Hardware and OS Concepts

Question 1

What is an Operating System (OS)?

Answer 1

software that controls a computer’s core functions and allows interaction with computer programs.

Question 2

What are the two main functions of an OS?

Answer 2

• Abstract Interface
• Resource Manager

Question 3

What is a Processor?

Answer 3

The brain of a computer.

Question 4

What does a Program Counter (PC) point to?

Answer 4

The next Instruction.

Question 5

What does the stack pointer (SP) point to?

Answer 5

The top of the current stack.

Question 6

What is the difference between Kernel mode and User mode?

Answer 6

KM executes any instruction in the instruction set, while UM only executes a subset of instructions.

Question 7

A request by a user program to the OS to perform a task on its behalf, via software, is called …….

Answer 7

System Call

Question 8

What are the steps for an interrupt?

Answer 8

1. state of process is saved
2. CPU switches to kernel mode
3. Find the interrupt handler in the interrupt vector table (IVT)
4. Execute interrupt handler
5. Control of CPU returned to the process.

Question 9

What are the 2 sections of memory?

Answer 9

• Code (typically static)
• Data (volatile)

Question 10

When it comes to memory what is a base ?

Answer 10

start location

Question 11

When it comes to memory what is a limit?

Answer 11

The range of legal memory address the proces can access.

Question 12

A chip or set of chips that accepts commands from OS is called a …..

Answer 12

controller

Question 13

The software that “talks” to the controller is called a …..

Answer 13

device driver

Question 14

What are 3 ways to invoke device actions?

Answer 14

• busy wait
• DMA
• interrupt

Question 15

Busy Wait is when you……..

Answer 15

execute a kernel level system call, and the wait ties up processor.

Question 16

What does DMA stand for?

Answer 16

Direct Memory Access

Question 17

What Does a DMA do?

Answer 17

allows device to write directly to memory once rules are established.