What is 7-mode cluster architecture

Can someone explain me how 7-mode architecture has got that name. I can see and understand what is and how does a 7-mode architecture looks like but I didn't get how did it get the name 7-mode . I'm a newbie. 

Re: What is 7-mode cluster architecture


Clustered mode started on a separate product that they acquired from spinnaker networks (started as ontap 10/gx). On ontap 8 they have implemented this 10/gx on top of their existing product (ontap 7) as a nblade (node blade). When customers wanted to activate this latest greatest functionality they needed to switch mode in the loader to the clustered one. If they wanted to stay on their well known stable mode as in the previous version (7) on their latest greatest ontap 8, the mode in the loader had to be kept as “7-mode”.