Wikipedia:Reference desk/Archives/Computing/2014 June 23

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June 23

Do I need to restart PC if I Hibernate?

If I understand correctly, Windows PCs need regular restarting to counter against memory leak. If I Hibernate after every time I use my Windows 8.1 laptop, will I still need to restart the laptop occasionally? Does Hibernating and then turning on the laptop again equal a restart? Thanks Acceptable (talk) 03:51, 23 June 2014 (UTC)

Well the short answer is no, a hibernate is not a restart, or else, what would be the point of making the distinction? Theoretically, hibernation saves the RAM state to disk and re-loads the SAME memory state back into RAM when the computer is resumed, so theoretically any memory leak would also be loaded back into RAM. Whether that actually happens in PRACTICE, or whether there are "smarts" to prevent that from happening, I'm not sure, the answer is quite possibly: "sometimes". Vespine (talk) 04:15, 23 June 2014 (UTC)

Since no memory leakage occurs during hibernation, so it can delay how often you will need to reboot, but not prevent it. StuRat (talk) 04:21, 23 June 2014 (UTC)

Know what a PC/Computer is. A computer consists of CPU(s), Memory, Long Term Storage(aka harddisk), Communication Interface, Input devices and Output devices. That's it.

When a Computer sleeps, everything shuts down with the exception of Memory. Now ask yourself this. Can the Memory be corrupted? If the computer is a laptop then it has its own battery which will keep the Memory alive. But if the computer is a desktop (and it is not connected to a UPS) then the only thing keeping the Memory alive is the main electrical supply. If there are any brownouts, even a short one, the memory is likely to be corrupted. This will result in the failure in the Integrity of the computer system. That is why you need to restart your desktop computer regularly. 202.177.218.59 (talk) 05:21, 23 June 2014 (UTC)

Sorry, IP, but that's not the true issue here. If the data in the RAM are physically corrupted, nothing is safe. Computers with that kind of problem usually don't work at all, or bomb out once the RAM fills up beyond the corrupted spot.

Some programs can leave RAM areas which look "used" but are not; the program never returned them to the OS and so they count as still in use even if the program has forgotten about them. Windows has many hiding places, like shared DLLs and services, which usually don't terminate while the PC is running.

OTOH, when an application terminates, the OS reclaims all RAM that was used by it, and can redistribute it to other processes (i.e. to applications, services, etc) when they need more.

The DLL distinction is a bit tricky. One way to use a DLL by many processes separately is to pretend that every process is its only user. However, this is not always desired; there is a need for "uniqueness" sometimes, where all uses of the DLL must be synchronized. This requires shared data, which can accumulate until all users of that DLL terminate (or explicitly state that they aren't going to use the DLL any more). Now, if one of these users (i.e. a process) just doesn't terminate, the OS (Windows) cannot safely reclaim the RAM occupied by the DLL; after all, that process could (from the OS point of view) continue using the DLL at any time. One method to terminate all the processes is to restart the PC, or in some less severe cases, to log out and back in. - ¡Ouch! (^{hurt me} / _{more pain}) 07:06, 23 June 2014 (UTC)

If you have a memory leak problem, rebooting probably will help (temporarily) and hibernation probably won't. But you shouldn't have a memory leak problem. Plenty of Windows machines (servers) go months or years between reboots. -- BenRG (talk) 18:29, 23 June 2014 (UTC)

Don't you have to reboot after updating the system? Have the machines not being updated in such a long time?OsmanRF34 (talk) 20:09, 23 June 2014 (UTC)

They are hot patched. Windows has supported this for years, but consumer security updates normally don't use it; I don't know why. -- BenRG (talk) 17:54, 24 June 2014 (UTC)

Every Windows computer I've had (6, as of now) has required periodic reboots. Maybe if you used the Windows computer right out of the box, and never downloaded or installed anything, you might have one you would never need to reboot, but that would make it pretty much useless, too. And I'm not even confident that all of Window's own software is free of memory leaks. StuRat (talk) 23:03, 23 June 2014 (UTC)

I wonder if anyone can find reliable statistics on how often iPads get rebooted. I suspect they average an uptime of approximately forever, but I'd love to see reliable third-party statistics. Nimur (talk) 04:24, 24 June 2014 (UTC)

See above. -- BenRG (talk) 17:54, 24 June 2014 (UTC)

How often should I reboot a modern Windows 7 or Windows 8.1 machine? How often do OSX machines need to be rebooted? How often do Linux machines need to be rebooted? Acceptable (talk) 14:34, 24 June 2014 (UTC)

It depends on the components and age of your computer. If you have something like 2GB of RAM, your machine will become sluggish quickly, and you will likely have to reboot more often than if you have something like 32GB. -- 140.202.10.134 (talk) 16:17, 24 June 2014 (UTC)

