Disk Slack Checker v2.5.1

** Updated Mar 29, 2005

Download your copy of Karen's Disk Slack Checker

Because of the way Windows allocates disk space, almost every file is given more disk space than it needs. This extra space is sometimes called "slack". In most cases, the amount of slack, or wasted, space increases with drive size, especially when the drive is formatted with the FAT16 filesystem.

How much of your disk space is being wasted? Karen's Disk Slack Checker will let you know. You'll also discover which filesystem is used on each of your drives, and the drive's "cluster size", or smallest unit of disk space allocation.

For more information, read these back issues of Karen's Power Tools newsletter:


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Enhancements/Bugs Fixed

  • Version 2.5.2: Fixed bug that caused program to crash when trying to display an invalid Overhead value.
  • Version 2.5.1: Worked around bug in Windows' GetDriveFreeSpace API call that sometimes causes it to fail if drive letter specification of a local drive is not followed by a trailing backslash ("\").
  • Version 2.5: Added several new items to program's main display. Also changed the "Tabbed Dialog" control to enable the program to work better with screen readers -- tools that help blind and vision-impaired users.
  • Version 2.3.1: Fixed bug that could cause program to fail, when computing slack per file, if first folder on a drive was empty.
  • Version 2.3: Now displays Slack Space per File. Ideally, this number should be 1/2 a drive's cluster size. If not, there are probably a large number of small files (which tend to waste more disk space) than average.
  • Version 2.2.1: Changes way program estimates cluster size for FAT32 drives.
  • Version 2.1: Recognizes DVD drives, improves cluster size detection for older versions of Windows.
  • Version 2.0: Improves support for large drives, and used grid to display results on-screen.
  • Version 1.4: Now uses the GetDiskFreeSpaceEX API call, available only in Win95 OSR2 and later, when available to obtain the size of a drive, and its mount of free space. Older versions used the original GetDiskFreeSpace API call, which didn't handle large drives (2GB+) correctly.
  • Version 1.3: Now detects hidden and system files. Thanks to reader Hellmut Golde for this report!
  • Version 1.2.1: Correctly identifies FAT32 filesystems.
  • Version 1.2: Was ported to VB 6.0. Main window is no long resizable the user (the program handles that automatically). The program also remembers the last screen location of its main window, and automatically places the main window there the next time it is executed.
  • Version 1.1: Fixes an overflow problem that occurred with drives larger than 2 GB.
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