WGU D686 Operating Systems questions with 100% correct answers + rationales(PASSED)

Operating system

A program that manages a computer's hardware, provides a basis for application programs, and acts as an intermediary between the computer user and the computer hardware

Operating system

Software that manages a computer's hardware, helps applications work, and lets users interact with the computer

hardware

The CPU, memory devices, input/output devices, and any other physical components that are part of a computer

application program

a program designed for end-user execution, such as a word processor, spreadsheet, compiler, or Web browser

ease of use

the amount of difficulty and complexity involved in using some aspect of computing

resource utilization

the amount of a given resource (hardware or software) that is being used

touch screen

a touch-sensitive screen used as a computer input device

voice recognition

a computer interface based on spoken commands, which the computer parses and turns into actions

Siri

the Apple voice-recognition system

embedded computer

a computer system within some other, large system (such as a car) that performs specific, limited functions and has little or no user interface

resource allocator

an operating system or application that determines how resources are to be used

control program

a program that manages the execution of user programs to prevent errors and improper use of the computer. it is especially concerned with the operation and control of I/O devices

Moore's law

the idea that the number of parts on a computer chip doubles about every 18 months

kernel

the main part of an operating system that starts running as soon as a computer turns on

system program

software related to the operating system but designed for smaller and more specific tasks

bus

a pathway that moves data and instructions between parts of a computer, like the CPU and devices

device driver

software that helps the operating system talk to and control hardware like printers or keyboards

interrupt

a signal from a device telling the computer's brain (the CPU) that something important needs attention right away

interrupt vector

a list that shows where the computer should go to handle different kinds of interruptions

interrupt-request line

a wire or circuit that lets devices send signals to the CPU to ask for attention

interrupt-handler routine

a special program that the computer runs when it gets an interrupt signal

interrupt-controller hardware

parts of the computer that manage when and how interrupts are handled

nonmaskable interrupt

an urgent signal that the CPU must deal with immediately, like a major error

maskable

describes an interrupt that the CPU can choose to ignore briefly, usually when it's busy doing something very important

interrupt chaining

a method where the computer checks a list of programs to find the right one to handle the interrupt

interrupt priority level

a way of deciding which interrupts are most urgent, so that the computer can handle them in the right order

random-access memory (RAM)

a computer's main memory that can be used quickly to run programs

dynamic random-access memory (DRAM)

a type of RAM that is fast and used a lot in computers

volatile

describes memory that loses its information when the computer turns off

electrically erasable programmable read-only memory (EEPROM)

a type of nonvolatile memory that can be electrically erased and reprogrammed to store data

bootstrap program

the first program that starts a computer by getting everything ready for the main software to run when the computer is turned on

bit

the smallest unit of data storage containing one of two values, 0 (off) or 1 (on)

byte

8 bits

word

a unit of data representing multiple bytes, such as 4 bytes in a 32-bit system or 8 bytes in a 64-bit system

hard disk drive (HDD)

a storage device that uses spinning disks and read/write heads to store and retrieve data

nonvolatile memory (NVM)

memory that retains data even when power is turned off

nonvolatile storage (NVS)

storage that keeps data without needing power, such as hard drives and SSDs

solid state drive (SSD)

a storage device that uses flash memory to store data with no moving parts

big data

extremely large sets of data; distributed systems are well suited to working with big data

MapReduce

a Google-created big data programming modal and implementation for parallel processing across nodes in a distributed cluster. a layer on top of the Google file system (GFS), it allows developers to carry out large-scale parallel computations easily

system daemon

a service that is provided outside the kernel by stem programs that are loaded into memory at boot time and run continuously

trap

a software interrupt. the interrupt can be caused either by an error (e.g., division by zero or invalid memory access) or by a specific request from a user program that an operating-system service be performed

exception

a software-generated interrupt caused either by an error (such as division by zero or invalid memory access) or by a specific request from a user program than an operating-system service be performed

system call

software-triggered interrupt allowing a process to request a kernel service

multiprogramming

a technique that increases CPU utilization by organizing jobs (code and data) so that the CPU always has a job to execute

process

a program loaded into memory and executing

mutlitasking

the concurrent performance of multiple jobs. a CPU executes multiple jobs by switching among them, but the switches occur so frequently that users can interact with the processes

response time

the amount of time it takes the system to respond to user action

CPU scheduling

the process by which the system chooses which job will run next if several jobs are ready to run at the same time

