Operating Systems Final (ch 9-14)

the operating system must make ____ types of scheduling decisions with respect to the execution of processes.

3

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

False

a file is a collection of fields, which is in turn a collection of related records.

False

access right are managed at the physical organization layer

False

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

False

eCos has a fixed scheduling algorithm that cannot be changed at configuration time.

False

in most traditional multiprocessor systems processes are dedicated to processors

False

in the c-scan disk scheduling algorithm, the disk arm is required to move in one direction only until it reaches the last track or there are no more requests to service in that direciton, then it reverses direction and the scan proceeds in the opposite direction in the same fashion.

False

in the highest response ration next (HRRN) scheduling policy, longer jobs are favored because they yield a larger ratio from the smaller denominator in the equation.

False

many tinyOS configurations are multiprocessor.

False

most embedded systems use an general-purpose OS usch a linux or a modification of a general-purpose OS.

False

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

False

reliability problems can occur when the disk allocation table and file allocation table are stored on disk.

False

the address information element of a file directory maintains data about the owner of the file, the file access information, and a list of actions permitted on the file.

False

the cluster is not the fundamental unit in NTFS

False

the eCos bitmap scheduler allows up to 16 threads at each priority levels.

False

the medium-term scheduler is invoked whenever an event occurs that may lead to the blocking of the current process or that may provide an opportunity to preempt a currently running process in favor of another.

False

the use to wich a device is put does not have an influence on the software and policies in the operating system and supporting utilities

False

tinyOS is NOT designed with wireless sensor networks in mind

False

typically, embedded systems do not have real-time requirements

False

windows has no way to support the encryption of entire volumes

False

with independent parallelism there is an explicit synchronization among processes.

False

RAID 5 is organized in a similar fashion to ___, but is different in the fact that RAID 5 distributes the parity strips across all disks.

RAID 4

the advantage of ___ is that it provides extremely high data availablity.

RAID 6

A disadvantage for simulation is that results for a given run only apply to that particular collection of processes under that particular set of assumptions

True

A key aspect of I/O is the use of buffers that are controlled by I/O utilities rather than by application processes.

True

Direct memory access is the dominant form of transfer that must be supported by the operating system.

True

RAID is a set of physical disk drives viewed by the operating system as a single logical drive.

True

The term embedded system refers to the use of electronics and software within a product, as opposed to a general-purpose computer, such as a laptop or desktop system.

True

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

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

True

an embedded software system built using tinyOS consists of a set of small modules, called components, each of which performs a simple task or set of tasks and which interface with each other and with hardware in limited and well defined ways.

True

at the lowest level of the file system architecture, device drivers communicate directly with peripheral devices or their controllers or channels

True

cache memory reduces average memory access time by exploiting the principle of locality.

True

device drivers are separate packages and not integrated into the eCos kernel

True

double buffering is when a process transfers data to (or from) one buffer while the operating system empties (or fills) the other.

True

eCos makes use of a configuration tool that runs on Windows and Linux to configure an eCos package to run on a target embedded system

True

examples of human readable external I/O devices are printers, terminals, and keyboards.

True

in most interactive operating systems adequate response time is a critical requirement

True

in the free block list strategy of free disk space management, each block is assigned a number sequentially and the list of the numbers of all free blocks is maintained in a reserved portion of the disk.

True

in the general indexed file structure, there are no key fields and variable-length records are allowed.

True

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

True

one problem with a pure priority scheduling scheme is that lower priority processes may suffer starvation

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

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

True

the hierarchical philosophy is that the functions of the operating system should be separated according to their complexity, their characteristic time scale, and their level of abstraction.

True

the key field in a sequential file acts as an identifier for each record and must therefore be unique to that record

True

the traditional unix scheduler employs multilevel feedback using round robin within each of the priority queues

True

the unix kernel views all files as streams of bytes, any internal logical structure is application specific

True

tinyOS provides a virualized resource interface as an option.

True

two of the most widely used approaches to improve disk I/O performance are disk scheduling and disk cache

True

typically, an interactive user or a process has associated with it a current directory, often referred to as the working directory.

True

file allocation in a UNIX system has the following characteristics:

dynamic allocation using non-contiguous blocks with indexing

with the ____ approach the numer of threads in a process can be altered during the course of execution.

dynamic scheduling

____ is one of the most widely used embedded operating systems.

eCos

indexed sequential files similar to sequential files, but contain two added features:

file index and overflow file

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

the _____ category of external devices are suitable for communicating with the computer user

human readable

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

idle user

fixed file blocking experiences the following potential problem:

internal fragmentation

processes at ____ priority levels are guarenteed to be selected to run before any time-sharing process but must defer to real-time processes

kernel

the level of the file system architecture that enables users and applications to access file records is called the:

logical I/O level

this is a decision whether to add a new process to the set of processes that are currently active:

long-term scheduling

____ external devices are suitable for communicating with electronic equipment

machine readable

the technique of free disk space management that employs a pointer and length value of each free portion is the:

none of the above

which scheduling policy allows the OS to interrupt the currently running process and move it to the ready state?

preemptive

in the ___ approach, a priority is associated with each resource.

priority ceiling

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

the ____ determines which process, among ready processes, is selected next for execution

selection function

____ are an efficient way of making consistent snapshots of volumes so that they can be backed up.

shadow copies

the decision as to which available process will be executed by the processor:

short-term scheduling

The traditional unix scheduler divides processes into fixed bands of priority levels, with the highest priority band being the _____ .

swapper band

typically, the swapping-in function for processes is based on the need to manage ____ .

the degree of multiprogramming

The one portion of tinyOS that must be present in all systems is:

the scheduler

Which of the following characterizes a mutex:

the thread that locks the mutex must be the one to unlock it working directory

task switching latency is:

the time it takes from when a thread becomes available to when actual execution begins

interrupt latency is:

the time it takes to respond to an interrupt and begin executing an interrupt service routine

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

time-shared

response time in an interactive system is an example of:

user-oriented criteria for short-term scheduling policies

with coarse and ___ grained parallelism, there is synchronization among processes, but at a very gross level

very coarse

which of the following does not properly characterize eCos:

works best with predictable rather than real-time requirements

the ___ unit is capable of mimicking the processor and of taking over control of the system bus just like a processor.

direct memory access

_____ considers the execution history of a related group of processes along with the individual execution of each process in making decisions.

FSS (fair share scheduling)

Events in TinyOS must be tied directly to hardware events

False

FCFS performs much better for short processes than long ones

False

First-come-first-served (FCFS) is a simple scheduling policy that tends to favor I/O bound processes over processor bound processes

False

The primary issues involved in the simultaneous access of files for updating or appending are mutual exclusion and starvation.

False

a risk with ____ is the possibility of starvation for longer processes, as long as there is a steady supply of shorter processes

SPN (shortest process next)

in the case of the ___ policy, the scheduler always chooses the process that has the shortest

SRT (shortest remaining time)

NTFS file system, the smallest physical storage unit on the disk (almost always 512 bytes) is called a:

Sector

Direct or hashed files are often used where:

all of the above

the convention for dealing with tinyOS resources is that resources are:

all of the above

which of the following is a typical os characteristic

all of the above

sequential file are optimal in scenarios involving:

application that require the processing of all records in the file

blah

blah

____ is a technique that smoothes out peaks in I/O demand

buffering

____ suitable for communicating with remote devices like digital line drivers and modems.

communication

the _____ specifies the instants in time at which the selection function is exercised.

decision mode