Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
11 Cards in this Set
- Front
- Back
|
What are Type 0 Hypervisors? |
Subdivision of hardware between processes, so different processes can exclusively use different types of hardware for their needs. Common on old mainframes |
|
|
What are Type 1 Hypervisors? |
Essentially an OS that runs - along with other OSes - on top of the hardware . |
|
|
What are Type 2 Hypervisors? |
These run on top of another OS which sits on top of the hardware. |
|
|
Implementations of VMs: |
Enhancement to guest OS so it can communicate directly with the OS for certain operations |
|
|
Implementations of VMs: What is "programming-environment virtualization"? |
i.e. like Java Virtual Machine Not virtualizing hardware but just creating an optimized virtual system |
|
|
Implementations of VMs: What are "emulators"? |
Each machine instruction issued by an application is translated so it can be used on a different piece of hardware. |
|
|
Who invented virtual machines and when? |
IBM in 1972 |
|
|
What are some benefits of VMs? |
1) Guest OS is isolated from main OS, so viruses less likely to spread 2) You can freeze or suspend a running VM and move somewhere else 3) Great for OS research 4) running multiple OSes on same machine 5) Packaging an OS and an application to ship to users 6) Live migration - move a running vm to another machine with no interruption to users. |
|
|
What is Virtual CPU? |
Represents the CPU differently to each guest VM. Each guest VM thinks it has control of the CPU the whole time, but really it is being switched in and out. The VCPU holds all the context info and is loaded onto the actual CPU when the VM is scheduled to run |
|
|
True or False: Guest OS kernel mode instruction run on the kernel mode of the underlying machine. |
False. The kernel instruction in the VM are run as user mode instructions to the underlying OS. As far as the host OS is concerned, only it itself can run in kernel mode. |
|
|
What is Trap-and-Emulate? |
A mechanism to implement virtual kernel mode in the VM. The VM "Traps" kernel code in Guest OS and passes it one to the host OS. |
