C191 questions

A memory area that stores data being transferred between two devise or between a device and an application

Buffer

CLI

Command Line Interface

CreatePipe()

Communication- system call

mmap()

Communication- system call

In an access matrix, the ____ right allows a process to change the entries in a row.

Control

A thread library available for Solaris systems

Green thread

Spool

Is a buffer that holds output for a device that cannot accept interleaved data streams.

spool

Is a buffer that holds output for a device that cannot accept interleaved data streams.

Host-attached storage

Is accessed via local I/O ports

message-passing model

Is easier to implement than a shared memory model for intercomputer communication

low-level formatting

Is the process of dividing a disk into sectors that the disk controller can read and write, before a disk can store data

sequential access

Is the simplest file access method

process

Is the unit of work in a system.

For a deadlock to arise, which of the following conditions must hold simultaneously?

Mutual exclusion, Hold and wait, No preemption

Compiled, machine language, not linked

Object

An address seen by the memory unit, loaded into the memory-address register of the memory

Physical address

exit()

Process control- system call

The bounded buffer problem is also known as:

Producer - Consumer problem

What is major feature of segmentation?

Program is divided into pieces having different access rights

A sequence of characters organized into lines, possibly pages

Text file

Markup

Textual data

Which of the following statements is false?

The difference in storage capacity between a mobile device and laptop is shrinking.

How many philosophers may eat simultaneously in the Dining Philosophers problem with 5 philosophers?

2

Real time systems must have:

preemptive kernels

Masquerading

pretending to be another person online

In capability lists, each object has a ____ to denote its type.

tag

RPC provides a(an) --?-- on the client side, a separate one for each remote procedure.

stub

The Linux CFS scheduler identifies _____________ as the interval of time during which every runnable task should run at least once.

targeted latency

The register context and stacks of a thread are deallocated when the thread:

terminates

Optimal Page Replacement Algorithm

the algorithm that has the lowest page-fault rate of all algorithms and will never suffer from Belady's anomaly.

In a paired-password system, ____.

the computer supplies one part of a password and the user enters the other part

Role Base Access Control

The program and the processs can be assigned roles when using role-based access control

Protection domain

The specific resources that a process may access

Protection and security

The process of controlling the use of information on a computer system

Privileged instructions

They may case harm to a system, They can only be executed in kernel mode, They can be attempted from user mode, They are used to manage interrupts.

TLS

Thread-local storage is when a thread needs its own copy of certain data

The number of processes that are completed per time unit

Throughput

The procedure by which an application can schedule user threads onto an available virtual processor

Upcall

Round-Robin

Was designed for time sharing systems.

Mainframe

are designed primarily to maximize resource utilization.

Scheduling is done so as to:

decrease the turnaround time

Virtual memory is normally implemented by:

demand paging

On media that uses constant linear velocity the:

density of bits per track is uniform

On media that uses constant linear velocity, the ____.

density of bits per track is uniform

A process that has terminated, but whose parent has not yet called wait(), is known as a ________ process.

Zombie

A semaphore:

can be accessed from multiple processes

Timer

can be used to prevent a user program from never returning control to the operating system.

contiguous allocation

ensures that only one access is needed to get a disk block using direct access

Protection bits

ensures the integrity of memory in a paged environment

The header and trailer of a sector contain information used by the disk controller such as --?-- and --?--

error correcting codes (ECC) & sector number

The usual effect of abnormal termination of a program is:

core dump file generation

Dtrace

facility that dynamically adds probes to a running system both in user processes and in the kernel Compiler, Provider of probes, and consumers.

ReadFile()

file manipulation- system call

get_file_attributes()

file manipulation- system call

open()

file manipulation- system call

reposition()

file manipulation- system call

Mapping of file is managed by:

file metadata

The series of accesses between the open and close operations is a:

file session

In UNIX, domain switch is accomplished via:

file system

One difficulty of contiguous allocation is:

finding space for a new file

In Peterson's solution, the ____ variable indicates if a process is ready to enter its critical section.

flag[i]

The two phase locking protocol consists of:

growing & shrinking phase

inverted page table

has one page entry for each real page (or frame) of memory. Reduces memory usage to store addresses.

If the extents are too large, then the problem that comes in is:

internal fragmentation

Task parallelism

involves distributing tasks across multiple computing cores.

