18.04 Virtual machines

System virtual machine

Software that allows for provision of multiple, separate operating system software and simulates the hardware components of the physical computer. The component that enables this virtualization is a hypervisor/virtual machine monitor. Some tasks that the virtual machine software undertakes are: backing up the existing OS, building and deploying apps to the cloud, enabling experimentation with new OS’s.

Advantages of System virtual machine

1. Isolation or Security: virus or crashing does not affect others.

2. Cost-efficiency: fewer hardware resources needed

3. Flexibility and scalability: Resource provisioning, creation and modification is simple

4. Compatibility and cross-platform: virtual machines can run on different operating systems

5. Simplifies Software Testing and Development: testing in different environments and operating systems

Disadvantages of System virtual machine

1. Complexity: specialized knowledge is needed

2. Resource intensive: each individual virtual machine requires its own CPU, and memory

3. Performance overhead: shared resources with host machine

4. Potential for Overprovisioning: since creating, modifying etc. VM is easy this can lead to underutilization of resources

Guest operating system

A piece of software that runs inside a virtual machine which can run applications that are incompatible with the host operating system or require a different environment. Access to hardware resources is limited so it relies on the host operating system to communication with hardware and perform operations. The guest operating system is isolates from the host and other guest operating system. This means it can run without being affected by them or affecting components.

Host operating system

A piece of software that runs on a computer and connects with the hardware. It can create and manage multiple virtual machines, each with its own guest operating system. It also has direct control over the hardware, such as CPU memory, storage and peripheral devices and allocates these resources to the guest operating system and other applications. The host operating system is depending on the hardware and virtualization software.