The Commodore 1540 (also known as the VIC-1540) introduced in 1982 is the companion floppy disk drive for the

VIC-20 The VIC-20 (known as the VC-20 in Germany and the VIC-1001 in Japan) is an 8-bit home computer that was sold by Commodore Business Machines. The VIC-20 was announced in 1980, roughly three years after Commodore's first personal computer, the ...

home computer. It uses single-sided 5¼" floppy disks, on which it stores roughly of data utilizing Commodore's GCR data encoding scheme. Because of the low price of both the VIC-20 and the 1540, this combination was the first computer with a disk drive to be offered on the US market for less than although the combination of the Commodore 64 and 1541 would prove more enduring. The 1540 is an "intelligent peripheral" in that it has its own

MOS Technology 6502 The MOS Technology 6502 (typically pronounced "sixty-five-oh-two" or "six-five-oh-two") William Mensch and the moderator both pronounce the 6502 microprocessor as ''"sixty-five-oh-two"''. is an 8-bit microprocessor that was designed by a small te ...

CPU (just like its VIC-20 host) and the resident

Commodore DOS Commodore DOS, also known as CBM DOS, is the disk operating system used with Commodore's 8-bit computers. Unlike most other DOSes, which are loaded from disk into the computer's own RAM and executed there, CBM DOS is executed internally in the dr ...

on board in

ROM Rom, or ROM may refer to: Biomechanics and medicine * Risk of mortality, a medical classification to estimate the likelihood of death for a patient * Rupture of membranes, a term used during pregnancy to describe a rupture of the amniotic sac * ...

– contrary to almost all other home computer systems of the time, where the

DOS DOS is shorthand for the MS-DOS and IBM PC DOS family of operating systems. DOS may also refer to: Computing * Data over signalling (DoS), multiplexing data onto a signalling channel * Denial-of-service attack (DoS), an attack on a communicat ...

was loaded from a boot floppy and was executed on the computer's CPU. Due to a timing conflict with the C64's video chip, the C64 doesn't work properly with the 1540. The better-known 1541 is mechanically and nearly electronically identical to the 1540 but has a revised ROM that permits it to work with the C64 by slowing the drive down slightly. However, it is possible to revert the 1541 into 1540 mode with a

Commodore BASIC Commodore BASIC, also known as PET BASIC or CBM-BASIC, is the dialect of the BASIC programming language used in Commodore International's 8-bit home computer line, stretching from the PET of 1977 to the C128 of 1985. The core is based on 6502 ...

software command (OPEN 15,8,15, "UI-" : CLOSE 15) to permit better speed when used with a VIC-20. The 1540 is relatively rare. While cheaper than most other drives of the day, it was more expensive than the VIC-20 computer itself, and the disk media was also still relatively pricey. Also, the relatively small memory of the VIC meant that the faster program loading times of the drive did not gain more than a few seconds compared to tape media. Thirdly, almost all commercial software for the VIC-20 was sold on cartridge or cassette tape media, giving low incentive to buy a floppy drive. The C64 followed close on the heels of the VIC-20, quickly discontinuing the 1540. Most 1540s still in existence were modified with a 1541 ROM so it would work with a C64. Unmodified 1540s are now considered collector's items. The launch price in Germany was (approximate The US-American version is named and the German version

References

VIC-20 CBM floppy disk drives {{compu-storage-stub