The trademarked name for Digidesign’s software drivers that allow programs such as audio sequencers from various companies to directly access Digidesign audio hardware installed in a computer. Without Direct I/O drivers most audio programs can only interface with the Apple’s built in audio, which can then often be interfaced with the hardware-recording card. The disadvantage is that this only allows for two channel input and output because that is all the computer supports. Direct I/O gives the software the ability to directly interface with multi-channel hardware, such as Digidesign’s Pro Tools and Project systems, thereby allowing multiple inputs and/or outputs to be used simultaneously. Direct I/O drivers have to be specifically written for each hardware type. Most of the popular audio sequencer manufacturers (MOTU, Opcode, EMAGIC Steinberg, etc) have written their own Direct I/O drivers that work with Digidesign hardware and hardware from other companies.