When they talk about RPC, what do they mean?

You click into the article probably because you had the same doubt as what the title says.

I had the same question when I heard from colleagues talking about RPC.

I tried to google “what is RPC”, and this is what shows up.

Remote Procedure Call is a software communication protocol that one program can use to request a service from a program located in another computer on a network without having to understand the network’s details. RPC is used to call other processes on the remote systems like a local system. A procedure call is also sometimes known as a function call or a subroutine call.

When I read above description, a sequence of new questions popped out:

... communication protocol that can request a service from another computer… Isn’t that similar to HTTP? Then what’s the difference between HTTP and RPC? The above said that it’s a function call… what exactly is a function call?

With the new questions, I dived deeper.

RPC was put into practical use in the 80s whereas HTTP emerged in the 90s.

In HTTP, we all know that if the server needs to access resources from outside, we pass a URL for the request and the server returns the response.