U2T1 - Data Representation Flashcards Preview

CCEA AS Digital Technology > U2T1 - Data Representation > Flashcards

Flashcards in U2T1 - Data Representation Deck (29)
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1
Q

What is our number system? (2 names)

A

Denary number system (base 10)

2
Q

What number system do computers use?

What is it also known as?

A

Binary

The base 2 number system

3
Q

From right to left, how do the columns to show binary go?

A

1, 2, 4, 8, 16, 32, 64, 128.

4
Q

What is the highest number you can make in binary with 8 digits?

A

255

5
Q

Convert denary to binary…
42
146

A

00101010

10010010

6
Q

Convert binary to denary…
01101011
11100110

A

107

230

7
Q

What are 2 ways to show negative numbers in binary?

A

Ones complement + twos complement

8
Q

Describe ones complement…

A

Convert 1’s to 0’s and 0’s to 1’s.

9
Q

Find ones complement of…

01100011 (99)

A

10011100 (-99)

10
Q

Describe twos complement…

A

Convert to binary, invert 1’s and 0’s, add one.

11
Q

Using twos complement:

Convert -5 to binary.

A

0101
1010
1011 (-5)

12
Q

Convert 1111 to decimal using twos complement.

A

1111
0000
0001
= -1

13
Q

How might you find the highest number a set of bits could create?

A

2n - 1

14
Q

What is the bit position on the right hand side called?

What about the left?

A

Least significant bit (LSB)

Most significant bit (MSB)

15
Q

How might a bit be represented in a computer’s main memory?

A

Transistor switched on/off, capacitor charged/discharged etc.

16
Q

How is data transmitted over telephone/radio?
What about magnetic disks (floppy/hard)?
Audio CDs, CD-ROMs & DVDs?

A

High + low pitched tones for 1s & 0s.
Magnetic field on coated surface (North-South/South-North)
Optically, surface does/doesn’t reflect light.

17
Q

What is a bit?

A

A binary digit. (0 or 1)

18
Q

How many bits in a byte?

A

8

19
Q

How many bytes in a KB?

A

1024

20
Q

How many KB in a MB?
MB in a GB?
GB in a TB?

A

1024

21
Q

How many bytes in a megabyte?

A

1,048,576

22
Q
Typical size + price for:
Hard Drive
DVD
Flash Drive
External Hard Drive
A

1 - 5 TB, £40 - £150.
4.7GB, £10.
8 - 32 GB, £8 - £11.
1 TB, £50.

23
Q

What is a character?

A

A letter/digit/special character represent with bits and bytes.

24
Q

What does a character set contain? Examples?

A

Letters, digits, punctuation marks, ‘control characters’ which are non-printing & used for special purposes. E.g. ASCII & Unicode.

25
Q

What is ASCII?

A

American Standard Code for Information Interchange.
7 bit code representing 128 characters. Bits represents symbols + characters in ASCII. 8th bit is a parity digit for error checking. 96 displayable characters, 32 control codes, 8 bits would give a range of 255.

26
Q

What is Unicode?

A

A worldwide character standard which allows for interchange, processing & display of written texts of majority of languages of the modern world. 16 bit, 65536 characters.

27
Q

Why is data stored in binary?

A

It’s either on or off

28
Q

What is a nibble?

A

4 bits, half a byte.

29
Q

What is a crumb?

A

2 bits