On Mon, 19 Aug 2019, Andrea Vai wrote: > Hi Alan, > I attach the two traces, collected as follows: > > - start the trace; > - wait 10 seconds; > - plug the drive; > - wait 5 seconds; > - mount the drive; > - wait 5 seconds; > - copy a 500 byte file; > - wait 5 seconds; > - unmount the drive; > - wait 5 seconds; > - stop the trace. Still no noticeable differences between the two traces. They both include a 1.2 second delay shortly after the writing starts, and the initialization sequences are the same. I really don't know where to look for this. The only thing I can think of at this point is to repeat this test, but using a file large enough for the difference in writing speed to show up plainly. By the way, it would be best to run the tests with the smallest possible number of other USB devices plugged in. None at all, if you can arrange it. Alan Stern