35mm
Yes, a lot of people have been suggesting MS buy it and how great that would be. I'm not sure it would be so great. Sonar had personality and character. I wonder if they may have also bought the name 'Microsoft Cakewalk'.
Just so you know: I migrated to Cakewalk when Microsoft bought out The Blue Ribbon Bakery, developers of Bars n Pipes Pro, which at the time was head and shoulders above every other sequencer out there, apart from it being Amiga only.
MS then closed the doors on BPP and set the BRB devs to working on Direct X software for windows instead.
After some considerable time (year or so) MS did agree to let the BRB developers set the program AND THE CODE free, but by that time musicians had moved on to stuff that was still in existence and development.
Don't hold your breath waiting for MS to actually rescue Sonar.