Remembering the Amstrad PCW ... Mallard Basic on the PCW supported the CHAIN MERGE syntax for merging in external BASIC files with the current program, so it was easy to load overlays out of the RAM disk (for non-Liams: overlays were CP/M's precursor to DLLs, statically linked but could be loaded in from external files). It also supported indexed database files via ISAM -- not as easy to use as dBase II, but viable for bespoke business applications of the day.