Abstract: The storage space of a RAID striped mass storage system is topologically organized as a plurality of basic units of storage space for storing data items in data blocks. A topological data formatter includes a write data buffer for each data type and an initial data classifier initially categorizes each data item as a structured data type having defined data characteristics or a general data type having variable data characteristics and writes each structured data type data item into a corresponding type buffer. A topological data classifier topologically categorizes each general data type data item as a full-basic unit data type forming data blocks or as a partial-basic unit data type forming partial data blocks and writes each data item into corresponding full-basic type buffer or partial-basic type buffer.