barakuda28
Posts: 3
Joined: Sat Mar 17, 2012 7:54 pm

Re: "Power-ON-on-power-fail" functionality?

Sat Mar 17, 2012 7:59 pm

Hi,

I intend to use the Raspberry Pi as a server and I would like to know if it has "Power-ON-on-power-fail" functionality, or I will need a UPS for it?

Stupid question - does it have something like BIOS? I was not able to find any information about that...

Kernel
Posts: 395
Joined: Sat Mar 03, 2012 12:53 pm

Re: "Power-ON-on-power-fail" functionality?

Sat Mar 17, 2012 8:38 pm

if you mean will it turn itself back one - as it has no power button when the power comes back on I guess it will boot up and run whatever startup options are configured

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reiuyi
Posts: 165
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Contact: Website

Re: "Power-ON-on-power-fail" functionality?

Sat Mar 17, 2012 9:26 pm

The device doesn't actually have a standby or "off" mode. It's always on when powered on. To answer your question: yes the raspberry pi will switch on again after a power failure, though there is a chance it'll have corrupted part of the filesystem if it was writing. For like 10 dollars you can buy one of those "emergency back up batteries for cellphones", even a really cheap one connected parallel to wall-power would supply the raspberry pi with half an hour of power. A bit of logic would even trigger it to shut-down automatically if you use the GPIOs to measure if wall-power is "on"

I guess when you try to power it down in the operating system it should say "it's now safe to shut down your computer" OH THE NOSTALGIA

A bios is a bootloader, this is supplied on the SD card. It's on the fat32 partition if you burn one of the ISOs from this site onto an SD-card. Part of the bootloader is the GPU code.

barakuda28
Posts: 3
Joined: Sat Mar 17, 2012 7:54 pm

Re: "Power-ON-on-power-fail" functionality?

Sat Mar 17, 2012 10:10 pm

So, if I use an SD card of my own, the bootloader will come from the OS I use (downloaded from the site). Did I got this right?

Joe Schmoe
Posts: 4277
Joined: Sun Jan 15, 2012 1:11 pm

Re: "Power-ON-on-power-fail" functionality?

Sat Mar 17, 2012 10:20 pm

Look for, find, and read the thread entitled "config.txt".

It reveals all about the boot sequence.  The short answer to your question is:  The first stage is something called "The Blob" (see: Steve McQueen movie of the same name for further details).  You cannot modify the blob.
And some folks need to stop being fanboys and see the forest behind the trees.

(One of the best lines I've seen on this board lately)

Kernel
Posts: 395
Joined: Sat Mar 03, 2012 12:53 pm

Re: "Power-ON-on-power-fail" functionality?

Sat Mar 17, 2012 10:46 pm

DeliciousRaspberryCake said:

I guess when you try to power it down in the operating system it should say "it's now safe to shut down your computer" OH THE NOSTALGIA
Actually I just had a great feeling of nostalgia on being reminded of that screen - oh those were the days! 

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Chromatix
Posts: 430
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Location: Helsinki

Re: "Power-ON-on-power-fail" functionality?

Sun Mar 18, 2012 7:39 pm

I modded a couple of Windows computers to read:


It is now safe to start using your computer.

The key to knowledge is not to rely on people to teach you it.

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