BBC BASIC Course Disc

This is the disc image the site's BBC BASIC course is written against. Mount it in MAME, type BBCBASIC at the DOS prompt, and a few seconds later BBC BASIC signs on and gives you its >. It is equally useful on its own if you want to try the Einstein's BBC BASIC and be able to keep what you write.

What Is on It

• BBCBASIC.COM, Einstein BBCBASIC Version 2.31 (R.T. Russell, 1984), exactly as it came on the BBC BASIC disc.
• ANIMAL, the guessing game that learns, from the same disc, with ANIMAL.DAT, everything it has learned so far. CHAIN "ANIMAL", think of an animal, and teach it the ones it does not know.
• GAME, the game the course builds, finished: DRIFT. See below.
• 160K of free space, which is where your own programs go.

Why It Is an .mfi and Not a .dsk

This matters more than it sounds, and it is the reason this disc exists.

MAME will not write to a .dsk image. It will read one perfectly well, so BBC BASIC starts and runs and everything looks fine, until you save a program: on a .dsk, SAVE answers Bad Data, Drive 0: and Try Again(Y/N)?, which says nothing about the real cause - and answering N drops you out of BBC BASIC. The course has you save your work at every stage, so a disc you cannot write to is no use for it. The .mfi format is MAME's own flux-level format, and MAME does write to it, so anything you save is still there next time.

If you want the disc as it was sold, that is here too, as BBC Basic. It is fine for looking. It is no good for working. The Einstein Disc Tools will convert between the two formats in either direction.

Using It

Put the file somewhere you can find again and point MAME at it:

mame -rompath ~/roms einstein -flop1 ~/einstein/bbcbasiccourse.mfi -window

The Einstein boots to TATUNG/XtalDOS 1.11 and a 0: prompt. Type BBCBASIC and it signs on with Einstein BBCBASIC Version 2.31. SAVE "NAME" keeps your program on the disc, LOAD "NAME" brings it back, and *DIR lists what is there. *BYE takes you back out.

Four things worth knowing before you start, all of which stop people dead:

• BBC BASIC's words must be in capitals, and it starts with CAPS LOCK on. Leave it on: print is answered Mistake.
• Minus is SHIFT and =. The key marked with a minus types an underscore. " is SHIFT and 2, : is the ' key, and + is SHIFT and ;.
• The arrow keys do not move the cursor; they type characters. CTRL-H and CTRL-D move left and right, CTRL-K and CTRL-J to the start and end of the line.
• ESC stops a running program. And if a program you meant to keep is gone after NEW or a trip out to DOS, type OLD straight away.

DRIFT

CHAIN "GAME". You wake from cryosleep on a cargo ship drifting dead in space. The main power is off, the bridge door is sealed, and the air is running down one turn at a time. Type what you want to do - E, OPEN LOCKER, GET CELL, READ PAD - and find a way to get the engines going before the air runs out. HELP lists the words it knows.

It is the program the course builds a section at a time: 211 lines of BBC BASIC. Once you have played it you can LIST it and see how it was done.

Real Hardware

If you have a real Einstein and the BBC BASIC disc, it already has this BBC BASIC and ANIMAL on it, and you do not need this download except for GAME. The Einstein edition's manual is archived as BBC Basic Manual (Z80). This image exists for emulation and for the free space. Nothing on this page has been tried on a real machine.

How It Was Made

It is the BBC BASIC disc with everything the course does not use taken off: the help files and viewer, the conversion, checksum and unlisting utilities, the READ.ME, and the file-handling and sorting examples. Nothing that remains was altered, and XtalDOS 1.11 is still on the system tracks underneath.

GAME was typed in and saved by the machine itself, on the emulated Einstein, from the course's final listing, and locked with *LOCK like the rest. Nothing was tokenised or patched off the machine.

The disc was then tested in MAME end to end: it boots, BBC BASIC starts, GAME loads and is played through to the end, ANIMAL learns an animal and remembers it the next time it is run, and a program saved to the disc loads and runs again after a restart. The file on this page was downloaded back and checked byte for byte against the tested one.