Wolfgang Denk wrote: > In message <44485B3F.8080308 at orkun.us> you wrote: > >> If your bootloader is U-Boot and you are using standard bootm command to >> boot, U-Boot decompresses the initrd image to RAM before passing the >> file system to Linux. So, you are not working with flash copy and >> updating the flash copy is not a problem at all. This applies to ext2, >> cramfs or squashfs based initrd. >> > > But it makes no sense to use cramfs or squashfs on a ramdisk. > You *want* to run these directly from flash. > But then, of course, you need alternate images (or other tricks) > for full image updates. > Well, we lose a couple of MB of RAM but squashfs as initrd has been reliable, very compact and since the file system is in RAM, it is faster and we can tune a bit for smaller cache etc.
Image updates have been extremely easy as a result, we did not need to resort to alternate images and other tricks as a result. If you have more flexibility in RAM than in flash, our approach makes sense without complicating the matter much. I understand that not everyone might have this option. > [Single file updates can be done using overlay file systems; see the > DULG for details.] I know about the overlay fs. There is also unionfs that works similarly. Best regards, Tolunay
