Knowing the Computer
Storage and memory
Measure information in bits and bytes, work out the bigger units from the smaller ones, and tell memory that forgets from storage that keeps.
A computer stores everything as bits. A bit is the smallest piece of information there is: a single 0 or 1, nothing smaller. Eight bits together make one byte, and one byte is about enough to hold a single letter. Everything else is just bigger heaps of bytes.
The ladder of units
1 byte = 8 bits. 1 kilobyte = 1024 bytes. 1 megabyte = 1024 kilobytes. 1 gigabyte = 1024 megabytes. 1 terabyte = 1024 gigabytes. Every step up is 1024 of the step below — not 1000, because computers count in twos and 1024 is what you get from doubling ten times.
Worked example
How many bits are there in 4 bytes?
Write down what one byte is worth: 8 bits.
Every one of these questions starts by naming the exchange rate.
Try it together
Now let us work out how many bytes a 5 kilobyte file holds.
Remember that one kilobyte is 1024 bytes. Take it one step at a time.
1.How many bytes are there in 1 kilobyte?
Have a go
Have a go on your own. One byte is 8 bits. How many bits are there in 10 bytes?
Ready to practise?
Eight questions on what you have just read. Nothing is timed, and you can play as many times as you like.