If we intend the protocol to support Printers which cannot spool jobs, or which
have limited spool space, then I think we need an attribute which expresses
this fact so that a client can use the protocol appropriately for that client.
I've spent some time reviewing the proposal I made at the San Jose meeting with
our control unit developers. While depending upon the underlying wire protocol
to handle the pacing of data works okay when there is infinite spool space, we
strongly believe that an application layer protocol, such as that which I
suggested, is required when the printer must print while receiving data. We
have implemented a very similar scheme for TCP/IP IPDS printers and it works
quite well.