Tech Talk (03/02)
NTFS vs. FAT 32
by Brian K. Lewis, Ph.D.*
Member of the Sarasota Personal Computer Users Group, Inc.
No, I haven't bitten the bullet and installed Windows XP, yet. However, I have been working with a number of people that have purchased new computers with XP preloaded on them I know others are seriously thinking about upgrading to XP. In addition, there is a lot of information available on XP. So it's time to look at some of the pros and cons of the two file systems that are available if you now have XP or if you want to upgrade your operating system.
The FAT32 (File Allocation Table) file system is what you used in Windows 98, SE and ME. The NTFS system was first available with Windows NT, then Win2000 and now Windows XP. The NTFS stands for "New Technology File System" just as the NT in Windows NT meant "New Technology". Wow! Anyway, these are two very different methods of organizing and recording information on the files stored on your computer's hard drive. NTFS can work with single drive partitions up to 8?petabytes, that's 8 followed by ? 15?zeros. Apparently Microsoft has actually tested NTFS with a 19?terabyte partition (19?followed by 12?zeros). If you have trouble with the large numbers used in hard drive sizes here's a table that might help.
Compare this large drive capability of NTFS with FAT32 that is limited to about 2?terabytes. Don't think this may not be a problem? Just remember that we now have drives with more than 100GB capacity. Terabyte sizes are not that far in the future. FAT32 has other problems as well. As you increase the volume or partition size in a FAT32 system, the cluster size also increases. The cluster size ranges from 4K to 32K. You reach the 32K maximum with drives larger than 32?gigabytes, at least according to Microsoft. Some references indicate otherwise. However, the following table is taken from two different Microsoft references on cluster size in FAT32.
The whole point of the cluster size problem is that the minimum file storage space is ONE cluster. Therefore, if you have a 512K file or a 1 K, it will take up one full cluster. On the 40GB drives that are now commonly available, that cluster takes 32 thousand bytes of space. However, the maximum cluster size with an NTFS partition is 4K even up to the maximum partition of 8 petabytes. So file storage is far more efficient with NTFS. You might say "So What?," with my 40GB drive why should I worry about file size? That may be true, but there are other efficiencies provided by NTFS as well as some problems if you are converting a FAT32 system to NTFS.
As I mentioned, NTFS is a very different filing system than FAT32. Except for very small files, NTFS is much faster in locating files because of its B-tree structure. Now I know this means nothing to you unless you are a programmer. So lets look at this a little. In a FAT file structure each folder entry contains an index into the file allocation table. This identifies the starting cluster of the folder. When you want to load or view a file, the system has to walk the folder structure to get to the file. First it finds the starting cluster of the folder, then the starting cluster of any subfolder, then the starting cluster of the file, and finally, the clusters that contain the file. In mathematical terms, the average time to find a file using FAT32 is N/2, where N is the total number of files in the File Allocation Table. You can also see that to find the file, the command to load or read the file must contain the complete path (all the directories and subdirectories) that must be searched to find the final file. Not a rapid process, especially when you realize that even a 2GB hard drive can have 12-15,000 files! I have seen larger drives with over 20,000 files.
In the NTFS system, the file index is stored quite differently by using the B-tree structure. This diagram outlines the general setup:
This is also referred to as a clustered index. The entry point to the index is through the root at the top of the tree. The branches are used to navigate to the leaf or page level which identifies the file we wish to use. I'm not going to beat this to death as I know you don't want to become programmers. However, this structure does allow for faster searching for files. In mathematical terms, the average time is the log of N. As long as LogN is less than N/2, the file will be found faster in NTFS. (Consider that the logN of 10,000 is 4, while N/2 is 5,000.) For small files, NTFS can even store them in the Master File Table, which increases the speed of reading the file.
NTFS has more benefits such as reliability. It is a transaction logging system, which allows NTFS to recover quickly from a disk problem or power failure. It does not guarantee that no user data will be lost. However, each transaction is logged before it is written to the disk. If a power failure or other disk problem occurs, NTFS checks the transaction log to see if the transaction was completed successfully. If it was not completed, NTFS backs out the transaction. No incomplete modifications to the hard disk are allowed.
OK, so NTFS sounds like the file system of choice. What are the problems? If you have purchased a new system with Windows XP pre-installed, you probably already have NTFS. However, some early systems were installed with 512?byte 0.5K clusters. These systems have shown a massive slow down in disk I/O performance. These systems need to have the cluster size increased to 4K. Unfortunately, to do this you need a third party software application since there is no conversion available from Microsoft. One application that has been recommended, but that I haven't tested, is Paragon Partition Manager. It is available from this web site: http://www.partition-manager.com/n_pm_main.htm at a cost of $40.00. As I write this article, PowerQuest has not yet upgraded Partition Magic to handle this problem.
The other problem is for upgraders from Windows 98, 98SE and ME. It seems that the Windows XP upgrade keeps the FAT32 system when these computers are upgraded. You can convert to the NTFS system after the upgrade. Unfortunately, the conversion sets up the 512?byte clusters, not the more desirable 4K clusters. So you may have to use the cluster conversion software I mentioned in the previous paragraph. For Windows 2000 users, you are given the option of which file system you want when you upgrade. However, choosing NTFS results in a system with 512?byte clusters. It would be nice if Microsoft would eliminate this problem in the first service pack for XP.
There are some desirable aspects to using Windows XP. The NTFS file system is one part in that it contributes to the reliability of the operating system. There are still too many other problems associated with this operating system so I continue to wait for a major modification before I consider upgrading any of my computers. Since I know many of you will be using XP, I will continue to try to provide you with reliable information on its advantages and disadvantages.
*Dr. Lewis is a former University and Medical School professor. He has more than 20 years of experience working with personal computer hardware and software. He can be reached via e-mail at brian_klewis@hotmail.com or voice mail at 941-925-3047. :
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