Units Flashcards
Computers use 1s and 0s for what?
- to represent the flow of electricity
- 1 is sued to show that electricity is flowing
- 0 shows that it’s not flowing
What is a bit (b)?
A single binary digit (1 or 0)
What is a nibble?
4 bits
What is a byte (B)?
- 8 bits
- enough to store one character
What is a kilobyte (kB)?
- 1000 bytes
- most files (e.g. songs, pictures and documents) are measured in kB or MB
What is a megabyte (MB)?
- 1000 kilobytes
- most files (e.g. songs, pictures and documents) are measured in kB or MB
What is a gigabyte (GB)?
- 1000 megabytes
- high definition videos and complex applications are often measured in gigabytes
What is a terabyte (TB)?
- 1000 gigabytes
What is a petabyte (PB)?
- 1000 terabytes
Secondary storage capacity is normally measured in what?
gigabytes or terabytes
If each bit can take two values how man values can a nibble take? How many values can a byte take?
nibble = 4 bits = 2 to the power of 4 == 16 different values byte = 8 bits = 2 to the power of 8 == 256 different values
What are check digits?
- a way of checking if data has been entered and read correctly
- they are digits added to the end of numbers (e.g. ISBNs on books) and are calculated using the other digits in the number.
- if the check digit is correct when data is read, then it’s likely the data has been read/entered correctly.
What is a check digit called in binary data?
A parity bit
What is an even parity bit?
- added to make a binary string have an even number of 1s
What is an odd parity bit?
- added to make a binary string have an odd number of 1s.
