[Coco] Fixing OS-9 format for those that "roll their own"

[Gene Heskett]

On Thursday 14 November 2013 21:40:03 Robert Gault did opine:

> Gene Heskett wrote:
> ><snip>
> >
> > I am not convinced the numsides checking is correct for a hard drive.
> > 
> > Why? We access hard drives, or at least the superscsi drivers I use
> > do, by addressing the LSN, and the drive is smart enough to figure
> > out the side/platter that LSN is on.  So our descriptors should be
> > considered complete when they simply say its a hard drive.
> > 
> > Do we have drivers that do care?  That I don't know.  Discuss?
> > 
> > --
> 
> OS-9 probably doesn't care and the driver for a hard drive should be
> able to query the hard drive itself for the configuration. The problem
> is present with emulators and utility programs that generally have to
> cope with nothing more than a file name to determine the type of disk.
> After guessing the type of disk based on the file name, the descriptor
> or LSN0 may need to inform the driver of all low level parameters as
> the disk can't talk back to the driver (unless there is a detailed
> header.)
> 
> I'm pretty sure my message resulted from answering a person trying to
> write a PC utility that could read/write to disk images. The program
> needed to determine the structure of the disk via the information in
> LSN0 (assuming OS-9) and DD.FMT was providing confusing information.
> So..., rbf.d provides a detailed description of IT.TYP but this was not
> getting through to the format command source code.

And the superdriver, rbsuper IOW, is built with a different set of defs 
unless rbf.d has been pulled into the 21st century.  There are now quite a 
few bits in the various bytes of the descriptor that now change meanings 
between the floppy, and the hard drive.

Cheers, Gene
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