CHAPTER 2: Computer Abstract / Tech Flashcards

1
Q

personal computer (PC)

A

A computer designed for use by an individual, usually incorporating a graphics display, a keyboard, and a mouse

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2
Q

server

A

A computer used for running larger programs for multiple users, often simultaneously, and typically accessed only via a network

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3
Q

supercomputer

A

A class of computers with the highest performance and cost; they are configured as servers and typically cost tens to hundreds of millions of dollars

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4
Q

embedded computer

A

A computer inside another device used for running one predetermined application or collection of software

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5
Q

personal mobile devices (PMD)

A

small wireless devices to connect to the Internet; they rely on batteries for power, and software is installed by downloading apps. Conventional examples are smart phones and tablets

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6
Q

cloud computing

A

large collections of servers that provide services over the Internet; some providers rent dynamically varying numbers of servers as a utility

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7
Q

Software as a Service (SaaS)

A

delivers software and data as a service over the Internet, usually via a thin program such as a browser that runs on local client devices, instead of binary code that must be installed, and runs wholly on that device. Examples include web search and social networking

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8
Q

multicore microprocessor

A

microprocessor containing multiple processors (“cores”) in a single integrated circuit

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9
Q

acroynm

A

word constructed by taking the initial letters of a string of words. For example: RAM is an acronym for Random Access Memory, and CPU is an acronym for Central Processing Unit

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10
Q

terabyte (TB)

A

1,099,511,627,776 (240) bytes, although communications and secondary storage systems developers started using the term to mean 1,000,000,000,000 (1012) bytes

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11
Q

tebibyte (TiB)

A

240 bytes, defining terabyte (TB) to mean 1012 bytes. The figure below shows the full range of decimal and binary values and names

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12
Q

systems software

A

software that provides services that are commonly useful, including operating systems, compilers, loaders, and assemblers

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13
Q

operating system

A

supervising program that manages the resources of a computer for the benefit of the programs that run on that computer

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14
Q

compiler

A

program that translates high-level language statements into assembly language statements

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15
Q

binary digit (bit)

A

one of the two numbers in base 2 (0 or 1) that are the components of information

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16
Q

instruction

A

command that computer hardware understands and obeys

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17
Q

assembly

A

program that translates a symbolic version of instructions into the binary version

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18
Q

assembly language

A

symbolic representation of machine instructions

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19
Q

machine language

A

binary representation of machine instructions

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20
Q

high-level programming language

A

portable language such as C, C++, Java, or Visual Basic that is composed of words and algebraic notation that can be translated by a compiler into assembly language

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21
Q

input device

A

mechanism through which the computer is fed information, such as a keyboard

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22
Q

output device

A

mechanism that conveys the result of a computation to a user, such as a display, or to another computer

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23
Q

consumer-oriented embedded applications

A
  • dependability should be achieved through simplicity - emphasis on doing on function as perfectly as possible
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24
Q

touchscreen

A

people are electrical conductors, if an insulator like glass is covered with a transparent conductor, touching distorts the electrostatic field of the screen, which results in a change in capacitance

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25
Q

input device

A

mechanism through which the computer is fed information, such as a keyboard

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26
Q

output device

A

mechanism that conveys the result of a computation to a user, such as a display, or to another computer

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27
Q

liquid crystal display (LCD)

A

display technology using a thin layer of liquid polymers that can be used to transmit or block light according to whether a charge is applied

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28
Q

active matrix display

A

liquid crystal display using a transistor to control the transmission of light at each individual pixel

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29
Q

pixel

A

smallest individual picture element. Screens are composed of hundreds of thousands to millions of pixels, organized in a matrix

30
Q

integrated circuit (chip)

A

device combining dozens to millions of transistors

31
Q

central processor unit (CPU)

A

active part of the computer, which contains the datapath and control and which adds numbers, tests numbers, signals I/O devices to activate, and so on

32
Q

datapath

A

component of the processor that performs arithmetic operations

33
Q

memory

A

storage area in which programs are kept when they are running and that contains the data needed by the running programs

34
Q

dynamic random access memory (DRAM)

A

memory built as an integrated circuit; it provides random access to any location. Access times are 50 nanoseconds and cost per gigabyte in 2012 was $5 to $10

35
Q

cache memory

A

small, fast memory that acts as a buffer for a slower, larger memory

36
Q

static random access memory (SRAM)

A

memory built as an integrated circuit, but faster and less dense than DRAM

37
Q

instruction set architecture (architecture)

