Multi-laptop naming scheme for build files

[Daniel Drake]

Hi,

Right now, build files for XO-1.5 and XO-1.75 have the same filename
(#11226). There have been a few requests that we move to a naming
scheme that has a different filename in this case so that the files
can live together on a USB disk and generally not be so easily
confused.

Some work needs to be done before that is possible, but we also need a
naming scheme. I think the key considerations for this are:

1. Future proofing. It should be resilient to the introduction of
future products that use the same architecture and disk image format.

2. Short names. OFW only understands 8.3 for FAT. Also, deployments
sometimes like to customise the 8 part too e.g. per703-2.img for Peru,
and I've seen others putting codes after the osXXX part, e.g.
os880j.img. Let's try and leave space for customisation here.

3. Uses only file name (the 8 part), not the extension (the 3 part).
This sticks with general computing world conventions and agrees with
some olpc-os-builder implementation details which allow the user to
customise the name but not extension, where olpc-os-builder can
guarantee that output files from different modules do not have
conflicting names.


Based on this and previous discussions I think we could go with something like:

1. single-character ID for product type. 'a' for XO-1, 'b' for XO-1.5,
'c' for XO-1.75, ...
2. build number
3. a "."
4. extension

e.g.

'a900.img' - build 900 copy-nand image for XO-1
'b900.zd4' - build 900 4GB image for XO-1.5
'c900.zd4' - build 900 4GB image for XO-1.75

Thoughts/other ideas?

Thanks,
Daniel