My personal opinions:
On Thu, 2014-06-26 at 18:51 -0600, Chris Murphy wrote:
1a. Does preserve preexisting include providing a working menu entry in the boot manager (e.g. in the GRUB menu)?
Yes.
1b. Or is it sufficient to just preserve the installation data — meaning it's permissible for its bootability to be either non-obvious or broken?
No. Users will not be able to recover from this scenario.
- If the answer to 1a. is yes, and 1b. is no, does this dual-boot
requirement apply to both BIOS and UEFI?
Yes.
- If resources cannot meet the dual-boot requirement by ship time,
should the installer inform the user that their previous installation will be preserved but may not be bootable?
I think that would be OK, if the warning is clear and you have to click a red button to bypass it.
Can you link to the discussion on why the above requirements are problematic?
- Why is the preservation of an existing Linux OS, including a
previous Fedora, not explicit in the spec? Should it be?
This would be nice to have. When I tried dual-booting a year or so ago, the status quo was that os-prober usually worked, but not really reliably.
If we adopt the bootloader spec, then it we should add a guarantee that we preserve the ability to boot other Linux systems that adhere to that spec (which is admittedly none). But there was significant debate over whether Fedora should adopt that spec.