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It has been running continuously on mains power for several hours quite happily while I back up to Virginmedia but now it gives 3 beeps every few minutes even though I’ve closed the internet connection. What does this mean? Have I missed something in the manual?
Welcome to the forum, uptodat 🙂
Try a cold boot of your NC10 by pressing and holding the on/off button until your Sammy shuts down. Then restart it. Let us know how you get on.
[quote1243164618=TCMuffin]Try a cold boot of your NC10 by pressing and holding the on/off button until your Sammy shuts down. Then restart it. Let us know how you get on.
[/quote1243164618]
Why not just perform a standard shutdown and startup?
Or if it is needed to make sure the RAM or other memory locations are clear shutdown, unplug and pull the battery for a short period of time.Isn’t a cold boot only generally used as a last resort when a computer has locked up completely as it can result in the filesystem being left in an inconsistent state.
Well – if possible – I’d close all open programs before cold booting, but it is a good way of clearing all the system caches.
Touch wood – I’ve never had a problem with the filesystem being inconsistent after a cold boot 😕
Apologies for derailing the thread, but I thought a cold boot had the opposite effect where caches that are normally flushed on shutdown are not cleared during a cold boot.
I think there are even some attacks which make use of cold booting to access information from the RAM such as encryption keys.
EDIT: not that I would expect shutting down cleanly to clear the RAM either.[quote1243252727=Alfihar]
I thought a cold boot had the opposite effect where caches that are normally flushed on shutdown are not cleared during a cold boot.
[/quote1243252727]
Oh. My understanding is that a warm boot restarts a computer by closing all running programs. All data that has not been saved is lost.A cold boot also restarts the computer, but this process erases all stored records and entries from RAM. In addition a cold boot resets the hardware and checks the hardware before reloading the operating system.
[quote1243252727=Alfihar]
I think there are even some attacks which make use of cold booting to access information from the RAM such as encryption keys.
[/quote1243252727]
Very interesting – I wasn’t aware of this type of attack by a hacker with physical access to a computer. Thank you, Alifhar.If anyone wants more information, researchers at Princeton University have produced a paper Lest We Remember: Cold Boot Attacks on Encryption Keys
[UPDATE] Clicking on the link to the YouTube video on the above page caused FF to stop responding on my computer, so I followed the link to the Videos and Images page. Again clicking on the link to the YouTube video caused FF to stop responding, but I have been able to download the .wmv file and viewed the video overview.
[UPDATE TO THE UPDATE] Having studied this – it seems the only protection against an attacker wandering into your office/home/etc and nicking the data from your RAM is to shut down your computer at least five minutes before you want to leave your office/home/etc. You have been warned 😉
Oh. I use FF 3.0.10 with Noscript and was able to watch the video fine on that page. It is a bit of an eye-opener! :-O
Yes it was. As I said – I think the best defence is to turn off your computer at least five minutes before you want to leave it where it could be accessed by a potential attacker. In fact for maximum protection, shut down the computer when you are not present.
I thought I had locked down my NC10 by applying a Supervisor, User and HDD password in the BIOS so I would be interested in knowing how easily these defences are bypassed 😕
I have FF 3.5b4, so maybe that’s why I couldn’t watch the video without downloading it 😕
[quote1243290213=TCMuffin]I thought I had locked down my NC10 by applying a Supervisor, User and HDD password in the BIOS so I would be interested in knowing how easily these defences are bypassed :?[/quote1243290213]
Hmm well the supervisor and user passwords are easy to bypass, just reset the CMOS. I had an issue with the CMOS being reset when I entered standby at one point so it should be possible to do this using software, at worst you take the RAM out and short the CMOS reset pins.As for the HDD password there are some software utilities which can remove it from some drives, for others there’s a piece of hardware which you can use to remove it. You will probably need to remove the drive and place it into another computer, I think it is possible with most hard drives.
EDIT: This looks easy, AFF Repair Station.
Oh and incase anyone is wondering the Windows password is also very easy to bypass/change.
These do rely on having physical access to the computer though.
