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''I attempted to run liblitmus/rtspin, and got the following error''
{{{
could not setup rt task params: Function not implemented
}}}

This error is caused when your liblitmus build is out of sync with your LITMUS^RT^ kernel build. Recompile LITMUS^RT^ followed by liblitmus to fix the problem.

This page serves to collect frequently asked questions and corresponding answers. Please ask questions that are not answered here on the mailing list (and augment this list afterwards).

FAQ

I would like to write a real-time application that uses the LITMUSRT API. Where should I start?

Have a look at the task bin/base_task.c in the liblitmus repository. It's a documented task skeleton that shows how to implement a periodic or sporadic real-time task.


Can I use pthreads with LITMUSRT?

Yes. An example for a multithreaded real-time application is provided in bin/base_mt_task.c in the liblitmus repository.


I tried booting with one of the provided kernel configurations on my hardware, but the kernel kernel hangs during boot with the following message: "kernel panic not syncing vfs unable to mount root fs on unknown-block (0,0)". What's wrong?

This is a generic Linux problem, not a LITMUSRT problem. The configuration is missing support for your root device and/or your root file system. To boot LITMUSRT on your machine, you first need to have working configuration for an unmodified Linux kernel. Once you have mainline Linux working your machine, LITMUSRT should boot without problems as well.


When testing with kvm using -nographic, the system appears to hang where normally a "login:" prompt would appear. However, I can log in via ssh. How can I enable local logins?

Your Linux distribution is not spawning a shell for the console. On distributions using /etc/inittab, you need to edit the inittab file to spawn a login process for console. Some distributions (such as Ubuntu and RedHat), do not use inittab. Instead, you must create a file named ttyS0 in /etc/events.d. Here is an example /etc/events.d/ttyS0 that works in Ubuntu 8.04:

start on runlevel 1
start on runlevel 2
start on runlevel 3
start on runlevel 4
start on runlevel 5

stop on runlevel 0
stop on runlevel 6

respawn
exec /sbin/getty -L 19200 ttyS0 vt102

Note that RedHat systems may use /sbin/agetty instead of /sbin/getty.


I am trying to boot a virtual test system in kvm, but I get the following error message (repeatedly).

hda: possibly failed opcode: 0x39
hda: task_pio_intr: status=0x41 { DriveReady Error }
hda: task_pio_intr: error=0x04 { DriveStatusError }

What is causing this?

This error message can occur if kvm cannot write to the image file that is backing hda. Check the file permissions.


I attempted to run liblitmus/rtspin, and got the following error

could not setup rt task params: Function not implemented

This error is caused when your liblitmus build is out of sync with your LITMUSRT kernel build. Recompile LITMUSRT followed by liblitmus to fix the problem.

FAQ (last edited 2014-04-14 08:20:48 by bbb)