Proper way to find out if an (initial) installation is being performed?

[Thomas Neumann]

Hello

In the original prepareapt hook, there are (were?) two different if-clauses:

if [ -f /var/run/fai/FAI_INSTALLATION_IN_PROGRESS ]; then

if [ $do_init_tasks -eq 1 ] ; then

I'm not too sure what they are supposed to mean so I ask for
clarification. Judging from the code/names they seem to guard the enclosed
code against running during a softupdate.

a) What's the difference between these two? Is there any?
b) What is the proper/best/most obvious/recommended way to let code run
only during the initial installation?
c) Does install/dirinstall make a difference?

bye
thomas