[yocto] per-image ROOTFS sizes

[Robert P. J. Day]

On Wed, 12 Dec 2012, Trevor Woerner wrote:

> On Wed, Dec 12, 2012 at 3:46 PM, Robert P. J. Day <rpjday at crashcourse.ca> wrote:
> > so what happens if you try to set the appropriate variables above?
>
> When Yocto creates a VMDK, it creates 2 partitions:
> - an MSDOS partition for the syslinux stuff
> - the ext{3,4} partition of your root image
>
> When it then shmushes these two together into 1 file, it has to make
> sure all the sizes are set correctly as per the information in the
> disk's partition table. That's what all these calculations are doing
> (I recognize it from similar work in my own scripts).
>
> Personally I have my own approach that can use either LILO or syslinux
> for booting x86 (it can also create bootable ARM images with the
> appropriate uboot/mlo); neither of the x86 solutions require a
> separate MSDOS partition. Hopefully I'll find some time to examine how
> Yocto is doing things and perhaps integrate my own findings into the
> broader project(?).
>
> (please see https://github.com/twoerner/qemu-image-builder)
>
> I believe Yocto calculates the sizes (using IMAGE_ROOTFS_SIZE) from
> code in poky/meta/classes/image_types.bbclass, which is also run for
> the VMDK's calculations too.

  and here's where i'm confused.  i'm *assuming* that the
image-vmdk.bbclass file defines the creation of vmdk images, yes?  but
that class file inherits directly only boot-directdisk.bbclass, and if
i look in that class file, i don't see any further inherits that might
process IMAGE_ROOTFS_SIZE.  i just see hardcoded calculations that
build an image based on actual rootfs directory size.

  so what am i missing?

rday

-- 

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Robert P. J. Day                                 Ottawa, Ontario, CANADA
                        http://crashcourse.ca

Twitter:                                       http://twitter.com/rpjday
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