I would consider the quality of the software and drivers on the system to be the biggest factor, although if there is a memory leak then more RAM will delay the problem. I've developed Windows 7 based images that run industrial systems and I know we have customers that have had them running for a few years with no reboots. I also have coworkers running engineering software that loads a driver (not sure why it needs it, but it does) that slowly leaks memory forcing them to reboot every few days. My own Windows PCs reboot about once a month, but that's just because of Windows Update, not because of any performance or resource issue. Katie R (talk) 19:47, 24 June 2014 (UTC)

Reboot if it locks up or starts acting flaky. A reboot often fixes it and is the first thing to try. Bubba73 ^{You talkin' to me?} 01:46, 25 June 2014 (UTC)

Thanks for the responses everyone. So with a, for example, Dell Latitude or XPS laptop running Win7/8.1 with 4 or 8 GB of RAM, I don't need to reboot it every day right? For some reason, I got the idea of needing daily reboots in my head. Acceptable (talk) 16:10, 25 June 2014 (UTC)

The old laptop on which I am typing this comment has only 1GB of RAM and runs Vista on a Centrino processor. It manages up to half a dozen simultaneous applications with regular sleep and hibernation, but is never turned off. It runs happily for more than a month without rebooting because Vista updates are now rare. Dbfirs 18:32, 25 June 2014 (UTC)

Tap water on laptop keyboard

I spilled about 1 ounce of tap water on my laptop keyboard (which is theoretically spill-resistant). Turned the laptop off and waited 2 days. When I turned it on, some selected keys were not working. Is something that can be done to repair this? Might cleaning it with WD-40 be a solution? Or is the only solution to replace the keyboard? I suppose that the mainboard was not affected, since everything else is working well and a normal keyboard that I connected through USB works flawlessly. OsmanRF34 (talk) 15:01, 23 June 2014 (UTC)

It really depends on the laptop, and what is causing the non-responsiveness. But the cheapest thing to try would be to take off each key and re-seat it, so that you can make sure the connections are being made. My Apple laptops have keys that can be individually popped off so that you can clean underneath. For any model though, you have to be careful not to break the little plastic scissor spring things. I recommend googling for /[laptop make/model] key replacement/ or /[...] stuck key/. With a little luck, there might even be a nice youtube video showing the angles to pry from. SemanticMantis (talk) 17:10, 23 June 2014 (UTC)

Tried it, didn't work. OsmanRF34 (talk) 21:25, 23 June 2014 (UTC)

Did you notice any obvious water damage under the keys? WD-40 is the wrong cleaner to use if you found something to clean - you can buy "contact cleaner" specifically designed for removing corrosion and other deposits from electrical contacts. It comes in a spray can, but you probably want to use a cotton swab or toothbrush to do the cleaning on something like a laptop keyboard. Replacement keyboards are also surprisingly cheap for some models - I replaced a laptop keyboard for $15 after some spill damage. Katie R (talk) 11:40, 24 June 2014 (UTC)

No obvious water damage could be seen. The replacement tip is good. I didn't know it was so cheap to replace. Probably will do that, if the main keyboard doesn't come to life alone.OsmanRF34 (talk)

I did that recently with a cheapo laptop I bought to see if my habit of only buying what my research says are great quality products is really necessary. I thought it would be fine once it had time to dry out but that spill made the entire keyboard stop working. I returned it because the laptop was 1 star terrible and there was really nothing else to do. My advice is to use the temporary keyboard and try the original keyboard every few days, maybe it'll work eventually. — Preceding unsigned comment added by 2602:306:8051:4D60:75DB:AD14:BC7F:8F6 (talk) 22:33, 23 June 2014 (UTC)

Which keys don't work ? If they are keys you don't really need, I'd be tempted to continue using that keyboard. You might also be able to remap some keys. But if keys you use all the time are affected, then I'd keep the external keyboard attached. It's probably a lot easier to use than the micro keyboards most laptops have anyway. Yes, it's a bit less portable, but I'd be willing to accept that. I'd just stuff the keyboard in a bag with the laptop and call it good enough. From my own experience, once you or a repair tech takes a laptop apart, you are just as likely to break something else. They are extremely fragile. StuRat (talk) 22:54, 23 June 2014 (UTC)

yuiop and enter. I suppose the water damaged the connector of such keys. The replacement of the keyboard for $15 seems like a good idea. OsmanRF34 (talk) 12:52, 24 June 2014 (UTC)

Impact of computing power

There is a discussion at the Science reference desk on the impact of increasingly powerful computers on science that might be of interest. Robert McClenon (talk) 23:54, 23 June 2014 (UTC)