I started learning xv6 recently and was trying to implement a shutdown mechanism in xv6 and i was able to kill all the process running gracefully and wait for some of them to finish and then terminate them. But i am not able to close qemu from the shutdown process.
Could someone suggest how to close qemu from a a xv6 process?
I googled and found out someone used 'outb' and 'outw' commands but both of them don't work.
I don't know if I fully understood your question, but to close the xv6 process running with qemu I use the key combination CTRL + A--> C
It then should show you the (qemu) terminal line that you can close with the command "q".
I am running xv6 in ubuntu OS, for me to close qemu following command worked "control+a, release both keys and type x".
In QEMU, "exit the QEMU process" happens when the guest powers down the emulated hardware. So your guest OS 'shutdown' needs to work by doing the correct hardware operations to power down. (How that is done depends on what hardware QEMU is emulating -- for instance some Arm boards don't have any mechanism for software controlled powerdown at all. Check the documentation for the relevant hardware.)
Related
I recently started playing with an ESP8266 and wanted to try uploading to it using WSL. I found the Arduino-CLI command and followed some tutorials but couldn't figure out how to upload to the board. The command I tried running is arduino-cli upload -p /dev/ttyS5 --fqbn esp8266:esp8266:arduino-esp8266 Testing because I know that the board is an ESP8266 and the is connected to COM5 on the Windows Arduino app. The code compiles and attempts to connect to the board, but cannot get past that part.
This is the code I was trying to upload.
void setup() {
pinMode(0, OUTPUT);
}
void loop() {
digitalWrite(0, HIGH);
delay(1000);
digitalWrite(0, LOW);
delay(1000);
}
When I execute arduino-cli board list, it shows this.
Port Protocol Type Board Name FQBN Core
serial Unknown
I'm using Windows Terminal for Ubuntu 20.04 and just installed Arduino-CLI.
I also am not sure how to ask stuff cuz it's my first time using StackOverflow, so pls tell me if I'm doing something wrong :)
Edit: So it turns out that I was uploading using the wrong core. I ended up trying every single core listed by arduino-cli board listall esp8266 and it eventually worked with esp8266:esp8266:nodemcuv2 instead of esp8266:esp8266:arduino-esp8266.
Just educated guesses here from my understanding of WSL rather than Arduino.
I'm assuming that you are using WSL2, which doesn't have access to most Windows hardware, including the serial ports.
If that's the case, two options that you might try:
WSL1 does have some better direct hardware access, at the expense of some kernel compatibility (since it attempts to translate syscalls rather than virtualize them). You can try converting the distribution to WSL1 via:
wsl -l -v
# Confirm distribution name
wsl --set-version <distro_name> 1
You might want to back it up first with wsl --export <distro_name> backup.tar.
As mentioned in the comments, you should be able to use the Windows toolchain. You can even run this under WSL2, since Windows commands can be executed there through interop (and would have hardware access). Remember to use the full executable, like /mnt/c/arduino-cli/arduino-cli.exe. And also you'll need to convert any Linux/WSL paths to their Windows equivalent with wslpath.
I use remote shh interpreter in PyCharm regularly, using the configured deployment. I often run remote programs from PyCharm GUI (using F5 key), that takes hours to complete (e.g. training a deep net). This unfortunately means that any network outage causes running script to exit and I have to run the script over again. Is there a way to detach the running script so it keeps running? In the sense similar to what screen or nohup is doing? I know I can run it in screen manually via ssh, but it is a bit inconvenient.
Ok. I found out that this feature is not implemented yet. There is however a suggested workaround
I got a simple program written for freeRTOS (implements a timer).
I want to run this program in an empty virtual machine (VirtualBox, or QEMU, or something else).
I need to make a binary file that can run in and empty VM.
Any advice or direction of how can i do this?
I checked many stuff on freeRTOS homepage but couldn't find something useful.
For virtual box, you will need a binary of freeRTOS that is x86 or amd64 compatible. Check if this is of any benefit for you.
You can check this link, as I understand it's a simulator for freeRTOS which may enable you to test it without a virtual machine.
For QEMU, check this link
Emm..., if you need run just binary file without any OS started you can use qemu for that. Just pass your binary through option '-bios' into qemu. And after qemu will start it to run. Also use '-S -s' options in for enabling gdb server in qemu. After you can connect to qemu with gdb client and debug you binary step by step.
Ever since I have upgraded my laptop (Click here for hardware specs.) my screen usually freezes. Mostly in chrome or Firefox browser. I am pretty sure this is a Nvidia driver problem but I can't seem to find the solution. I am running a Nvidia Quadro K2100M.
