| 摘要 |
PURPOSE:To avoid a system halt caused on purpose or due to a misoperation by constituting so that a power source on/off switch of a computer body and an IPL switch are controlled by an operating system. CONSTITUTION:When a power source on/off switch 2 is depressed in the off- direction, a power-off signal is generated to a computer body 1, a state of the computer body 1 is safe-stored, and an interruption is inhibited. Subsequently, the contents of a system control status register 11 are retrieved, and a P flag is checked. When the P flag is on, a request of power-off is disregarded. When the P flag is off, the power-off is executed. Subsequently, when an IPL switch 3 is depressed, an IPL signal is outputted, a state of the computer body 1 is safe-stored, and an interruption is inhibited. Next, the contents of the register 11 are retrieved, and an IPL flag is checked. When the IPL flag is on, an IPL request is disregarded, and when the IPL flag is off, a start of input/output is executed. |
