Representing data

Question 1

How do you convert binary to base 10?

Answer 1

You lay out the byte under the values 128, 64, 32, 16, 8, 4, 2 & 1, and add up the values that are above a 1.

Question 2

What are the first 5 data values?

Answer 2

byte, kilobyte, megabyte, gigabyte and terabyte.

Question 3

How many of each value is in the next?

Answer 3

1024 (eg, 1024 megabytes in a kilobyte), except byte, which contains 8 bits.

Question 4

What is the name of half a byte?

Answer 4

A ‘nibble’ - contains 4 bits.

Question 5

How do you convert base 10 into binary?

Answer 5

You take away the values 128 to 1 until you have zero.

Question 6

How do you add binary numbers?

Answer 6

Line them up one above the other. Where there is two zeros, write zero. Where there is a one, write one. Where there is two ones, write zero, carry one.

Question 7

Say the table of nibbles (probably only a good idea to do this once)

Answer 7

0000, 0001, 0010, 0011, 0100, 0101, 0110, 0111, 1000, 1001, 1010, 1011, 1100, 1101, 1110, 1111.

Question 8

How do you convert a byte to hexadecimal?

Answer 8

Split the byte in two and select the correct symbols from the table.

Question 9

What is the character set of a computer?

Answer 9

All of the characters that the computer can interpret.

Question 10

What is the difference between ASCII and Unicode?

Answer 10

ASCII only uses 7 or 8 bits, where as Unicode uses 16, meaning that Unicode provides a much larger character set.

Question 11

What is meta data?

Answer 11

The data stored at the begging of an image or sound file that tells the computer how create the sound or image (sample rate, resolution, height/with, colour depth etc)

Question 12

What is the color depth?

Answer 12

The amount of bits assigned to each pixel. The more bits per pixel, the more possible colors. (1 bit = two colors, 8 bit = 256 colors etc.)

Question 13

How do you work out the amount of colors a bit depth can represent?

Answer 13

2^n (eg 16 bit = 2^16 = 65,536 colors.)

Question 14

What is the problem when storing sound files?

Answer 14

Sounds are analog waves, computers produce digital waves.

Question 15

What is the sample rate?

Answer 15

The interval between each sample taken to construct the sound wave.

Question 16

What effect does reducing the sample rate have?

Answer 16

It decreases the file size, but also depletes the quality of the sound.

Question 17

What is the bit rate?

Answer 17

The amount of bit’s each sample is assigned. This means that the sample value is closer to the actual real life value.

Question 18

What is bit rate measured in?

Answer 18

Bits per second (amount of data stored for each second of sound), more commonly seen as kbits per second.

Question 19

What is the accumulator?

Answer 19

A small register in the CPU which contains the results of any current arithmetic calculation (Think back to the LMC)

Question 20

How are instructions stored?

Answer 20

Each 1 byte instruction contains an Operator and an operand. The operator refers to a operation, such as add, divide, subtract, store, etc, and the Operand represents data. (10011011 - 1001 1011 - ADD 11)

Question 21

How does the CPU execute an instruction?

Answer 21

It reads the Operator and manipulates whatever is in the accumulator accordingly.

Question 22

How does the CPU tell the difference between an Operator and an Operand?

Answer 22

It can’t. It just deals with them as it expects them to be ordered (Operator, Operand, Operator, Operand etc).