gdat.m was first created to get JET data using jetRDA system

It is now generalised to be machine independent in its structure and trace name.

Each machine dependent functions should be in respective directory

Adding a new machine means:
create new subdirectory
change gdatpaths

In new subdirectory, named say: NEWMACHINE
create function: loadNEWMACHINEdata.m (for load NEWMACHINE data)

etc.

The explanation of the different traces are in "help gdat" for generic names.
The specificity of a given machine are in "help loadNEWMACHINEdata"

Thus the head comments of these functions should be correctly updated and self-explanatory