virtual memory

a technique that allows the execution of a process that is not completely in memory. also, separation of computer memory address space from physical into logical allowing easier programming and larger name space

logical memory

memory as viewed by the user; usually a large uniform array, not matching physical memory in virtual memory systems

user mode

a CPU mode for executing user processes in which some instructions are limited or not allowed

kernel mode (supervisor mode, system mode, privileged mode)

a CPU mode in which all instructions are enabled. the kernel runs in this mode

mode bit

a CPU status bit used to indicate the current mode: kernel (0) or user (1)

privileged instructions

instructions that can execute only if the CPU is in kernel mode

protection rings

a model of privilege separation consisting of a series of rings, with each successive ring representing greater execution priveleges

virtual machine manager (VMM)

the computer function that manages the virtual machine; also called a hypervisor

timer

a hardware component that can be set to interrupt the computer after a specific period

batch operating system

executes similar jobs in batches to optimize CPU use without user interaction

multiprogramming

keeps multiple programs in memory to maximize CPU usage by switching between them

main memory management

the process of handling the system's primary memory (RAM) to ensure efficient use by programs

CPU scheduling

the method used by an operating system to decide which process gets to use the CPU and for how long

time-sharing system

an operating system that allows multiple users to share computer resources simultaneously

multitasking

the ability of an operating system to run multiple tasks or programs at the same time

real-time system

ensures tasks are completed within defined time limits, including hard (strict) and soft (flexible) real-time systems

hard real-time

handles critical tasks that must meet strict, predefined time constraints without virtual memory or time-sharing

soft real-time

handles tasks with deadlines that are more flexible than hard real-time systems, allowing for some timing variability

multiprocessor system

a computer system with more than on CPU working together to process tasks

parallel systems

systems with multiple CPUs sharing memory and communicating directly, enabling simultaneous task execution for improved performance

virtual memory system (VMS)

a memory management technique that extends the apparent amount of RAM by using disk space

distributed operating system

handles networked processors that collaborate on tasks, enabling resource sharing and high-speed processing

loosely coupled systems

systems where each component or computer is independent and communicates over a network

local area network (LAN)

a network that connects computers and devices within a small geographic area, like a building

wide are network (WAN)

a network that connects computers and devices over large geographic distances, such as across cities or countries

fault tolerance

the ability of a multiprocessor system to handle the failure of a processor by redistributing its tasks to other processors, ensuring continuous operation

resource manager

part of the operating system that controls and assigns computer resources like CPU time, memory and devices

I/O subsytem

part of the operating system that handles input and output tasks, managing devices and data transfers

program counter

a CPU register that holds the memory address of the next instruction to execute

file

named data collection stored on a device and managed by the operating system

context switching

the process of saving and restoring the state of a process or thread

paging

memory management technique where data is stored and retrieved in fixed-size blocks (pages) to optimize memory use

segmentation

memory management method dividing memory into variable-sized segments for flexible allocation

malware

malicious software designed to disrupt, damage, or gain unauthorized access to computer systems

ransomware

malware that encrypts files and demands payment for decryption, often causing data loss or operation disruption

emulator

software or hardware that enables one computer system to mimic another to run incompatible software or use different peripherals

protection

system functions that control access to computer resources to ensure only authorized users can use them

security

systems and measures to protect a computer from attacks and threats, both from outside and within

user interface (UI)

a method by which as user interacts with a computer

graphical user interface (GUI)

a computer interface comprising a window system with a pointing device to direct I/O, choose from menus, and make selections and, usually, a keyboard to enter text

touch-screen interface

a user interface in which touching a screen allows the user to interact with the computer

command-line interface (CLI)

a method of giving commands to a computer based on a text input device (such as a keyboard)

shared memory

in interprocess communication, a section of memory shared by multiple processes and used for message passing

message passing

in interprocess communication, a method of sharing data in which messages are sent and received by processes. packets of information in predefined formats are moved between processes or between computers

command interpreter

the operating system component that interprets user commands and causes actions based on them

shell

one of the command interpreters on a system with multiple command interpreters to choose from

desktop

in a GUI, the standard workspace represented by the GUI on the screen in which a user executes tasks

icons

images representing objects (such as files or applications) that users can choose via the GUI

folder

a file system component that allows users to group files together

gestures

a user interface component in which motions cause computer actions (i.e. "pinching" the screen)

springboard

the iOS touch-screen interface