freeze interview questions

Top freeze frequently asked interview questions

Why do damaged hard drives freeze the entire system?

Why does a hard drive which is known to have bad blocks (verified in HDTune and HDDScan), freezes down my entire system?

It is not the OS drive; it is attached to another SATA port, and I'm trying to copy files from it to another healthy drive.

I have experienced this issue with almost every damaged hard drive and every Windows PC.

I would expect to see freezing only for the program I'm using to copy the files (Windows Explorer, etc.), but instead my entire PC gets jerky, and I cannot browse web or watch movies while copying files from the damaged drive.

The long story.

I live in a rural area where there are problems with electricity (brownouts, etc.). I myself am using a UPS and my own hard drives are perfectly fine. But my neighbors often ask for help with their PC issues, and I often find that their hard drives are damaged, most probably because of electricity issues. Of course, after replacing the damaged drive I suggest my neighbors to buy an UPS.

I have always wondered, why my PC freezes entirely while retrieving data from damaged drives. Is it a hardware issue? Is it caused by the way OS reads data? Is it something Windows-specific, and I won't experience it on *nix?

Anyway, from now on I will use some dedicated software (such as Roadkil's Unstoppable Copier) instead of Windows Explorer, although I'm not sure if this will work differently, without freezing entire PC.

It is not a request for help, it is more for educational purposes, so I know why the things work that way.

Source: (StackOverflow)

How do I troubleshoot a Windows 7 freeze or slowness? [duplicate]

Possible Duplicate:
What are the first steps for diagnosing a slow machine?

I have a new pc with windows 7 which freezes randomly. I hit every single key on the keyboard and it works again. Is there a way to prevent windows 7 from freezing?

Source: (StackOverflow)

Hung process in Windows: Is there any way to see why?

I tried to print a doc in word, and word froze. Is there any way for me to see what resource it's waiting for?

I'm using windows XP and word 2007 (though I imagine the answer doesn't depend on the process that froze)

Source: (StackOverflow)

How to kill tasks in Windows 7 when even Task Manager won't open or respond?

Occasionally one of my computers will get so bogged down that everything locks up, Ctrl+Alt+Del doesn't work, Task Manager won't open, or they work, but are opening so slowly that it will take hours or days to shut down other processes and regain control of the computer, etc.

Is there a way to, for instance, force Task Manager to be highest priority so it always opens immediately with Ctrl+Shift+Esc even when some other process/driver is hogging the CPU? Is there some other program that can run in the background and open immediately like this?

This question isn't about fixing "underlying problems". No matter how much memory you have, it's still possible for a rogue process to eat it all up and lock up the computer in page fault thrashing, hog the CPU, etc. This question is about how to take back control of the computer when that happens.

Basically when these kind of lock-ups happen, I want to open some kind of task manager that pauses every other process and allows me to kill one of them, and then let everything resume so I can save my work, etc. Otherwise my only option is to hold down the power button.

Antifreeze is supposed to do exactly what i want, pausing all other applications and starting a task manager to kill the offender, but in my testing, it actually does neither.

Source: (StackOverflow)

How do I quickly stop a process that is causing thrashing (due to excess memory allocation)?

We've all experienced it--some program is asked to do something that requires a huge amount of memory. It dutifully tries to allocate all this memory, and the system immediately begins thrashing, swapping endlessly and becoming sluggish or non-responsive.

I most recently experienced this on my Ubuntu laptop due to a Matlab script trying to allocate a ridiculously huge matrix. After ~5+ minutes of thrashing, I was able to Ctrl-F1 to a console and kill Matlab. I would much rather have some hot-key that would have given me control of the system immediately and allowed me to kill the offending process; or, perhaps, simply silently refuse to allocate such a large buffer.

  1. What is the quickest way to regain control of a Linux system that has become nonresponsive or extremely sluggish due to excessive swapping?

