Making 4GB card bootable: what's the risk exactly?

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Making 4GB card bootable: what's the risk exactly?
« on: 18 / November / 2008, 18:59:30 »
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Hi. I noticed the following warning in the FAQ, but don't really understand what this means / what the risk would be... could someone explain this to a non-techie?  ??? Thanks!

"4 GB cards can support the autoload feature if they are formated in FAT16 manually. ... But be aware that the formatting of 4 GB cards in FAT16 leads to non-standard 64K cluster size."

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Offline fe50

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Re: Making 4GB card bootable: what's the risk exactly?
« Reply #1 on: 18 / November / 2008, 19:35:46 »
"4 GB cards can support the autoload feature if they are formated in FAT16 manually. ... But be aware that the formatting of 4 GB cards in FAT16 leads to non-standard 64K cluster size."

A file system with FAT16 was originally designed with a max. cluster size of 32 kB, so the maximum partition size was 2 GB, this is the 'original FAT16 standard'.

With Windows NT Microsoft increased the maximum cluster size to 64 KB, so a partition size of 4GB now is possible.
But such 4 GB partitions may not be supported by all devices or operating systems.
Since MS Windows NT / Windows 98 most OS can use this 'big' partitions without problems, also all Canon Digi-cams with SD-card storage support can handle such 4 GB partitions well.

On other operating systems like DOS or older Windows versions there may be incompatibilities.

All CHDK-supported cameras can use 4 GB SD cards with the FAT16 format without problems, actual operating systems like Windows XP/Vista/2k3, Linux, Mac OS works flawless, too.

Re: Making 4GB card bootable: what's the risk exactly?
« Reply #2 on: 19 / November / 2008, 19:50:56 »
The only trouble I've found with such a card has been with a hi-fi mini chain that can record in both SD cards and USB Flash: if I try to record music in a 4 GB SD card formatted like that, it corrupts the folder where the songs are stored. Other than that, in XP and Linux (Ubuntu) I've found no problems.

 

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