Abstract: A data processing apparatus for handling multi-thread programs comprises a data processor coupled with a random-access memory (HM) containing a plurality of data objects (DO). Each data object is accessed via respective pointers carried by memory stacks (SF) associated with respective threads. Periodically, a garbage collection procedure is applied to the random-access memory with those data objects (DO) having no extant pointers thereto from any source being identified and deleted. Subject to a locking constraint applied to some of the data objects, the remainder are compacted to free space in the memory (HM). To enable localizing of the garbage collection procedure, reference stacks (RS) are provided for each thread stack frame (SF) such as to identify, preferably via a per-thread reference table (TT), data objects (DO) referenced from only a single frame, which objects are deleted on conclusion of that frame.

Abstract: A method and apparatus are provided for management of stored data in the form of data blocks interspersed with free blocks in a fixed size system memory. A compaction procedure, periodically applied to the memory, repositions those data blocks identified (107) as moveable such as to increase the extent of free block contiguity within the memory. The search for a suitable free block (114-117) for housing a relocated data block is sequentially applied for each data block; a data block is moved (118) to a free block if the free block is greater than or equal to the data block size and less than or equal to the size of the data block when added to the size of any free block abutting the original data block position.