TCB subsets: the next step

The advantages of TCB (trusted computing base) subsetting for building multilevel database systems are discussed, and the architectural impact on the database system when the TCB subsetting approach is used in a real implementation is described. Particular attention is given to such areas of difficulty as concurrency controls, recovery management, and buffer management. In discussing implications for the architecture of the database system, it is noted that the standard ORACLE database system already supports those architectural features that are required, and ORACLE is proceeding with product development and product evaluation projects to extend the promise of TCB subsetting to commercially available ORACLE RDBMS (relational database management system) products on a wide variety of platforms. The SeaView prototype takes advantage of the architectural features of ORACLE with a TCB subsetting approach to achieve a class A1 system that reuses existing TCB and database technology