Operating Systems (NOT FINISHED)

Question 1

Define Application Software

Answer 1

The software was written to address specific needs

Question 2

Define System Software

Answer 2

Software that manages a computer system at a fundamental level

Question 3

What are the 5 roles of an Operating System

Answer 3

System software that manages computer resources such as memory and input/output devices, provides an interface through which a human can interact with the computer, allows an application progra to interact with other system resources, the various roles of an operating system generally revolve around the idea of ‘sharing nicely’, an operating system manages resources, and these resources are often shared in one way or another among program that want to use them

Question 4

What are the services provided by the OS

Answer 4

Editors and debuggers, Program execution, System access, Controlled access to files, Access I/O devices, Error detection and response, Accounting

Question 5

What resource management does the OS provide

Answer 5

Multiprogramming, Memory management, Process management, CPU scheduling

Question 6

What are desirable features for an OS

Answer 6

Memory protection for OS, timer, privileged instruction and interrupts

Question 7

What are two approaches to Batch Processing

Answer 7

Uniprogramming, Multiprogramming

Question 8

Define Uniprogramming

Answer 8

Processor must wait for I/O instruction to complete before proceeding

Question 9

Define Mulitprogramming

Answer 9

When one job needs to wait for I/O , the processor can switch to another job

Question 10

Define Timesharing system

Answer 10

A system that allows multiple users to interact with a computer at the same time

Question 11

Define Virtual Machine

Answer 11

The illusion created by a time-sharing system that each user has his/her own machine

Question 12

Define Device driver

Answer 12

A small program that knows the way a particular device expects to receive and deliver information

Question 13

What are the 5 states an instruction can be in

Answer 13

New, Ready, Waiting, Running, Terminated

Question 14

PROCESS CREATION: Define Parent process

Answer 14

The original, creating, process

Question 15

PROCESS CREATION: Define Child process

Answer 15

The newly created process

Question 16

PROCESS TERMINATION: What would be a reason to terminate a process

Answer 16

New batch job, HALT/STOP instruction, Interactive login, user logs off, Service/application completed, Fault/error, Terminating a Parent Process can terminate a child Process, …

Question 17

PROCESS SUSPENSION: Why would you suspend a process

Answer 17

The process needs an unavailable resource, OS suspects the process of causing a problem, An interactive user wishes to pause the process, The process may only need to run periodically, OS needs resources for another process, …

Question 18

PROCESS MANAGEMENT: How would you manage a process

Answer 18

Using a queue

Question 19

What are the two suspended states

Answer 19

Blocked/Suspended, Ready/Suspended

Question 20

Define Blocked/Suspended

Answer 20

The waiting process swapped out

Question 21

Define Ready/Suspended

Answer 21

The process could be executed, but swapped out

Question 22

Define CPU Scheduling

Answer 22

The act of determining which process in the ready state should be moved to the running state

Question 23

What are the two types of Scheduling

Answer 23

Non pre-emptive scheduling, pre-emptive scheduling

Question 24

Define non pre-emptive scheduling

Answer 24

The currently executing process gives up the CPU voluntarily

Question 25

Define pre-emptive scheduling

Answer 25

The operating system decides to favour another process over the currently running one

Question 26

What are some CPU Scheduling Approaches

Answer 26

First-come, First-Served, Shortest Job Next, Round Robin

Question 27

Define First-Come First-Served

Answer 27

Processes are moved to the CPU in the order in which they arrive in the running state

Question 28

Define Shortest Job Next

Answer 28

A process with the shortest estimated running time in the ready state is moved into the running state first

Question 29

Define Round Robin

Answer 29

Each process runs for a specified time slice and moves from the running state to the ready state to await its next turn if not finished

Question 30

Factors to evaluate an approach

Answer 30

Turnaround time, Delay, Processor Utilization

Question 31

Define Turnaround time

Answer 31

The time between when a process first arrives in the ready state and when it exits the running state for the last time

Question 32

What is the formula for delay

Answer 32

(turnaround - service time) / service time * 100

Question 33

Define Processor Utilization

Answer 33

Percentage of time CPU doing useful work

Question 34

Define Logical Address

Answer 34

Reference to a stored value relative to the program making the reference

Question 35

Define Physical Address

Answer 35

Actual address in main memory, where the instruction/data is stored