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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 s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bhyve
bhyve (pronounced "bee hive", formerly written as BHyVe for "BSD hypervisor") is a type-2 hypervisor initially written for FreeBSD. It can also be used on a number of illumos based distributions including SmartOS, OpenIndiana, and OmniOS. A port of bhyve to macOS called xhyve is also available. Features bhyve supports the virtualization of several guest operating systems, including FreeBSD 9+, OpenBSD, NetBSD, Linux, illumos, DragonFly and Windows NT (Windows Vista and later, Windows Server 2008 and later). bhyve also supports UEFI installations and VirtIO emulated interfaces. Windows virtual machines require VirtIO drivers for a stable operation. Current development efforts aim at widening support for other operating systems for the x86-64 architecture. Support for peripherals relies on basic and VirtIO drivers and supports: eXtensible Host Controller Interface (xHCI) USB controllers, NVM Express (NVMe) controllers, High Definition Audio Controllers, raw framebuffer device ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FreeBSD
FreeBSD is a free and open-source Unix-like operating system descended from the Berkeley Software Distribution (BSD), which was based on Research Unix. The first version of FreeBSD was released in 1993. In 2005, FreeBSD was the most popular open-source BSD operating system, accounting for more than three-quarters of all installed and permissively licensed BSD systems. FreeBSD has similarities with Linux, with two major differences in scope and licensing: FreeBSD maintains a complete system, i.e. the project delivers a kernel, device drivers, userland utilities, and documentation, as opposed to Linux only delivering a kernel and drivers, and relying on third-parties for system software; FreeBSD source code is generally released under a permissive BSD license, as opposed to the copyleft GPL used by Linux. The FreeBSD project includes a security team overseeing all software shipped in the base distribution. A wide range of additional third-party applications may be installe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kernel-based Virtual Machine
Kernel-based Virtual Machine (KVM) is a virtualization module in the Linux kernel that allows the kernel to function as a hypervisor. It was merged into the 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 ported to S/390, PowerPC, IA-64, and ARM. KVM provides hardware-assisted virtualization for a wide variety of guest operating systems including Linux, BSD, Solaris, Windows, Haiku, ReactOS, Plan 9, AROS Research Operating System and macOS. In addition, Android 2.2, GNU/Hurd ( Debian K16), Minix 3.1.2a, Solaris 10 U3 and Darwin 8.0.1, together with other operating systems and some newer versions of these listed, are known to work with certain limitations. Addition ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operating-system-level Virtualization
OS-level virtualization is an operating system (OS) paradigm in which the kernel allows the existence of multiple isolated user space instances, called ''containers'' ( LXC, Solaris containers, Docker, Podman), ''zones'' (Solaris containers), ''virtual private servers'' (OpenVZ), ''partitions'', ''virtual environments'' (VEs), ''virtual kernels'' (DragonFly BSD), or ''jails'' (FreeBSD jail or chroot jail). 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. However, programs running inside of 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 apparent root folder ... [...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] |
Kernel Module
In computing, a loadable kernel module (LKM) is an object file that contains code to extend the running kernel, or so-called ''base kernel'', of an operating system. LKMs are typically used to add support for new hardware (as device drivers) and/or filesystems, or for adding system calls. When the functionality provided by an LKM is no longer required, it can be unloaded in order to free memory and other resources. Most current Unix-like systems and Microsoft Windows support loadable kernel modules under different names, such as kernel loadable module (kld) in FreeBSD, kernel extension (kext) in macOS (although support for third-party modules is being dropped), kernel extension module in AIX, kernel-mode driver in Windows NT and downloadable kernel module (DKM) in VxWorks. They are also known as kernel loadable modules (or KLM), and simply as kernel modules (KMOD). Advantages Without loadable kernel modules, an operating system would have to include all possible anticipated fu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Process
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 mu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Z/VM
z/VM is the current version in IBM's VM family of virtual machine operating systems. z/VM was first released in October 2000 and remains in active use and development . It is directly based on technology and concepts dating back to the 1960s, with IBM's CP/CMS on the IBM System/360-67 (see article History of CP/CMS for historical details). z/VM runs on IBM's IBM Z family of computers. It can be used to support large numbers (thousands) of Linux virtual machines. (See Linux on IBM Z.) On September 16, 2022, IBM released z/VM Version 7.3 which requires z/Architecture, implemented in IBM's EC12, BC12 and later models. See also * z/OS * OpenSolaris for System z * z/TPF * z/VSE * PR/SM * Time-sharing system evolution This article covers the evolution of time-sharing systems, providing links to major early time-sharing operating systems, showing their subsequent evolution. Time-sharing Time-sharing was first proposed in the mid- to late-1950s and first impleme ... References ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SIMMON
SIMMON (SIMulation MONitor) was a proprietary software testing system developed in the late 1960s in the IBM Product Test Laboratory, then at Poughkeepsie, N.Y. It was designed for the then-new line of System/360 computers as a vehicle for testing the software that IBM was developing for that architecture. SIMMON was first described at the IBM ''SimSymp 1968'' symposium, held at Rye, New York.Lehman MM (ed) ''Proc. SimSymp 1968'', IBM Res. Div., Yorktown Heights, NY; Nov. 1968, 3 vols. SIMMON was a hypervisor, similar to the IBM CP-40 system that was being independently developed at the Cambridge Scientific Center at about that same time. The chief difference from CP-40 was that SIMMON supported a single virtual machine for testing of a single guest program running there. CP-40 supported many virtual machines for time-sharing production work. CP-40 evolved by many stages into the present VM/CMS operating system. SIMMON was a useful test vehicle for many years. SIMMON was desig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bare Machine
In computer science, bare machine (or bare metal) refers to a computer executing instructions directly on logic hardware without an intervening operating system. Modern operating systems evolved through various stages, from elementary to the present day complex, highly sensitive systems incorporating many services. After the development of programmable computers (which did not require physical changes to run different programs) but prior to the development of operating systems, sequential instructions were executed on the computer hardware directly using machine language without any system software layer. This approach is termed the "bare machine" precursor to modern operating systems. Today it is mostly applicable to embedded systems and firmware generally with time-critical latency requirements, while conventional programs are run by a runtime system overlaid on an operating system. Advantages For a given application, in most of the cases, a bare-metal implementation will ru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Robert P
The name Robert is an ancient Germanic given name, from Proto-Germanic "fame" and "bright" (''Hrōþiberhtaz''). Compare Old Dutch ''Robrecht'' and Old High German ''Hrodebert'' (a compound of ''Hrōþ, Hruod'' ( non, Hróðr) "fame, glory, honour, praise, renown" and ''berht'' "bright, light, shining"). It is the second most frequently used given name of ancient Germanic origin. It is also in use Robert (surname), as a surname. Another commonly used form of the name is Rupert (name), Rupert. After becoming widely used in Continental Europe it entered England in its Old French form ''Robert'', where an Old English cognate form (''Hrēodbēorht'', ''Hrodberht'', ''Hrēodbēorð'', ''Hrœdbœrð'', ''Hrœdberð'', ''Hrōðberχtŕ'') had existed before the Norman Conquest. The feminine version is Roberta (given name), Roberta. The Italian, Portuguese, and Spanish form is Roberto (given name), Roberto. Robert is also a common name in many Germanic languages, including English ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
