CSC 351 - Chapter 13

Question 1

Concurrency Occurance

Answer 1

• machine instruction level
• high level language statement level
• unit level
• program level

Question 2

Physical Concurrency

Answer 2

• multiple threads of control (All Independent)

Question 3

Logical Concurrency

Answer 3

• design as if there were multiple threads of control (appearance of physical concurrency using one processor)

Question 4

Thread of Control

Answer 4

• sequence of program points reached as control flows through a program

Question 5

Task/Process/Thread

Answer 5

• program unit that can be in concurrent execution with other program units

Question 6

Heavyweight Tasks

Answer 6

• execute in its own address space

Question 7

Lightweight Tasks

Answer 7

• run it the same address space

Question 8

Cooperation

Answer 8

• one task must wait for another task to complete some activity before it can continue executing

Question 9

Competition

Answer 9

• two or more tasks must use a resource that cannot be simultaneously used

Question 10

Liveness

Answer 10

• unit will eventually complete its execution

- concurrent tasks can easily lose its liveness

Question 11

Deadlock

Answer 11

• when all concurrent tasks lose their liveness

Question 12

Semaphore

Answer 12

• data structure that has a counter and a queue for storing task descriptors
• has two operations: wait and release

Question 13

Monitor

Answer 13

• abstract data type for shared data