I was trying to find out all possible values of this message.  Browsing senders reveals a need to factor this out into a first-class SqueakPlatform -- we have way too many places which employ switch statements to determine what to do:

    Smalltalk platformName = "Mac OS" 

       ifTrue: 

          [ #('/System/Library/Fonts' '/Library/Fonts') do: [:fontDir | aBlock value: fontDir]. ]

Others check for "Win32", I'm not sure what #platformName is answering on 64-bit VM on Windows these days, could someone running Windows please tell me?

Still others check for "Risc OS" or "unix".  So, the full list I have so far is:

    unix

    Win32

    Mac OS

    Risc OS

If you know of any others, please let me know.

 - Chris