Ch5-8 cps590

When a new block of data is read into the cache the __________ determines which cache location the block will occupy.

mapping function

Most operating systems contain two fundamental forms of concurrent activity: processes and _________ .

interrupts

A process or task in Linux is represented by a __________ data structure.

task_struct

The Clouds operating system implements the concept of a thread as primarily an entity that can move among address spaces which represents the __________ Thread-to-Process relationship.

clouds operating system

It is necessary to __________ the activities of various threads so they do not interfere with each other or corrupt data structures.

synchronize

The basic form of communication between processes or threads in a microkernel operating system is _________ .

message

The management of multiple processes within a uniprocessor system is __________ .

A) multiprogramming

B) structured applications

C) distributed processing

D) multiprocessing

multiprogramming

A situation in which a runnable process is overlooked indefinitely by the scheduler, although it is able to proceed, is __________ .

A) mutual exclusion

B) deadlock

C) starvation

D) livelock

starvation

The requirement that when one process is in a critical section that accesses shared resources, no other process may be in a critical section that accesses any of those shared resources is _________ .

A) critical section

B) livelock

C) mutual exclusion

D) atomic operation

mutual exclusion

A means for two processes to exchange information is with the use of ___________ .

A) spinlocks

B) event flags

C) condition variables

D) messages

messages

A semaphore that does not specify the order in which processes are removed from the queue is a _________ semaphore.

A) weak

B) general

C) strong

D) binary

weak

A _________ occurs when multiple processes or threads read and write data items so that the final result depends on the order of execution of instructions in the multiple processes.

A) atomic operation

B) race condition

C) livelock

D) deadlock

race condition

A _________ is an integer value used for signaling among processes.

A) semaphore

B) message

C) mutex

D) atomic operation

semaphore

_________ is when the sequence of instruction is guaranteed to execute as a group, or not execute at all, having no visible effect on system state.

A) Critical section

B) Mutual exclusion

C) Atomic operation

D) Starvation

Atomic operation

__________ are memory words used as a synchronization mechanism.

A) Semaphores

B) Event flags

C) Counting semaphores

D) Mailboxes

Event flags

The term _________ refers to a technique in which a process can do nothing until it gets permission to enter its critical section but continues to execute an instruction or set of instructions that tests the appropriate variable to gain entrance.

A) spin waiting

B) general semaphore

C) critical resource

D) message passing

spin waiting

A _________ is a data type that is used to block a process or thread until a particular condition is true.

A) deadlock

B) general semaphore

C) condition variable

D) mutex

condition variable

A semaphore whose definition includes the policy that the process that has been blocked the longest is released from the queue first is called a __________ semaphore.

A) general

B) strong

C) weak

D) counting

strong

The _________ is a programming language construct that provides equivalent functionality to that of semaphores and is easier to control.

A) atomic operation

B) coroutine

C) critical section

D) monitor

monitor

Probably the most useful combination, __________ allows a process to send one or more messages to a variety of destinations as quickly as possible.

A) blocking send, blocking receive

B) nonblocking send, blocking receive

C) nonblocking send, nonblocking receive

D) blocking send, nonblocking receive

nonblocking send, blocking receive

A __________ relationship allows multiple server processes to provide concurrent service to multiple clients.

A) many-to-many

B) one-to-many

C) many-to-one

D) one-to-one

many-to-many

_________ arises in three different contexts: multiple applications, structured applications, and operating system structure.

concurrency

_________ was invented to allow processing time to be dynamically shared among a number of active applications.

multiprogramming

A situation in which two or more processes are unable to proceed because each is waiting for one of the others to do something is a __________ .

deadlock

In the case of competing processes three control problems must be faced: mutual exclusion, deadlock, and __________ .

starvation

A ___________ is a semaphore that takes on only the values of 0 and 1.

binary

A situation in which multiple threads or processes read and write a shared data item and the final result depends on the relative timing of their execution is a __________ .

race condition

__________ is a function or action implemented as a sequence of one or more instructions that appears to be indivisible; no other process can see an intermediate state or interrupt the operations.

atomic operation

A __________ is a programming language construct that encapsulates variables, access procedures, and initialization code within an abstract data type.

monitor

_________ is a section of code within a process that requires access to shared resources and that must not be executed while another process is in a corresponding section of code.

critical section

In the case of __________ , processes are sharing resources without being aware of the other processes.

competition

A _________ is a mutual exclusion mechanism in which a process executes in an infinite loop waiting for the value of a lock variable to indicate availability.

spinlocks

Only three operations may be performed on a semaphore: initialize, increment, and __________ .

Decrement

A monitor supports synchronization by the use of __________ that are contained within the monitor and accessible only within the monitor.

condition variables

In the case of _________ , messages are not sent directly from sender to receiver but rather are sent to a shared data structure consisting of queues that can temporarily hold messages.

indirect addressing

The classic concurrency problem that involves multiple readers that can read from a shared data area when no single writer is exclusively writing to it is the _________ Problem.

readers/writers

_________ can be defined as the permanent blocking of a set of processes that either compete for system resources or communicate with each other.

Deadlock

A _________ resource is one that can be safely used by only one process at a time and is not depleted by that use.

Reusable

A _________ resource is one that can be created and destroyed.

Consumable

The _________ is a directed graph that depicts a state of the system of resources and processes, with each process and each resource represented by a node.

