The scan engine works together with the virus pattern file to perform the first level of detection, using a process called pattern matching. Since each virus contains a unique signature or string of telltale characters that distinguish it from any other code, the virus experts at TrendLabs capture inert snippets of this code in the pattern file. The engine then compares certain parts of each scanned file to the pattern in the virus pattern file, looking for a match. When it finds a match, it sends a notification through an email message to the system administrator.