In formatting drives to exFAT, are these limitations in force and valid at present?

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Level 1

92 points

In formatting drives to exFAT, are these limitations in force and valid at present?

I've been revamping the external drives I use with my Mac. One of the drives is to be used with an old Windows machine from time to time, so in order for it to be both writeable and readable on both systems and also to not be restricted to a 4GB max size for a folder, I've reformatted and repartitioned that particular drive to exFAT (otherwise known as FAT64).

Using the features in the Partition tab of the Mac's 'Disk Utility', the basic operation of revamping that particular drive to exFAT went okay in the end , but along the way I came up against a couple of issues, and I now wonder whether I in fact set up the exFAT partitions in the correct way. Maybe somebody can confirm?

First, I found that the length of the partition name in each case had to be kept to 10 characters or less, otherwise Mavericks beeped at me and undid all the configuring done so far. Is this correct? In any FAT partition, is the name you give to the partition restricted to 10 characters or less?

As regards the Partition Scheme, which you get to by clicking on the Options button in the configuring of the partitions, I chose 'Master Boot Record', rather than 'GUID Partition Table', as otherwise again Mavericks seemed to object. Did I choose correctly?

iMac (27-inch, Late 2013), OS X Mavericks (10.9.2)

Posted on Apr 30, 2016 8:26 AM

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Answer 1

a brody

Level 10

82,925 points

May 2, 2016 5:24 AM in response to carefulowner

The only reason to use ExFAT is if you want your Mac to share data with a PC without using any networking. Networking allows you to maintain your Mac's formatting for booting while sharing files between platforms. That's where an SMB network can be helpful. ExFAT and NTFS offer file sharing compatibility in the "sneakernet" mentality for hard drives. But neither offers booting for Mac OSes. And NTFS you need third party software to be able to write to from a Mac. See my tip:

https://discussions.apple.com/docs/DOC-3003

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Answer 2

carefulowner Author

Level 1

92 points

May 2, 2016 6:41 AM in response to a brody

Yes, for transferring data to/from Mac and PC, using an external, portable drive. My understanding is that if the external drive's capacity is in excess of 64 GB, it can still be used for this purpose when formatted to FAT32. However, whether it's always wise to do that could depend on the machines you're using and the sizes of files/folders. For example, if the PC is a 32-bit machine it's likely to suffer from the '4GB single file or folder size' limitation. Also, there'll not be full read and write compatibility between NTFS on the PC and HFS+ on the Mac. Formatting the external drive to exFAT gets around these two issues, and you can freely use the external drive for data between the two machines.

In setting my external drive up for exFAT, however, I got momentarily caught out - if that's not too strong a description - by what appears to still be a naming limitation for FAT drives, and also by the need to set the Partition Scheme to MBR. However, thinking back some decades to the old days when I built and used PCs, I do now vaguely recall there being a restriction in the FAT drivename and of the partitioning/formatting being referred to as MBR. I'd have thought that when exFAT was later introduced the filename restriction would have been eased, but it appears not.

There's one other small aspect of exFAT that might need some consideration sometimes - exFAT doesn't store files as efficiently as FAT16 or FAT32 or HFS+, as it uses a much higher minimum block size. However, the loss in usable drive capacity, when using drives of typical face-value sizes as 256GB, 500GB, 1TB, 2TB, tends to work out to a very small percentage of the overall formatted size.

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