  2. Is there an effective way to prevent such swapping from occurring in the first place, for instance by limiting the amount of memory a process is allowed to try to allocate?

Source: (StackOverflow)

Interrupting the "Spinning Wheel of Death"?

I am running Snow Leopard. It is up to date. Every few days, I get the "Spinning Wheel of Death."

  • I can't do anything except hold down the power button to shut off my MacBook Pro.
  • I've even tried a kill -9 -1 from a root shell that was already opened. It just hangs.
  • The Spin Control app just says "Sampling" on a few of the apps but is unresponsive.

Do I have any other options to shut down my laptop? I don't like to just power it off.

Update: I have no idea which app is doing this. At the moment it appears random. My fan does not spin up. Maybe it's a networking thing?

Update: Dead again. This time I had X11 running and no matter what app I switched to, I got that app's menu bar and the X11 screen. I ping and the Internet doesn't respond. My Apple router is working because I'm streaming Pandora over WiFi. I turn off the wifi and I'm still screwed. I try to power off and it won't shutdowm because X11 is running. If course, I can't kill it. Press and hold... boom. This is not how an OS is supposed to work!

Source: (StackOverflow)

Windows 7 running slowly with low CPU usage and memory

I have a relatively new (under 2 yrs old) Windows 7 machine. It has 9GB of RAM, and an i7 core CPU (930 @ 2.8GHz w/ 8 CPUs). After about 8 months since a clean install, I noticed my computer was running slowly. I figure it was fragmentation etc, and I did a complete wipe & clean reinstall.

However, my problems are somehow persisting. The computer is running painfully slowly (but in leaps and bounds - sometimes it will work fine for 3 hrs, then suddenly freeze up just from clicking the start button). The 'freezes' happen randomly - not during any especially intensive computing. I initially thought something might be eating through my CPU and/or Memory, but Task Manager indicates that neither the CPU or Memory spike. In fact, even during serious lag, CPU usage remains at less than 5% and Memory at ~ 1.5GB.

It's beyond me why a fresh install on a powerful machine is performing so poorly. And it certainly is frustrating! What could be causing the poor performance, and what can I do to fix it?

Source: (StackOverflow)

increase desktop responsiveness on linux while swapping

All GNU/Linux distributions I tested so far have the problem that whenever the ram gets filled and the system begins swapping, the whole desktop and graphical user interface becomes unresponsive as hell to an extent that sometimes I have to wait about 5-10 seconds after having moved the physical mouse until the mouse pointer is actually moving.

This is kind of an annoying behaviour, especially on systems with low ram.

Is there any way to give some applications/jobs, like the desktop environment etc., a higher priority to stay in ram than other applications, so that the application actually hogging all the memory gets swapped before the desktop environment etc.?

EDIT: I'm talking of the case when the entire RAM is used so it will always start swapping if it isn't disabled (I don't want processes to be killed randomly). I had this problem not only in low ram environments, but as well with 8GiB of ram on my desktop machine, partly due to many VMs partly because of memory leakage. ZRAM isn't a solution either as it's only delaying the problem. The only solution I can think of for this problem is some userspace utility or kernel API that allows to prevent certain jobs to be swapped at all or at least make it very unlikely. Does anybody know another solution or knows anything about such a tool or API in existence or being planned?

2nd EDIT: ulatencyd doesn't seem to work with newer versions of systemd, according to and . This may be because systemd took over full control of cgroups from a userspace perspective if I understand it correctly.

Source: (StackOverflow)

Why does my Windows 7 PC / SSD drive keep freezing?

I have a ~1 yr old PC with a primary SSD hard drive. I notice quite often that the PC will freeze for 30secs to several minutes, displaying the "Spinning blue wheel" mouse icon during this period. It then releases and returns to normal.

When I look at the Resource Monitor during this period, I notice that the disk activity is always at "100% Highest Active Time" solidly for this period. But the actual amount of disk activity doesn't look that high to me (<1Mb per second). Memory and CPU are never remotely stressed.

