1541 floppy drive
From Computer History Wiki
The 1541 was a single sided 5 1/4" floppy disk for the Commodore 64. It utilized a serial connection to the host computer, and was better known for being SLOW. On reset, the 1541 would crash the head to 'find' the home sector making this a very LOUD drive, giving the impresion that it was broken.
The drive housed a 6502 cpu, memory and rom set, that made the 1541 almost a full computer onto itself, which also kept it's cost up very high.