Optimal page replacement ____.

is used mostly for comparison with other page replacement schemes

Peterson's solution

is/are not a technique for managing critical sections in operating systems.

Cache memory

is/are not a technique for passing parameters from an application to a system call.

If the semaphore value is negative:

its magnitude is the number of processes waiting on that semaphore

Sometimes the overhead of keeping track of a hole might be:

larger than the hole itself

The file-allocation table (FAT) used in MS-DOS is an example of:

linked allocation

The most common secondary storage device is ____.

magnetic disk

Kernel

maintains pending and blocked bit vectors in context of each process.

The --?-- can be turned off by the CPU before the execution of critical instruction sequences that must not be interrupted.

maskable interrupt

The most common method used by attackers to breach security is ____.

masquerading

address space identifier

matches the process with each entry in the TLB.

Priority inversion

occurs when a higher-priority process needs to access a data structure that is currently being accessed by a lower-priority process.

stack

of a process contains temporary data such as function parameters, return addresses, and local variables.

Windows uses the ____.

one-to-one model

A write of a block has to access:

parity disk the disk on which the block is stored a parity block

In systems that support virtual memory, ____.

physical memory is separated from logical memory

Grand Central Dispatch handles blocks by

placing them on a dispatch queue

The index contains:

pointers to the various blocks

Memory that is dynamically allocated during a process run time

Heap

The common system bus connecting the process-memory subsystem to fast devices

PCI Bus

The scheme by which a many-to-one or many-to-many system schedules user-threads

PCS

How is disadvantage of all-or-nothing approach overcome?

Tagged architecture

System calls OS

provide(s) an interface to the services provided by an operating system.

Standard C library

provides a portion of the system call interface for UNIX and Linux.

thread library

provides an API for creating and managing threads.

A circular buffer:

writes to the end of its space and then continues at the beginning

The growing phase is a phase in which:

A transaction may obtain locks, but does not release any

Hard disk

- array of logical blocks mapped onto the hard disk is - done onto the sectors of the disk sequentially. average latency is 3 milliseconds. - Smallest unit of transfer is Block.

Worms

- use the spawn mechanism to ravage system performance -can shut down an entire network -continue to grow as the Internet expands

SSDs

-They have the same characteristics as magnetic hard disks, but can be more reliable. -They are generally more expensive per megabyte than traditional hard disks. -They have no seek time or latency.

An interrupt priority scheme can be used to ____.

-allow the most urgent work to be finished first -make it possible for high-priority interrupts to preempt the execution of a low priority interrupt -defer the handling of a low-priority interrupt without masking off all interrupts

DMA controller

000-00F

What is the numeric priority of a Windows thread in the HIGH_PRIORITY_CLASS with ABOVE_NORMAL relative priority?

14

One-third of all memory may be unused.

50-percent rule of memory fragmentation state when allocating additional memory using the first-fit method

LWP

A LWP (lightweight process) is the intermediate data structure between the user and kernel

rendezvous

A blocking send() and blocking receive() is known as rendezvous

Clustered systems

A clustered system gathers together multiple CPUs to accomplish computational work.

microkernel

A microkernel is a kernel that is stripped of all nonessential components

Child processes inherit UNIX ordinary pipes from their parent process because:

A pipe is treated as a file descriptor and child processes inherit open file descriptors from their parents.

cooperative scheduling

A process keeps the CPU until it releases the CPU, either by terminating, or by switching to the waiting state

The scheme in which the sender process and the receiver process must name the other to communicate

ALPC

advantage of compiler-based enforcement of access control

Access privileges are closely related to the linguistic concept of a data type.

Key types of access permissions

Append List

The attempt to break security

Attack

Memory register that holds the smallest, legal physical-memory address

Base register

working-set model

Based on the assumption of locality, using a moving working-set window. Prevents trashing, while allowing the highest degree of multiprogramming. References the most recent set of delta parameters

Commands to the command interpreter

Batch

Transfers between memory and disk are performed a ____.

Block at a time.

A region of fast memory that holds copies of data

Cache

Deferred

Cancellation points are associated with deferred cancellation.

The technique of terminating all child processes when a parent process terminates

Cascading

A property of peer-to-peer systems

Clients and servers are not distinguished from one another.

