Consider the following application case . There is a 250G-byte hard disk and it has 160G bytes of files. (Note that 160 x 109 bytes 2372 bytes.) These files can be treated as single big file in the following analysis 237.2 . The CPU of your computer has one core, with 4G clock speed (note that 4G4x 109) Its registers have 64 bits. Let's assume that it can do 8-character comparison in one CPU clock cycle. As a result, this computer can do 4 x 109 8-character comparisons