> Is this a pedantic argument about a specific definition for "message passing"? No. This is just colloquial usage of the term “message passing”. Yes, you can

> Is this a pedantic argument about a specific definition for "message passing"? No. This is just colloquial usage of the term “message passing”. Yes, you can use doors to pass messages. That is not the only thing you can do. > If so, then I retreat to the argument above: there is nothing about "Remote Procedure Call" as a metaphor that requires "message passing". Yeah. Everyone else here agrees with that. The original comment you replied to said, “Doors at the end of the day aren't message passing based RPC.” This absolutely indicates that the poster agrees with you on that point—that not all forms of RPC are based on a message passing system. There are other forms of RPC, and this is one of them. Ultimately, I think you can conceive of “message passing” broadly enough that, well, everything is message passing. What is a CPU register but something that receives a message and later re-transmits it? I would rather think of the colloquial use of “message passing”. Likewise, you can probably dig into doors and find some message system somewhere in the implementation. Or at least, you’ll find something you can call a message.