uefi

[claydoh]

I am guessing that the spec may have changed. As they tend to do.

I must confess to never having read the actual UEFI specs

Good lord, that beast is quite... hefty

[Qqmike]

I fixed the wrong link in post #6.

Well, we all got some clarity on this, anyway. Nice thing about UEFI is its flexibility. I must confess to never having read the actual UEFI specs, something I suppose I should have done from the get-go. When I wrote the UEFI how-to's for KFN, there were only just a few decent, brief sources on it, mostly on a specific topic. That's all I went by. Rod Smith remains the expert source on it all. Nice guy, he does respond to email questions/issues.

[jlittle]

Clearly, I was quite wrong, and have been misleading people. What got me going on this is that a lot of people seem to assume "may choose ... on each target OS" is "must choose". My bias against the historic Windows way of doing things has influenced me, I think.

[Qqmike]

I didn't catch that either, about only ONE ESP per computer. I don't recall Rod Smith saying that. Anyway, always under the impression you could have as many as you wish. Even on just one disk (although there are other ways of separating/identifying the boot files of different OSs).

Those interested,
Dual-booting: How to Use Multiple ESPs
https://www.kubuntuforums.net/forum/...l=1#post539379
https://www.kubuntuforums.net/forum/...-fixing-things

It's not hard to keep them straight. And you set them up in a foolproof way. (When you set up a given ESP to work with a specific OS, you turn OFF the boot flags of all the other ESPs on that system; install that certain OS; then, later, turn all ESPs back on).

[claydoh]

claydoh's reply is detailed, but I would like to emphasize that with UEFI there's supposed to be only one ESP on a computer, according to the UEFI spec.

Hmmm

13.3.3
Number and Location of System Partitions UEFI does not impose a restriction on the number or location of System Partitions that can exist on a system. System Partitions are discovered when required by UEFI firmware by examining the partition GUID and verifying that the contents of the partition conform to the FAT file system as defined in Section 13.3.1.1. Further, UEFI implementations may allow the use of conforming FAT partitions which do not use the ESP GUID. Partition creators may prevent UEFI firmware from examining and using a specific partition by setting bit 1 of the Partition Attributes (see 5.3.3) which will exclude the partition as a potential ESP.

Software installation may choose to create and locate an ESP on each target OS boot disk, or may choose to create a single ESP independent of the location of OS boot disks and OS partitions. It is outside of the scope of this specification to attempt to coordinate the specification of size and location of an ESP that can be shared by multiple OS or Diagnostics installations, or to manage potential namespace collisions in directory naming in a single (central) ESP.

So at least I know I have not been doing it wrong all these years

I do believe that multiple ESPs can be an issue, if they are on the same disk, and Windows is involved. Windows may not like such a layout.

[Programinjo]

@claydoh

Thx

[jlittle]

...why is not installed in ssd2 on kubuntu

claydoh's reply is detailed, but I would like to emphasize that with UEFI there's supposed to be only one ESP on a computer, according to the UEFI spec.

[claydoh]

Unless you manually create the partitions on ssd2, and use the custom installation options to specify which partitions to use, the installers normally use the existing efi directory if present - this is not wrong or bad.

There is nothing wrong with sharing the efi partiton with Windows, or other distros even.
But if you don't you will need to do some manual setup work.


Some examples of how you can do this.

https://www.ubuntubuzz.com/2020/09/h...nal-drive.html

https://www.youtube.com/watch?v=p6Aycry9lFc (not for dual boot, but does show the partitioning steps more clearly)

You do have to make sure you specify which drive to use for the boot loader files - it won't automatically do that. The images for Step 6 in my first link show this.

You can do the partitioning from a live session using KDE Partition Manager as well, before starting the installer. Then, all you need to do is assign the correct settings to each one.

[Programinjo]

Hello!
Am a windows user and wanna try kubuntu (tryed kde neon,fedora)
the problem
windows is install on ssd1(1TB)
kubuntu is install on ssd2(1TB)
boot is installed on ssd1(windows uefi),whay is not installed in ssd2 on kubuntu