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Originally Posted by Ralph Sir Edward
Dennis, all I know is I have gadgets both music players and video players, that can't read exFat chips, but if I reformat the chips into Fat32 they will work fine. I have done that for chips up to 512GB. (Sansa Clip, KDLinks HD-700, for example)
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Please reread what I posted, with special attention to the link I provided for SD card slot specifications.
The limitation I spoke of is in the slot hardware,
not the file system on the media. An SDHC card
slot cannot read media whose volume size is over 32GB. What file system is on the media is irrelevant.
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Now if it is implemented in hardware, (mostly high end Japanese gadgets), then, yes you're SOL.
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In fact, the reverse is true.
Lower end devices tend to have SDHC slots. SDXC and SDUC occur in more expensive devices.
(While the analogy is imperfect, think of the difference between USB 2 and USB 3. There, the limitation is in data transfer speed. The desktop I use now is a older USB 2 machine, and does not have USB 3 USB ports on the motherboard. I fixed that not long back when I found a USB 3 card that would fit into the unused mini-PCI-e slot on my motherboard. USB 2 was not a deal breaker for my normal use of USB - supporting keyboard, mouse, and a handful of USB thumb drives I use to archive data. Transfer speed was not a major issue. With some things I'm planning to do, like boot an OS off a thumb drive, USB 3 is a necessity. It's all USB, but data transfer rate is a matter the hardware design of the slot you plug into and the supporting hardware on the motherboard.)
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I have found the most gadgets implement SDHC reading in software, so they can use "off the shelf" card readers (to save money). Those don't care what Fat is being pitched at them 16, 18, or 32. . .
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They don't implement SDHC reading in
software. Once again, that's a
hardware spec.
Just about everything understands FAT*. It's been around for decades, and is well understood. The FAT file system imposes volume size limitations. The smallest unit of space readable/writable on a FAT formatted drive is the cluster. Each cluster must have a unique address. FAT16, as the name implies, uses 16 bit addressing, so you have a maximum of 65,536 unique clusters. The maximum cluster size produced by DOS/Windows format is 32KB, so FAT16 volume size tops out at 2GB. FAT32, using a 32 bit address, was developed precisely to get past that limit as hard drives got progressively larger. We now have exFAT, which is the next step beyond FAT32.
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Worth a reformat on a sample card to see. If it doesn't work, you can format back real easy.
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It will work just fine, but why should I
bother? What I have works, and the change won't give me any real gain. FAT32 offers more efficient storage if you have lots of small files that take less than a cluster because it uses smaller clusters and there is less wasted space. I don't
care, and
haven't cared in some time. The 64GB card isn't used for storing small files, and SD cards are cheap and getting cheaper. The wasted space simply isn't a concern.
The fact that you have things that grok FAT32 but
not exFAT is curious indeed, but not a factor here. The main difference I'm aware of is that exFAT uses a larger cluster size than FAT32, and is less efficient at storing small files which won't fill the cluster and leave wasted space. That's not what the 64GB card here is used for, and it's been a while since I had any reason to care about the issue. Hardware is cheap and getting cheaper, and wasted space on a storage medium simply doesn't matter.
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Dennis