Generations of Computers
The computers of today find their roots in the second half of the twentieth century. Later as time progressed, we saw many technological improvements in physics and electronics. This has eventually led to revolutionary developments in the hardware and software of computers. In other words, soon the computer started to evolve. Each such technological advancement marks a generation of computers.
Cleaning up a system helps clear up the space on the drives. It may also clear up processor usage, ram usage if you uninstall programs that automatically started when the system booted. You may also delete some unwanted programs in the process.