Allowing all running tasks to make progress

Concurrency

Assume an adaptive mutex is used for accessing shared data on a Solaris system with multiprocessing capabilities. Which of the following statements is not true?

Condition variables and semaphores are never used in place of an adaptive mutex.

Synonymous with non-preemptive scheduling

Cooperative

Which of the following statements is true?

Counting semaphores can be used to control access to a resource with a finite number of instances.

Someone attempting to breach security

Cracker

The Process Control Block is:

Data Structure

Which of the following would be an acceptable signal handling scheme for a multithreaded program?

Deliver the signal to only certain threads in the process. Deliver the signal to every thread in the process. Deliver the signal to the thread to which the signal applies.

Mechanisms

Determine how something will be done. Remain the same.

Polices

Determine what will be done. may change from place to place

An access method allowing programs to read and write records rapidly in no particular order

Direct access

SMP-type system

Each processor performs all tasks within the operating system.

Which of the following is true of multilevel queue scheduling?

Each queue has its own scheduling algorithm.

Embedded computers

Embedded computers typically run on a real-time OS

real-time

Embedded computers typically run on a real-time operating system.

What is true regarding the relative merits between access rights enforcement based solely on a kernel, as opposed to enforcement provided largely by a compiler?

Enforcement by the kernel is less flexible than enforcement by the programming language for user-defined policy.

Read-to-run machine-language program

Executable

A series of code sections that the loader can bring into memory and execute

Executable file

Global

Global replacement allows a process to select a replacement frame from the set of all frames, even if the frame is currently allocated to some other process.

Confinement problem

Guaranteeing that no information initially held in an object can migrate outside of its execution environment

Raw

I/O accesses a block device as a simple array of blocks.

A mechanism allowing the exchange of data and information between cooperating processes

IPC

A unique tag which identifies a file within the file system, in non-human-readable format

Identifier

debugger

If a program terminates abnormally, a dump of memory may be examined by a debugger to determine the cause of the problem.

flag[i]

In Peterson's solution, the flag[I] variable indicates if a process is ready to enter its critical section.

Memory Mapped Files

In Windows, it represents the shared-memory object that will enable communication between processes

dump()

Information maintenance- system call

The processes on the disk that are waiting to be brought into memory for execution

Input queue

The hardware mechanism that enables a device to notify the CPU

Interrupt

What is a long-term scheduler?

It selects which process has to be brought into the ready queue

What is a medium-term scheduler?

It selects which process to remove from memory by swapping

access matrix is a compromise between two other implementations

Lock-key

Spinlocks are:

Locks that avoid time wastage in context switches Locks that work better on multiprocessor systems CPU cycles wasting locks over critical sections of programs

Microkernels communication

Microkernels use message passing for communication

Middleware

Middleware is a set of software frameworks that provide additional services to application developers

monitor

Monitor (synchronization) In concurrent programming (also known as parallel programming), a monitor is a synchronization construct that allows threads to have both mutual exclusion and the ability to wait (block) for a certain condition to become false. Is characterized by a set of programmer defined operators

What is a principle that can improve the efficiency of I/O

Move processing primitives into hardware.

A file attribute defining the symbolic file name, in human readable format

Name

state of a process

New, Running, Waiting.

A process may transition to the Ready state by which of the following actions?

Newly-admitted process Awaiting its turn on the CPU Completion of an I/O event

When a process switches from a running state to the waiting state or when a process terminates

Nonpreemptive

Communications

One process exchanging information with another process

An OS table containing information about all open files

Open-file table

Which of the following statements is incorrect?

Operating systems provide both command line as well as graphical user interfaces.

Which of the following statements is true??

Operations on atomic integers do not require locking.

Performing more than one task simultaneously

Parallelism

chmod()

Protection- system call

chown()

Protection- system call

System calls

Provides an interface to the services provided by an OS

POSIX threads

Pthreads

The data-in register of I/O port is:

Read by host to get input

Pipes

Reading and writing to ordinary pipes on both UNIX and Windows systems can be performed like ordinary file I/O.

Suppose that a process is in "Blocked" state waiting for some I/O service. When the service is completed, it goes to the:

Ready state

techniques for passing parameters from an application to a system call.

Registers Stack Special block in memory

How does the Hardware trigger an interrupt?