Usually the anti-virus software (Kaspersky anti-virus is the most active user of disk activity, but that doesn't seem so unusual to me. I'm typically not stressing my PC too much during these periods, just a bit of light web surfing etc.

My guess is that it is a problem with the drive, but I'm not sure what to do next (other than buy a new one).

Any ideas?


Source: (StackOverflow)

Why does Windows 7 mouse freeze after resuming from sleep?

A similar question previously posted at Super User is Why Does My Windows 7 PC Freeze After Waking from Sleep?, but none of the previous answers intially appeared to solve my problem or were the same as my initial answer.

On one of my Windows 7 machines, the mouse would be permanently frozen after the machine woke up from sleep. The mouse would not move though the cursor was displayed. I had no option but to power down the machine and reboot.

This happened often, though not always. If the machine had only been sleeping a few minutes, I could wake it up and use the mouse. If the machine had been sleeping an hour or so, then the mouse would be permanently frozen when the machine woke up.

Source: (StackOverflow)

How to diagnose repeated freezing of windows 7 (comes back alive in few seconds)

I installed Windows 7 in a 3 year old machine, it installed successfully, took all drivers and running great, but what happens is every 5-6 minutes it freezes for few seconds... 30 seconds to 1 minute and then comes back alive.

I checked Event Viewer, nothing matching the frozen timeline.

I would appriciate any help on how to detect causing service/hardware.

After it comes alive, everything runs normal, I did run task manager and checked cpu usage, at time it freezes just before and after that no task took more cpu or memory, it was like idle machine.

No external usb drives or no devices, on board intel desktop board with SATA HDD, SATA hdd running in absolute good mode.

Source: (StackOverflow)

Perf samples too long, lowering kernel.perf_event_max_sample rate to

My machine freezes from time to time and I can get it back to working normally by pressing the space key.

I've been having this problem for two weeks now, but it was just once per day max. Now it's starting to be many per hour, until the point where the computer freezes and I'm not able to get it back.

I first thought it was the RAM, so I did a MemTest86+. The first try froze at 51 seconds. I decided to remove one of my 4 RAM and do the test again.

It ran for 40 minutes, did a full test suite without any problem. So I decided to boot my computer with the "default" RAM not plugged in.

The computer ran for 5 minutes and started freezing again.

I went to see the logs in dmesg and found a line containing:

Perf samples too long, lowering kernel.perf_event_max_sample rate to ...

Pressing escape worked, and I was able to work for a few minutes, and then another freeze, and a new line in dmesg (with the rate lowered from 25.000 to 13.000, then 7.000, 4.000 and 2.000).

At 2.000, the computer frozen one last time, and I had to force a reboot.

So it appears that either MemTest didn't find the problem or it's not related to my RAM.

Either way I don't know what to do or what to check (and with what tool). So far, I removed all the RAM except one (random) and I didn't had any freezes (which is good, I don't want to re-write this question ;)).

Here's my computers specs:

AMD Phenom(tm) II X6 1055T Processor 4 * 2048 RAM (GSkill DD3-1600 PC3 12800) One SSD for the OS Two RAID -1 for the data

I'm running Fedora 20 x64

Here's my uname -a :

Linux localhost.localdomain 3.14.4-200.fc20.x86_64 #1 SMP Tue May 13 13:51:08 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

Thank you for your help!

Note: The last time it froze, I was watching a Youtube video. But before that, it froze when I was working (coding).

Update 1 : I decided to remove all the RAM except one. The computer worked correctly for about 15 hours and then crashed. I was downloading a heavy file (380Mo) at the time. I'm starting to think it's related to disks.

Final Update : I finally located the problem to be the motherboard. I bought a new one and replaced it a month ago and since then, I didn't had any crash or odd behavior from my computer. I believe the issue is now fixed.

Source: (StackOverflow)

Can a process be frozen temporarily in linux?