I am currently running Nvidia 361.42. I have tried using open source Xorg server without any luck.
The only solution I have found so far is forcefully turning off the computer by holding down the power button.
Things that I have tried:
I got keyboard input
I cannot switch to another terminal to restart lightdm
This problem came to me occasionally, making me really annoyed.
As illustrated in many blogs, this may be caused by graphic driver problem. For me, my desktop has a NVIDIA video card, you can run lspci | grep VGA to see what type of your video type, in my case, it returned:
02:00.0 VGA compatible controller: NVIDIA Corporation G98 [GeForce 8400 GS Rev. 2] (rev a1)
I followed the instruction on jiakai zhang's blog to reinstall proper drivers for the desktop, hope this will help you.
The key steps in [1] are to reinstall the ubuntu desktop and nvidia drivier by:
$ sudo su
$ apt-get update
$ apt-get install --reinstall ubuntu-desktop
$ apt-get install unity
$ apt-get remove --purge nvidia*
$ reboot
$ sudo apt-get install nvidia-current
$ sudo reboot
Updating the grub settings worked for me! Do the following:
1. Open the GRUB configuration
sudo vi /etc/default/grub
2. Change the value of GRUB_CMDLINE_LINUX_DEFAULT from "quiet splash" to
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash intel_idle.max_cstate=1"
and save the file.
3. Update & Reboot
sudo update-grub
sudo reboot
More info:
This is a bug in the processor, known as the c-state bug. It causes total freezes when the CPU tries to enter an unsupported sleep state. It's a problem for many Bay Trail devices especially with newer (4.*) kernels. There is a simple workaround until it gets properly fixed upstream. You just need to pass a kernel boot parameter and the random freezing stops completely. The parameter may increase battery consumption slightly, but it will give you a usable system. You do this by editing the configuration file for GRUB as described above.
GRUB - boot loader package from the GNU Project, which provides a user the choice to boot one of multiple operating systems
installed on a computer or select a specific kernel configuration available on a particular operating system's partitions;
Intel Bay Trail - new Atom Processors from Intel. Atom is Intel's family of x86 and x86-64 processors that are optimized
for small computing devices, such as smartphones and mobile Internet devices;
C-States - used to optimize optimize or reduce power consumption in idle mode (i. e. when no code is executed) - (C0 to C8)
Reference: here.
I have since fixed this problem by re-installing Ubuntu 16.04 and not switching from the nouveau video driver. I also disable updates and everything been working good for about 2 months now.
Gaming is pretty good but I usually play steam games so doesn't push any kinda hard core graphics
Well, I had the same problem: My PC was freezing randomly. I tried Ubuntu 16, 17 and 18.04 and everything was the same. I tried several drivers and didn't get a solution. I tried several solutions that I found in the forums (including this) and got bad and harmful results.
My solution was: I stopped using the graphical nvidia card, removed it and now I'm using the integrated Intel HD graphics card (Intel® HD Graphics 530 card (Skylake GT2)) and all the problems were solved!
I fixed mine using a few commands from #Qoros solution above. i just ran apt-get update, apt-get install nvidia-current, and sudo reboot. cheers to #Qoros btw!
For me, none of the approaches described in rest of the answers worked.
I was opening multiple terminal tabs running some heavy processes and ubuntu used to freeze when I had 6-7 tabs. I tried monitoring the resources used while I was starting my processes in terminal tabs. You can do it by opening System Monitor app and going to Resources tab.
What I noticed is that when my RAM(8GB) and my swap space(1GB) were completely used up, ubuntu would freeze.
As a solution, I increased my swap space and made it 16GB. After this memory never gets used completely and ubuntu doesn't freeze.
https://askubuntu.com/questions/178712/how-to-increase-swap-space decsibes how to increase swap space.
I trying to write a small c program witch reads out an GPIO pin to shutdown the pi externally. The triggering of the signal is working well. The program is started by LXDE as autostart application. If the program detects the shutdown signal it's performing:
sync();
system("halt");
Why does this program damage my ext4 file system after a couple of reboots. There is no fixed number of reboots necessary to damage the system. I don't see any difference by writing halt to command line. I'm using the newest version of the firmware(last update today) and also the kernel is up to date(last update today).
Does anybody have an good idea about it?
This app is a good idea, i wonder nothing like this is already existing...
I think the problem is the "halt" command.
You shuold use the explicit command "shutdown -h now" instead.
For further reading see Anthony Lawrence