When I ran JkDefrag on my daughter's laptop, it finished after the analysis phase without defragging the drive. The log file showed this:-
12:15:46 JkDefrag v3.33
12:15:46 Date: 2008/01/08
12:15:46 Commandline argument '-l' accepted, logfile = JkDefrag.log
12:15:46 Commandline argument '-a' accepted, optimizemode = 3
12:15:46 Commandline argument '-f' accepted, freespace = 1.0%
12:15:46 Commandline argument '-e' accepted, added '*\pagefile.sys' to the excludes
12:15:46 NtfsDisableLastAccessUpdate is inactive, using LastAccessTime for SpaceHogs.
12:15:46 Starting JkDefrag for 'c:\*'
12:15:46 Opening volume '\\?\Volume{85eac6b0-00db-11d9-b92e-806d6172696f}' at mountpoint 'c:'
12:15:46 Input mask: c:\*
12:15:46 Phase 1: Analyze
12:15:46 This is an NTFS disk.
12:15:56 This is a FAT12 disk.
12:15:56 Phase 2: Defragment
12:15:56 Phase 3: Fixup
12:15:56 Phase 3: Fixup
12:15:56 Finished.
12:15:56 - Total disk space: 8389783552 bytes (7.8136 gigabytes), 2048287 clusters
12:15:56 - Bytes per cluster: 4096 bytes
12:15:56 - Number of files: 0
12:15:56 - Number of directories: 0
12:15:56 - Total size of analyzed items: 0 bytes (0.0000 gigabytes), 0 clusters
12:15:56 - Number of fragmented items: 0
12:15:56 - Total size of fragmented items: 0 bytes, 0 clusters
12:15:56 - Free disk space: 499363840 bytes, 121915 clusters, 5.9520% of disk
12:15:56 - Number of gaps: 951
12:15:56 - Number of small gaps: 604, 63.5121% of all gaps
12:15:56 - Size of small gaps: 9498624 bytes, 2319 clusters, 1.9021% of free disk space
12:15:56 - Number of big gaps: 347 (36.4879% of all gaps)
12:15:56 - Size of big gaps: 489865216 bytes, 119596 clusters, 98.0979% of free disk space
12:15:56 - Average gap size: 128.1966 clusters
12:15:56 - Biggest gap: 85798912 bytes, 20947 clusters, 17.1816% of free disk space
12:15:56 - Average end-begin distance: 0 clusters, 0.0000% of volume size
The disk was apparently both NTFS and FAT12!
I then ran it again with parameter -d 6. The log is attached. Apparently there was a CRC error when reading the MFT which caused JkDefrag to report that the disk was FAT12. The CRC error was subsequently confirmed by running Spinrite on the disk.
I would suggest that CRC errors should be reported in the log at -d 0 level, and that defragging should stop gracefully if CRC errors occur.
