Chapter 3

Question 1

Functions of operating systems

Answer 1

• Oversee the operation of a computer.
• Store and retrieve files.
• Schedule programs for execution.
• Coordinate the execution of programs.

Question 2

Job

Answer 2

a program to be executed with its inputs and outputs

Question 3

Batch processing

Answer 3

execution of a batch of jobs without any interaction of a user (originally operated by a computer operator)

Question 4

Interactive processing

Answer 4

support of interaction between programs and users during execution (originally via terminals)

Question 5

Real time processing

Answer 5

execution of tasks in accordance with deadlines in an external real world environment.

Question 6

Multiprogramming

Answer 6

multiple programs can be executed “at the same time” (originally during batch processing) on a processor

Question 7

Time-sharing

Answer 7

a computer provides service to multiple users “at the same time” (time slices)

Question 8

Multitasking

Answer 8

multiple programs can be executed “at the same time” by a single user

Question 9

Operating system components

Answer 9

User interface

Kernel

Question 10

File

Answer 10

a named separate group of data

Question 11

Directory (folder)

Answer 11

a named collection of files and other directories (subdirectories)

Question 12

Directory/file path

Answer 12

a branching list of directories containing the directory/file, for example “C:\Users\Peter\Documents\MyDocument.doc”

Question 13

Memory manager

Answer 13

Allocates/deallocates main memory to processes.

Question 14

Paging

Answer 14

rotates (pages of) programs and data back and forth between main memory and mass storage.

Question 15

Virtual memory

Answer 15

the computer works as if it has more main memory (using paging) than the actual physical main memory

Question 16

Bootstrapping

Answer 16

the start up process of a computer.

Question 17

Boot loader

Answer 17

a program stored in ROM (non-volatile read only memory), which is run by the CPU when power is turned on

Question 18

Process

Answer 18

the activity of executing a program

Question 19

Scheduler

Answer 19

keeps track of all processes by maintaining a process table (stored in main memory). [Task Manager]

Question 20

Dispatcher

Answer 20

controls the allocation of time slices (for execution) to the processes in the process table.

Question 21

process switch

Answer 21

The procedure of changing from one process to another

Question 22

Critical region

Answer 22

a group of instructions that should be executed by only one process at a time

Question 23

Mutual exclusion

Answer 23

the requirement that only one process at a time is allowed to execute a critical region

Question 24

Semaphore

Answer 24

a flag that controls a critical region to obtain mutual exclusion

Question 25

Test-and-set

Answer 25

a machine instruction that both tests and sets a flag (in the same non-interruptible instruction).

Question 26

Deadlock

Answer 26

Processes block each other from continuing

Question 27

Conditions required for deadlock:

Answer 27

* competition for non-sharable resources, * resources requested on a partial basis, * allocated resources cannot be forcibly retrieved.

Question 28

Spooling

Answer 28

holding data for output at a later more convenient time (example: printer)