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

[Alan Hourihane <alanh@fairlite.co.uk>]

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:
>> 	max(MIN_BLOCK,2*max_sect_siz)
>> 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
>> bytes.
>>
>> 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 ?

Thanks!

Alan.