernel-based Virtual Machine
Kernel-based Virtual Machine (KVM) is a free and open-source virtualization module in the Linux kernel that allows the Kernel (operating system), kernel to function as a hypervisor. It was merged into the Mainline Linux, mainline Linux kernel in version 2.6.20, which was released on February 5, 2007. KVM requires a processor with hardware virtualization extensions, such as Intel VT or AMD-V. KVM has also been ported to other operating systems such as FreeBSD and illumos in the form of loadable kernel modules. KVM was originally designed for x86 processors but has since been porting, ported to IBM ESA/390, ESA/390, PowerPC, IA-64, and ARM architecture, ARM. The IA-64 port was removed in 2014. KVM supports hardware-assisted virtualization for a wide variety of guest operating systems including BSD, Solaris (operating system), Solaris, Microsoft Windows, Windows, Haiku (operating system), Haiku, ReactOS, Plan 9 from Bell Labs, Plan 9, AROS Research Operating System, AROS, macOS, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oracle VM Server For X86
An oracle is a person or thing considered to provide insight, wise counsel or prophetic predictions, most notably including precognition of the future, inspired by deities. If done through occultic means, it is a form of divination. Description The word ''oracle'' comes from the Latin verb ''ōrāre'', "to speak" and properly refers to the priest or priestess uttering the prediction. In extended use, ''oracle'' may also refer to the ''site of the oracle'', and the oracular utterances themselves, are called ''khrēsmoí'' (χρησμοί) in Greek. Oracles were thought to be portals through which the gods spoke directly to people. In this sense, they were different from seers (''manteis'', μάντεις) who interpreted signs sent by the gods through bird signs, animal entrails, and other various methods.Flower, Michael Attyah. ''The Seer in Ancient Greece.'' Berkeley: University of California Press, 2008. The most important oracles of Greek antiquity were Pythia (priestes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VirtualBox
Oracle VirtualBox (formerly Sun VirtualBox, Sun xVM VirtualBox and InnoTek VirtualBox) is a hosted hypervisor for x86 virtualization developed by Oracle Corporation. VirtualBox was originally created by InnoTek Systemberatung GmbH, which was acquired by Sun Microsystems in 2008, which was in turn acquired by Oracle in 2010. VirtualBox may be installed on Microsoft Windows, macOS, Linux, Solaris (operating system), Solaris and OpenSolaris. There are also ports to FreeBSD and Genode. It supports the creation and management of guest virtual machines running Windows, Linux, Berkeley Software Distribution, BSD, OS/2, Solaris, Haiku (operating system), Haiku, and Hackintosh, OSx86, as well as limited virtualization of guests on Apple hardware. For some guest operating systems, a "Guest Additions" package of device drivers and system applications is available, which typically improves performance, especially that of graphics, and allows changing the resolution of the guest OS automati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virtual Machine
In computing, a virtual machine (VM) is the virtualization or emulator, emulation of a computer system. Virtual machines are based on computer architectures and provide the functionality of a physical computer. Their implementations may involve specialized hardware, software, or a combination of the two. Virtual machines differ and are organized by their function, shown here: * ''System virtual machines'' (also called full virtualization VMs, or SysVMs) provide a substitute for a real machine. They provide the functionality needed to execute entire operating systems. A hypervisor uses native code, native execution to share and manage hardware, allowing for multiple environments that are isolated from one another yet exist on the same physical machine. Modern hypervisors use hardware-assisted virtualization, with virtualization-specific hardware features on the host CPUs providing assistance to hypervisors. * ''Process virtual machines'' are designed to execute computer programs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
