TTS MPU401 Multiple Client Driver

Driver Included with Cakewalk

Most drivers you will use are either included with Windows or provided by the manufacturer of the MIDI interface or sound card. However, we have included a multi-client driver with all Windows versions of Cakewalk.

Roland MPU-401 and compatibles

Windows includes a driver for MPU-401 compatible MIDI interfaces. You may want to use our driver instead. It can be opened for output by more than one program at the same time, so that you don't have to quit one MIDI program before starting another. Important: Be sure to Remove the Microsoft driver before you Add ours. If both drivers are installed, you will experience problems.

Please see the Cakewalk Installation Guide for instructions on adding or removing drivers using the Windows Control Panel. Insert the Cakewalk CD Rom in the drive when prompted.

What Does "Multi-Client" Mean?

If you plan on running Cakewalk concurrently with another Windows-based MIDI software program, you will need a "multi-client" Windows driver for your MIDI interface or sound card. A multi-client driver allows you to use multiple programs in Windows to access the same MIDI output port simultaneously.

Running Status

Within the MIDI 1.0 Specification, special provisions have been made to reduce the need for conveying redundant MIDI data. This mode, known as Running Status, allows a series of consecutive MIDI messages that have the same status byte type to be communicated without repeating redundant status bytes each time a MIDI message is sent. For example, we know that a standard MIDI message is made up of both a status byte and one or more data bytes. When using running status, however, a series of pitch-bend messages that have been generated by a controller (like a MIDI keyboard or guitar) would transmit an initial status and data-byte message, followed only by a series of related data (pitch-bend level) bytes, without the need for including redundant status bytes. The same could be said for note-on, note-off, or any other status message type. Upon receiving a message that includes a new status byte value, the device will respond to it in a standard fashion until the next series of like status bytes are encountered.

Although the transmission of running-status messages is optional, all MIDI devices must be able to identify and respond to this data-transmission mode.

If you have a slow computer, using Running Status mode is recommended, since it won't make the CPU work as hard.

Installing the Twelve Tone Systems MPU-401 Driver

Please see the Cakewalk Installation Guide for instructions on adding or removing drivers using the Drivers icon of the Windows Control Panel. Insert the Cakewalk diskette in the drive when prompted.

Twelve Tone Systems MPU-401 vs. Roland MPU-401

The Twelve Tone Systems MPU-401 driver gives you multi-client access. It also provides you with proper buffering for Sysx messages, as well as running status.

If your MIDI interface (not sound card) is 100% Roland MPU-401 compatible, it is highly recommended that you use the Twelve Tone Systems MPU-401 driver instead.

If Your MIDI Interface Doesn't Provide a Multi-Client Driver

Many Windows MIDI drivers do not support simultaneous use by more than one program at once. If you have such a MIDI driver, this can be very annoying if you want to simultaneously run patch development (editor/librarian) software with sequencing software, for example.

Cakewalk Professional supports a method where it closes MIDI devices when you switch away from Cakewalk to another program, and then reopens them when you switch back. This allows the other program to access a single-client MIDI driver. If both programs do this, then you can run them simultaneously with single-client drivers, with the limitation that only the active program can access the driver. Note that you only want to do this if you have a single-client driver, since ideally multiple programs should have simultaneous access rather than this one-at-a-time access.

To enable this behavior, add the following line to the [Wincake] section of CAKEWALK.INI:

ShareDrivers=1

Default is 0 (no sharing).

Don't Use The Twelve Tone Systems MPU-401 Driver with Sound Cards

Not all MIDI interface or sound card manufacturers provide multi-client drivers for their hardware, so consult your manufacturer to make sure. It is recommended that you only use the Twelve Tone Systems MPU-401 driver with 100% Roland MPU-401 MIDI interfaces, not sound cards. In some cases, the Twelve Tone Systems MPU-401 driver will work with certain sound cards, but in most cases you will experience problems.

Most sound cards use only one driver for both wave audio and MIDI. If you use the Twelve Tone Systems MPU-401 driver on these cards, you will lose the capability to play back .WAV files and audio in Cakewalk.

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