Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

IGCSE Computer Science > Chapter 1 - Data Representation > Flashcards

Chapter 1 - Data Representation Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

What is the building block of all computers and why

A

Binary number system, because it is only made up of 0’s and 1’s. Computers contain millions of tiny switches that must be in either the ON or OFF position. These positions can be represented by the binary number system.
1=ON(high)
0=OFF(low)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What do switches in a computer do and what is another name for them

A

Make use of logic gates and store and process data
Microtransistors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Whaty does binary allow computers to do

A

Carry out calculations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is a bit

A

A basic computing element that is either a 0 or 1, comes from BInary digiT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the binary number system

A

A number system based on 2, and only contains 0’s and 1’s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the denary system also called

A

A base 10 number system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the uses of the hexadecimal system (4)

A

Error codes
Mac address
IPv6 adress
HTML colour codes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are error codes

A

They are codes that are usually automatically generated, and refer to the memory location of the error

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does the MAC address stand for

A

Media Access Control address

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What does NIC stand for

A

Network interface card

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a MAC address

A

A number which uniquely identifies a device on a network, it refers to the NIC.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Why are MAC addresses rarely changed

A

So that a particular device can always be identified no matter where it is

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does the NN-NN-NN in a MAC address identify
What does the DD-DD-DD in a MAC address identify

A

The number of the manufacturer
The device serial number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What do IP addresses stand for

A

Internet protocol addresses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the difference between an IPv4 and an IPv6 (2)

A

32 vs 128 bit number. IPv6 uses a colon instead of a decimal point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does HTML colour codes stand for

A

Hyper text markup language colour codes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the maximum denary value of an 8-bit binary number

A

255
(2^8-1)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is it called when there is more than 8 bits generated after calculations and what does it mean

A

Over flow
The number is too big to be stored in the computer using 8 bits
A bigger register needs to be used

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is an overflow error

A

The result of carrying out a calculation where the result is too big for the computers word size.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

hexadecimal

A

A number system based on 16, goes from 0-9 and then A-F

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is HTML

A

It is a mark-up (NOT PROGRAMMING) language used when writing and developing web pages
It uses tags<>
Often represents colours of text on screen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is a logical shift

A

An operation that shifts buts left/right in a register and replaces shifted bits with 0
Left shift= multiply binary number by 2
Right shift=divide binary number by 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the left most bit reffered to as

A

The most significant bit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

ASCII

A

American Standard Code for Information Interchange
It is a set of characters for each character on a standard keyboard and 32 control codes control code. (0-31 denary, 00-19 Hex)
Was used in Communication and computer systems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

character set

A

A set of characters that have been defined by computers hardware and software. It is used so that the computer can understand human characters.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What does the standard ASCII code character set consist of and what is it used for

A

7-bit codes(0-127 in denary/00to 7F in hex)
Represent the letters numbers and characters found on a standard keyboard together with 32 control codes(0-31 denary, 00 to 19 hex)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What does ASCII vs unicode use to represent a character

A

1 vs 4 bytes

28
Q

goals of unicode (5)

A

To have uniform code
Unambiguous code
Reserve part of the code for private use
Universal standard
More efficient coding system

29
Q

What is unicode

A

Character set that represents the languages of the world (first 128 are the same as ASCII)

30
Q

What does the aplitude of a wave specify

A

The loudness of the sound

31
Q

analouge data

A

Data that varies continuously

32
Q

How do computers store sound wave data

A

They convert it from anolouge to digital using an ADC, sampling the amplitude at regular intervals. The amplitude cannot be precicely measured so approximate values are stored.

33
Q

How could you get a more accurately sampled sound

A

By iincreasing the sampling resolution(bit depth)

34
Q

sampling resolution

A

Also known as bit depth
The number of bits used to represent sound amplitude in a digital recording

35
Q

What is bit depth

A

The number of bits used to represent the smallest unit in a sound file

36
Q

What is the sampling rate

A

The number of sound samples taken per second
Measured in hertz where 1 herts means one sample per second

37
Q

How is sampling used to record a clip (3)

A

The amplitude is first determined at set time intervals
An approximate representation of the wave is produced
Each sample is then encoded to a series of binary digits

38
Q

What are the advantages of a higher sample rate/larger resolution (3)

A

Larger dynamic range
Less sound distortion
Better sound quality

39
Q

What are the disadvantages of a higher sample rate/larger resolution (3)

A

Produces larger file size
Takes longer to transmit/download
Requires a greater processing power

40
Q

bitmap image

A

An image made up of pixels

41
Q

What is colour depth

A

The number of bits used to represent the colours of a pixel

42
Q

What is an image made up of

A

A two-dimentional matrix of pixels

43
Q

What bit depth do modern computers have

A

24 bit depth

44
Q

What is image resolution

A

The number of pixels that make up an image

45
Q

Explain the drawbacks of high resolution images

A

They increase file sizes, which impacts how many images can be stored on the eg. Hardrive. It takes longer to download and transfer the images.

46
Q

what is pixel density

A

The number of pixels per square inch

47
Q

How big is a byte

A

8 bits

48
Q

How big is a nibble

A

4 bits

49
Q

What is the largest memory size metioned in the texbook

A

Exabyte
X10^18

50
Q

What is a more accurate way of measuring memory sizes, and what should be measured using this

A

IEC memory size system
International electronical commision
RAM and ROM

51
Q

Why would data need to be compressed (5)

A

Storage
Time taken to stream
Reduce file size=reduce costs
Reduce time to download/transmit
Reduce bandwidth usage

52
Q

What is bandwidth

A

Where maximum rate of data transfer accross a network measured in kbps or mbps

53
Q

What is lossy file compression
Eg. (3)

A

A compression process that eliminates unneccesary date and some detail which cannot be recovered during the decompression process
JPG
MP3
MP4

54
Q

How does lossy file compression affect MP3 (2)

A

It removes sounds out of the human hearing range
If there are 2 sounds at the same time, one is removed

55
Q

What is audio compression

A

A method used to reduce the size ofa sound file using perceptual music shaping

56
Q

What is the difference between MP3 and MP4 files

A

MP3 is for music
MP4 allows multimedia storage.

57
Q

What is the JPEG file reduction process based on

A

Human eyes dont detect differences in colour as well as they do differences in brightness
By separating pixel colour from brightness, images can be split into 8x8 pixel blocks which allows information to be easily discarded with minimal quality loss

58
Q

When should lossless file compression be used (2)

A

When comressing large/complex spreadsheets or downloading a large computer application

59
Q

What is RLE and what does it do

A

Run-length encoding
Form of lossless file compression
Reduces size of a string of adjacent,identicsl data
This string is then encoded into 2 values, the first being the number of identical items in the run, the second the code of the data (eg. ASCII)
Only effective if there are long runs of repeated bits

60
Q

What is the left most bit refered to as

A

The most significant bit

61
Q

What is the right most bit refered to as

A

The least significant bit

62
Q

Character set

A

List of characters that have been defined by computer hardware and software, neccessary so that computers can understand human characters.
Standard ASCII code character set has 7 bits (0-127 binary, 00 to 7F Hex)

63
Q

Difference between upper and lowercase in ASCII

A

Upper has the 6th bit as 0, lower as 1
Eg. Uppercase: 0 0 00001
Eg. Lowercase 0 1 00001

64
Q

Extended ASCII

A

Uses 8 bit codes, gives an extrea 128 codes to allow non-english characters and graphical characters

65
Q

Compression

A

Reduction of file size through removing repeated or redundant pieces of data (can be lossless or lossy)

IGCSE Computer Science (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions