# Formatting USB Drive for Mac and PC access



## milhaus (Jun 1, 2004)

I can't check at the moment with my PC, but I've just purchased a large USB drive for backing up key documents. I'd like to be able to mostly use it with my mac, but also be able to use it with a PC. What format should I use when formatting with Disk Utility? Or can I even do this?


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## shooting_rubber (Mar 22, 2008)

milhaus said:


> I can't check at the moment with my PC, but I've just purchased a large USB drive for backing up key documents. I'd like to be able to mostly use it with my mac, but also be able to use it with a PC. What format should I use when formatting with Disk Utility? Or can I even do this?


Format the drive with FAT... You will be able to use it with a Mac and a PC.


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## screature (May 14, 2007)

What he said.  One caveat though, if you have any files over 4GB they will be a no go go as they surpass the limitation of FAT.


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## milhaus (Jun 1, 2004)

screature said:


> What he said.  One caveat though, if you have any files over 4GB the ywill be a no go go as they surpass the limitation of FAT.


Aside from that, any performance issues to be expected? Or any other issues like data loss?


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## screature (May 14, 2007)

milhaus said:


> Aside from that, any performance issues to be expected? Or any other issues like data loss?


Yes FAT is slower on large volumes but it is really the only truly cross platform option you have. Make sure you format it with you Mac and not your PC as on a PC you will be restricted to 32GB partitions (volumes).


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## irontree (Oct 28, 2006)

I also remember reading that your files will be restricted to being under 4gb each.


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## shooting_rubber (Mar 22, 2008)

irontree said:


> I also remember reading that your files will be restricted to being under 4gb each.


This is true. The only other option is formatting the drive as NTFS and then downloading "NTFS-3G" When I used it, it wrote to the drive terribly slow when using large files. With NTFS you can have files larger than 4 GB, but it will take forever to copy them until a better driver version is released.

NTFS-3G for Mac OS X


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## MacGenius24 (Mar 4, 2008)

shooting_rubber said:


> Format the drive with FAT... You will be able to use it with a Mac and a PC.


Yeah he's right but i think you should just go with mac os extended. or just format on a pc and your go 2 go


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## screature (May 14, 2007)

MacGenius24 said:


> Yeah he's right but i think you should just go with mac os extended. or just format on a pc and your go 2 go


No *DON'T* format on a PC, 32GB volume restriction. Format it FAT with your Mac, 2TB volume restriction.

There are two other options, format it Mac OS Extended and install MacDrive on your PC to read and write to the volume. Or format it NTFS and install NTFS for You Mac by Paragon on your Mac to read and write from your Mac. $49.95 for MacDrive or $39.95 for NTFS for Your Mac, your choice. Personally, if you want speed and flexibility I would go with MacDrive even if it is $10.00 more expensive.


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## kb244 (Apr 23, 2002)

The other option is format it Mac OS Extended (Journaled), then buy MacDrive for windows. (This of course is only practical if you own the windows machines you'll be hooking the drive up to).

(Or format it as NTFS, then use NTFS3G + MacFuse for Mac).


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## screature (May 14, 2007)

kb244 said:


> The other option is format it Mac OS Extended (Journaled), then buy MacDrive for windows. (This of course is only practical if you own the windows machines you'll be hooking the drive up to).
> 
> (Or format it as NTFS, then use NTFS3G + MacFuse for Mac).


Hey kb244 you chimed in just as I was editing my response above, sorry for making your post look redundant.


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## kb244 (Apr 23, 2002)

screature said:


> Hey kb244 you chimed in just as I was editing my response above, sorry for making your post look redundant.


PS: MacFuse is free, Paragon is not. Both work just fine for me.


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## screature (May 14, 2007)

kb244 said:


> PS: MacFuse is free, Paragon is not. Both work just fine for me.


Too bad for me, never heard of MacFuse before. Good to know.


