Difference between reboot and Off then On again?

Which resolves to hardware/driver issues, in that at soft reboot the hardware is not in a state that allows it to be reset by the software.

whether that means smarter driver software to detect a non powerup hardware state and reset it on boot, or a driver that understands power down and resets the hardware, is relatively immaterial.,

It could also be hardware that has gone partially flaky.

--
Everything you read in newspapers is absolutely true, except for the  
rare story of which you happen to have first-hand knowledge. ? Erwin Knoll

The RPi with fixing holes has a position to add a 2-pin connector for a reset button. It's close to the HDMI output, next to the voltage regulator. Shorting those pads will reset the RPi without disconnecting the power.

But is that anymore graceful than pulling the plug?

--

Graham. 

%Profound_observation%

Yes, for two reasons: (1) it doesn't wear out the micro-USB plug (2) it minimises the risk of corrupting the SD card [*]

[*] which can happen if the system (and therefore the card's controller) is powered off in the middle of a lengthy process such as remapping blocks during wear-levelling.

--
martin@   | Martin Gregorie 
gregorie. | Essex, UK 
org       |

I agree with 1. It's for that reason that I always try to pull the plug at the other end. I disagree with 2. Using the reset header P6 just crashes the operating system in exactly the same way as pulling the plug would.

I believe he said that asserting reset instead of cycling power allows a CF controller (inside the card) to complete its critical housekeeping before it acts on the reset, permitting the journaled file system to recover at the next boot.

--
-michael - NadaNet 3.1 and AppleCrate II: http://home.comcast.net/~mjmahon

I guess that's true, if that is indeed how power lines are switched (ie. no voltage drop to the card adapter, at least). Can't find anything conclusive/official.

Can you easily/cheaply put a second RPi beside it? They could monitor and reset each other:

Would you count the released schematics of the Model B to be conclusive/official? ;)

Vdd of the SD card slot is directly connected to the +3V3 line, which is supplied by RG2 (NCP1117-3v3) from the +5V0 power input.

The RESET jumper pulls the RUN pin of the BCM2385 to 0V and halts and restarts it.

Thanks!

The colocation people have promised for a year now that they would build and install equipment that allows one to powercycle the Pi from the hosting control panel.

However, it still hasn't materialized. But I don't complain, the hosting is free and they have over 2000 of them so it is quite an undertaking to make such changes.

That's what I was getting at with (2) - pull the plug and, if the SD card is in the middle of any operation (writing a block, wear-levelling etc) that alters its memory its going to get forceably stopped with completing the operation. Result is very often a corrupted card and, for the insufficiently paranoid, no backup.

--
martin@   | Martin Gregorie 
gregorie. | Essex, UK 
org       |