Abstract: An application module of a data processing apparatus requires various quantities of memory space for the buffering of data to be processed. In particular, image and audio files are to be read from a CD-ROM disc and decoded in real-time. The operating system provides a memory manager to allocate buffer space from the available memory. To alleviate the problem of fragmentation, a fragmented memory manager module secures at the outset an allocation of buffer space sufficient for all requirements of the application module, and partitions the allocation into small units of buffer space (fragments), which are linked into a list by respective list pointers. Any subsequent requirement for buffer space is met by the fragmented memory manager, by un-linking the requisite number of fragments from the list of unallocated fragments. The application module is adapted to use fragmented buffer space where possible, while the allocation of buffer space in contiguous blocks is not excluded when necessary.