It refers to the size of files which is what is used in a computer. Byte: 1 Kilobyte: 1,000 bytes Megabyte: 1,000,000 bytes Gigabyte: 1,000,000,000 bytes
These are the units to measure the computer storage size:
1 gigabyte = 1024 megabyte
1 megabyte = 1024 kilobyte
1 kilobyte = 1024 byte
1 byte = 8 bit
each bit is a binary no. i..e a 0 or a 1