Editing BASIC-PLUS (section)

==BASIC Plus 2==
{{Main|VSI BASIC for OpenVMS}}
A related product called '''Basic Plus 2''' ("BP2" or '''BASIC-Plus-2'''), was later developed by DEC to add additional features and increased performance.

It used true compilation into [[threaded code]] and wrote its output to object files compatible with the machine code object files produced by the assembler and other language systems. These object files could be kept in libraries. A linker (the TKB, also known as the taskbuilder) then created executable files from object files and the libraries. TKB also supported overlays; this allowed individual routines to be swapped into the virtual address space as needed, overlaying routines not currently being used.

Additionally, BP2 programs ran under the RSX Run Time System; this RTS only occupied 8KB of the user's virtual address space, leaving 56KB for the user's program.<ref>{{cite book|url=http://www.dmv.net/dec/pdf/bp2v27rm.pdf|title=BASIC V2 Reference Manual|publisher=Digital Equipment Corporation|year=1991|location=Maynard, Massachusetts}}</ref> (RSTS/E version 9 introduced separate Instruction and Data space, and the "disappearing" RSX Run Time System, permitting up to 64KB of each of instruction code and data.) These two factors allowed individual BP2 programs to be much larger than BASIC-PLUS programs, often reducing the need for CHAINing among multiple programs.

Unlike BASIC-PLUS (which was only available on RSTS/E), BP2 was also available for the [[RSX-11]] operating system. BP2 programs were also more compatible with the later [[VSI BASIC for OpenVMS|VAX BASIC]].