at the moment i can not test, but next week i will try to have a look unless someone else say
some time linux keep you in it own directory so you could try cd / then do ls to see if it give you the whole file system
if it does not then you do not have root access so you never see the / directory
cd / worked! Nice one. I don't know why I didn't try that before.
I have now have a directory /usr, but there is no /usr/src directory