Sending signals to CPU through system bus

A swap space can reside in:

Separate disk partition

An access method where the information in the file is process in order, one record after another

Sequential access

What is the problem of mutually suspicious subsystem?

Service program can malfunction and retain some rights of data provided by user

Used in UNIX to notify a process that particular event has occurred

Signal

Source code in various languages

Source code

A sequence of functions, further organized as declarations followed by executable statements

Source file

When priority scheduling results in a process that is ready to run but waiting for the CPU

Starvation

The scheme of moving a process in and out of memory

Swapping

Swapping

Swapping works in conjunction with virtual memory techniques. Some systems allow for multiple swap spaces (disks). Solaris only swaps pages of anonymous memory.

Close a file

The close() call in Unix is used to close a file. The equivalent system call in windows in CloseHandle()

Immutable file

The file name may not be reused.

layered operating system

The major difficulty in designing a layered operating system approach is appropriately defining the various layers

User interface

The method via which a user interacts with an operating system

error detection

The process by which an operating system detects and responds to errors

File-system manipulation

The process by which programs read, write, create and delete files and directories

I/O operations

The process by which the operating system manages input and output to and from a running program

Program Execution

The process of a system loading a program into memory to run

Resource allocation

The process of an OS managing the allocation of resources to multiple jobs

What is a benefit when using the slab allocator?

There is no memory fragmentation.

Hashed page table

They are a common approach for handling address spaces larger than 32 bits.

What is breach of confidentiality?

This type of violation involves unauthorized reading of data

Accounting

Tracking usage statistics for users

The surface of a magnetic disk platter is divided into:

Tracks

A code segment that tries to misuse its environment

Trojan horse

In the UNIX operating system, a domain is associated with the ____.

User

A fragment of code embedded in a legitimate program

Virus

WAFL file system

WAFL is used exclusively on networked file servers. Part of caching uses non-volatile RAM (NVRAM). Clones are similar to snapshots.

Java Protection

When a class is loaded, the JVM assigns the class to a protection domain that gives the permissions of that class.

The control register of an I/O port can be:

Written by the host to start a command or to change the mode of a device.

In a multi level directory structure:

a mechanism for directory protection will have to applied

A page fault occurs when:

a page cannot be accessed due to its absence from memory

To ensure that the hold and wait condition never occurs in the system, it must be ensured that:

a process can request resources only when it has none whenever a resource is requested by a process, it is not holding any other resources each process must request and be allocated all its resources before it begins its execution

A locality is:

a set of pages that are actively used together

Pthreads refers to ____.

a specification for thread behavior

What is compaction?

a technique for overcoming external fragmentation

What is the correct order of operations for protecting a critical section using mutex locks?

acquire() followed by release()

The wait-for graph is a deadlock detection algorithm that is applicable when:

all resources have a single instance

Buddy system

allocated from a fixed-size segment consisting of physically contiguous pages

Modules

allow operating system services to be loaded dynamically

Memory mapping

allows a portion of a virtual address space to be logically associated with a file.

Processor affinity

allows a thread to run on only one processor.

Inter process communication: (IPC)

allows processes to communicate and synchronize their actions without using the same address space

Direct access method

allows programs to read and write records in no particular order.

named pipe

allows several unrelated processes to use the pipe for communication.

Copy-on-write

allows the parent and child processes to initially share the same pages, but when either process modifies a page, a copy of the shared page is created.

The portion of the process scheduler in an operating system that dispatches processes is concerned with:

assigning ready processes to CPU

Frames

associated with the paging scheme

Signals can be emulated in windows through

asynchronous procedure calls

Signals can be emulated in windows through ____.

asynchronous procedure calls

The OpenMP #pragma omp critical directive ___________.

behaves much like a mutex lock

Transfers between memory and disk are performed a ____.

block at a time

A process can be:

both single threaded and multithreaded

By operating system, the resource management can be done via:

both time and space division multiplexing

In polling:

busy - wait cycles wait for I/O from device

stack algorithms

can never exhibit Belady's Anomaly

DMA controllers

can steal memory access cycles from the main CPU

In the reacquisition scheme for implementing the revocation of capabilities, ____.

capabilities are periodically deleted from each domain

In the reacquisition scheme for implementing the revocation of capabilities:

capabilities are periodically deleted from each domain

unified buffer cache

contains the same pages for memory-mapped IO as well as ordinary IO.

