Performing Data Operations

An apparatus configured to convey instructions to a central station, comprising:

• an input device for receiving input commands in response to a graphical user interface displayed on an output device;
• a processor;
• and
• a communication channel to a central station;
• wherein said processor is configured to:
• change a graphical representation displayed on said output device from a first condition to a second condition to show that said input command has been acted upon by said central station, and to asynchronously convey said input command to said central station as a background process for said central station to act upon;
• cache the input command in a local cache;
• receive a message from the central station stating that the central station has been prevented from acting upon said input command;
• read details of the input command from said local cache to identify the first condition of said graphical representation;
• and
• revert said graphical representation from said second condition to said first condition, to show that said input command has not been acted upon at said central station.

Apparatus at a central station configured to receive instructions from a remote station, in which a received command is prevented from being acted upon, comprising:

• a processor;
• and
• a communication channel to said station;
• wherein said processor is configured to:
• return a message back to said remote station confirming that said received command has not been acted upon;
• and
• ensure that a graphical representation of the status of the central station is maintained consistently at the remote station, in which, at the remote station:
• the received command generated via a graphical user interface has been stored locally in a local cache, wherein the graphical representation has changed from a first condition to a second condition;
• details of said stored command are read from said local cache in response to receiving said returned message, to identify the first condition of the graphical user interface;
• and
• said graphical representation is reverted to show said first condition.