Unit 3 Computer systems

Question 1

What is meant by a “sign bit”?

Answer 1

The first Bit in a binary number that indicates if the number is positive or negative

Question 2

Which sign bit do we use for negative numbers?

Answer 2

1

Question 3

Which sign bit do we use for positive numbers?

Answer 3

0

Question 4

What do Bit-mapped graphics do?

Answer 4

They store every pixel necessary to store an image

Question 5

What is meant by the term resolution?

Answer 5

Resolution is used to state the total number of pixels in an image

Question 6

Why are Bit-mapped graphics said to be “resolution-dependent”?

Answer 6

As once an Bit-mapped graphics’ resolution is created it is set and will not change

Question 7

Why is compression of a Bit mapped graphic necessary?

Answer 7

• To reduce the size of an image so that it is less demanding of storage and memory
• To reduce the file size of an image to allow faster transmission across a network

Question 8

What are the different types of Compression of bit-mapped graphics/

Answer 8

• Run length encoding (RLE)
• Lempel, Ziv, Welch (LZW)

Question 9

Where can Run length encoding compression be used?

Answer 9

if a block of pixels in a sequence are the same colour

Question 10

What does LZW compression do?

Answer 10

LZW compression will store patterns of repeated colours and store them in an index where they can be looked up

Question 11

What are the factors that affect computer performance?

Answer 11

• number of processors
• Width of Data-bus
• Cashe memory
• Clock speed

Question 12

Why does an increased number of processors increase performance?

Answer 12

As by increasing the number of processors, more data can be processed at one time meaning that the overall speed of the machine is faster

Question 13

Why does increasing the width of the data bus increase the performance of the computer?

Answer 13

By increasing the data bus, you are increasing the amount of data that can be passed between the processors and main memory

Question 14

What does increasing cashe memory have to do with increasing computer performance?

Answer 14

Cache is a memory that is closer to the CPU than RAM and holds instructions for the CPU, cashe memory improves the performance of the computer as more cashe memory means that more instructions can be held in cashe and cashe is easier to obtain instructions from than RAM, this also saves time improving the processing speeds