Week 1

Question 1

Design Goals

Answer 1

Abstraction
Performance
Protection

Question 2

Operating System

Answer 2

Body of software that abstracts and arbitrates system hardware

Question 3

Virtualization

Answer 3

Use of software to to create a layer over the hardware

Question 4

Point of Virtualization

Answer 4

Allow system hardware to be used efficiently to generate max output: easy to use.

Question 5

Virtualizing the CPU

Answer 5

Turning CPU into infinite number of processors to allow programs seemingly run at once

Question 6

Virtualizing Memory

Answer 6

Assigning private address space to programs such that they think they have the whole physical memory to themselves.

Question 7

Memory

Answer 7

Array of bytes with specific address to allow reads(loads) and writes(stores)

Question 8

System calls

Answer 8

Interfaces the OS provides users to access system resources.

Question 9

Trap

Answer 9

Hardware instructions to initiate a system call

Question 10

Procedural call

Answer 10

Libraries are accessible without any real privilege

Question 11

Standard library

Answer 11

Provided by OS to all applications make system calls

Question 12

File system

Answer 12

Software that manages the disk in an OS

Question 13

What does the file system do?

Answer 13

Figures out where to store new data(file created by the user)
Keeps track of various structures

Question 14

Device driver

Answer 14

Code responsible for handling a particular device in an OS

Question 15

How does the system handle crashes under persistent data storage

Answer 15

Journaling or copy-on-write: ordering writes to recover a to a reasonable state in case of failure.

Question 16

Explain the transition of OSs

Answer 16

Libraries
Protection(through system calls, abandoning procedural calls)
CPU optimization (multi programming)
Modern Era(more on memory protection, sort of has the goals)

Question 17

What’s the main difference between system calls and procedural calls

Answer 17

Privileges and access. Systems made it better and more rigorous.

Question 18

User mode

Answer 18

Apps cannot initiate I/O requests to some hardware or even access some system hardware

Question 19

Kernel mode

Answer 19

OS has full access to hardware