sequencing

Monolithic set ups are where you do all your work in one program. This is the most common approach people using Windows and Mac audio software will be used to. In Linux, JACK allows for very modular set ups, although some applications are fully featured and can also be used as monolithic set ups, eg. Ardour and Qtractor.

If you get an xrun, it basically means that your systems CPU wasn't able to keep up with the information it was being fed from your soundcard. There are many factors at play.

More information about the causes of xruns

A MIDI controller is any device that sends out MIDI data to control another MIDI device or program. Some MIDI controllers are also capable of recieving MIDI data. Two examples of a MIDI controller would be a MIDI keyboard which can be used to control softsynths/external hardware synths or a MIDI DAW controller used to control fader/pan levels in your DAW as well as other things such as plugin parameters.

A DAW, which stand for Digital Audio Workstation, is software used for the recording, editing and mixing of digital audio. DAW's started off as integrated hardware units but nowadays, a DAW most commonly refers to recording software.

DAW's follow many conventions from hardware recording set ups. You even have a virtual mixer console and can route audio similarly to hardware set ups. You can also process individual audio tracks using plugins such as EQ, compressors and reverbs.

Due to Linux audio's flexibility, very modular set ups are possible. Session management makes this easy by remembering software and their connections. You can launch various programs, connect them up and have you session manager remember, and later, relaunch the whole session, connections included. Some popular session management tools include Non Session Manager (NSM), Ladish and Jack session.