An exFAT experiment in Vista SP1

[KNIGHT]

So, as many of you know, there is now support for exFAT in Vista SP1. For those who don't know, exFAT is the file system originally introduced in Windows Embedded CE 6. It was primarily introduced into Vista SP1 for USB/Mobile devices because of its low overhead. NTFS takes up about 40MB on a freshly formated 2GB USB drive. exFAT, however, only takes up about 40kb on the same device after a fresh format. A much lighter file system with huge capabilities.

Well, to make a long story short, I decided to see what would happen if I formated one of my drives with exFAT and used it on a day by day basis. Mind you, not a USB drive. I created a 300GB partition on my internal SATA2 HDD and formated it thru the Command Prompt. Windows Vista wont give you the option to format a none USB/Mobile drive in the regular GUI. In case you're wondering, it isn't my main C: partition (I don't think my computer would boot from an exFAT partition. At least, not yet). I used the following command to format the drive:

format G: /fs:exfat /q /a:4096

Well, I've been using it for a while now. I primarily play video games from the partition. Seems to be working great. I later decided to create a second exFAT partition for video, audio, and picture storage.

I wonder if the claims that exFAT partitions don't suffer from fragmentation will prove to be correct.

[Argi]

What other advantages does it have over NTFS apart from the lower overhead?

[KNIGHT]

The advantages over previous File Allocation Table (FAT) file system versions include:

* theoretical file size limit of 16 Exabytes

* cluster size of up to 2²⁵⁵ bytes, implementation limit of 32MB

* free space allocation performance improved due to introduction of a free space bitmap

* support for more than 1000 files in a single directory

* support for access control lists (not supported yet in Windows Vista SP1)

The disadvantages compared to previous FAT versions include:

* Devices using exFAT will not be able to use Windows Vista's ReadyBoost capability.

Source

I'm not sure if it's preferable over NTFS or not. It seems to have very similar features, minus the space and processing overhead.

[|Rapture|]

Managed to install any programs to it yet? Would be interested to see load times and stuff :)

[KNIGHT]

Yep, I'm currently running Tabula Rasa, Unreal Tournament 3, and Microsoft Office from it. They seem to load and run just as well if not better.

Working on seeing if I can come up with some benchmark numbers of an exFAT vs an NTFS drive.

[Evolution]

Can you creation junctions and symlinks on it? Can you use volume shadow on the partition? Does it support EFS? And most importantly does it support transactions?

[KNIGHT]

Ok, yes you can create junctions and symlinks on it. As far as I can tell, Vista doesn't support volume shadow on an exFAT partition. Not sure if that is a limitation of exFAT or just of Vista. No, it doesn't support EFS, and transactions aren't supported in Vista but it is an optional function of exFAT that vendors can enable on mobile devices. On the subject of security, exFAT does support ACLs but Vista SP1 doesn't support ACLs on exFAT partitions yet.

[David3k]

I'm very interested in this.

If you do happen to run benches and take notes on fragmentation, please do tell! Report numbers and screenshots. (for fragmentation)

I'll be keeping my eye on this.

[Glowstick]

Every file system fragments files.

[X'tyfe]

this is very interesting indeed

if it obviously supports more than USB drives

then why not have made it possible out of the box? seems silly

NTFS is very old, we need something new for this decade :D

[neufuse Veteran]

Every file system fragments files.

Yep, this is true, never understood why people think fragmentation can be eliminated, its just the nature of how data is stored... it fills the free space as needed... delete a file in the middle of a large block of data... put something larger then it in there its gona fragment... happens on HPFS, exFAX, FAT, FAT32, NTFS, and all the others... now maybe their allocation tables fragment less but the actual data storage is always going to fragment when space is needed and its only available inbetween existing files....

[Evolution]

While NTFS was created a while ago, it's updated with each version of Windows.... so it's still "new".

[Angel Blue01]

They claim that Ext2/3 doesn't have fragmentation.

I wonder if this is supported in Mac/Linux or XP yet?

[+BudMan MVC]

The NTFS version in XP (v3.1 or 5.1), or Vista or 2k8 server is no old. NTFS is not the same that is was when released with NT 3.5 back in the early 90's

The vista version is either 5.2 or 6 depending on how you look at it.

exFAT was designed for FLASH drives -- it makes little sense to use it on a normal hard drive.

