DEC pack, unpack and disk-images

[Gribouillis]

stupid question, are both 'table' and 'res' global variables, if not what makes a global variable?

Yes they are global variables because they are defined at module level and not in the body of a function. In the following code

spam = 25

def eggs():
    ham = 36

spam is a global variable and ham is a local variable of function eggs(). When function eggs() is called, ham is destroyed at function exit. Spam is never destroyed, unless we write at module level

del spam

We could also do

spam = "...some memory intensive data..."

spam = None  # does not destroy the name 'spam' but destroys the value at which it points.