Rockbox Technical Forums

Support and General Use => Hardware => Topic started by: Frankenpod on June 17, 2022, 04:58:27 PM

Title: Is there any possible way round the FAT32 2TB capacity limitation?
Post by: Frankenpod on June 17, 2022, 04:58:27 PM
I'm getting to the point where I might upgrade a flash-modded ipod to greater than 2Tb total storage.  I realise there are some big problems in doing that - am curious whether they are likely to be insurmountable.

I'm frankly confused about the whole topic.  I gather FAT32 can cope with larger partitions, by using larger cluster sizes, but the problem is with the limitations of MBR?  And, I gather Rockbox itself would need major work to use GPT?  (and it's not likely to happen for a long time, if ever).  Or would using different cluster sizes in itself create a problem?

There's also the question of whether Windows could see the disk properly in order to sync files to it.

How about using more than one partition?  Would that be a possible workaround?  (Is the limit on partition size or on total disk size?)

I'll most likely just carry on increasing the ipods I have towards 2TB (upgrading the smallest one, then making a new one with the cards removed, and so on...), but every time 1Tb cards come down in price I get tempted and wonder about the possibility of exceeding that limit.
Title: Re: Is there any possible way round the FAT32 2TB capacity limitation?
Post by: amachronic on June 18, 2022, 06:08:22 PM
The 2 TB limit is on total disk size and solving that would require a lot of work. Adding partitions won't help. We can only address 32 bits worth of sectors (= 2^32), and at 512 bytes per sector that's 2 TB.

That said, I think the iPod 6g has 4k physical sectors so it might be able to "cheat" and go up to 16 TB in theory. I have no idea if that would work as expected with MBR / FAT32.
Title: Re: Is there any possible way round the FAT32 2TB capacity limitation?
Post by: Frankenpod on June 20, 2022, 10:12:03 AM
Hmmm, OK.  Probably will settle for 2Tb max for the foreseeable future, then.  Really wasn't sure whether the limit applied to partition size or total disk size.  I guess the crucial issue is the use of MBR?

With cards increasing in capacity, I presume this will eventually become an issue for other players, not just modded ipods? (Always assuming there is any future for standalone players and native-RB anyway)