Delphi

Question:
What is the difference between single and multiple instance
application servers in a multi-tier application?

Answer:
This can best be thought of from the point of view of the
application server and how many clients can it support.
One multi-instance server can support multiple clients.
A single instance server can only support one client.

Multi-instance servers create multiple data modules in one
instance of the server. Single instance servers are launched
for each client.