midterm 2

The ____ is also called a high-level scheduler.

Job Scheduler

In a paged memory allocation scheme, a simple ____ has one entry for each page frame that shows its location and its free/busy status.

Memory Map Table

The transition from ____ can be initiated by the Process Scheduler or the Job Scheduler.

RUNNING to FINISHED

Each thread in a process is represented by a data structure called a ____ that contains basic information such as the thread's unique identification, state, and priority.

Thread Control Block

____ allows for faster turnaround of CPU-bound jobs.

Variable time quantum per queue

Some systems use a strategy known as ____ to increase the priority of jobs that have been in the system for an unusually long time in order to expedite their exit.

aging

The Job Scheduler seeks to ____ when scheduling jobs.

balance CPU and I/O intensive jobs

The first-come, first-served (FCFS) algorithm is fine for most ____ systems.

batch

The purpose of cache memory is to keep handy the most recently accessed data and instructions so that the CPU can access them repeatedly without wasting time. This purpose is similar to that of the ____ of a Web browser.

bookmark file

A variation of the LRU page replacement algorithm known as the ____ replacement policy is implemented with a circular queue.

clock page

A disadvantage of segmented memory allocation is ____.

external fragmentation

A job's state moves from HOLD to WAITING when it's ready to run but is waiting for the CPU.

false

A program is an active entity that requires a set of resources, including a processor and special registers, to perform its function.

false

CPU-bound jobs (such as printing a series of documents) have many brief CPU cycles and long I/O cycles.

false

Dual core or quad core multi-core chips are larger than a single-processor chip but produce less current leakage and heat.

false

First-come, first-served (FCFS) is a preemptive scheduling algorithm that handles jobs according to their arrival time.

false

Paged memory allocation offers the advantage that it doesn't require the entire job to be stored in memory during its execution.

false

The Processor Manager is a composite of at least two submanagers: one in charge of job scheduling and the other in charge of program scheduling.

false

The control program that handles the interruption sequence of events is called the event scheduler.

false

The shortest remaining time (SRT) algorithm is often used in interactive systems.

false

When using priority scheduling, priorities are assigned to jobs by the owner of the job (the user).

false

The ____ page replacement policy is based on the theory that the best page to remove is the one that has been in memory the longest.

fifo

No movement between queues is a very simple policy that rewards those who have ____ jobs.

high-priority

In a paged memory allocation scheme, the ____ contains two values for each active job: the size of the job and the memory location where its Page Map Table is stored.

job table

The term "____" means that during any phase of its execution, a program references only a small fraction of its pages.

locality of reference

The primary advantage of storing programs in noncontiguous locations is that ____.

main memory is used more efficiently

____ requires that the processor be allocated to each job or to each process for a period of time and deallocated at an appropriate moment.

multiprogramming

An I/O request is called a(n) ____ wait in multiprogramming environments.

natural

The Process Scheduler assigns the CPU to execute the processes for those jobs placed on the ____ queue by the Job Scheduler.

ready

With segmented memory allocation, each job is divided into several ____ of different sizes, one for each module that contains pieces that perform related functions.

segments

Cache memory is divided into blocks of equal size called ____.

slots

In demand paging schemes, the ____ in a Page Map Table indicates whether the page is currently in memory.

status bit

In demand paging, pages are ____ between main memory and secondary storage.

swapped

When the operating system detects a nonrecoverable error, the following step is performed first by the interrupt handler: ____.

the type of interrupt is described and stored

In demand paging, when an excessive number of pages are moved back and forth between main memory and secondary storage, it is called ____.

thrashing

A(n) ____ is created by a process, and it can be scheduled and executed independently of its parent process.

thread

A processor is also known as a CPU.

true

A single processor can be shared by several jobs, or several processes, but only if the operating system has a scheduling policy, as well as a scheduling algorithm, to determine when to stop working on one job and proceed to another.

true

As a process moves through the system, its status changes. Possible process statuses include FINISHED, HOLD, READY, RUNNING, and WAITING.

true

Context switching is required by all preemptive algorithms.

true

Demand paging introduced the concept of loading only a part of the program into memory for processing

true

If one job monopolizes the system, the extent of its overall effect on system performance depends on the scheduling policy and whether the job is CPU-bound or I/O-bound.

true

In Round Robin scheduling, if processing isn't finished when time expires, the job is preempted and put at the end of the READY queue and its information is saved in its Process Control Block.

true

In a paged memory allocation scheme, to find the actual position of an instruction in memory, first the page number and displacement are determined. Then the operating system refers to the job's PMT to correlate the page with its page frame.

true

It is possible to minimize response time by running only interactive jobs and letting batch jobs wait until the interactive load ceases.

true

Most computer programs alternate between CPU cycles and I/O cycles.

true

Shortest job next (SJN) is a nonpreemptive scheduling algorithm (also known as shortest job first, or SJF) that handles jobs based on the length of their CPU cycle time.

true

The Job Table (JT) contains two values for each active job: the size of the job and the memory location where its Page Map Table is stored.

true

The primary advantage of storing programs in noncontiguous page frames (in a paged memory allocation scheme) is that main memory is used more efficiently because an empty page frame can be used by any page of any job.

true

Web browsers use multithreading routinely. For example, one thread can retrieve images while another sends and retrieves e-mail.

true

When using a multiple-level queue strategy, aging is used to ensure that jobs in lower-level queues will eventually complete their execution.

true

In a paged memory allocation scheme, a page size that is too small will generate ____.

very long Page Map Tables

One of the most important innovations of demand paging is that it makes ____ feasible.

virtual memory

____ effectively removes restrictions on maximum program size.

virtual memory

In demand paging, the collection of pages residing in memory that can be accessed directly without incurring a page fault is called the ____.

working set

To access a location in memory when using segmented memory management, the address is composed of two entries: ____.

. the segment number and the displacement

Assume that jobs A-D arrive in the READY queue in quick succession and have the CPU cycle requirements listed below. Using the SRT algorithm, the average turnaround time is ____.

6.25

A general rule of thumb for selecting a proper time quantum in Round Robin scheduling is that it should be long enough to allow ____ percent of the CPU cycles to run to completion.

80

Assume that four jobs, A-D, require the CPU cycles listed below. Using the SJN algorithm, the average turnaround time is ____. Job: A B C D CPU cycle: 5 2 6 4

9.0

Assume that four jobs, A-D, are in the READY queue at Time 0 and require the CPU cycles listed below. Using the SJN algorithm, the ____ job is run first. Job: A B C D CPU cycle: 5 2 6 4

B

The ____ demonstrates that when using a FIFO policy, in rare cases, adding more memory to a system can cause an increase in page interrupts.

Belady Anomaly

____ can be thought of as being an intermediary between main memory and the special-purpose registers, which are the domain of the CPU.

Cache memory

____ is a dynamic-priority preemptive scheduling algorithm built to address the critical processing requirements of real-time systems and their pressing deadlines.

Earliest Deadline First

When a job is accepted by the system, it's put on ____ and placed in a queue.

HOLD

The transition from ____ is initiated by the Job Scheduler according to some predefined policy. At this point, the availability of enough main memory and any requested devices is checked.

HOLD to READY