10.2 Filesystem Tweaks

The guts of the filesystem of both Windows 2000 and NT 4.0 are mostly self-tuning. This is on purpose, following the theory that the filesystem can adjust its own caching and buffering better than you can. Whether this is true or not, there are still some changes you can make to control whether the filesystem does certain things. These changes apply to FAT, NTFS, and NTFS 5 filesystems.

10.2.1 Change Low Disk Space Warning Threshold

Even though you may never have encountered it, Windows NT and 2000 can display an alert warning you that your disk is almost full. The threshold for these alerts is 90% disk usage; while this may seem generous, if you're using a large disk, a 10% margin results in you seeing these warnings even when the amount of space remaining is large in absolute terms. My local Internet service provider runs an NT news server with more than 80GB of disk storage, so getting a warning that there's "only" 8GB free is not very useful to them.

The DiskSpaceThreshold value controls when you see this alert; it sets the minimum amount of free space (as a percentage) that triggers a warning. Add this value (it's a REG_DWORD) to HKLM\System\CurrentControlSet\Services\LanmanServer\Parameters; the value you specify should be the percentage of free space, from to 99, which should trigger a warning. When the amount of free space on any volume falls below this value, you get a warning.

10.2.2 Use Longer File Extensions

Even though Win95 ostensibly supports long filenames, there's an ugly secret involved: it really supports only three-character file extensions! That means that the names medical.doc, medical.doctor, and medical.doctrine all point to the same file. Since NTFS doesn't have that restriction, you can make it take advantage of the longer extensions instead of being stuck with the three-character versions.

The value of HKLM\System\CurrentControlSet\Control\FileSystem\Win95TruncatedExtensions controls this behavior. On Windows NT machines, it's set to by default. This truncates extensions to the first three characters. Set it to 1 (the Windows 2000 default) and reboot to take advantage of full-length extensions on NTFS volumes.

10.2.3 Turn Off CD-ROM AutoRun

Ahh, "AutoRun." While Microsoft undoubtedly did a favor for some users who like to have CDs start running automatically when they're inserted, many of the users I talk to don't like this feature. If, for example, you're loading the Windows 2000 Resource Kit CD to copy a tool you need, do you really want to wait while the AutoRun-invoked setup tool loads, or would you rather just copy the file you need?

Happily, you can banish AutoRun from your Windows 2000 or NT machine with a simple change. Add a REG_DWORD value named HKLM\SYSTEM\CurrentControlSet\Services\Cdrom\Autorun and set its value to 0, and you'll no longer be forced to wait for AutoRunning-CDs to do their stuff. You can later change the value to 1 if you want to reenable AutoRun for CD-ROMs.

For more specific AutoRun control of all your Windows 2000 drives, add a REG_DWORD named HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Explorer\NoDriveAutoRun. Populate this value with a bit mask of the drives (lowest bit representing drive A) you want to disable AutoRun on. For example, the hex value 0x18 (binary 0001 1000) disables AutoRun on drives D and E.

10.2.4 Suppress "Last Access" Timestamp on NTFS Volumes

NTFS volumes store a "last access" timestamp for every directory on the volume. That means that every time you look at a directory listing, the operating system is busily updating the timestamps on each directory it detects. As you might guess, this is often a waste of CPU cycles and disk bandwidth that could better be used elsewhere. To prevent Windows from updating the "last access" timestamp for directories under NTFS volumes, add a REG_DWORD value named NtfsDisableLastAccessUpdate to HKLM\System\CurrentControlSet\Control\FileSystem and set its value to 1. Note that this change has no effect on the "last modified" timestamp.

While suppressing "last access" timestamps can increase the speed of directory listings and prevent the NTFS log buffer from becoming filled with timestamp update records, be aware that these timestamps are useful for NT auditing. Disabling last-access update decreases available auditing information.