Sysinternal was a website (formerly known as "ntinternals") operated by the company Winternals Software LP, which was located in Austin, Texas. It was started by software developers Bryce Cogswell and Mark Russinovich in 1996, and was acquired by Microsoft on July 18, 2006.
The website featured several freeware tools to administrate and monitor computers running Microsoft Windows operating system. The software can now be found at Microsoft. The company also sold data recovery utilities and professional editions of their freeware tools.
It was Mark Russinovich who sparked the 2005 Sony BMG CD copy protection scandal in a October 2005 posting to the Sysinternals blog.