Multiple Programs – DFSDKS.EXE
You may see dfsdks.exe and mstdfsdks.exe described as MST Defrag SDK Service. These files install with MST Defrag Home Edition, Workstation Edition, and Server Edition from MST Software. MST Defrag prevents and eliminates the file fragmentation. The utility can also monitor how the system records the data in the disk, in search of file fragmentation. When there are available system resources, the program defragments it. It works for FAT32 and NTFS file systems. You'll find more information at http://www.mstsoftware.com/en/Products/mst-Defrag. You'll find a FAQ at http://www.mstsoftware.com/en/Products/mst-Defrag/FAQ.
A file called dfsdks.exe also appears to install with Ashampoo WinOptimizer 6 or later. It's likely that the defrag utility that installs as part of this program was based upon the MST Software SDK. You'll find more information at http://www2.ashampoo.com/webcache/html/1/product_2_2106___USD.htm.
Safe
MST Software