Lam et al. explore concurrency control issues in real-time database systems. Various concurrency control protocols are investigated for different types of real-time and non-real-time transactions.

The paper constitutes a valuable contribution to the field of real-time databases. It proposes and proves the effectiveness of various strategies for resolving interclass data conflicts and providing concurrency control for the execution of all possible types of transactions. The real-time environment provided for the evaluation of the strategies is more realistic compared to the previous works in which the number of priority levels supported in the system is limited.

Overall, the paper is well-written and easy to follow for anyone with a general background in the fields of database concurrency control and real-time scheduling. The reference list provided for the real-time concurrency control literature is good.