Hardware method of detecting for an "eject" command on the IDE bus.
Original Publication Date: 2002-Jun-11
Included in the Prior Art Database: 2003-Jun-21
Some PC manufacturers may design a system in a special form factor box where the CDROM is hidden from immediate view and access to the CD-ROM requires a particular manipulation to the configuration of the mechanical. In one particular case with the Destiny project, the CDROM (while in the retracted position) is hidden under the flat planel display and requires being "dropped" in order to eject and access the CDROM tray. During the Destiny project development we were faced with this problem of releasing the CDROM tray, which was in the retracted position, when a OS initiated "eject" command was issued to the CDROM device. If the CDROM tray was not released, the CDROM door will be jammed in the TFT back panel. This invention will release the CDROM tray when the "eject" command is issued via the OS and prevent the CDROM tray from being jammed into the back of the TFT panel. The invention will effectively snoop on the IDE bus and "decode" for an "eject" command. The decoding is done such that the full command does not have to be issued for a positive decode. A snoop-ahead method is used to positively decode an "eject" command. A postive decode will result in the release of the CDROM tray . Below is a state diagram illustrating how advantage is achieved.