(ATA, AT Attachment or "Integrated Drive Electronics", IDE) A disk drive interface standard based on the IBM PC ISA 16-bit bus but also used on other personal computers. ATA specifies the power and data signal interfaces between the motherboard and the integrated disk controller and drive. The ATA "bus" only supports two devices - master and slave. ATA drives may in fact use any physical interface the manufacturer desires, so long as an embedded translator is included with the proper ATA interface. ATA "controllers" are actually direct connections to the ISA bus. Originally called IDE, the ATA interface was invented by Compaq around 1986, and was developed with the help of Western Digital, Imprimis, and then-upstart Conner Peripherals. Efforts to standardise the interface started in 1988; the first draft appeared in March 1989, and a finished version was sent to ANSI group X3T10 (who named it "Advanced Technology Attachment" (ATA)) for ratification in November 1990. X3T10 later extended ATA to Advanced Technology Attachment Interface with Extensions (ATA-2), followed by ATA-3 and ATA-4.