kilo- (k)
x10^3
mega- (M)
x10^6
giga- (G)
x10^9
tera- (T)
x10^12
Hexadecimal values
0-9, A-F
Applications of hexadecimal
HTML Colour Codes
MAC (Media Access Control) Addresses
Assembly language and machine code
Debugging via memory dumps
kibi- (ki)
x2^10
mebi- (Mi)
x2^20
gibi- (Gi)
x2^30
tebi- (Ti)
x2^40
Binary Coded Decimal
BCD is a system where each denary digit is represented by a nibble. Only the binary nibbles for 0-9 are used as each nibble can only represent one digit at a time. It is easy to convert between denary and BCD
nibble
sequence of 4 bits
byte
8 bits
Applications of BCD
Displaying a string of digits on an electronic device (calculator, digital alarm clocks, microwaves)
Accurately measuring decimal fractions
Electronically coding denary numbers
Storage of date and time on PCs
Two’s Complement
used to represent denary values between -128 and 127 in an 8-bit binary value by taking the Most Significant Bit (MSB) and using it as an indicator whether or not the number is positive
Denary/Binary –> Two’s Complement
- 8-bit Binary value
- One’s complement (flip all 0s and 1s)
- Add 1
Two’s Complement –> Denary/Binary
- One’s complement (flip all 0s and 1s)
- Add 1
- Calculate denary value from 8-bit binary
Character set
contains all of the characters that a computer can use; each character has its own unique corresponding binary value
ASCII
only the English alphabet can be represented
7 bits; 128 character capacity
smaller storage space
Extended ASCII
also includes most European languages’ alphabets
8 bits; 256 character capacity
Unicode
superset for ASCII and Extended ASCII
recognised by various global languages; wide range of characters due to representation of multiple languages
16 bits; 2-4 bytes per character
2-4x more storage space per character