A
  • abstract interface between the hardware and the lowest-level software that encompasses all the information necessary to write a machine language program that will run correctly, including instructions, registers, memory access, I/O, and so on
  • most important example of abstraction
38
Q

application binary interface (ABI)

A

user portion of the instruction set plus the operating system interfaces used by application programmers. It defines a standard for binary portability across computers

39
Q

implementation

A

Hardware that obeys the architecture abstraction

40
Q

volatile memory

A

Storage, such as DRAM, that retains data only if it is receiving power

41
Q

nonvolatile memory

A

form of memory that retains data even in the absence of a power source and that is used to store programs between runs. A DVD disk is nonvolatile

42
Q

main memory (primary memory)

A

memory used to hold programs while they are running; typically consists of DRAM in today’s computers.

43
Q

secondary memory

A

nonvolatile memory used to store programs and data between runs; typically consists of flash memory in PMDs and magnetic disks in servers

44
Q

magnetic disk (hard disk)

A

form of nonvolatile secondary memory composed of rotating platters coated with a magnetic recording material. Because they are rotating mechanical devices, access times are about 5 to 20 milliseconds and cost per gigabyte in 2012 was $0.05 to $0.10

45
Q

flash memory

A

nonvolatile semiconductor memory. It is cheaper and slower than DRAM but more expensive per bit and faster than magnetic disks. Access times are about 5 to 50 microseconds and cost per gigabyte in 2012 was $0.75 to $1.00

46
Q

transistor

A

on/off switch controlled by an electric signal

47
Q

Very large-scale integrated (VLSI) circuit

A

device containing hundreds of thousands to millions of transistors

48
Q

wafer

A

slice from a silicon ingot no more than 0.1 inches thick, used to create chips

49
Q

defect

A

microscopic flaw in a wafer or in patterning steps that can result in the failure of the die containing that defect

50
Q

die

A

individual rectangular sections that are cut from a wafer, more informally known as chips

51
Q

yield

A

percentage of good dies from the total number of dies on the wafer

52
Q

response time (execution time)

A

total time required for the computer to complete a task, including disk accesses, memory accesses, I/O activities, operating system overhead, CPU execution time, and so on

53
Q

throughput (bandwidth)

A

measure of performance, it is the number of tasks completed per unit time

54
Q

performance

A

the inverse of execution time

55
Q

CPU execution time

A
  • actual time the CPU spends computing for a specific task
  • only valid and unimpeachable measure of performance
56
Q

User CPU time

A

CPU time spent in a program itself

57
Q

system CPU time

A

CPU time spent in the operating system performing tasks on behalf of the program

58
Q

clock cycle (tick, clock tick, clock period, clock, or cycle)

A

time for one clock period, usually of the processor clock, which runs at a constant rate

59
Q

clock period

A

length of each clock cycle

60
Q

clock cycles per instruction (CPI)

A

average number of clock cycles per instruction for a program or program fragment

61
Q

instruction count

A

number of instructions executed by the program

62
Q

instruction mix

A

measure of the dynamic frequency of instructions across one or many programs

63
Q

workload

A

set of programs run on a computer that is either the actual collection of applications run by a user or constructed from real programs to approximate such a mix. A typical workload specifies both the programs and the relative frequencies

64
Q

benchmark

A

program selected for use in comparing computer performance

65
Q

pitfall: improvement is affected by how much time a feature is used

A

Expecting the improvement of one aspect of a computer to increase overall performance by an amount proportional to the size of the improvement

66
Q

amdahl’s law

A

rule stating that the performance enhancement possible with a given improvement is limited by the amount that the improved feature is used. It is a quantitative version of the law of diminishing returns

67
Q

fallacy: Computers at low utilization use little power

A

non energy-proportional computing

68
Q

fallacy: Designing for performance and designing for energy efficiency are unrelated goals

A

it is often the case that hardware or software optimizations that take less time save energy overall even if the optimization takes a bit more energy when it is used

69
Q

pitfall: Using a subset of the performance equation as a performance metric

A
  • nearly all proposed alternatives to the use of time as the performance metric have led eventually to misleading claims, distorted results, or incorrect interpretations
  • common mistake is to use only two of the three factors to compare performance
70
Q

million instructions per second (MIPS)

A
  • measurement of program execution speed based on the number of millions of instructions. MIPS is computed as the instruction count divided by the product of the execution time and 106
  • MIPS = instruction count/(execution time x 10^6)
  • cannot compare computers with different instruction sets using MIPS
  • if a new program executes more instructions but each instruction is faster, MIPS can vary independently from performance
  • varies between programs on the same computer; thus, a computer cannot have a single MIPS rating