3 Fundamentals Of Data Representation Flashcards
What is the capacity of a device?
The capacity of a device is how much data it can store
Why is it important to know the units of capacity of a device?
It is important to know the units of capacity so that we can compare the capacity of different devices
What is a bit?
A bit is the smallest amount of data that we can store. It is a binary digit, often called a bit for short.
The value can only be either a 0 or 1
Why don’t we use bits to measure data?
The bit is too small for measuring data
How large is a nibble?
4 bits
How large is a Byte?
8 bits
What are the most common units for comparing storing data?
Kilobyte (KB) (1000 bytes).
Megabyte (MB) (1000 KB).
Gigabyte (GB) (1000 MB).
Terabyte (TB) (1000 GB).
What are the three things required to calculate the amount of data that can be stored within a certain capacity?
The three things required to calculate data required storage in a capacity are:
- Size of data being stored
- Available Capacity
- How to convert between units
Why is it important to know the size of data being stored?
The bigger the size of the data being stored, the bigger capacity media will be needed
Why is it important to know the available capacity of our device?
The more capacity available, the more data we can store
Why is it important to know how to convert between units?
To find out if we have enough capacity, it is important to put the capacity of the media and the size of the data into the same units
What is the equation to calculate required capacity of a device?
Required capacity = number of files × size of a single file
What is Denary?
Denary is our number system where we use 10 symbols to represent each digit
What is Binary?
Binary is a number system where only the digits zero and one are used.
Each digits place is multiplied by 2 as we move from right to left.
What is hexadecimal?
Hexadecimal uses 16 different symbols for each place. Hexadecimal uses the digits 0-9 and A-F
Each digits place value is multiplied by 16 as we move from right to left
How do you convert binary into hexadecimal?
First, you split the binary into groups of 4 bits, starting from the right
You then convert each group separately and put the digits together
How do you convert hexadecimal to denary?
To convert from hexadecimal to denary, you should:
Write out the powers of 16 above each hexadecimal digit.
For each place column, multiply the hexadecimal digit by the power of 16 above it.
Add together all of these results.
What are overflow errors?
If a number is carried past the last place column during binary arithmetic, then this is called an overflow error
What do overflow errors lead to?
Overflow errors can lead to inaccurate results and software crashes
What is a binary shift?
A binary shift is a technique for performing multiplication or division on a binary number
Extra 0 bits are added to the start or end of the binary number to fill any missing spaces
What is a right binary shift?
A right binary shift is when each digit is moved once place to the right
This has the effect of dividing the number by two
You must take care when performing a right shift that no data is shifted off the right hand side. This can cause a loss of accuracy.
What is a left binary shift?
A left binary shift, is when each digit is moved one place to the left.
This has the effect of multiplying the number by two.
You must take care, when performing a left shift, that there is no overflow error (where we run out of space to store the last digit of the number)
What is text data made up of?
Text data is made up of characters
What is a character set?
A character set is a collection of all the characters that a computer recognises, along with their binary codes
What is included in a character set?
Alphanumeric characters e.g. letters, numbers, and symbols
Special characters e.g. new line
What are the two main character sets in use?
American Standard Code for Information Interchange (ASCII)
Unicode
What does ASCII stand for?
American Standard Code for Information Interchange
What is the most common character set?
American Standard Code for Information Interchange
What is each character in ASCII represented by?
Each character in ASCII is represented by a seven-bit binary code
What is the maximum amount of characters allowed in ASCII?
There is a maximum amount of 128 characters that can be included in ASCII
What does ASCII include?
ASCII includes all the commonly used letters and symbols in the English language