I was wondering if there is a way to freeze any process for a certain amount of time?

What I mean is that: is it possible for one application (probably running as root) to pause the execution of another already running process (any process, both GUI and command line) and then resume it later? In other words I don't want certain processes to be scheduled by the linux scheduler for a certain amount of time.

Source: (StackOverflow)

My computer freezes irregularly

My computer started to freeze at irregular times for 3 weeks now.

Please note that this question change with each things that i try. (For additional details)

What happens

  • My computer freezes, the video stops. (No graphic glitches, it just stops)
  • Sounds stops too.
  • Sometimes, randomly, the screen on my G-15 keyboard flickers and I see characters not at the right places. Usually happens for about 1-2 seconds and a bit before my computer freezes.
  • I have to keep the power button pressed for 4 seconds to shut my computer down.
  • I still hear my hard drives and fans working.
  • Sometimes it works with no problems for a full day, some other times it just keeps freezing each time I restart my computer and I have to leave it for the rest of the day.
  • Sometimes my mouse freezes for a fraction of a second (Like 0.01 to 0.2 seconds) quite randomly, usually before it freezes.
  • No errors spotted by the "Action center" unlike when I had problems with my last video card on this system (Driver errors).
  • My G-15 LCD screen also freezes.
  • Sometimes my G-15 LCD screen flickers and characters gets carried around temporary under heavy load.
  • Now, most of the times, the BIOS hard disks boot order gets reversed for some reason and I have to put it to the right one and save each times I boot. (Might be unrelated, not sure, but it first started yesterday)

What I did so far

  • I have had similar problems in the past and I had changed my hard drive (It was faulty), so I tested my software RAID-0 array and it was faulty so I changed it. (I reinstalled Windows 7 with this part). I also tested with unplugging my secondary hard drive.
  • My CPU was running at about 100 degree Celsius, I removed the dust between the fans and the heat sink and it's now between 45-55.
  • I ran a CPU stress-test and it didn't froze during the tests (using Prime95 on all cores)
  • Ran a memory test (using memtest86+) for a single pass and there were no errors.
  • Ran a GPU stress test with ati-tools and furmark and it didn't froze during the tests. (No artefacts either)
  • I had troubles with my graphic card when I got it, but I think that it got fixed with a driver update.
  • I checked the voltages in my BIOS setup and they all seemed ok (±0.2 I think).
  • I have run on the computer without problems with Fedora 15 on an external hard drive (apart that it couldn't load Gnome 3 and was reverting to Gnome 2, didn't want to install drivers since I use it on multiple computers) I used it to back up my files from the raid array to my 1TB hard drive for the reinstallation of Windows. (So the crashes only happened on Windows) [The external hard drive is plugged directly on a SATA port]
  • I contacted EVGA (My graphic card vendor) and pointed them on this question, I'm looking for an answer.
  • Ran sensors on Fedora 15 and got this output:
  • Ran 6 short different CPU stress test on Fedora 15 (Haven't found any complete stress testers for Linux) and it didn't crash.
  • Changed the thermal paste to some Artic Silver 5 for my CPU and stress tested the CPU, temperature was at 50 idle, then 64 highest and slowly went down to 62 during the test.
  • Ran some stress testing with a temporary graphic card and it went ok.
  • Ran furmark stress test with my original graphic card and it froze again. GPU had a temp of 74C, a CPU temp of 58C and a mobo temp of 40C or 45C (Dunno which one it is from SpeedFan).
  • Ran a furmark stress test and a CPU stress test at the same time, results:
  • I have been using my computer without stressing it for about 2 hours now and no crashes yet. I also have disabled the AMD Cool'n'quiet function on the BIOS for a more regular power to the CPU. When I ran Furmark without C'n'q my computer didn't freeze but I had a "Driver Kernel Error" that have recovered (And Furmark crashed) all that while running a CPU stress test. The computer eventually froze without me being at it, but this time my screen just went on sleep and I couldn't wake it.
  • Using the stability tester in nTune my computer froze again (In the same manner as before). I noticed that Speedfan gives me a -12V of -16.97V and a -5V of -8.78V.
  • I have swapped my G-15 with another basic USB keyboard (HP) and I have run furmark for about 10 minutes with a CPU stability test running each 60 seconds for 30 seconds and my computer haven't crashed yet.
  • Ran some more extended tests without my G-15 and it freeze like it usually do.
  • Removed the nForce Hard disk controller.
  • Disabled command queuing in the NVIDIA nForce SATA Controller for both port 0 and port 1 (Errors from the logs)
  • Used CPUID HwMonitor, here are the voltages:
  • Changed some configurations in the motherboard BIOS: Disabled PEG Link Mode, Changed AI Tuning to Standard, Disabled the 1394 Controller, Disabled HD Audio, Disabled JMicron RAID controller and Disabled SATA Raid.
  • "A little hope", my computer frozen while watching a youtube video, but not from GPU and CPU 10 hours straight test.
  • I have put my BIOS back to defaults and: Disabled PEG Link Mode, Disabled HD Audio, Disabled JMicron RAID Controler, Disabled Serial Port Address, Disabled Parallel Port Address and Disabled Onboard 1394 Controller.
  • I changed the SATA cable for the 750GB hard drive and I also changed the slots at which they were plugged (1->2, 2->3, 3->4).
  • Changed the power saving feature of my graphic card from "Adaptive" to "Maximum performance".
  • Ran ECGA OC Scanner and got no freeze and no artifacts
  • I installed the Logitech drivers for my G-15 keyboard and my G-500 mouse and it restarted to freeze.
  • I removed the Logitech drivers for my G-15 keyboard and my G-500 mouse and it still freeze.
  • After changing everything except the hard drives, graphic card and power supply my computer is running very fine and I haven't run into any problems (This is with the exact same install of Windows that I had problems with my old motherboard). After removing my motherboard I have found some cambered capacitors (2) which might be the source of the problems. Since it almost clearly was a motherboard problem caused by these capacitors I am going to accept the answer that is the most related to this solution.

