Visto che Raf diceva qualcosa tipo: "Tutto è OpenSource se si conosce l'assembler..." aveva perfettamente ragione!!! 
[...]
However - one day a tester raised the issue that he could not find the source code for IDLE.COM.
When he alerted Program Management and Development about this the Virtual PC Lead Developer - Aaron Giles (http://www.aarongiles.com/) - responded by smiling and saying 'The
binary is the source'.
Needless to say this resulted in a number of blank stares and furrowed brows - until Aaron explained that he hand-constructed IDLE.COM in assembly using DEBUG. So he was completely justified in saying that the binary was the source. Since this time we have added a second hand-constructed file - 'VMADD386.SYS' which was also built by Aaron.
And - on a slightly related
note - it turns out that this is not the first instance of this at
Microsoft. The following Knowledge Base article on 'REBOOT.COM':
http://support.microsoft.com/kb/q67929/ tells users how to 'build their own REBOOT.COM' using DEBUG. Hmmm... You have to think it would have been easier to just let people download the file 
Source: What do you mean 'The binary is the source'?