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## kb244 (Apr 23, 2002)

screature said:


> Too bad for me, never heard of MacFuse before. Good to know.


macfuse - Google Code

The Project is about two years old, the last version 1.7 was put out in June. Its one of those open source projects designed to mount any file system written for MacFuse (NTFS-3G being one of them)

I found it primarily because I had a habit of googling for solutions. Paragon is going to be of course more 'understandable' to average users. But MacFuse once installed is practically invisible, the drives just mount, period.


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## bgw (Jan 8, 2008)

Another downside with FAT is that some files will be a lot larger when copied from your hard drive to the FAT formatted key drive. I had a 6.1 MB folder swell to about 16 some MB when I backed the file up on to a 2 GB thumb drive. I reformatted the drive as OS X journalled and the file stayed the same size.


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## kb244 (Apr 23, 2002)

bgw said:


> Another downside with FAT is that some files will be a lot larger when copied from your hard drive to the FAT formatted key drive. I had a 6.1 MB folder swell to about 16 some MB when I backed the file up on to a 2 GB thumb drive. I reformatted the drive as OS X journalled and the file stayed the same size.


That doesn't make any sense. Even with the resource key (often seen on windows as the same file name but with a period in front), the size of the file wouldn't grow at all. 

For example if I have a 4MB song (mp3), it's 4MB regardless if it is on a HFS+ or FAT file system. The only exception would be if you formated the device with some ridiculously large cluster setting that it has to use up the next cluster because the end of the file seeped into it. (most clusters on FAT/NTFS are between 4K to 16K). 

The only thing I can possibly think of is, maybe you had a zip file, and somehow unzipped it to the destination.


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## bgw (Jan 8, 2008)

The key drive was formatted FAT16, which is really inefficient for disk space. The folder I copied had a lot of small files so I guess they were allocated in a very poor manner. A quick re-format and recopying of all the files saved considerable space.


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## kb244 (Apr 23, 2002)

bgw said:


> The key drive was formatted FAT16, which is really inefficient for disk space. The folder I copied had a lot of small files so I guess they were allocated in a very poor manner. A quick re-format and recopying of all the files saved considerable space.


FAT12/16 was only needed for some very old file systems, theres really no reason to hae done so. But even with Fat16 that behavior would not have occurred. Basically yet another reason to refrain from blanket statements about a file system based only on the assumption of one of them (or an outdated format).

Besides from either Disk Utility, or windows own format. Fat 12 and 16 wouldn't even be used for a larger external drive, as 12 can only support 32MB, and 16 only 2GB max (where as Fat32 can support up to 2TB). So if the behavior truely occurs with FAT16, he'd never experience it anyways. 

One of the main reasons NTFS and HFS+ took over in mainstream file systems is their ability to assign permission to files and folders (think chmod in linux) was there, where as its not possible in FAT32 other than attribute tags (which could be ignored or reset by any process). That and the filesystem's increased performance when it came to very large volumes.


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## Paddy (Jul 13, 2004)

Whether/if you decide to format it FAT32 or NTSF, make sure you change the partitioning scheme to Master Boot Record (it's available when you click on "options" after choosing a number of partitions). Otherwise the PC won't see it.


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## EvanPitts (Mar 9, 2007)

Or just by a Keychain drive that has the driver for both systems, like a Kingston DataTraveller. Just ignore the DS_Store files and resource forks when going Windoze.

If you are not going to stuff giant video files on a giant keychain - then the FAT32 format is entirely preferred over NTFS - there are too many undocumented tags and other chicanery in NTFS to reverse engineer to guarantee reliability. Video files do not really belong on keychains anyways, they are usually too slow for decent playback - and with the low cost of decent DVD disks that would be compatible on many computers and most DVD players, it would be silly to use a keychain that is not up to the task.

The FAT system is quite ancient, but is quick and nasty and most everything supports it. If a file has become "bloated" in transfer, I'd say there is something rotten in Denmark. Sector sizing is one thing, but that would only affect the very last allocation unit. (So massive bloat could be expected if one had a lot of small files on a drive that has a cluster of 64kB...)


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## bgw (Jan 8, 2008)

Yes, the folder was a back up of source code. With the code came a Mercurial code backup. Hence the sudden bloat.


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