Microsoft - Windows - WinSxS

Information about the <drive>:\Windows\WinSxS\ directory.

Blogposts/Articles

MSDN Blogs > Engineering Windows 7 > Disk Space
Ask the Core Team - What is the WINSXS directory in Windows 2008 and Windows Vista and why is it so large?
TechNet Blogs » if (ms) blog++; » Don't Trust All Your Eyes Tell You... (hard links in Windows Vista)

TechNet Forum - How do I delete the WinSxS folder?

How-To Geek - How to Reduce the Size of Your WinSXS Folder on Windows 7 or 8
Microsoft Pro - How to cleanup the winsxs folder on Windows 7 (SP1)/ Windows 2008 / Windows 2008 R2 (SP1) /spsuperseded (only) cleans service pack related files.