Traditionally, ASE databases are designed for applications that need to strictly adhere to ACID transaction semantics (ACID is short for: Atomic, Consistent, Isolated, Durable). These ACID properties are implemented by means of a write-ahead transaction log, located on persistent storage (i.e. disk). However, many business applications contain elements that may not require full ACID semantics and could accept a compromise on some of these properties in order to achieve performance gains. Against this background, the IMDB feature in ASE 15.5 allows the 'Durable' and 'Atomic' aspects of transactional behavior to be relaxed in exchange for lower response times and higher throughput. This is achieved by partly or completely omitting transaction logging, and by avoiding persistent disk storage.