 
                                                                                | Article ID: | iaor1999180 | 
| Country: | United States | 
| Volume: | 9 | 
| Issue: | 4 | 
| Start Page Number: | 351 | 
| End Page Number: | 362 | 
| Publication Date: | Sep 1997 | 
| Journal: | INFORMS Journal On Computing | 
| Authors: | Lenstra Jan Karel, Aarts Emile H.L., Korst Jan | 
| Keywords: | heuristics | 
We consider the problem of nonpreemptively scheduling periodic tasks on a minimum number of identical processors, assuming that some slack is allowed in the time between successive executions of a periodic task. We prove that the problem is NP-hard in the strong sense. Necessary and sufficient conditions are derived for scheduling two periodic tasks on a single processor, and for combining two periodic tasks into one larger task. Based on these results, we propose an approximation algorithm.