| 摘要 |
PURPOSE:To make I/O operation easy by inserting a channel control word for specifying an address conversion mode into a series of I/O operation specifying channel words. CONSTITUTION:In addition to normal I/O operation specifying channel control word (CCW)4, a logical address mode specifying CCW(LM)5 and a real address mode specifying CCW(RM)6 are prepared. The LM5 specifies a CCW logical address in a logical space by a logical address part NCA. Information in a 2-level address conversion table 8 is held in a leading address part STQ and a segment table length specification part STL. If the LM5 is applied to an I/O channel device, all information to execute the succeeding I/O operation is applied. |
