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

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.


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   ---- File information -----------
     File:  MIN_BLOCK.patch
     Date:  11 Jan 2015, 19:23
     Size:  1830 bytes.
     Type:  Unknown

Attachment: MIN_BLOCK.patch
Description: Binary data