4) Organisation and structure of data

Question 1

Hexadecimal to binary

Answer 1

Split each character into 4 bits - work out binary for each

Question 2

Hexadecimal

Answer 2

0 1 2 3 4 5 6 7 8 9 A B C D E F

Question 3

Denary

Answer 3

Denary/Base 10/ Decimal counting system.

0 1 2 3 4 5 6 7 8 9

Question 4

Binary

Answer 4

Base 2/ Binary digits
1 0
Bits
1 = on
0 = off

Question 5

Arithmetic shift

Answer 5

Shifts are manipulations of bit patterns.

Moving the bits a specified amount of times each direction.

Question 6

How sound can be stored digitally

Answer 6

Sound is converted into a digital signal by sampling

Sampling is when a device measures the level of
sound many times per second and records this as binary digits

Question 7

How an image is represented by pixels in binary format

Answer 7

1 = black pixel
0 = white pixel

Colour bitmap is stored by replacing 1s and 0s with a longer number that represents RGB

Question 8

Why metadata needs to be included

Answer 8

metadata = data about data
Needed to store an image correctly
Image’s height, width, colour depth

Question 9

Binary digits representing chartacters

Answer 9

Unicode
Ascii
(American standard code for information interchange)

Question 10

Data types

Answer 10

Integer
Real
Boolean
Character
String

Question 11

Data structure

Answer 11

Specific way of organising data within memory so that it can be processed efficiently.

Question 12

Static data structure

Answer 12

Designed to store a know number of data items.

Values can be changed but memory size is fixed

Question 13

Dynamic data structure

Answer 13

Designed to allow the data structure to grow and shrink at runtime

Question 14

List

Answer 14

Data items stored in the order they were originally added to memory

Question 15

Array

Answer 15

Data structure that can hold a fixed number of data items which must be same data type.

Question 16

1D array

Answer 16

Used to store a list of data in memory that can be used by a program at runtime.

Question 17

Insertion

Answer 17

You can add an element to an array at a given index

myArray[3] = 27

Question 18

Traversing

Answer 18

Using a loop to use each element of an array in a section of a program

Question 19

Deletion

Answer 19

myArray[6] = “”

Question 20

Search

Answer 20

Arrays can search using the index or the value stored

Question 21

2D array

Answer 21

Must all be same data type

Table with columns and rows

Question 22

Records

Answer 22

Records can hold all data types

Uses more memory - less efficient

Question 23

Key field

Answer 23

An item of data that is unique and can be used to identify the individual record

Question 24

Validation

Answer 24

Process to check if data is reasonable or sensible

DOES NOT CHECK IF DATA IS CORRECT

Question 25

Types of validation

Answer 25

``` Presence check Format check Range check Length check Type check Lookup check ```

Question 26

Verification

Answer 26

Process for checking data is correct.

Question 27

Algorithm design

Answer 27

Make a table with data name and data type and validation checks