When it happens

  • When I play video games (Mostly)
  • When I play flash games (Second most)
  • When I'm looking at my desktop background (It rarely happens when I have a window open, but it does, sometimes)
  • When my Graphic card and my CPU are stressed.
  • Sometimes when my Graphic card is stressed.
  • Sometimes when my CPU is stressed.


  • Windows Seven x64 Home Premium
  • Motherboard: M2N-SLI Deluxe
  • Graphic card: EVGA GTX 570 (The non-oc one) [nVidia driver version 275.33 from EVGA's website]
  • CPU: AMD Phenom 9950 x2 @ 2.6GHz
  • Memory: Kingston 4x2GB Dual Channel (Pretty basic memory sticks)
  • Hard drives: Was 2x250GB (Western digital caviar) in raid-0 + 1TB (WD caviar black), I replaced the raid array with a 750GB (WD caviar black) [Yes I removed the array from the raid configurations]
  • 750W Power supply
  • No overclocking. Ever.
  • There have been some power-downs like 4-5 weeks ago, but the problem didn't start immediately after. (I wasn't home, so my computer got shut-down)
  • Event logs (Warnings, errors and critical errors) for the last 24 hours:

I would like to thank everyone who have been participating, it's really nice to see that much people ready to help others. There was many great answers that might help other people with similar problems in the future (at least I hope so).

In this situation, how can I successfully pin-point the current hardware problem? (If it's a hardware problem)

Source: (StackOverflow)

How do I create a memory dump of my computer freeze or crash?

As a lot of us encounter freezes or crashes, I am wondering how do I manually initiate a computer to freeze in order to create a memory dump to view and diagnose any issues that may be involved with the crash?

I am looking on how to force the computer to crash instead of waiting for the computer to do it itself.

Source: (StackOverflow)