Family BASIC on the FDS, from the 80's

If you're going to make a Disk Operating System for the FDS, you might as well port Family BASIC to it. Backwards compatibility with user programs on tape would have been a consideration if it was done back then. Also, the FDS BIOS includes a keyboard reading routine at $EB13 but its implementation differs somewhat from what was used in Family BASIC.

So it turns out there was enough demand for a port of Family BASIC to the FDS back then. An unofficial process to create "Disk BASIC" was documented in a few books from the time, namely "ファミコン改造マニュアルVol.3" (Famicom Hacking Manual Vol.3). It requires a Family BASIC keyboard, tape deck with blank tape, Family BASIC cartridge (2.1 or 2.1A), FDS with 2 blank disk sides, Tonkachi Editor, and of course the code/patch listings in the book. The process is as follows:

1. Write and execute Family BASIC programs as instructed by the book to dump the PRG and CHR data to tape.
2. Load up Tonkachi Editor and create disk files as instructed by the book. Save them onto a disk side (we'll label it side A).
3. Load up side A, which will instruct you to load the data from tape and save it onto another disk side (we'll label it side B).
4. Load up Tonkachi Editor again and edit+save the disk data on side B as instructed by the book.
5. You now have Disk BASIC on side B. It should boot up with the version number as "2.1D".

Pros:

• It boots straight into Game BASIC. (no more holding the T key)
• It allocates 8126 bytes of user program space. (almost double that of 3.0!)
• There is the possibility of editing the CHR data on the disk.
• It's novel, to be honest. It really makes you wish it was official.

Cons:

• The process is tedious, time-consuming, and requires an understanding of Japanese. People online have also noted that there are errors in some of the code/patch listings.
• Code/patch listings are not fully documented online yet.
• Family BASIC 3.0 never got this treatment, so the newest version you can use is 2.1A.
• BG Tool is non-functional.

Unconfirmed details:

• It may still be limited to tape I/O.
• It may introduce a new risk of POKEing data into the PRG-RAM region.
• It may break anything which relies on the cart's address space mapping.

This Japanese blog (3 pages) goes over the process (even going so far as to create their own disk save utility) but the pictures provided are not in the best quality and lack crucial listings. The book in question seems to be available on some Japanese stores online at reasonable prices compared to the single listing I found for Disk BASIC (+ the aforementioned disk save utility) itself.

In relation to this, I2 (the company behind Tonkachi Editor) seems to have sold something called the "I2 Disk Basic Generator Kit". The small amount of information I found online suggests that it uses their Souseiki Fami/Fammy (an interface to dump carts to disk, among other things) to create Disk BASIC from a Family BASIC 2.1(A) cart. I haven't seen any dumps of software related to this thing.

I just found this all interesting and wanted to document it here. There doesn't seem to be any detailed documentation online for the process nor are there any dumps of Disk BASIC and its related utilities, so I hope someone can get a hold of them in one way or another.

Statistics: Posted by TakuikaNinja — Thu Mar 21, 2024 4:35 am — Replies 1 — Views 149

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