Troubleshooting Windows NT File Systems

Tweak your file systems
This month I discuss how to improve your file system performance and how to manipulate the way Windows NT handles file systems. Tweaking file system performance involves modifying the Registry, so you need to create an Emergency Repair Disk (ERD).

The easiest way to boost your file system performance is to defragment your hard disk regularly. The blocks that make up a file become separated over the disk, so the physical disk heads must move over more of the disk to find them. Disk defragmentation moves these blocks to contiguous disk areas and thus results in faster access.

Microsoft originally thought NTFS did not fragment, so NT does not come with a defragmentation tool. You can use a third-party disk defragmenter such as Diskeeper Lite, Executive Software's free defragmentation tool. You can download this scaled-down version or order the full version (Diskeeper 3.0) from http://www.execsoft.com.

How do I convert a FAT or High-Performance File System (HPFS) partition to NTFS?

You can use Windows NT's convert.exe utility to convert a FAT or HPFS partition to NTFS. Go to the command line and type

convert <drive>: /fs:ntfs [/v]

The /v setting is an optional command that runs the conversion in verbose mode and gives you conversion details on a file-by-file basis. Listing 1, page 156, shows the output of a nonverbose conversion.

Sometimes you cannot lock a drive for exclusive use (e.g., if you convert the boot partition, which is where NT resides). If you cannot lock the drive you want to convert, the conversion schedules for the next reboot. If you need to cancel the conversion, you must edit the Registry.

Start regedt32.exe, and go to the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager key. Double-click the BootExecute value in the right-hand pane. Select autocheck autoconv \??\drive: /FS:ntfs, as Screen 1, page 156, shows, and press the delete key. Click OK, and close the Registry editor. You might get a warning such as the one in Screen 2, page 156, because the line you deleted left a blank string. If you get this message, click OK. To prevent this message, press the backspace key rather than the delete key.

After you convert a FAT partition to NTFS, users have full permissions. If you converted the boot partition, you'll want to modify users' permissions. For a list of suggested permissions, see the Microsoft Support Online article "Default NTFS Permissions in Windows NT" (http://support.microsoft.com/support/kb/articles/q148/4/37.asp).

You can use the Microsoft Windows NT Server 4.0 Resource Kit, Supplement Two fixacls.exe utility to automatically set file protections. Log on as an account with backup file and folder privileges. From the Start menu, select Run, and enter

fixacls.exe

Click OK. You need access to %systemroot%\inf\perms.inf to run fixacls.exe, because the utility sets permissions on this file.

NT's convert.exe utility does not work in reverse, so you cannot convert an NTFS partition to FAT. Instead, you need to back up the data, reformat the partition as FAT, and restore your backup.

How much hard disk space do I need to convert a FAT partition to NTFS?

You can use the following calculation for standard disks with 512 bytes per sector. Divide the size of the partition by 100. If the result is less than 1,048,576, use 1,048,576 as the value. If the result is greater than 4,194,304, use 4,194,304. Then, divide the size of the partition by 803, and add the result to the first number you obtained (i.e., 1,048,576 or 4,194,304). Next, multiply the number of files and directories by 1280, and add the result to the last number you obtained. (To determine the number of files and directories, use the dir /s command at the base of the partition.) Finally, add 196,096 to your previous result.

Does Windows NT support FAT32?

NT 5.0 will support FAT32. NT 4.0 does not support FAT32, but you can download a free read-only FAT32 driver for NT 4.0 from http://www.sysinternals.com. You can download a fully writable FAT32 driver for NT 4.0 from http://www.winternals.com.