Chap 10

Question 1

A loosely coupled or distributed multiprocessor consists of a collection of relatively autonomous systems, with each processor having its own main memory and I/O channels.

Answer 1

True

Question 2

With independent parallelism, there is an explicit synchronization among processes

Answer 2

False

Question 3

A typical use of independent parallelism is in a time-sharing system

Answer 3

True

Question 4

A disadvantage of static assignment is that one processor can be idle, with an empty queue, while another processor has a backlog.

Answer 4

True

Question 5

In most traditional multiprocessor systems processes are dedicated to processors.

Answer 5

False

Question 6

An application can be implemented as a set of threads, which cooperate and execute concurrently in the same address space

Answer 6

True

Question 7

Because of the potential disadvantages, load sharing is not one of the commonly used schemes in current multiprocessors.

Answer 7

False

Question 8

The operating system, and in particular the scheduler, is perhaps the most important component of a real-time system.

Answer 8

True

Question 9

One useful measure of the ability of an operating system to function deterministically is the maximum delay from the arrival of a high-priority device interrupt to when servicing begins.

Answer 9

True

Question 10

User control is generally much broader in an ordinary operating system than in a real-time operating system.

Answer 10

False

Question 11

Static table-driven scheduling is applicable to tasks that are periodic.

Answer 11

True

Question 12

One of the more promising methods of resolving multitask scheduling conflicts for periodic tasks is rate monotonic scheduling.

Answer 12

True

Question 13

Real-time tasks are not handled any differently than non-real-time tasks in the priority queues.

Answer 13

False

Question 14

Linux provided a real-time scheduling capability coupled with a scheduler for non-real-time processes that made use of the traditional UNIX scheduling algorithm

Answer 14

True

Question 15

In the real-time-priority class, all threads have a fixed priority that never changes and all of the active threads at a given priority level are in a round-robin queue.

Answer 15

True

Question 16

The multiprocessor system which consists of a set or processors that share a common main memory and are under the integrated control of an operating system is a _________ .

Answer 16

tightly coupled multiprocessor

Question 17

With coarse and __________-grained parallelism, there is synchronization among processes, but at a very gross level.

Answer 17

very coarse

Question 18

An example of __________ is an I/O processor.

Answer 18

functionally specialized processors

Question 19

A __________ is one that must meet its deadline, otherwise it will cause unacceptable damage or a fatal error to the system.

Answer 19

hard real-time task

Question 20

Typically, there will need to be a rather high degree of coordination and interaction among the threads of an application, leading to a __________ level of synchronization.

Answer 20

medium grain

Question 21

The __________ approach is a set of related threads scheduled to run on a set of processors at the same time, on a one-to-one basis.

Answer 21

gang scheduling

Question 22

A _________ has an associated deadline that is desirable but not mandatory.

Answer 22

soft real-time task

Question 23

With the __________ approach the number of threads in a process can be altered during the course of execution.

Answer 23

dynamic scheduling

Question 24

__________ perform static analysis of feasible schedules of dispatching with the result of the analysis being a schedule that determines, at run time, when a task must begin execution.

Answer 24

Static table-driven approaches

Question 25

__________ is the time required to execute the task to completion.

Answer 25

Processing time

Question 26

The basic idea of _________ is that a lower-priority task inherits the priority of any higher-priority task pending on a resource they share.

Answer 26

priority inheritance

Question 27

In the __________ approach, a priority is associated with each resource.

Answer 27

priority ceiling

Question 28

Processes at _________ priority levels are guaranteed to be selected to run before any time-sharing process but must defer to real-time processes.

Answer 28

kernel

Question 28

__________ is the lowest-priority process, intended for user applications other than real-time applications.

Answer 28

Time-shared

Question 29

The __________ class is intended for applications that will only consume processor time when no other threads are ready to execute.

Answer 29

idle user

Question 30

A good way of characterizing multiprocessors and placing them in context with other architectures is to consider the synchronization __________, or frequency of synchronization, between processes in a system.

Answer 30

granularity

Question 31

Linux uses _________ , in which threads are moved for a queue for one processor to a queue for another processor.

Answer 31

dynamic load balancing

Question 32

In a __________ architecture, the kernel can execute on any processor, and each processor does self-scheduling from the pool of available processes.

Answer 32

peer

Question 33

The _________ approach is the opposite of the load-sharing approach and provides implicit scheduling defined by the assignment of threads to processors.

Answer 33

dedicated processor assignment

Question 34

__________ is useful for medium-grained to fine-grained parallel applications whose performance severely degrades when any part of the application is not running while other parts are ready to run.

Answer 34

gang scheduling

Question 35

__________ computing is defined as that type of computing in which the correctness of the system depends not only on the logical result of the computation but also on the time at which the results are produced.

Answer 35

real-time

Question 36

An _________ has a deadline by which it must finish or start, or it may have a constraint on both start and finish time.

Answer 36

aperiodic task

Question 37

An operating system is __________ to the extent that it performs operations at fixed, predetermined times or within predetermined time intervals.

Answer 37

deterministic

Question 38

_________ is a characteristic that refers to the ability of a system to fail in such a way as to preserve as much capability and data as possible.

Answer 38

Fail-soft operation

Question 39

No feasibility analysis is performed with __________ approach, and the system tries to meet all deadlines and aborts any started process whose deadline is missed.

Answer 39

dynamic best effort

Question 40

__________ is the time at which a task becomes ready for execution.

Answer 40

ready time

Question 41

For __________ scheduling, the highest-priority task is the one with the shortest period, the second highest-priority task is the one with the second shortest period, and so on.

Answer 41

rate monotonic

Question 42

__________ occurs when circumstances within the system force a higher-priority task to wait for a lower-priority task.

Answer 42

Priority inversion

Question 43

Processes at _________ priority levels are guaranteed to be selected to run before any kernel or time-sharing process.

Answer 43

real-time

Question 44

A thread is considered to be _________ if the ratio of its voluntary sleep time versus its runtime is below a certain threshold.

Answer 44

interactive