BIB-VERSION:: CS-TR-v2.0
          ID:: STAN//CSL-TR-89-395
       ENTRY:: November 08, 1994
ORGANIZATION:: Stanford University, Computer Systems Laboratory
       TITLE:: Design of Run Time Monitors for Concurrent Programs
        TYPE:: Technical Report
      AUTHOR:: Helmbold, David
      AUTHOR:: Bryan, Doug
        DATE:: October 1989
       PAGES:: 20
    ABSTRACT:: We address the problem of correctly monitoring the run time
               behavior of a concurrent program. We view a program as having
               three (potentially different) sets of behavior: computations
               of the original program when monitoring is not performed,
               computations after the monitor is added to the program, and
               "observations'' produced by the monitor. Using these sets of
               behaviors, we define four properties of monitor systems:
               non-interference, safety, accuracy and correctness. We define
               both a minimal level and a total level for each of these
               properties. The non-interference and safety properties
               address the degree to which the presence of the monitor
               alters a computation (the differences between the first two
               sets of computations). Accuracy is a relationship between a
               monitored computation and the observation of the computation
               produced by the monitor. Correctness is a relationship
               between observations and the unmonitored computations.

               A run time monitor for TSL-1 and Ada has been implemented.
               This monitor system uses two techniques for constructing the
               observation. We show that any monitoring system using these
               two techniques is at least minimally correct, from which the
               (minimal) correctness of the TSL-1 monitor follows.
       NOTES:: [Adminitrivia V1/Prg/19941108]
         END:: STAN//CSL-TR-89-395