resource counter()
  int count = 0
  sem mutex = 1        # Semaphor zum Schutz von count


  # increment count by 100
  process inc1000 [id=1 to 10] { 
    int local
    int top = 100
    for [j=1 to id] {
      # increment global counter - critical section
      P(mutex)
      local = count; writes(id,": get counter = ",local); write()
      for [k = 1 to top] { 
          local += 1
      }; nap(int(random()*100))
      count = local;  writes(id,": put counter = ",local); write()
      V(mutex)
      # wait for some time - non-critical section
      nap(int(random()*100))
    }
  }
  final { 
  write(count)
  }
end  counter