Desktop search engines

List of Desktop search engines with Names and its Platforms:
Ask.com - Windows
Autonomy - Windows
Beagle - Linux
Copernic Desktop Search - Windows
Docco - cross-platform (Java)
Docfetcher - Cross-platform
dtSearch Desktop - Windows
Easyfind - Mac OS
Google Desktop - Linux, Mac OS, Windows
GNOME Storage - Linux
imgSeek - Linux, Mac OS, Windows
InSight Desktop Search - Windows
ISYS Search Software - Windows
Likasoft Archivarius 3000 - Windows
Meta Tracker - Linux, Unix
Recoll - Linux, Unix
Spotlight - Mac OS
Strigi - Linux, Unix, Solaris, Mac OS X and Windows
Terrier Search Engine - Linux, Mac OS, Unix
Tropes Zoom - Windows
Windows Search - Windows
X1 Professional Client - Windows