Newb: Telnet 'cooked data','EOF' queries.

[glen]

While experimenting with telnetlib, Ive come across a couple of 
'features' that confuse me a little (lot!).
Could someone explain what "cooked data" is.
Also when trying read_all() the program seems to lock up, which I assume 
is because it is waiting for an EOF, but 'when' is an EOF received.
Glen