The project of the Computer Systems and Networks Department is targeted on the implementation of a new system architecture based on the principles of data structures processing. The data access mechanisms in the computer systems with multiple-instruction streams and single-data stream architecture are based on the dedicated hardware unit, named Structure Processor, which operates under the control of the low-level instructions: adding, deleting, searching, union, intersection, complementation and others. This paper describes the data access fundamentals in a such system. The performance testing of operations for the Structure Processor are shown. The hardware complexity of the Structure Processor with universal microprocessors, used for the same problem decision, compared.