Timer-Based Device Configurator
Original Publication Date: 1989-Mar-01
Included in the Prior Art Database: 2005-Jan-27
A process allows displays and printers to be turned on at any time without pre-configuring them and without having to re-IPL the system. Messages are sent to the host any time that a device powers on or off. The host system specifies when to start polling for unconfigured devices and when to stop. The rate at which new devices are polled is dependent on how many powered-up devices are already up. The configurator function is performed by initiating autopoll to one device at a time. Autopoll means that the device is polled by the hardware once every 15 - 20 milliseconds. When autopoll is initiated for a device, a software timer is set. If the autopoll function detects that the device is powered on before the timer expires, then the device is made available to the host system.