Real-time file system monitor.

Sonar is a security tool that reports file change activity on your hard drive in real-time. It can show you every time a program changes a file on your hard drive. Sonar can be useful for several purposes:

• Run Sonar before installing a new program so you can see exactly what gets installed. Then you can remove it later if necessary.
• Use Sonar to troubleshoot Spotlight-related slowdowns on your computer. Sonar will show you highly active files that you might want to consider adding to the Spotlight exclusion list to avoid frequent re-indexing.
• Developers can use Sonar to monitor how frequently their software writes to the hard drive. Developers can use this information to optimize their program's hard drive usage.