Hello, First an introduction, I am Stuart Mumford I am doing a solar physics PhD at Sheffield University in the UK. I work primarily on MHD wave simulations of the solar atmosphere studying energy propagation and wave excitation. The code SAC (http://www.aanda.org/10.1051/0004-6361:200809800) solves for perturbations ontop of a fixed background to deal with the very wide range of the parameters e.g. density and temperature in the solar atmosphere. I also attended SciPy this year, where I met some of you and discovered yt, mainly as a consequence of my contributions to SunPy (www.sunpy.org) which is a solar physics data analysis library. So that's that over with, now having been playing with yt on and off since SciPy I started using it properly this week, as the need arose. I am very impressed with yt's capabilities and I want to be able to make better use of it. To that end I am trying to write a frontend for SAC, as I have been speaking to some of you about in IRC (I am Cadair in IRC and on GH). I have some questions regarding this, as far as I can ascertain a frontend provides a mapper between the stored data and a abstracted format that yt understands? I have started looking in the code for FLASH and Stream to try and get an idea where to start and not got very far. So some questions to start: Where should the file handling be done? Where is the file opened? What things should the StaticOutput subclass define? Thanks once again for your help on IRC over the last few days and I hope you can point me in the right direction. Stuart