Operating Systems Concepts Quiz 1 8e

A large job can have problems with a first-fit memory allocation scheme.

True

A variation of the LRU page replacement algorithm known as the clock page replacement policy is implemented using a pointer to step through the reference bits of the active pages, simulating a clockwise motion.

True

In the bit-shifting variation of the LRU page replacement policy, the process of shifting bits to the right and resetting the leftmost bit to 1 when a page is referenced gives a history of each page's usage.

True

Memory defragmentation is performed by the operating system to reclaim fragmented space.

True

One of the problems with the best-fit algorithm is that the entire table must be searched before the allocation can be made because the memory blocks are physically stored in sequence according to their location in memory.

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 bounds register is used to store the highest (or lowest, depending on the specific system) location in memory accessible by each program.

True

The optimal selection of cache size and replacement algorithm can result in 80 to 90 percent of all requests being in the cache.

True

The ____ method keeps the free/busy lists organized by memory locations, from low-order memory to high-order memory.

first-fit memory allocation

The most common mechanism for implementing multiprogramming was the introduction of the ____ concept, whereby the CPU was notified of events needing operating systems services.

interrupt

The four memory management techniques presented in this chapter share the requirement that the entire program being executed must be ____.

loaded into memory

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

locality of reference

A(n) ____ in the busy list occurs when a memory block between two other busy memory blocks is returned to the free list.

null entry

By compacting and relocating, the Memory Manager optimizes the use of memory and thus improves throughput. However, it also requires more ____ than the other memory allocation schemes discussed in this chapter.

overhead

One approach to performing compaction is to do it when a certain ____ of memory becomes busy.

percentage

Main memory is also known as ____.

random access memory

Single-user, fixed partition, and dynamic partition memory schemes share unacceptable fragmentation characteristics that were resolved with the development of ____.

relocatable dynamic partitions

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

A hybrid system is a combination of ____ systems.

batch and interactive

In a relocatable dynamic partition scheme, the ____ ensures that, during execution, a program won't try to access memory locations that don't belong to it.

bounds register

Starting in the 1950s, to reduce the discrepancy in speed between the I/O and the CPU, an interface called the ____ was placed between them to act as a buffer.

control unit

Single-user contiguous allocation schemes have the problem of partition intrusion.

False

The best-fit allocation method keeps the free/busy lists organized by memory locations, low-order memory to high-order memory.

False

The content of a random access memory (RAM) chip is nonvolatile, meaning that it is not erased when the power is turned off.

False

The key to the successful implementation of demand paging is the use of a high-speed CPU.

False

With distributed operating systems, users need to be aware of which processor is actually running their applications.

False

____ is where the data and instructions of a computer must reside to be processed.

Main memory

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, pages are ____ between main memory and secondary storage.

swapped

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

the segment number and the displacement

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

thrashing

The efficiency of a batch system is measured in ____, which is the number of jobs completed in a given amount of time.

throughput

In active multiprogramming, each program is allowed to use only a preset amount of CPU time before it is interrupted so another job can begin its execution. The interrupted job resumes execution at some later time. This idea is called ____.

time slicing

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

very long Page Map Tables

A system with ____ divides programs into parts and keep them in secondary storage, bringing each part into memory only as it is needed.

virtual memory

____ systems are used in time-critical environments where reliability is key and data must be processed within a strict time limit.

Real-time

In active multiprogramming schemes, a job can monopolize the CPU for a long time while all other jobs waited.

False

The word ____ is used to indicate that a program is permanently held in ROM (read only memory), as opposed to being held in secondary storage.

firmware

The ____ uniquely identifies each resource, starts its operation,monitors its progress, and, finally, deallocates it, making the operating system available to the next waiting process.

Device Manager

____ 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 the practice of using Internet-connected resources to perform processing, storage, or other operations.

Cloud computing

____ of memory is performed by the operating system to reclaim fragmented sections of the memory space.

Compaction

Fixed partitions are also called ____ partitions.

Complete

General-purpose operating systems such as Linux or Windows are used in embedded systems.

False

____ consists of fragments of free memory between blocks of allocated memory.

External fragmentation

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

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

____ effectively removes restrictions on maximum program size.

Virtual memory

____ allows separate partitions of a single server to support different operating systems.

Virtualization