Operating Systems Midterm Flashcards

1
Q

operating system definition

A

a program that acts as an intermediary b/w a user of a computer and the computer hardware

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2
Q

operating system goals

A

execute user programs and make solving user problems easier, make the computer system convenient to use, use computer hardware efficiently

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3
Q

computer system can be divided into four components

A

hardware, operating system, application programs, users

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4
Q

bootstrap program definition

A

the first program that a computer will run when you push its power button

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5
Q

what does a bootstrap program do

A

initializes the hardware system, loads the OS kernel, and starts execution

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6
Q

where is the bootstrap program located

A

read-only memory (ROM) or EPROM, aka firmware

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7
Q

volatile

A

loses its contents when power to the device is removed (ex: main memory)

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8
Q

nonvolatile

A

loss of power does not result in loss of content (ex: solid-state disks, magnetic disks, optical disks, magnetic tapes; also flash memory and NVRAM, which is DRAM with battery backup power)

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9
Q

software-generated interrupt

A

code error (exception) or system call (trap)

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10
Q

hardware-generated interrupt

A

keyboard, insert ethernet cord

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11
Q

cache

A

a temporary storage system for easy/faster access to recently used information

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12
Q

when new information is needed but not in the cache, what will happen?

A

it will be loaded into the cache

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13
Q

two design issues for cache

A

size and management/replacement

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14
Q

if the cache size is too big

A

too expensive

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15
Q

if the cache size is too small

A

slows down performance

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16
Q

cache management/replacement refers to

A

figuring out when to remove or replace data in the cache

17
Q

cache coherency

A

in multi-processor systems, multiple CPUs, each with own cache; copies of same data on different caches should be kept updated

18
Q

asymmetric architecture

A

one CPU/machine standby (as a master) to monitor/control others (as slaves)

19
Q

symmetric architecture

A

monitor each other (in cluster), equal role to run tasks, tasks may be divided evenly among CPUs/computers

20
Q

how does the OS protect itself from other system components?

A

dual mode and timer

21
Q

dual mode

A

refers to kernel mode and user mode: trap in user mode, then switch to kernel mode to the OS so that the OS can check about the privileged instruction to see if it should be executed or not, return from trap generated interrupt and go back to user mode

22
Q

timer

A

set the timer to interrupt periodically so OS can check if a program uses too much CP time (e.g., infinite loop) – terminate if so, otherwise return CPU control back to the program

23
Q

what is the unit of work in a system?

A

a process

24
Q

difference between a program and a process

A

process: an initiated program; a program loaded into main memory and in execution
a program is passive while a process is active

25
Q

to execute a program, what must happen?

A

its instructions and data must be in main memory

26
Q

cloud computing

A

delivers computing, storage, and applications as services across a network

27
Q

CLI stands for ? and allows ?

A

command-line interface; it allows direct command entry to be performed by the OS

28
Q

GUI stand for ? and allows ?

A

graphical user interface; it allows user-friendly desktop metaphor interface (usually mouse, keyboard, and monitor; icons represent files, programs, actions, etc.)

29
Q

application programmers typically use ? rather than directly invoking system calls

A

an API

30
Q

Android uses the ? virtual machine to run Java programs

A

Dalvik

31
Q

does C use classes and objects?

A

no

32
Q

pointer

A

a variable whose value is the address of another variable