| 摘要 |
PURPOSE:To decrease the number of dynamic steps needed to fix pages of an input/output buffers by using a means which allocates the real pages instantaneously when a request is given for acquisition of an input/output buffer area of an extended region, etc. CONSTITUTION:When an input/output buffer area request part 10 request an extended region by an area acquisition macroinstruction 13, an area acquisition processing part 11 secures an idle area. Then it is decided whether said secured area is equal to a new page or the extended area. If a new page of the extended area is confirmed, an extended region real page allocation processing part 12 is called out and an idle real page is allocated to a logical page of the secured area. Then the allocated real page number is set at the corresponding page table entry and the CPU-DAT invalid display is erased. When the part 10 is reset, a real page is allocated to an acquired page and a page fixing error is not reset with the following process of an input/output request macroinstruction 14. Thus the useless dynamic steps are eliminated.
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