Computer Science - Representing data in a computer + databases 📀

Question 1

How is data stored?

Answer 1

Data is stored in each memory location in a pattern of bits.

Question 2

Bit patterns can represent different types of data such as…

Answer 2

Bit patterns can represent different types of data such as numbers, text, audio, images, graphics, and video.

Question 3

Computers store and manipulate data in the form of…

Answer 3

Computers store and manipulate data in the form of electronic pulses.

Question 4

What are the 2 signal states that a computer represents data with?

Answer 4

ON (The high voltage level) OFF (The low voltage level)

Question 5

How is the digitized data represented numerically?

Answer 5

It is represented using the binary number system (base 2) which only uses 1s and 0s.

Question 6

Since there are only 2 states in a computer, it is called a _______.

Answer 6

Since there are only 2 states in a computer, it is called a bi-stable device.

Question 7

How does you pressing a letter lead to it being shown on the screen?

Answer 7

Electrical signals are sent from the keyboard to the CPU. The CPU turns the signals into binary code. Then, the computer reads the code and sends it to the monitor to display the letter.

Question 8

A bit is a ____.

Answer 8

A bit is a single digit in a binary number; it is either a 0 or a 1. It is the smallest unit of memory the computer stores.

Question 9

What is a byte?

Answer 9

A byte is a group of 8 bits, representing a single character. It is normally the smallest grouping used by computers.

Question 10

8 bits =

Answer 10

1 byte

Question 11

1024 bytes =

Answer 11

1 kibibyte

Question 12

1024 kibibytes =

Answer 12

1 mebibyte

Question 13

1024 mebibytes =

Answer 13

1 gibibyte

Question 14

1024 gibibytes =

Answer 14

1 tebibytes

Question 15

What are the three most common number systems?

Answer 15

Decimal (denary), Binary, and Hexadecimal.

Question 16

What is the base of the decimal number system?

Answer 16

10

Question 17

What is the base of the hexadecimal number system?

Answer 17

16

Question 18

Since the base of the hexadecimal number system is 16, what are the characters used to represent the final 5 digits?

Answer 18

A (10), B (11), C (12), D (13), E (14), F (15).

Question 19

How do you convert a decimal (denary) number to its binary equivalent?

Answer 19

1) Write down the decimal number.
2) Continually divide by 2 to give a remainder of 1 or 0
3) Keep doing this till the final result is 1 or 0
4) You can get the binary result by putting the binary numbers together, starting from the bottom. If the result is not a byte, fill in the spaces before the answer with zeros.
Recommended to see the method in book as it is hard to visualise.

Question 20

How do you convert a binary number to its decimal/ denary equivalent?

Answer 20

I can’t explain the method in writing and cannot put images in the answers without a pro subscription but uhh here’s a link to a picture of the method, keep it open in a new tab and open it whenever you get this flashcard… https://i.pinimg.com/originals/68/57/33/68573306c2979a81384b814e53adbaa2.gif

Question 21

What is a database?

Answer 21

A database is a store of data that has been organised in some way.

Question 22

Why are databases useful?

Answer 22

Databases are so useful because they store data in a structured way. When data is structured, it can be manipulated easily and then output in different ways.

Question 23

Databases consist of:

Answer 23

1) Files/tables
2) Records
3) Fields

Question 24

What is a file/table?

Answer 24

A collection of records and fields is called a file.

Question 25

What is a record?

Answer 25

One single row of a database represents one record.

Question 26

What is a field?

Answer 26

Each cell of a table indicates a single field. A single field can hold one piece of data.

Question 27

What is a key field?

Answer 27

A key field is an individual piece of data that is unique.. A key field is used to differentiate one record from another.