[night_stalker_z]

They claim that Ext2/3 doesn't have fragmentation.

I wonder if this is supported in Mac/Linux or XP yet?

I thought they claimed it doesnt have fragmentation until it reaches ~15% free space.

[KNIGHT]

exFAT introduces a free space bitmap allowing faster space allocation and faster deletes, support for files up to 2⁶⁴ bytes, larger cluster sizes (up to 32 MB in the first implementation), an extensible directory structure and name hashes for filenames for faster comparisons. It does not have short 8.3 filenames anymore. It does not appear to have security access control lists or file system journaling like NTFS, though device manufacturers can choose to implement simplified support for transactions

Wikipedia

The free space bitmaps are said to help reduced fragmentation as well. Contrary to the Wikipedia entry, ACLs apparently are supported by exFAT, but not supported in Vista SP1. I guess they figured that ACLs wouldn't be a needed feature on you USB thumb drive.

[Skyfrog]

This really wasn't designed to be used on hard drives, it's just a replacement for the ancient FAT file system and is meant for large flash drives. It's nowhere near as advanced as NTFS. That's not to say it isn't any good, it's fine for it's intended purpose. There's just no reason to use it on hard drives, especially since Vista is designed for NTFS specifically. Until it's more widely supported it's not really that great for flash drives yet. I hope they add native support in XP SP3 and the xbox 360 at least.

Certainly nothing wrong with experimenting though. Just for curiosity I wanted to see if I could get the HPFS driver from NT 3.51 to work in Vista. It could be added to NT 4.0 and even XP after copying over the pinball.sys driver and setting up the registry. Believe it or not it still works, not that it's very useful. :laugh:

Edited March 16, 2008 by Skyfrog

[Brandon Live Veteran]

Are ACLs really supported by ExFAT? I thought that was one of the biggest differentiators. The main reason being that ACLs are hard to implement across platforms (that's why NTFS drivers for Mac / Linux tend to ignore them. And ext2 / ext3 drivers for Windows do the same for Linux drives). Mainly because you have no common authentication path. ACLs tend to be meaningless when a drive is moved from one PC to another.

ExFAT isn't meant to replace NTFS, ever. It has a lot of disadvantages versus NTFS. It's meant to be a better FAT system, to replace the FAT/FAT32 filesystems that everyone has been using on portable storage devices and mobile devices.

[KNIGHT]

All true. NTFS is better in many ways.

From what I've been able to gather on MSDN, exFAT does support ACLs on Windows CE 6 devices, but MS didn't choose to turn that feature (along with transactions) on in Vista SP1.

[gigapixels Veteran]

Can an exFAT formatted flash drive be read in a computer not running Vista SP1? I use a flash drive for work and it would be interesting to try this out, however I use the drive on computers running Windows 98 sometimes, and mostly XP. So would my flash drive be readable on those computers?

[KNIGHT]

Apparently not, but I have heard of people getting the exFAT drivers from Vista to work on XP. Not sure how they do it yet.

[gigapixels Veteran]

Well I can't hassle with that, especially when we're talking about customer computers. I'm not going to try ways of installing drivers not meant for their system just for my own uses :p

[iwod]

I think M$ should open up exFAT so finally we have a decent File System that is Cross platform!!

[MrA]

They claim that Ext2/3 doesn't have fragmentation.

I wonder if this is supported in Mac/Linux or XP yet?

Ext2/3 fragment. You just don't notice it much. And they have block allocation policies which try to minimize fragmentation.

exFAT was designed for FLASH drives -- it makes little sense to use it on a normal hard drive.

Then why doesn't it have wear-leveling. I would think any file system designed for flash drive would have this feature.

[+BudMan MVC]

Then why doesn't it have wear-leveling. I would think any file system designed for flash drive would have this feature.

Well why don't you ask the people that designed it that question ;) I did not have anything to do with its design -- I assure you :rofl:

http://download.microsoft.com/download/5/b...STO072_WH06.ppt

Personal Storage: Opportunities and challengesfor pocket-sized storage devices in the Windows world

If you do not like something about the file system, contact the designers.