ISO IEC TS 23167:2020 pdf free

ISO IEC TS 23167:2020 pdf free.Information technology一Cloud computing一Common technologies and techniques
A virtual machine (VM) is an isolated execution environment for running software that uses virtualized physical resources. In other words, this involves the virtualization of the system – and the software within each VM is given carefully controlled access to the physical resources to enable sharing of those resources without interference. Sometimes termed system virtual machines, VMs provide the functionality needed to execute complete software stacks including entire operating systems and the application code that uses the operating system (ISO/IEC 22123-1:-, 5.5.1). This is as depicted by the “guest OS” and “App x” within each VM shown in Figure 1.
The purpose of VMs is to enable multiple applications to run at the same time on one hardware system,while those applications remain isolated from each other. The software running within each VM appears to have its own system hardware, such as processor, runtime memory, storage device(s) and networking hardware. Isolated means that the software running within one VM is separated from and unaware of software running within other VMs on the same system and is also separated from the host OS. Virtualization commonly means that a subset of the available physical resources can be made available to each VM, such as limited numbers of processors, limited RAM, limited storage space and controlled access to networking capabilities.
Each VM contains a complete stack of software, starting with the operating system and continuing with whatever other software is required to run the application(s) that are executed within the VM. The software stack could be very simple (e.g. a native application written in a language like C, using only functions supplied by the operating system itself) or complex (e.g. an application written in a language such as JavaTM which requires a runtime and which makes extensive use of libraries and/or services which are not present in the operating system and which have to be supplied separately).
Each VM can in principle contain any operating system. Different VMs on a single hardware system can run completely different operating systems such as Linux and Windows. The only requirement is that all the software running within the VM is designed for the hardware architecture of the underlying system – the hardware is virtualized, but not emulated. So, for example, code built for an ARM processor will not run in a VM running on an Intel x86 system.ISO IEC TS 23167 pdf download.