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80

Ctrl-Q is indeed the answer. I thought I'd toss in a little history of this that is too long to fit in the margins of ak2's correct answer. Back in the dark ages, a terminal was a large piece of equipment that connected to a remote device (originally another terminal because teletypes were so much easier to learn to operate than a telegraph key) over a long ...


11

A better solution than turning off swap, which will at best cause random processes to be killed when memory runs low, is to set the per process data segment limit for processes that pull stuff off the net. This way a runaway browser will hit the limit and die, rather than cause the whole system to become unusable. Example, from the shell (ulimit -d ...


10

The pipe symbol is sending the ouput of nano to the input of the uniq command. However, nano is still running and receiving your keyboard input. It's just that you can't see its ouput as uniq won't ouput it's results until it sees an End-Of-File (this isn't important to the question). When you press ctrl-c it is 'caught' by nano, but it does not cause it ...


10

Are you using a 64-bit version of Linux with a lot of memory? In that case the problem could be that Linux can locks for minutes on big writes on slow devices like for example SD cards or USB sticks. It's a known bug that should be fixed in newer kernels. See http://lwn.net/Articles/572911/ Workaround: as root issue: echo $((16*1024*1024)) > ...


8

If the screen and input devices (keyboard and mouse or trackpad) froze, the first place to start by looking would be in /var/log/Xorg.0.log (assuming that Xorg is running on the first display server). If that doesn't yield any immediate clues, the next logs to check would be /var/log/messages.log and /var/log/dmesg.log. If you are unable to find anything ...


8

Disabling swap won't do what you want. You will still get violent I/O throughput, but it will be of clean pages rather than dirty ones. With no swap, the system will compress the cache of clean (unmodified) pages to near zero, because those are the only pages it can evict from physical memory. It can only evict dirty (modified) pages from memory by writing ...


5

To make this change pervasive you'll need to add these limits to the entire environment. Changes using the ulimit command are only to the current environment. NOTE: This will have no effect on the root user! Example Edit this file: vi /etc/security/limits.conf and add entries to the file limiting the number of processes (nproc) that a specific user or ...


5

The superuser or any process with the CAP_SYS_ADMIN or CAP_SYS_RESOURCE capabilities are not affected by that limitation, that's not something that can be changed. root can always fork processes. If some software is not trusted, it should not run as root anyway.


5

They are probably very related. STOP USING THAT COMPUTER UNTIL YOU FIX THE FAN It can only take milliseconds for the CPU to go from "OK" to "OMG I melted". They should never be used with out proper cooling. To do so, will cause damage, and could cause a fire, injury, and all manor of bad things. That warning aside Linux and most semi-modern computers ...


3

Disable all your browser plugins, and add-ons, and extensions. Then surf the web for a while. Try to note which site is open when your computer freezes. See if your can reliably replicate the issue. Gradually enable your plugins and addons. Note which one is enabled last before the system starts freezing again. My money's on Flash or Java.


3

There are the so-called "Magic SysRq keys" -- a set of keypresses that can be embedded at kernel level and will be honored as long as both the kernel process and the keyboard interrupt are still being listened to, and can be called by alt-SysRq-keypress. These can perform various emergency tasks such as an emergency S ync of all mounted filesystems, k I ...


3

You are presumably using the i915 driver for the integrated video, and I bet it has something to do with this bug: https://bugzilla.kernel.org/show_bug.cgi?id=58381 Since the "freezing" is a kernel panic. Try: grep i915_hangcheck_hung /var/log/* And see what turns up. You might try turning off "use hardware acceleration when available" in chrome ...


3

For some weird reason, cpio doesn't like to take a file argument. Instead, you have to pipe the archive into cpio. An inexperienced user would do the following: cat initramfs-linux.img | cpio -i However, this would get you the Useless Use of cat Award. A better way would be: cpio -i < initramfs-linux.img This uses the shell's built-in redirection ...


2

To me this sounds like the system is out of resources so the process needed by the server side of ssh cannot be allocated. The actual bottleneck can vary - out of processes or out of memory - and the only way to be sure is to look at the logs and console to see if anything is present there. You may want to set up a scenario of pre-started ssh-jobs - one to ...


2

I will bet dollars to donuts that you are running out of memory. The system is grinding to a halt as it tries to figure out where to get some from. It may be happening so quickly that your monitoring doesn't catch it. I'd step up monitoring, including remote logging of memory usage. Check in the logs for OOM messages as well. (You may even just want to have ...


