The user name for the password-protected PDFs and the attendee list is "sosp".

The password was sent to attendees by email.  If you've forgotten it, consider
the following quote from Roger Needham and David Hartley at SOSP in 1969:

  " In designing an operating system one needs both theoretical insight
    and horse sense.  Without the former, one designs an ad hoc mess;
    without the latter one designs an elephant in best Carrara marble
    (white, perfect, and immobile). "