MODEL:
  ! Model of a computer timesharing system;
  ! The mean think time for each user (more 
    generally, Mean Time Between Failures in a
    repair system);
    MTBF = 40;
  ! The mean time to process each compute request
    (more generally, Mean Time To Repair in 
    seconds);
    MTTR =  2;
  ! The number of users;
    NUSER = 32;
  ! The number of servers/repairmen;
    NREPR = 1;
  ! The mean number of users waiting or in service
    (more generally, the mean number of machines
    down);
    NDOWN = 
  ! The overall request for service rate (more
    generally, overall failure rate), FR, must 
    satisfy;
    FR = ( NUSER - NDOWN)/ MTBF;
  ! The mean time waiting for or in service (more
    generally, the mean time down), MTD, must 
    satisfy;
    NDOWN = FR * MTD;
END