To improve the efficiency of an I/O operation by eliminating a call to an operating system in an I/O base without executing copying between intermediate memories.
A part of a memory 206 which physically exists on the I/O device is mapped in the address space 208 of a device driver. The memory is mapped in the virtual address spaces of user processes 202 and 204 and therefore the user processes 202 and 204 can directly program the I/O adapter without. the overhead of the operating system such as a context. and a switch. The I/O device adapter is mounted with a snooping circuit for detecting reading or writing in the virtual address space. When access to the page of the physical memory is detected, the script of a specified action is executed by the I/O device adapter.
DAGURASU II HANDORII
PII KEISU MARAA
KAATEISU EICHI SUTEFURII
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