rdar://18907215: Resetting Network Settings on iOS removes networks in OS X:

While troubleshooting an iOS issue I hit Reset Network Settings. This apparently removes all the wireless networks from the keychain as a part of its magic. Unfortunately, the Keychain was synced to iCloud and my computers to that so ALL my wireless networks across ALL my computers were deleted as well.

Why are Mac OS X aliases so large? They’re huge! I’ve seen sizes from 1MB to 5MB for a single alias file. Back in the System 7 days, they were mere bytes in size. Their functionality hasn’t significantly ¹ changed since then.

I poked around an alias file (with the help of xattr, DeRez, and GetFileInfo) and found the answer: they’re storing icons in there now.

Twice. Once in the data fork of the file and then once in the resource fork of the file.