Unit 1 Flashcards
(19 cards)
Integers
Positive or negative whole numbers
Rational Numbers
Can be written as fractions or a ratio.
Irrational Numbers
Cannot be written as a fraction. Is a decimal that doesn’t recur or terminate.
Ordinal Numbers
Numbers that describe a value’s position e.g. first, second, fourth.
Denary
(Base 10) - ten choices of digits 0-9
Binary
(Base 2) - two choices of digits 0-1
Hexadecimal
(Base 16) - 0-9,A-F
Value of Using Hexadecimal
- Hex values easier to read and remember than binary strings.
- Quicker to write as a hex digit is only 1 character.
- Less chance of making an error.
- Used to define colours, MAC Addresses, assembly languages and machine code.
- Easy to convert between binary and hex.
Binary coded decimal
Each denary digit is converted individually e.g. 83 would be 10000011 instead of 01010011
Bit
Smallest unit of data that a computer can store. Each bit is represented as a binary number.
Byte
8 Bits. Keyboard characters take one byte of storage.
Nibble
4 Bits.
Unicode vs ASCII
Unicode can represent all characters of all languages whereas ASCII can only represent 128 total characters. Unicode takes up more storage as it uses 8-16 bits per character whereas ASCII only uses 7.
Two’s complement
- 7 in binary = 00000111
- Flip it to become = 11111000
- Add 1 = 11111001
- 11001101 to decimal
- Flip becomes = 00110010
- Add 1 = -00110011
- = -51.
Resolution Formula
= Pixel height x Pixel width
Resolution
Measures pixel density. The higher the resolution, the more memory needed to store the image.
File Size
Determined by the number of pixels used and the number of available colour combinations.
Metadata
Data about data and is stored in the same file as image data e.g. File format, resolution, time and date, colour depth.
