For a Caller ID project I did I wanted the user to be able to delete random messages from the stored message list. One of the iterations used a set of records in a array where each record element was call data plus "pointer" (index) to the next one. That allowed the list to grow and shrink as well as for insertion and deletion. If memory serves the final version was just a LIFO type array and when a record was removed, all the other ones moved up a slot. It was a fun exercise though. I've never used malloc in an 8051 project and doubt that I ever will. There is usually some other alternative.