Computer systems

Question 1

what does decimal or denary mean

Answer 1

numbers written in base 10 using the digits 0 - 9

Question 2

what does binary mean

Answer 2

means numbers are written in base 2 using the digits 0 - 1

Question 3

why do computer systems use binary numbers to encode all info

Answer 3

its electronically easier to represent only two values
it is easier to build electronic circuitry for carrying out calculations with only two numbers
the advances in hardware mean its possible to store and process large quantities of digital info.

Question 4

How does a computer system know what 10000010100101000100010110010001 represents?

Answer 4

It depends largely on what the computer is expecting! Each piece of data will carry a code indicating what type
of data it is

Question 5

what is an integer

Answer 5

a number with no fractional part e.g. 76, 2

Question 6

what is 73 in binary

Answer 6

01001001

Question 7

what is 10011100 in decimal

Answer 7

156

Question 8

whats the largest possible 8 bit binary number

Answer 8

11111111 - 255 = 2’8
– 1)

Question 9

what is a real number

Answer 9

a number that has a fractional part

Question 10

how is a real number stored

Answer 10

using floating point representation using a mantissa and an exponent e.g. 6527.802 = 0.6527802 x 104

Question 11

what is a character

Answer 11

– any symbol or letter found on a keyboard. Each character has a unique numerical value inside
the computer e.g. ‘A’ is 01000001 (= 65).

Question 12

what is a computer character set

Answer 12

a list of all characters a computer can process and store. Different
computers have different character sets

Question 13

what are control characters

Answer 13

do not print on the screen in the normal way. They control certain operations of the
computer such as ‘cursor up’, cursor down’, ‘clear screen’, ‘tab’, ‘return (enter)’, ‘delete’ etc. If you look at
the table below, they are characters with ASCII codes 0 to 31

Question 14

what is extended ASCII

Answer 14

american standard code for information interchange
its stored using one byte (8bits)
2’8 = 256 therefore ASCII can represent 256 different characters
In ASCII, codes 0 - 31 are used for control characters e.g. 0001001 is the tab key

Question 15

what are vector graphics

Answer 15

graphics made up of objects each having a set of attributes

Question 16

give examples of some vector graphic objects

Answer 16

rectangle, ellipse, line, polygon

Question 17

give examples of vector attributes

Answer 17

co-ordinates, fill colour, line colour

Question 18

what happens to vector graphic files as the complexity of the graphic increases

Answer 18

the file size increases

Question 19

what are bitmap graphics

Answer 19

bitmap graphic are graphics made up by pixels

Question 20

what are pixels

Answer 20

picture elements

Question 21

explain black and white bitmapped graphics

Answer 21

one bit per pixel (0 for white, 1 for black)
number of bits = no of pixels

Question 22

what is a bitmap

Answer 22

a grid of bits (1s and 0s) is used to represent the colour of the pixels of the graphic.

Question 23

explain colour bit mapped graphics

Answer 23

Several bits are assigned to each pixel to represent the colour of the pixel
- e.g. 10 bits per pixel means 1024 possible colours for each pixel
- True colour means 24 bits per pixel (the limit at which the human eye can distinguish between colours).
This gives a total range of 16777216 colours

Question 24

what is the resolution of a graphic

Answer 24

the no of pixels making up the graphics
determines the quality of the graphic
the smaller the pixels the higher the resolution of 8 mega pixels

Question 25

what is bit depth

Answer 25

If more than one bit is used for each pixel, then shades of grey or even colour can be represented. For example,
if two bits are used for each pixel then there are four possible combinations (00, 01, 10, 11) which can be used
to represent the colour of a pixel (e.g. white, light grey, dark grey, black). The greater the number of bits used
for each pixel, the greater the variety of colours)

Question 26

how many bits would 128 colours require

Answer 26

128 = 27

so 7 bits required

Question 27

What is the bit depth of a graphic allowing up to 1024 colours?

Answer 27

Ans: 1024 = 210 therefore bit depth = 10

Question 28

does changing the colours in a bitmapped graphic alter the storage requirement

Answer 28

no

Question 29

If the bit depth or
resolution of a bit-mapped graphic changed would the file size change

Answer 29

yes

Question 30

As bit depth and resolution increases what will happen

Answer 30

the quality of the image will increase but the file size will too,

Question 31

what happens when two shapes overlap in bit mapped graphics

Answer 31

package, the shape on top will “rub out”

Question 32

what happens when two shapes overlap in vector graphic

Answer 32

individual objects can be selected and layered

Question 33

what type of graphic can you edit at pixel level

Answer 33

bit mapped graphics

Question 34

what happens to the file size of a bitmapped graphic

Answer 34

stays the same regardless of the amount of detail in the
graphic because each pixel is stored regardless of its colour

Question 35

what happens to a vector graphic file size

Answer 35

it increases as
objects are added

Question 36

what is the ALU

Answer 36

Arithmetic logic unit

Question 37

what does the ALU do

Answer 37

carries out calculations and makes decisions and logical operations

Question 38

whats the control unit

Answer 38

controls all the parts of the processor and makes sure that the program instructions are synchronized to be executed in the correct order.
increases as
objects are added

Question 39

whats the register

Answer 39

Registers are storage locations inside the processor chip that hold data while the processor is using it

Question 40

Whats the MAR

Answer 40

Memory Address Register.

Question 41

what does the MAR do

Answer 41

holds the address of the location in memory that is currently being
accessed

Question 42

whats the MDR

Answer 42

memory data register

Question 43

what does the MDR do

Answer 43

holds the contents of the location currently being accessed