RE: Amstrad ppc640

["Riley Williams" <Riley@Williams.Name>]

Hi Richard.

 > Just been playing around with ELKS on my TI TravelMate 2000,
 > and I got the same problems with init and sh.
 >
 > When I compile the kernel to get drive info from INT13, it
 > seems to get the number of sectors on a floppy wrong - it
 > seems to think there's 19 sectors. Hence, loading init fails
 > miserably.

That indicates that your computer doesn't support INT 13 for
determining the parameters of a floppy disk. Such is common for
XT class computers as the INT 13 facility wasn't introduced
until the PC/AT came in. Since there is no means for the ELKS
kernel to determine whether INT 13 support is included, this is
something that |MUST be correctly configured when compiling the
ELKS kernel.

 > Re-compile turning "Use INT13" off, it correctly identifies
 > 18 sectors.

With INT 13 support disabled, the ELKS kernel simply tries to
read sectors on track 0 starting with the highest numbered one,
and counting down until it reads one successfully. It assumes
that the sector number read is the number of sectors that disc
is formatted with for all tracks, so will get copy-protected
floppies wrong and all other floppies correct.

 > I don't know if that's an issue with my laptop, or with the
 > code - it might be interesting if people conduct the same
 > experiment (kernels with and without using INT13) and post
 > the results.

As stated above, it's an issue with the fact that your laptop
is a PC/XT clone, and thus does not include facilities that
were not implemented on the genuine PC/XT. It's thus something
that is pretty much expected on that class of machine.

Incidentally, because of the above, the safe option is to
disable use of INT 13 and let it probe each floppy in turn.

Best wishes from Riley.
---
 * Nothing as pretty as a smile, nothing as ugly as a frown.

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