configure a PC to default on state

Question

I am writing device software for a PC and for that, I want the PC to be usable as a device. When power is supplied, it should switch on without requiring to press the power button. There are power options in BIOS settings but it starts the PC only when its uncleanly shutdown. The other concern I have is how would unclean shutdown affect the hard disk, filesystem and the OS (XP or Linux).

Answer 1

What you need is another PC and one of these devices attached to it.

http://www.relaypros.com/mm5/merchant.mvc?Screen=CTGY&Store%5FCode=NCD&Category%5FCode=RS-232%5FRelay%5FBoards&gclid=CMna8%5FyOo5wCFQxM5QodWjoflQ

What you do is send this some RS232 commands for a quick closure on one of the relays. The relay is connected to the Power On pins of the computer you want to control.

You possibly could find another relay contact closure for AC current that allows you to close a relay when AC is flowing, but you would only want to for a brief second.

Unsafe shut downs can be quite detrimental depending where the filesystem state is in. It would be quite hard on the hardware too.

Answer 2

There is also the alternative of booting from the network device. A quick search led to some information on wikipedia. Also, there is something related called preboot execution environment which seem to be something like what you are looking for.

Answer 3

Some software options - these aren't exactly what you asked for, but they might help

• Mac OS X: In the energy saver control pane's options tab, select "Restart automatically after a power failue. shutdown -hu now should then bring the system down but give you 5 minutes to remove power to simulate a dirty shutdown, and have the computer reboot automatically when power is restored. It's a slightly dirty shutdown anyway, I think. (ie, it doesn't log you off first)

• Windows: I don't have a windows machine so I can't try this, but you used to be able to tell windows not to power down the computer when you select shut down, but rather to put it in a safe state and display "It is now safe to turn off your computer". Perhaps you could then remove the power and have the bios believe it was a non-clean shutdown, and turn the machine on again when power is restored. There are some instructions on how to do this in Windows Server 2003 at the bottom of this microsoft help document. This forum discussion seems to suggest it might work on XP.

• Linux: Not sure about this one, but maybe this website can help.

I haven't tried any of these, so no guarantees that they'll work or work safely.