Resource Allocation Graph

Three conditions of policy must be present for a deadlock to be possible: mutual exclusion, no preemption, and _________ .

Hold and Wait

Three general approaches exist for dealing with deadlock: prevent, avoid, and __________ .

Detect

__________ allows the three necessary conditions but makes judicious choices to assure that the deadlock point is never reached.

Avoidance

The strategy of resource allocation denial is referred to as the ___________ .

Banker's Algorithm

The _________ of the system reflects the current allocation of resources to processes.

State

_________ strategies are very conservative and solve the problem of deadlock by limiting access to resources and by imposing restrictions on processes.

Prevention

Inspired by the concept of co-routines, a _________ is a circular buffer allowing two processes to communicate on the producer-consumer model.

Pipe

Two types of atomic operations are defined in Linux: integer operations and __________ .

Bitmap Operations

Linux provides three types of semaphore facilities in the kernel: binary semaphores, counting semaphores, and __________ .

Reader-Writer Semaphores

An executable entity within a process is a __________ object.

Thread

A program invocation, including the address space and resources required to run the program is a __________ object.

Process

In a uniprogramming system main memory is divided into two parts.

True

The use of unequal size partitions provides a degree of flexibility to fixed partitioning.

True

In a multiprogramming system the available main memory is not generally shared among a number of processes.

False

Programs in other processes should not be able to reference memory locations in a process for reading or writing purposes without permission.

True

The memory protection requirement must be satisfied by the operating system rather than the processor.

False

Any protection mechanism must have the flexibility to allow several processes to access the same portion of main memory.

True

Secondary memory provides fast access at relatively high cost.

False

A hardware mechanism is needed for translating relative addresses to physical main memory addresses at the time of execution of the instruction that contains the reference.

True

In a multiprogramming environment the programmer knows at the time of coding how much space will be available and where that space will be.

False

Overlay programming wastes programmer time.

True

The principal operation of memory management is to bring processes into main memory for execution by the processor.

True

A physical address is the location of a word relative to the beginning of the program and the processor translates that into a logical address.

True

The best-fit algorithm is usually the worst performer.

True

All segments of all programs must be of the same length.

False

Segmentation does not eliminate internal fragmentation.

False

The task of subdividing memory to accommodate multiple processes is carried out dynamically by the operating system and is known as ___________ .

memory management

A __________ is a variable length block of data that resides in secondary memory.

Segment

In a practice known as _________ , the program and data are organized in such a way that various modules can be assigned the same region of memory with a main program responsible for switching the modules in and out as needed.

overlaying

A __________ is an actual location in main memory.

physical address

A fixed length block of data that resides in secondary memory is a __________ .

Page

When there is wasted space internal to a partition due to the fact that the block of data loaded is smaller than the partition is referred to as __________.

internal fragmentation

_________ in a computer system is organized as a linear, or one-dimensional, address space, consisting of a sequence of bytes or words.

main memory

A _________ is a fixed length block of main memory.

Frame

As time goes on, memory becomes more and more fragmented and memory utilization declines, creating a phenomenon referred to as _________ .

External Fragmentation

A compromise to overcome the disadvantages of fixed partitioning and dynamic partitioning is the __________ .

Buddy System

A __________ is a reference to a memory location independent of the current assignment of data to memory.

Logical Address

The __________ shows the frame location for each page of the process.

Page Table

A __________ can occur as a result of a programming error when a process attempts to store data beyond the limits of a fixed-sized buffer and consequently overwrites adjacent memory locations.

Buffer Overflow

Countermeasures to defend systems against attacks can be classified into two categories: compile-time defenses and _________ .

Run-Time Defenses

The basic tools of memory management are paging and __________ .

segmentation

The size of virtual storage is limited by the actual number of main storage locations.

False

The addresses a program may use to reference memory are distinguished from the addresses the memory system uses to identify physical storage sites.

True

Most of the memory management issues confronting the operating system designer are in the area of paging when segmentation is combined with paging.

True

Segmentation is not visible to the programmer.

False

The placement policy determines where in real memory a process piece is to reside.

True

Virtual memory allows for very effective multiprogramming and relieves the user of the unnecessarily tight constraints of main memory.

True

The principle of locality states that program and data references within a process do not tend to cluster.

False

The smaller the page size, the greater the amount of internal fragmentation.

False

The design issue of page size is related to the size of physical main memory and program size.

True

Segments may be of unequal, indeed dynamic, size.

True

The page currently stored in a frame may still be replaced even when the page is locked.

False

One way to counter the potential performance problems of a variable-allocation global scope policy is to use page buffering.

True

The PFF policy evaluates the working set of a process at sampling instances based on elapsed virtual time.

False

A precleaning policy writes modified pages before their page frames are needed so that pages can be written out in batches.

True

UNIX is intended to be machine independent; therefore its memory management scheme will vary from one system to the next.

True

The address assigned to a location in virtual memory to allow that location to be accessed as though it were part of main memory is the __________ .

virtual address

_________ is a storage allocation scheme in which secondary memory can be addressed as though it were part of main memory.

virtual memory

The size of virtual storage is limited by the addressing scheme of the computer system and by the amount of __________ available.

secondary memory

The __________ policy treats the page frames allocated to a process as a circular buffer and pages are removed in round robin style.

FIFO