Data processing system with means for detecting status of data processing device receiving commands.

摘要

The invention relates to a data processing system comprising a processor means (2) for issuing communications commands on a first communications channel (4), a peripheral means (5, 6, 7) connected to the first communications channel and to a second communications channel (8) operating asynchronously, for performing operations specified by commands from the processor means and for responding to communications on the second communications channel, and status indicating means for indicating to the processor means the status of the peripheral means. According to the invention the data processing system is characterised in that the status indicating means comprises control means for providing a status word to the processor means in response to a command issued to the peripheral means by the processor means, the status word indicating the status of the peripheral means at a time when the peripheral means initiates an operation specified by the issued command.