I see Raymond Del Tondo has dealt with the HP-17BII info, so I'll just add some notes on BASIC interpreters:
Good luck getting your hands on the source code for Altair BASIC. As Bill Gates wrote in his infamous letter to the Homebrew Computer Club, people sharing source code are spoiling this business for those who want to become squillionaire monopolists.
However, if you can get your hands on Volume 1 of "Dr Dobb's Journal of Computer Calisthenics & Orthodontia; Running Light Without Overbyte" (People's Computer Company, Menlo Park, 1976), ISBN 0-918790-01-8, you will find therein the source code to no less than 10 (ten) different Tiny Basic implementations (and a lot of other weird stuff, including an 8080 cross-assembler written in COBOL).
I dare say there are other implementations out there, but nothing recent - BASIC is regarded with some horror by Linux advocated, for example.
Best,
--- Les [http://www.lesbell.com.au]