Patent ID: 7406570
Filing Date: 2008-07-29
Classification: G06F,H04N

Abstract:
1. A multisystem network comprising: a first device with a first processor and a first file descriptor management table; a second device with a second processor, a second file descriptor management table and a file descriptor correspondence table; a data storage unit having a first data storage area for the first device and a second data storage area for the second device; and a connection circuit connected between the first and second devices and the data storage unit, the connection circuit having provided therein an emulation register equivalent to a register for storage of a command or control data used for access to the data storage unit by the first processor; data transfer between the first device and data storage unit being made by the first processor directly accessing the data storage unit via the connection circuit; and data transfer between the second device and data storage unit being made by the second processor accessing the emulation register and by the first processor accessing the data storage unit correspondingly to the content of the emulation register, wherein the first file descriptor management table is a file system to manage data read from or written to the data storage unit, wherein file descriptors issued by the first and second devices are managed by the first and second file descriptor management tables respectively, a correspondence relationship between the file descriptors is stored in the file descriptor correspondence table.