Virtual input/output in a virtual environment

The purpose of this paper is to investigate the possibility of allowing an I/O channel, regarded as a special purpose processor, to execute a program allocated in the user's virtual space. The environment is a multiptogramming-multiaccess system with a virtual memory implemented by paging. For easiness of comparison, a standard system is sketched first, where the supervisor takes care of translating the channel program from virtual to real space. Next, the proposed system is outlined, and the extra logical requirements for the channel are pointed out. The most relevant advantages are: I) The process information is treated in the virtual space, homogeneously; II) channel programs and their priorities can be dynamically modified; Ill) lower system overhead and greater flexibility are achieved.