Binary, headecimal signed 2s compliment

Question 1

Computer technology has all components that recognise only two states. What are they?

Answer 1

1 or 0 (binary aka on or off)

Question 2

Binary code is used inside the computer to do what?

Answer 2

.store and manipulate data

Question 3

What is a disadvantage of using binary code?

Answer 3

Difficult to document outside of the computer system

Question 4

What can be used to document instead of binary code?

Answer 4

Hexadecimal representation

Question 5

What type of system is binary?

Answer 5

Base 2

Question 6

What type of system is hexadecimal?

Answer 6

Base 16

Question 7

How is one hexadecimal symbol grouped?

Answer 7

in four bits (nibble)

Question 8

Convert 1011 0110 0111 0001 into Denary

Answer 8

46705

Question 9

Convert 485 into Binary - 16 bits

Answer 9

0000000111100101

Question 10

Convert 865 into Hexadecimal

Answer 10

361

Question 11

Convert 1011 0110 0111 0001 into Hexadecimal

Answer 11

B671

Question 12

Convert AE2 into denary

Answer 12

2786

Question 13

How many bits in a byte?

Answer 13

8 bits

Question 14

Why do we need signed numbers?

Answer 14

To see if a binary number is positive or negative

Question 15

How is a signed binary byte structured

Answer 15

The first bit is used to represent the + or - sign. 0 is positive and 1 is negative. The remaining bits total up the value. Another name for this is sign and magnitude.

Question 16

Give a disadvantage of using sign and magnitude method

Answer 16

You have a positive and negative 0.

Question 17

How do people normally store signed integers?

Answer 17

In 2’s complement

Question 18

State what is meant by one’s complement

Answer 18

The binary number obtained by subtracting each digit in a binary number from 1

Question 19

State what is meant by two’s complement

Answer 19

The one’s complement of a binary number plus 1

Question 20

Express the number 10100100 in 2’s complement

Answer 20

01011100

Question 21

How do you convert a negative denary number into binary Two’s
Complement

Answer 21

1. Find the binary equivalent of the denary number
2. Add an extra bit before the most significant bit and turn that into 0
3. Flip all the bits: 0 to 1; 1 to 0
4. Add 1

Question 22

How do you Converting Two’s Complement to denary

Answer 22

1. Flip all the bits: 0 to 1; 1 to 0
2. Add 1
3. Simple conversion from binary to denary

Question 23

Give an example of where 2’s complement can be used

Answer 23

Digital displays. This is because you take the lowest negative value, and each successive higher value is obtained by adding 1 to the binary code. When all numbers in the nibble is 1, it rolls over again to all 0 - just like a digital display.

Question 24

State what is meant by binary coded decimal?

Answer 24

Another method to grouping bits

Question 25

Why use BCD?

Answer 25

If you need an application where single denary digits are required to be stored or transmitted - BCD is used

Question 26

Give examples of BCD being used?

Answer 26

Calculator screen or digital time display or the display of currency on a computer

Question 27

If a currency is $300.25, display this in BCD

Answer 27

0011 0000 0000 0010 1001

Question 28

Add up 0.26 + 0.85 using BCD

Answer 28

0000 0001 0001 0001

Question 29

State what is meant by ASCII

Answer 29

It is a coding scheme that allows text to be stored via a character code

Question 30

State the columns of an ASCII table

Answer 30

Binary, Hexadecimal, Character, Description

Question 31

How many different codes are available for 7 bit code.

Answer 31

27 (128)

Question 32

What characters are contained in an ASCII table

Answer 32

Non-printing or control characters - there for data transmission or entering data in a computer terminal (not used much anymore). Upper and Lower Case letters; Punctuation symbols; Numerals and Arithmetic Symbols

Question 33

What is the problem with ASCII codes

Answer 33

Limited amount of characters can be stored not suitable for different languages.

Question 34

State what can be used instead of ASCII code

Answer 34

Unicode - the first 128 characters is ASCII and has different lengths

Question 35

How is Unicode structured

Answer 35

Uses a CODE POINT instead of character code (ASCII). e.g. U+0041 is the letter A where 0041 is hexadecimal. Where Unicode uses ASCII (the first byte) it starts with 0.