2

It sounds like your kernel panicked in some way such that sshd couldn't send the server keys. Possibly, the kernel was wedged in such a way that the network stack was still up, but the vfs layer was unavailable. When I experienced similar problems on a RHEL4 system, I set up the netdump and netconsole services, and a dedicated netdump and syslog server to ...


2

To make sure that swap is not used, you'd be better off preventing any swap being added at boot. This can be done, depending on the system, by disabling the swap boot service or just commenting out the swap entry in /etc/fstab. As far as your hangup is concerned, the stop() function in /etc/init.d/swap might give a clue: stop() { ebegin ...


2

Maverick was particularly prone to graphics freezes with the standard Open-Source nouveau drivers. You can uplift you X-System using the X-Updates PPA sudo add-apt-repository ppa:ubuntu-x-swat/x-updates sudo apt-get update && sudo apt-get upgrade You can then install the latest NVIDIA drivers. As you have noted, the Open-Source drivers still ...


2

Removing a file or directory is an atomic operation requiring one system call, so if the rm command hangs, it's because the kernel is stuck. On an NFS filesystem, this can be (and usually is) due to the server not responding. On a local filesystem, this can be (and usually is) due to a hardware failure. Your disk is probably failing; the kernel logs would ...


2

The natural state of things is that application data is in RAM, and files are on disk. The ideal state of things, performance wise, is that data in frequent use is in RAM, and data that isn't needed at the moment is on disk. On a normal system, the kernel does two things to attempt to reach this ideal: Application data that has not been used for a while ...


2

Test the partitions with a livecd of some distro more updated. Mount the partition, write a lot of files and check the dmesg. The kernel of Debian Stable is old and if your problem is a kernel bug, probably is solved. You also can try with other schedulers. Add "elevator=noop" or "elevator=deadline" to your grub. Sometimes, other schedulers can help with ...


2

Yes , the easiest way to archieve this , is enable the keys to kill Xorg server , and re-launch X session. To enable this , open System Settings -> Keyboard Layout options (or use keyboard command in Unity interface , hit ALT + F2) , and check this option: Control + Alt + Backspace So when it hangs , hit CTRL + ALT + Backspace will kill X server , and ...


2

If you want a way to reboot, without saving open documents, but without hitting the reset button, then there are ways that are less likely to cause data loss. First, try Ctrl+Alt+F1. That should bring you to a virtual console, as ixtmixilix said. Once you're in a virtual console, Ctrl+Alt+Delete will shut down and reboot the machine. If that technique ...


2

Strike Ctrl+X. Nano captures all keyboard input and inside Nano Ctrl+C has an entirely different meaning than in the shell. If you run a nano in a separate window, you can easily see what keys you have to enter to exit. Ctrl+X


2

The shell doesn't receive you Ctrl+C, nano does. Programs are able to define custom behavior for interrupt signals and nano is one such program. To see what the custom behavior is open nano without the redirection and send it a Ctrl+C.


2

As other answers have already explained, Ctrl+C doesn't kill Nano because the input of nano is still coming from the terminal, and the terminal is still nano's controlling terminal, so Nano is putting the terminal in raw mode where control characters such as Ctrl+C are transmitted to the program and not intercepted by the terminal to generate signals. When ...


2

To help debug, you can try reading the raw mouse events from /dev/input/mice. This python script, from johnroach.info, can help interpret the raw data. I've modified it slightly below: #!/usr/bin/python mouse = file('/dev/input/mice') while True: status, dx, dy = tuple(ord(c) for c in mouse.read(3)) def to_signed(n): return n - ...


2

I had also some trouble with my Nvidia Card at boot up and occasionnal freeze. What i've done was to add 'nomodeset' to the grub boot option. You should try it... if it solve the problem you can make the change permanent : Edit /etc/default/grub sudo nano /etc/default/grub Find this line : GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" Add the 'nomodeset' ...


1

Finally I got into something. I'm not 100% sure, but it seems, that it is a nasty malfunction in Intel GMA HD3000 integrated graphic card. The problem can be triggered, when using 3D-capabilities for long time. The not-Poisson failure rate is explained by the fact that sometimes I was using compositing, and sometimes not. I just failed to correlate ...


1

The kernel probably did log some information, but they never made it on time to the disk. If your laptop has got a serial port, set the kernel to use it as console (add console=ttyS[X] as boot option); you will see the messages there from another machine as it happens. If not, you can use an Ethernet port and try netconsole. In general, you have a problem ...



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