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Re: [MiNT] Launching MiNT from a DOS FAT partition

On 01/12/2015 03:44 AM, Alan Hourihane wrote:
On 12/01/15 02:01, Roger Burrows wrote:
On 24 Dec 2014 at 19:00, Roger Burrows wrote:

Mark Duckworth reported a problem on the ACP forum when trying to launch MiNT
from a DOS FAT partition under EmuTOS.  MiNT did not boot, because the startup
code refused to login his big DOS-style FAT partitions.  Looking at the
relevant MiNT code, I see that MiNT's FATFS will not login a drive where the
cluster size in bytes is bigger than cache.max_size.  In init_block_IO(),
cache.max_size is calculated as:
where MIN_BLOCK is 8192, and max_sect_siz is taken from the AHDI pun_info
structure, where it is the maximum logical sector size on any of the host's
drives.  For a system with only DOS-style partitions, this will be 512

So if you try to run MiNT from EmuTOS running on a DOS-style partition,
max_sect_siz will be set to 512, and thus cache.max_size to 8192.  Accessing a
partition with clusters larger than 8192 bytes (i.e. a partition larger than
512MB) is not possible, so MiNT will not start.

Attached is a patch to correct this.  NOTE: due to lack of a suitable setup,
this has not been tested!  It compiles clean and looks straightforward, but
I've been around too long to assume that makes it bug-free.

Hi Roger,

Thanks for the patch. Do you know if Mark tested the patch on his setup ?

Mark - if you are about - can you, if you haven't already ?



Oh I msgd to roger about testing this but I just realized I have to test a new kernel build rather than emutos. I'll test this out asap.