Loopbacks-rteth0: unknown interface No such device

[AnishaKaul]

Disclaimer: I am not asking about the rtnet in particular here. I just wish to understand the error messages.

I have installed the RTnet over Xenomai. RTnet compiled well, and I also tested loopback on the single machine and was able to ping.
However I noticed `./rtnet start` showing the following output: What should I interpret when all it says is "no such device"?

Code: Select all

linux-y3pi:/usr/local/rtnet/sbin # ./rtnet start

rteth0: unknown interface: No such device
rteth0-mac: unknown interface: No such device
ioctl: No such device
ioctl: No such device
ioctl: No such device
ioctl: No such device
ioctl (add): No such device
vnic0: unknown interface: No such device
SIOCSIFADDR: No such device
vnic0: unknown interface: No such device
SIOCSIFNETMASK: No such device
Waiting for all slaves...ioctl: No such device
ioctl: No such device

linux-y3pi:/usr/local/rtnet/sbin #

One more thing I would like to know about is "loopback". For loopback testing don't we need a cable which is connected on its both ends to the same computer?

From: http://www.xenomai.org/index.php/RTnet: ... oopback.29

Testing with a single node (local loopback)
The testing procedure is as follows:
Disconnect the RTnet node's network cable from your normal non real-time ehternet network
Restart the systems into the patched kernel mode.
Display the Network setup with the command

It just tells us to disconnect the normal cable. Doesn't tell us to add a loopback cable.
Can that be the reason for these error messages?

I am missing a big point here, I think.

[Solar]

What should I interpret when all it says is "no such device"?

"No such device" means that none of the hardware devices discovered by the kernel has been assigned that particular device name (i.e., there is no file /dev/<devicename>). Kernel and application are not in agreement on how the device is named -- or, indeed, there is no such device.

One more thing I would like to know about is "loopback". For loopback testing don't we need a cable which is connected on its both ends to the same computer?

You can mount image files through "loopback": The file system driver, instead of having its calls forwarded to a hard disk driver, has its calls "looped back" to the filesystem, i.e., the image file.

Similarily, a network "loopback" means that the network access is "looped back" to the NIC before it actually hits the cable. Loopback cables exist, but they are for looping back network traffic on old, stupid NICs that don't do proper internal loopback.

[AnishaKaul]

"No such device" means that none of the hardware devices discovered by the kernel has been assigned that particular device name (i.e., there is no file /dev/<devicename>). Kernel and application are not in agreement on how the device is named -- or, indeed, there is no such device.

Now I added the correct real time driver for the ethernet. Removed the LAN cable.
How to know "which" device is it looking for?

You can mount image files through "loopback": The file system driver, instead of having its calls forwarded to a hard disk driver, has its calls "looped back" to the filesystem, i.e., the image file.
Similarily, a network "loopback" means that the network access is "looped back" to the NIC before it actually hits the cable. Loopback cables exist, but they are for looping back network traffic on old, stupid NICs that don't do proper internal loopback.

Thanks very much for the explanation.

[AnishaKaul]

I have reduced the extra info from the above post. Shortened it.