The best known floppy disk drive for the Commodore 64. The 1541 was a single-sided 160 Kb drive but converting to flippy disks would give another 160 Kb.
The disk drive used Group Code Recording and contained a 6502 processor as a disk controller. Some people wrote code for it to vibrate the head at different frequencies to play tunes.
The transfer rate was about 300 bytes per second. The 1541 used a bit-serial version of the IEEE 488 parallel protocol. Some third-party speed-ups could transfer about 4 kilobytes per second over the interface, and some "fast loaders" managed up to 10 kbps.
The Commodore 1570 was an upgraded 1541 for use with the Commodore 128.