LEDs问世有一段时间了，但是主要作为电力器件上可以忽略不计小型红色指示灯。
LEDs have been around for some time, but mostly blinking away as little red indicator lights in electronic equipment.
NOC可以收到系统故障报警或者在Nagios web界面上看到一个闪亮的红色错误指示灯。
The NOC can be alerted of system failures or see a shiny red error light on the Nagios Web interface.
不能自动关机，但是有一个红色的指示灯显示机器是否运转。
Doesn't switch off automatically but a red light shows if the machine is still running.
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