1. An interrupt mechanism for an operating system which is portable to different data processing hardware, said interrupt mechanism comprising: a management component configured to be operable to manage at least one software interrupt process and to buffer system parameters in an interrupt stack during software interrupt processing, said management component being configured to be hardware independent; and a hardware dependent component configured to be operable to select said interrupt stack and then to call said management component for managing said software interrupt processing and further to be operable to deselect said interrupt stack on completion of said software interrupt processing.