TREG is a new, easy to use recoverable virtual memory library. It implements transactional services using Incremental Messages (IMs), a set of operating system kernel services that provide support for flexible and efficient user-level management of replicated data. Unlike other recoverable virtual memories, TREG automatically tracks data changes, relieving programmers from inserting set range-like services which are error-prone. Because IMs cope with most of the work, TREG is extremely com-pact and, using the network memory of commodity PCs with inexpensive 100 Mb/s interfaces, is able to outperform a disk based system such as RVM running on the same host hardware. This paper describes TREG's design and implementation, showing that IMs are an appropriate tool to build some transactional services with minimum development cost and, thus, with lower probability of introducing design and/or implementation faults.