Direct - A Distributed Computer Architecture for Supporting Relational Data Base Management Systems
The design of DIRECT, a distributed computer architecture for supporting relational data base management systems is presented. DIRECT has a MIMD (multiple instruction stream, multiple data stream) architecture. It can simultaneously support both intra-query and inter-query concurrency. The number of processors assigned to a query is dynamically determined by the priority of the query and the size of the relations it references. The size of a relation is not limited to that of the associative memory as in some previous data base machines. Concurrent updates are controlled through address translation tables which are maintained by a controlling processor. DIRECT is being implemented using LSI-11/03 microprocessors and CCD memories which are searched in an associative manner. A novel cross-point switch is used to connect the LSI-11 processors to the CCD memories. While cross-point switches have proven too expensive for use in general purpose parallel. processors, their application in DIRECT demonstrates that these switches can be successfully used in specialized applications.
Download this report (PDF)
Return to tech report index