The Commodore 1541, also known as the CBM 1541 and originally marketed as the VIC-1541, was Commodore International’s most widely recognized floppy disk drive for the Commodore 64 home computer. 

The original 1541 featured an internal power supply that was notorious for generating excessive heat, a quirk that became a frequent source of humor. For example, a humorous tip in the Finnish computer magazine MikroBitti (issue 5/1989) joked, “When programming late, coffee and kebab keep nicely warm on top of the 1541.” 

In 1988, Commodore released an updated model, the 1541-II, which replaced the internal power supply with an external one to reduce heat. MikroBitti’s review of the new model remarked that its external power source “should end the jokes about toasters.”

The 1541 was a single-sided drive for 5¼-inch disks, storing 170 kilobytes per side. It succeeded the Commodore 1540, which was designed for the VIC-20. The drive used Group Code Recording (GCR) and incorporated a MOS 6502 microprocessor, which served both as the disk controller and as the on-board disk operating system (DOS) processor. It supported a variable number of sectors per track - ranging from 17 to 21 - an early form of Zone Bit Recording. The built-in operating system was CBM DOS 2.6. Each 170 KB side was divided into 683 sectors across 35 tracks, with each sector holding 256 bytes, and the file system allowed every sector to be rewritten individually.