Computer programs are able to communicate with other MIDI compatible devices by using routing software and a hardware interface for the MIDI cables. The hardware interface used to connect all devices in the studio, is the MIDI Time Piece. The two most common MIDI routing programs are: Open Music System (OMS) by Opcode and FreeMIDI by Mark of the Unicorn.
"The Open Music System
(OMS) is a collection of software tools that manage the flow of MIDI information between
applications and MIDI hardware.
A typical MIDI studio contains multiple MIDI devices attached to one or more MIDI interfaces. Without OMS, each individual MIDI application must keep track of all interfaces, MIDI devices and data communication. With OMS, all applications simply use the central, standardized MIDI communication offered by OMS."
OMS-compatible applications refer to MIDI devices by name. An application doesn't need to have any specific knowledge of how MIDI data is routed to and from a specific synthesizer or MIDI device -- OMS manages the flow of MIDI data automatically. As an example, a MIDI sequencer which uses OMS can refer to a MIDI device simply as "Glen's DX7" rather than something obscure such as "Printer Port/Channel 11."
The relationships between MIDI device names, MIDI interfaces and channel assignments are managed by the OMS Setup application. With its icon-based user interface and on-line help, the OMS Setup program is intuitive and easy to use. If you change MIDI interfaces or connect your synthesizer to a different port, you need only run the OMS Setup to reflect the changes -- neither your OMS applications nor your saved MIDI sequences require modification."
Copyright 1998 Opcode Systems Inc.
"FreeMIDI
system extension, an optional OMS emulator extension (to emulate the Opcode MIDI System),
and a FreeMIDI Folder, which resides in the top level of the System Folder.
FreeMIDI automatically detects what type of MIDI interface is connected to the Macintosh modem and/or printer port, automatically detects what MIDI devices are connected to interface (it "knows" over 200 types of devices), and provides the user with a System 7-style graphical representation of their MIDI studio.
FreeMIDI also provides pop-up sound lists for over 100 popular MIDI synthesizers-as well as generic support for any General MIDI device. It even includes advanced features such as inter-application communication, multiple application real-time synchronization, and support for digidesign's Sample Cell Nubus card.