anybody know the exact difference between cold and warm start?

O.k., so I had this strange issue with an installation of MSE on my M4500, which makes it clear that there is a difference between a simple restart, and a full shutdown followed by a cold power-up. My question is, does anybody here know exactly what the difference is? Any pointers to a competent, detailed explanation would be fine, too. TIA.

 

I have wondered about this as well. I have, on occasion, noticed that there is indeed a difference. I can't remember the specifics but have noticed this. Never really dug any deeper than to just power off and back on.

I will follow this thread because I am curious what you might find.

Gary

 

I guess you'd have done a google on this but still from what I saw - Answers.com - What is the difference between cold and warm booting

Full search results:

https://encrypted.google.com/search...art+and+cold+boot&aq=f&aqi=&aql=&oq=&gs_rfai=

and

https://encrypted.google.com/search...+and+warm+boot&aq=f&aqi=g10&aql=&oq=&gs_rfai=

And I'm gonna follow this thread too... thanks for bringing it up.

Cheers.

 

Thanks but, yes, I did a search, and I did not find anything useful. Like the above link, which only provides trivialities that (just about) everybody knows already. My question, specifically, is, how is the startup procedure that Windows goes through on a warm start different from a cold start? Are some memory structures retained acrosss the restart, as opposed to a cold start (where that would not be possible)? Or are there some files that are written and/or read in one case but not the other? Or is the difference just on the BIOS level (hard to imagine, though...)?

Like I said, it is clear that there must be a difference, but what is it?

 

I doubt there is any difference for Windows startup. There is no way it would know the difference between a 'cold' and 'warm'(let's forget about shutdown, i.e. reboot).

If there is any difference, it would be about those tiny little controllers inside various components(as each of them is kind of running their own OS or firmware or whatever it is called). Like I would assume a HDD controller may go through a 'reboot' if power is cut from.

For Windows(or linux or any 'main' OS), they would all start from fresh.

 

Read my original post. There is a difference, in the particular example I talked about it is a very, very big difference: In one case Windows decides that some drivers are corrupt or missing and fails to start, in the other case it starts perfectly fine. The question is, why? How can there be a difference?

P.S.: But, yes, I cannot rule out that the difference is really not with the way Windows handles things, but with some controller firmware on the motherboard, or even in a hard drive, being re-initialized or not. But even if that were the case, how could that result in the kind of observations I described above? If there's one thing I am reasonably certain about, then it is that Windows will make sure all file buffers are flushed before it relinquishes control either for a restart or a shutdown.

 

A warm start/reboot keeps the BIOS hardware settings and configuration and such loaded. A cold start forces a re-reading of the DSDT and other tables from the BIOS.

It could be because you have a virus or something in your BIOS, or the AV is trying to hook into your BIOS table and failing.

 

Actually, I think chimpanzee is on to something. The issues I remember having were related to a disk not being recognized in Easus Partition Manager or Paragon Partition manager or maybe even Ghost. I was moving some partitions around on a fixed drive and a firewire external drive and remember having to do a cold boot to get the drive to appear. The details are very fuzzy, it was one of those 3 A.M. panicked, gotta get this fixed, sessions.

So windows was not even involved as I was booting from a CD.

Gary

 

My usb hard disk is not recognized if left pluged in during a reboot. Once unplugged and replugged it works fine.

I believe the problem is that Windows (or the driver) sends a shut down command to the hard disk. The hard disk is then shut down but still plugged in. Then there is no command to start the disk again so the disk remains plugged in. Once the power is cut and reapplied during replugging the issue is fixed. This only happens since on reboot on my HP laptop the power to usb devices is never cut. On a Macbook Pro it is cut for a second and then reapplied. After a shutdown the power is cut so there is no problem with a cold boot.

Maybe there are other internal devices that have to same problem?

 

theoretically, the os could boot faster in a reboot than a cold boot as it knows hw doesn't change. so it doesn't have to detect everything if something changed.

but it doesn't. on the other hand, hw might not be completely reset, that's true. i see it on some usb devices.

 

For me the description is temperatures

Back in the day when we would overclock with dry ice or liquid nitrogen a cold start was when the cpu was so cold it would not boot, so we had to let it heat up some first thus a warm start.

P.S. CPU's that wont boot when too cold actually have a term called "cold bug" associated with them.

 

Hmm, this might get us somewhere. There is no virus, of any kind, on this machine, but I know that there's issues with the BIOS on the M4500 that Dell still hasn't managed to get resolved, so maybe there's the problem.

Still, the observations are strange: If I restart the computer right after installing MSE, Windows goes into emergency repair mode, claiming that two files are corrupt or missing: It says Windows\system32\drivers\ndis.sys is corrupt, and NETIO.sys (in the root of the system drive) is missing. Now, first of all, I don't think NETIO.sys should even exist in that location, at least I have never seen it there on a live system. Second, Windows then tries to repair the issues, but fails. If I cancel out of the screen telling me this, and restart again, the same problem comes up again, and the problem remains no matter how often I try a restart. However, if I perform a shutdown and then power on again, everything is fine. The same is true if I install MSE, and then perform a shutdown rather than a restart. If I power on after that, Windows finishes its reconfiguration as programmed by the MSE installer, and boots normally.

 

i installed MSE (the new one) on some machines recently, and did not do any cold start on any of those. never had this issue. it's strange for sure

 

Oh yes, I installed it on a couple other machines, too, without any issues.

 

it at least looks like netio.sys is network related. so maybe the network card failed on reboots, and needed a hard reset?