Tracker 4.42

### 4.5.5: MM1 Port

The plain MM/1 is a bit too slow to enjoy tracker in full. Be patient when you start---it takes a lot of time to initialize. When the processor is not fast enough, pauses will occur during playing. This can often be cured by selecting a smaller reproduction sampling frequency with the command line parameter ``-frequency`'.

Mono output mode has been disabled since the MM/1 output is stereo. To save the processor time in the critical loop, mixing between the left and right channels has been disabled.

The original program sends output to the sound driver in relatively small pieces. I found that the quality of the output is improved when the sound is played only if the buffer is full. The price for this is that the tracker reacts rather slowly to the keyboard commands when playing. The code in question is in the `flush_buffer` function---it is disabled right now. If you prefer the faster keyboard reaction at the cost of the quality, you may reenable it and recompile.

Playing on MM/1 is done using the system call `_ss_play` and using two buffers, so that when the first buffer is played, the other is being filled.