boot image with write capability

Hi all,

I’m trying to figure out if/how I can create a boot image that will give me the ability to create/modify files that persist between reboots. I’ve done a bit of research already which has told me it’s doable, but hasn’t told me how to do it (atleast not in the level of detail that I need).

My application uses a config file that needs to be updated to reflect user settings. Can this be done using just an os image? I’ve read a little about the flash file system, do I need to use this too? If so, how do I do this?

BTW, I’m running QNX 6.3 on an x86 based single board computer that runs on a compact flash card.


Can’t do it on the image, you need a filesystem for that. If you are using compact flash then most probably fs4 or fs6 is the way to go. Check fdisk, dinit, dev-eide that should get you started.

can you be more specific. what do you mean by fs4 / fs6?

Strangly fs4 is the QNX4 filesystem, which QNX6 inherited from and has been use since the early day of QNX5. With 6.4.0 there is a new filesystem call qnx-fs6.

The two names can be confusion because it might lead someone to beleive fs4 is a QNX4 exclusive thing.

Can you explain how I go about creating the filesystem? I assume this is done using a build file and using mkefs, but I still don’t know what the build file should look like.

Once I have the filesystem, what do I need to do next?

You need a QNX machine to create the filesystem. Install QNX self hosted then connect the compact flash as a second disk (or via a USB adapter) then you can format it.