[otterdude]

When people talk about a single server they're not talking about one hunk of metal, they're talking about 1 server process.

This article describes the 10k client connection problem, you should be handling 256K clients :)

[marcosdumay]

When people talk about a single server they are pretty much talking about either a single physical box with a CPU inside or a VPS using a few processor threads.

When they say "most companies can run in a single server, but do backups" they usually mean the physical kind.

[Maxatar]

The term is absolutely ambiguous and I know I've run into confusion in my own work due to the ambiguity. For the purpose of the C10K, server is intended to mean server process rather than hardware.