write and read on real time pytables
This is definitely possible.  It is especially easy if you only have one process in 'w' and multiple processes in 'r' mode. Just make sure in your 'w' process to flush() the file and/or the datasets occasionally.  If you do this, the 'r' process will be able to see the data.
I am not sure if what I am thinking would be possible, I would need the help from someone experienced working with HDF5/PyTables.
The escenario would be like this:
Let's say that we have a process, or a machine or a connexion etc, acquiring data, and storing in a HDF5/PyTable format. I will call it store software.
Would it be possible to have another software, I will call it analysis software, running on time?.
If it helps, the store software and the analysis software would be totally independent, even wrote on different languages.
My doubt is that, if the store program is writing the PyTable, mode='w', then, at the same time, can the analysis program access in mode='r', and read some data to perform some basic analysis, averages, etc, etc??. 
The basic idea of this is to be able to analyze data stored in a PyTable on real time.
Of course any other proposed solution would be appreciated.