A 'byte' is the unit to measure digital information, like hard drive memory, file size, etc. Before there were pen drives and CDs, we stored and transferred data using floppy disks (which had a humble capacity of 1.44mb). We sure have come a long way from there. In fact, when Intel co-founder Gordon Moore noticed in 1965 that the capacity of the circuits had been doubling every two years since it had been invented, he predicted that the same trend would continue in the future. It looks like Moore's Law holds true even today.