Abstract: Memory management is important in realtime system. This paper develops a new dynamic memory management algorithm based on Buddy system and TLSF algorithm on consideration of both realtime and fragmentation rate. The new algorithm deals with large and small pieces of memory in different ways. Buddy system is used to manage small pieces while large ones are organized by twolevel segregating indices. This paper performs experimental study on μCosIII OS by implementing the new method and which shows good performance in both timeconsuming and fragmentation rate. At present  the method has been applied to an actual project.

Key words: dynamic memory management； &mu, CosIII； Buddy system； TLSF