How a computer boots up

Re:How a computer boots up by Hoff on Wednesday April 11, 2012 @12:51PM (#3828401)

In one box I'm working with, a switch (whether mechanical, or an outboard management processor, a received network packet with a "smart" NIC, or otherwise) triggers a pin or signal on the processor.

This signal causes the processor to then perform its own start up, which then causes various processor-specific initialization, and then causing the processor to load its soft-loaded firmware code from a SROM, and to jump to the start address for the console firmware.

The firmware then performs more configuration and testing, and which eventually gets around to allowing the user to enter commands, or to trigger an operating system bootstrap by finding and loading blocks from a specified boot device.

The SROM implementation allows the firmware code to be more easily upgraded.

This sequence is usually covered in a processor technical manual, for whichever combination of processor and main board you're looking at.

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Re:How a computer boots up by sliverstorm on Wednesday April 11, 2012 @02:11PM (#3828813)

Think of an old-fashioned tape computer. You feed the computer the tape, which causes the computer to do this or that in memory.

Initially, it knows nothing, but it is built to read in the tape, starting from the beginning. Then from there, what it reads on the tape controls what happens next.

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Re:How a computer boots up by dclowd9901 on Wednesday April 11, 2012 @02:54PM (#3829027)

This, more than any other explanation, has helped me understand what's happening. Thanks much.

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