 Synchronous clock regenerator for binary serial data signals |
| In accordance with the present invention, the incoming raw clock signal with arbitrary phase is fed ... |
|
| Data transfer apparatus with automatic transmission rate adjustment |
| It is an object of the present invention to provide a data transfer apparatus capable of minimizing ... |
|
| Data acquisition method and protocol controller circuit |
| Briefly, the present invention is directed to a data acquisition circuit for acquiring transfer ... |
|
| Transmission system with improved synchronization |
| The object of the present invention is to provide a transmission system according to the preamble ... |
|
| Managing connection requests in a dialup computer network |
| It is thus a primary goal of the present invention to manage service requests in a dialup computer ... |
|
| Access-method-independent exchange 3 |
| The present invention provides a virtual network, sitting "above" the physical connectivity and ... |
|
| Semiconductor processing systems |
| OF THE PREFERRED EMBODIMENTS This disclosure of the invention is submitted in furtherance of the ... |
|
|
Mechanism for arbitrating client access to a networked print server
| Details |
Inventors: Mogul, Jeffrey C.;
Assignee: Digital Equipment Corporation (Maynard, MA)
Primary Examiner: Clark; David L.
Assistant Examiner:
Attorney, Agent or Firm: Arnold, White & Durkee
In response to a print request, a print server returns a "window" message which specifies an amount of data that the process is permitted to send to the print server. The amount of data can be zero, indicating that the printer is not available. In this case the print server queues the print request, and when the printer becomes available to service the queued request, the queued request is removed from the queue and a "window" message indicating that the printer is available is sent to the requesting device. In response, the requesting device transmits a packet of data to be printed including the amount of data specified by the window message, and the requesting device waits for an acknowledgement of the print data packet. When the printer finishes printing the data, the print server acknowledges receipt of the data packet, and repeats the window message. This procedure is repeated until the printer has printed all of the data that the requesting device would like to have printed. Then, the requesting device terminates the connection by sending a termination request, which the print server acknowledges. Finally, the requesting device returns the acknowledgement. |
|
DETAILED DESCRIPTION In accordance with the present invention, the foregoing objectives are realized by providing a system using virtual circuits and "windows" for communication between client processes on a network and a print server in a network printer.
Furthermore, the printer server queues requests for later service when the printer is busy and receives a print request.
The print session begins when a client process establishes a connection with the print server by sending a request for connection.
The print server sends an acknowledgment back to the client to complete the connection.
The acknowledgment includes a "window" message which specifies an amount of data that the process is permitted to send to the print server.
The size can be zero, meaning the "window" is closed (the printer is not available, send no data) or positive, meaning the window is open (the printer is available, send an amount of data up to the size of the open window).
If the printer is busy when the connection is requested, it will complete the connection by sending the requesting process an acknowledgement including a "closed window" message.
The print server queues the requesting process, and dequeues it when the printer is available.
If the printer is available when the connection is requested, the printer will send an "open window" message, specifying a window size equal to the available memory in the printer.
This prevents the client from sending more data than the printer can handle and thus prevents the printer from losing data.
When the window is open, the process requesting the printer sends up to one window worth of data to the print server.
The process requesting the printer waits for an acknowledgment of the receipt of the data packet.
When the printer has printed some of the data, the print server acknowledges the receipt of the data packet, and repeats the open window message.
This procedure continues until the client has sent all of the data to be printed.
The client then terminates the connection by sending a termination message
|
|
Processing Data 
