Concurrency control in a VLSI design database
Ing Widya, T. G. R. van Leuken, Pieter van der Wolf · Design Automation Conference · 1988
This paper explores a concurrency control mechanism which is suitable for the protection of VLSI design data against interfering concurrent accesses. VLSI design transactions are typically of long duration with frequent concurrent read-write and read-read accesses. A version mechanism is known to be very effective in long duration transaction systems with frequent concurrent read-write accesses. Although a design version mechanism, which is offered to the designers to maintain the evolution of design objects, has different aims than a version mechanism for concurrency control, a two-version mechanism fits very well in the former. This paper shows that a two-version two-phase locking mechanism, slightly adapted to a design system, is sufficient. The existence of a design manager, which prevents certain sequences of design transactions, simplifies the concurrency control protocol significantly.