[quote1243290584=TCMuffin]A cold boot also restarts the computer, but this process erases all stored records and entries from RAM. In addition a cold boot resets the hardware and checks the hardware before reloading the operating system.[/quote1243290584]
Hmm well the only way to erase the records from the RAM is to turn the computer off for a while, so it shouldn’t matter if you do a clean shutdown or a cold boot. The hardware checks should also be done during startup from a clean shutdown the same as a cold boot.[quote1243291792=Alfihar]
Hmm well the supervisor and user passwords are easy to bypass, just reset the CMOS. I had an issue with the CMOS being reset when I entered standby at one point so it should be possible to do this using software, at worst you take the RAM out and short the CMOS reset pins.As for the HDD password there are some software utilities which can remove it from some drives, for others there’s a piece of hardware which you can use to remove it. You will probably need to remove the drive and place it into another computer, I think it is possible with most hard drives.
EDIT: This looks easy, AFF Repair Station.
[/quote1243291792]
That’s what I feared 🙁[quote1243291792=Alfihar]
Oh and in case anyone is wondering the Windows password is also very easy to bypass/change.
[/quote1243291792]
Too easy to crack – I don’t even bother with a Windows password.[quote1243291792=Alfihar]
These do rely on having physical access to the computer though.
[/quote1243291792]
This is the last line of defence – perhaps we’ll all be reduced to turning off our computers every time we leave them and locking them away in a drawer/office.We just have to accept that if someone is determined enough they can gain access to our data.
[quote1243291792=Alfihar]
Hmm well the only way to erase the records from the RAM is to turn the computer off for a while, so it shouldn’t matter if you do a clean shutdown or a cold boot. The hardware checks should also be done during startup from a clean shutdown the same as a cold boot.
[/quote1243291792]
But a cold boot actively resets the hardware, which a warm boot doesn’t.Poor uptodat has not returned to the forum since this thread was started. When he/she does return he/she will be surprised at what he/she started 🙂
[quote1243338509=TCMuffin]But a cold boot actively resets the hardware, which a warm boot doesn’t.[/quote1243338509]
Although a warm boot may not fully reset the hardware a standard shutdown and startup should.As for the Windows password, I still set one as it stops people for just wandering up to the computer and using it. Even if it is easy to bypass.
Hi folks, I (a he) am back and surprised at where the thread went. Thank you for your time and advice. I’m not sure if my re-boot was hot / cold or lukewarm but I switched everything off and removed the battery for a while. It was fine on re-start and hasn’t yelped since but I’m annoyed not to find out what it was. After previous niggles, I think I’ll put it down to Virgin PC Guard.
Interesting stuff here even if 90% of it went over my head by quite a margin! Nice to find somewhere where people are so helpful.[quote1243358469=uptodat]Hi folks, I (a he) am back and surprised at where the thread went.[/quote1243358469]
Ah well, apologies I seem to have a bit of a knack for derailing threads…[quote1243358469=uptodat]Thank you for your time and advice. I’m not sure if my re-boot was hot / cold or lukewarm but I switched everything off and removed the battery for a while. It was fine on re-start and hasn’t yelped since but I’m annoyed not to find out what it was. After previous niggles, I think I’ll put it down to Virgin PC Guard.[/quote1243358469]
Interesting, I also find these kind of issues annoying, where you don’t find the problem but it fixes itself. But as it hasn’t occurred since it’s probably not going to be worth worrying about too much.One thing I will say though is that the PC Guard software is known to cause slowdowns and to be resource heavy, it may be worth considering using something else instead, maybe Avira anti-virus.
[quote1243339183=Alfihar]
Although a warm boot may not fully reset the hardware a standard shutdown and startup should.
[/quote1243339183]
Only if you remove the battery on a laptop. Empirically (and for some reason especially for problems with wireless adapters) I have found that laptops do not reset the hardware during a standard shutdown and startup because of the trickle charge from the battery 🙁It is ‘easier’ to press and hold the on/off button to perform a cold boot. At my hourly rate my clients prefer the quick and dirty option 😉
[quote1243339183=Alfihar]
As for the Windows password, I still set one as it stops people for just wandering up to the computer and using it. Even if it is easy to bypass.
[/quote1243339183]
I do use Windows password on clients’ computers which I support. I just don’t use Windows passwords on my own systems. Only me, my other half, and Badger have access to these and it’s a poor do if you can’t trust your better half and the dog…… 🙂
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