Compaction

collect free space (i.e., garbage collection) together to provide more usable space

Contiguous allocation of a file is defined by:

disk address of the first block & length

The module that gives control of the CPU to the process selected by the short-term scheduler

dispatcher

FCFS algorithm

does not take into account the current position of the disk head

An instruction that executes atomically

executes as a single, uninterruptible unit

The file name is generally split into two parts:

extension & name

The first fit and best fit algorithms suffer from:

external fragmentation

global table

implementation of an access table consists of sets of ordered triples.

The most common technique for writing multithreaded Java programs is _____.

implementing the Runnable interface and defining its run() method

One way to ensure that the circular wait condition never holds is to:

impose a total ordering of all resource types and to determine whether one precedes another in the ordering

SetTimer()

information maintenance- system call

sleep()

information maintenance- system call

distribution

is a custom build of the Linux operating system.

terminal concentrator

is a front-end processor that multiplexes the traffic from hundreds of remote terminals into one port on a large computer.

Domain capability list

is a list of objects together with the operation allowed on these objects.

storage area network

is a private network connecting servers and storage units.

A digital certificate

is a public key digitally signed by a trusted party.

source file

is a sequence of functions.

RC4

is a symmetric stream cipher.

Green threads

is a thread library for Solaris that maps many user-level threads to one kernel thread.

command interpreter

is an example of a systems program.

Ensuring there is a sufficient number of cores

is not considered a challenge when designing applications for multicore systems.

For sharable resources, mutual exclusion:

is not required

LRU

is the algorithm implemented on most systems.

banker's algorithm

is the deadlock avoidance algorithm

Execution time binding

is the method of binding instructions and data to memory performed by most general-purpose operating systems.

TLB reach

is the number of entries in the TLB multiplied by the page size.

one-to-one

model maps each user-level thread to one kernel thread.

Which table contains the information about each mounted volume?

mount table system-wide open-file table per-process open-file table

FCFS

must be non-preemptive

Reentrant

non-self-modifying code that never changes during execution

Thread pools limit the number of threads that exist at any one point, hence:

not letting the system resources like CPU time and memory exhaust

fork()

process control- system call

INIT

process is assigned as the parent to orphan processes.

Which hardware triggers some operation after certain programmed count?

programmable interval timer

segmentation

programs are divided into variable length pieces.

allow_user()

protection- system call

The two general approaches to load balancing are __________ and ____________.

push migration, pull migration

The two general approaches to load balancing are:

push migration, pull migration

degree of multiprogramming

refers to the number of processes in memory.

critical section

refers to where a process is accessing/updating shared data.

Given a start of file address, the location of any given record can be computed from its:

relative record number

The first readers-writers problem:

requires that no reader will be kept waiting unless a writer has already obtained permission to use the shared database

A tree structure

restricts the sharing of files and directories.

In MULTICS, the protection domains are organized in a

ring structure

context switch

saves the state of the currently running process and restores the state of the next process to run.

With segmentation, a logical address consists of:

segment number and offset

variable-partition

sizes for efficiency (sized to a given process' needs) The OS keeps a table of available holes.

A sense key reports on the failure of a SCSI device by:

stating the general nature of the failure

A fork system call will fail if:

the limit on the maximum number of processes in the system would be executed

A mount point is:

the location within the file structure where the file system is to be attached

The degree of multiprogramming is:

the number of processes in memory

The implementation of the LFU and the MFU algorithm is very uncommon because:

they are expensive

Instead of starting a new thread for every task to execute concurrently, the task can be passed to a:

thread pool

Each set of operations for performing a specific task is a:

transaction

A character-stream device:

transfers data a byte at a time

TLB

translation look-aside buffer. A type of cache used to hold virtual-to-physical address translation information Also, a solution that resolves slow access time to user memory location when implementing paging

Swap space management

tries to provide the best throughput for the virtual memory system

A boot block

typically only knows the location and length of the rest of the bootstrap program

Associated with every interrupt is an identification number called a(n):

vector

polymorphic

virus changes each time it is installed to avoid detection by antivirus software.

In a(n) ____ temporary queue, the sender must always block until the recipient receives the message.

zero capacity