OS Design Patterns

Question 1

run OS as a single program in kernel mode

Answer 1

Monolithic

Question 2

organize the OS in layers:
5: operator
4: user programs
3: input/output management
2: operator-process communication
1: memory and drum management
0: processor allocation and multi-programming

Answer 2

Layered OS systems

Question 3

goal to achieve high reliability by splitting the OS into small modules. Only the ______ runs in kernel mode and the rest run as user processes

Answer 3

Microkernals

Question 4

Has servers and clients. Communicates by passing messages. The service does the work and sends back the answer
Works the same over the network as locally with services

Answer 4

Client-Server model

Question 5

• A timesharing system
• Has a virtual machine monitor, which runs on bare hardware and - does the multiprogramming and provides VMs to the next layer up
• CMS (Conversational Monitor System) for interactive timesharing users.

Answer 5

Virtual Machines

Question 6

The __ _ ____ has an added kernel module to do some of the heavy lifting so the VM can make system calls. The __ _ ____ makes use of the host OS to perform kernel level tasks. Also has a guest operating system.

Answer 6

type 2 hypervisor

Question 7

Downside of containers

Answer 7

it’s not possible to run a completely different OS. There is no strict resource partitioning.

The container may be restricted in what it may access on SSD or disk and how much CPU time it gets, but all containers still share the resources in the underlying host operating system.

Resources are process-level isolated so a container that messes with the stability of the underlying kernel will also affect other containers.