Title: Year 12 / Computer Science / Theory / 1 - Information Representation / 1.1 - Data Representation

Q: State the base number system for binary
A: base 2

Q: Describe what is meant by "base", in a number system context
A: the amount by which each place value multiplies by

Q: Explain the difference between a Kibibyte and a Kilobyte
A: a kibibyte is made up of 1024 bytes, a kilobyte is made of 1000 bytes

Q: State the base number system for hexadecimals
A: 16

Q: State what hexadecimal is most commonly used for and how its done
A: to represent colours, they store 24 bit binary number in 6 characters, and represent RGB numbers to create different colours
to represent a IPv6 address, which are in 128 bits, so theyre more easily represented with hexadecimal

Q: Explain how to convert from binary to hexadecimal
A: divide the binary number into individual 4 bit nibbles, and then convert each nibble into each digit of the hexadecimal number

Q: Describe what is meant by a character set
A: list of characters and symbols that the computers hardware and software recognises

Q: Describe the difference between ASCII and Extended ASCII
A: ascii uses 128 characters in 7 bits, extended ascii uses 256 characters in 8 bits

Q: Describe the disadvantages of ASCII
A: only 128 or 256 characters represented, uses values 0 to 127, many characters in other languages cant be represented, in eascii the 128 to 255 characters might be coded differently in different systems

Q: Describe what is meant by Unicode
A: character set that uses 32 bits, standardized, more languages represented, designed to be superset of ascii

Q: Explain why sign magnitude isnt used to represent number
A: because there are 2 zero values

Q: Explain how sign magnitude works
A: first bit stores sign, rest stores magnitude

Q: Explain how ones complement works
A: bits get flipped if number is negative

Q: Explain the problem with ones complement
A: has two zero values

Q: Explain how twos complement works
A: flips the bits and adds 1

Q: Describe 5 different applications of BCD
A: electronic calculator displays, date and time stored in bios of pcs, financial applications, latitude and longitude, barcodes