Software Fast Reset

A fast loader is a software program for a home computer - most commonly, the Commodore 64 - that accelerates the speed of file loading from the floppy disk drive.

Background

Fast loaders came about because of a discrepancy between the actual speed at which floppy drives could transfer data and the speed that was provided by the operating system's default routines. This discrepancy was most pronounced on the Commodore VIC-20 and 64. While the earlier Commodore PET series had used an industry-standard IEEE-488 parallel bus, this was replaced with a custom serial bus on the VIC-20. The serial bus was intended to be nearly as fast as its predecessor, due to the use of the 6522 VIA as a hardware shift register on both the drive and computer. Fast Reset. However, hardware bugs were discovered in the 6522 that prevented this function from working consistently. As a result, the KERNAL ROM routines were hastily rewritten to transfer a single bit at a time, using a slow software handshaking protocol. [1] Although the C64 replaced the 6522 VIA with two 6526 CIA chips, which did not suffer from this bug, Commodore chose to retain backward compatibility with VIC-20 peripherals at the expense of speed. Because of the transfer protocol, the Commodore 1540 and 1541 disk drives soon gained a reputation for extreme slowness.