CD-i floppy disk geometry/format and usage?

[InTheSand]

Hi,

Can an ex-CD-i developer perhaps shed some light on what the floppy drive was used for on the authoring/development CD-i players?

Also, does anyone have any information on the geometry/format (e.g. tracks, sectors per track, bytes per sector, filesystem) of a CD-RTOS formatted floppy disk?

Regards,

- Ali

[cdifan]

This list of "Floppy disc descriptors" from the "Technical documentation for CDI 605 users" document should pretty much answer your questions:

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d0      RBF	256 x 16 x 80 x 2 = 653,824 bytes
d0h     RBF	256 x 28 x 77 x 2 = 1,100,800 bytes
d0hd    RBF	256 x 34 x 80 x 2 = 1,388,032 bytes
d0tb    RBF	256 x 16 x 80 x 2 = 655,360 bytes
d0uv    RBF	256 x 16 x 79 x 2 = 647,168 bytes
pcd0    PCF	512 x 9 x 80 x 2 = 737,280 bytes
pct0h   PCF	512 x 18 x 80 x 2 - 1,474,560 bytes

The RBF types use the OS9 "Random Block File Manager" which is the standard OS9 disk format; info and tools for this format aren't hard to find (see below).

The PCF types use the OS9 "PC File Manager" which reads/writes MS-DOS compatible disks.

I think the floppy drives where used mostly for verification tests (see the earlier posts by KuroNeko) and quick program tests. You could also use them for getting screenshots etc. off the CD-i (provided your program could generate them, of course).

Yesterday I used CD-i Link to "upload" a floppy from my 605 to the PC, with the command

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cdilink -upcopy /d0@

(the "@" means "use raw device"). This worked without a hitch (it took a long time, though) and gave me a "d0@" file of 653,824 bytes that I could easily access with the os9.exe program mentioned here (on a TRS-80 page, no less!). This program comes with source, so that should answer any detailed format questions you might have

[KuroNeko]

Yeah, we used them for tests. But basically, those were OS9 system floppies, it looked and felt a bit like MSDOS. So you could do i.e. file operations on a command line, just like DOS

Neko

[cdifan]

I remember often using the floppy for preloading a RAM disk (on the 605 you can make these so they survive a reset) with basic OS9 system utilities like dir, copy, list...

[InTheSand]

Hi,

Thanks for the info - I'd forgotten about OS-9's earlier heritage!

Interesting to note the use of floppies for screen grabs... Better than attempting to photograph a monitor or television, I guess!

- Ali