Chap 10 Flashcards
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.
True
With independent parallelism, there is an explicit synchronization among processes
False
A typical use of independent parallelism is in a time-sharing system
True
A disadvantage of static assignment is that one processor can be idle, with an empty queue, while another processor has a backlog.
True
In most traditional multiprocessor systems processes are dedicated to processors.
False
An application can be implemented as a set of threads, which cooperate and execute concurrently in the same address space
True
Because of the potential disadvantages, load sharing is not one of the commonly used schemes in current multiprocessors.
False
The operating system, and in particular the scheduler, is perhaps the most important component of a real-time system.
True
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.
True
User control is generally much broader in an ordinary operating system than in a real-time operating system.
False
Static table-driven scheduling is applicable to tasks that are periodic.
True
One of the more promising methods of resolving multitask scheduling conflicts for periodic tasks is rate monotonic scheduling.
True
Real-time tasks are not handled any differently than non-real-time tasks in the priority queues.
False
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
True
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.
True
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 _________ .
tightly coupled multiprocessor
With coarse and __________-grained parallelism, there is synchronization among processes, but at a very gross level.
very coarse
An example of __________ is an I/O processor.
functionally specialized processors
A __________ is one that must meet its deadline, otherwise it will cause unacceptable damage or a fatal error to the system.
hard real-time task
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.
medium grain
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.
gang scheduling
A _________ has an associated deadline that is desirable but not mandatory.
soft real-time task
With the __________ approach the number of threads in a process can be altered during the course of execution.
dynamic scheduling
__________ 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.
Static table-driven approaches
__________ is the time required to execute the task to completion.
Processing time
The basic idea of _________ is that a lower-priority task inherits the priority of any higher-priority task pending on a resource they share.
priority inheritance
In the __________ approach, a priority is associated with each resource.
priority ceiling
Processes at _________ priority levels are guaranteed to be selected to run before any time-sharing process but must defer to real-time processes.
kernel
__________ is the lowest-priority process, intended for user applications other than real-time applications.
Time-shared
The __________ class is intended for applications that will only consume processor time when no other threads are ready to execute.
idle user
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.
granularity
Linux uses _________ , in which threads are moved for a queue for one processor to a queue for another processor.
dynamic load balancing
In a __________ architecture, the kernel can execute on any processor, and each processor does self-scheduling from the pool of available processes.
peer
The _________ approach is the opposite of the load-sharing approach and provides implicit scheduling defined by the assignment of threads to processors.
dedicated processor assignment
__________ 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.
gang scheduling
__________ 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.
real-time
An _________ has a deadline by which it must finish or start, or it may have a constraint on both start and finish time.
aperiodic task
An operating system is __________ to the extent that it performs operations at fixed, predetermined times or within predetermined time intervals.
deterministic
_________ 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.
Fail-soft operation
No feasibility analysis is performed with __________ approach, and the system tries to meet all deadlines and aborts any started process whose deadline is missed.
dynamic best effort
__________ is the time at which a task becomes ready for execution.
ready time
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.
rate monotonic
__________ occurs when circumstances within the system force a higher-priority task to wait for a lower-priority task.
Priority inversion
Processes at _________ priority levels are guaranteed to be selected to run before any kernel or time-sharing process.
real-time
A thread is considered to be _________ if the ratio of its voluntary sleep time versus its runtime is below a certain threshold.
interactive
