Here are the phases of development I envisage: Phase 1: The outcome of this phase is a tool which can be used to edit/browse/view/read/write *small* system files. Such a tool might alone be enough to encourage some users to=20 try PSPP --- the most frightening spss syntax is the DATA LIST commands. Phase 2: I said "small" in the above paragraph, because there'll be no use of casefiles. All cases are explicitly stored in the data sheet. Phase 2 will integrate our casefile object into Psppire, which will make handling of really big data sets manageable. And it'll open the way for the next phase .... Phase 3: Add the ability perform transformations on the data (eg. SORT, AGGREGATE etc). I suggest the best way to do this is to have the GUI generate a syntax string eg "SORT CASES BY /x" and pass this request to an external daemon, similar to the way Ben suggested earlier. The exact details of this protocol will have to be worked out --- eg it'll be necessary to specify a socket or pipe to stream the casefile from the gui to the backend, and vice-versa. Phase 4: Add procedures (eg EXAMINE, T-TEST, REGRESSION). This will work much the same way as Phase 3. The new issue will be how to display the output. One way will be to use our existing output mechanism and to add a GDK driver to it. This will however will=20 not allow for interaction with the "Pivot Tables" the way that spss does. Other options exist, which I've not really thought about much, and it's probably more in Ben's area of expertise.