One of VSI BASIC's more noteworthy features is built-in support for OpenVMS's powerful Record Management Services (RMS).
Before the release VAX BASIC, native RMS support was only available in DEC's COBOL compiler.
The VSI BASIC for OpenVMS product history spans a period of more than 30 years, and it has gone through many name and ownership changes in that time.
VSI BASIC began as BASIC-PLUS, created by DEC for their RSTS-11 operating system and PDP-11 minicomputer.
This command did not produce true machine language programs, but rather a byte code called "tokens".
The use of a shared memory section called core common also allowed programs to pass data among each other as needed; disk files could also be used but were slower.
The interpreter included a garbage collecting memory manager, used for both string data and byte-code.
Basic Plus 2 (BP2 or BASIC-Plus-2) was later developed by DEC to add additional features and increase performance.
It used true compilation into threaded code, and wrote its output to machine language object files.
TKB also supported overlays; this allowed individual routines to be swapped into the main memory space as needed.
VAX BASIC used the standard VMS calling standards, so object code produced by VAX BASIC could be linked with object code produced by any of the other VMS languages.