Kimbo, Adrian, Roy, Terry,
DFDs are good and they work. However the technique is 'old' and most of the newer IT people have never heard of them or they've done a brief assignment at university/college. I did a project ten years ago and most of the system/analyst then were DFD agnostic. Like Adrian, I've used BPMN for a few years now and the business users "like" them especially when you create diagrams in such a way that they can see their process (in a swimlane) relative to the other stakeholders.
I agree stick with it! Try www.bizagi.com and download their free BPMN tool.
Psst! you can apply DFD concepts to BPMN diagrams. if really you want too, you can use data objects as STORES (with writing to, and reading from); BUT, its not recommended!
warm regards,
K
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