4 ms·

why boot linux then boot linux again, rather than just booting linux once?

by throwaway2048 9y ago

megous 9y ago
bootstrapping
ganshun 9y ago
The current way an x86 platform is booted to linux today uses mostly closed source UEFI DXE drivers, so the current boot flow is really (simplified) like this: UEFI DXE loads disk/network -> Linux We're doing Linux (with commonly used open source drivers)-> Linux It's possible that if your end goal is a Linux system without too many requirements, you could stop at the first Linux system without ever booting the second. However the bios rom memory is pretty small, and we're mostly working with about 4-8mb of free space left not including the ME region or UEFI PEI.
- krylon 9y ago
  > you could stop at the first Linux system without ever booting the second Someone did that! Well, something like it, anyway.I have an Asus EeeBox sitting on my desk, gathering dust, that has something called "SplashTop" - if I hit the right key during the POST screen, it boots into a minimalistic Linux desktop in about 2 seconds. There is networking and a browser. I haven't used it in ages, but I think the problem was that it could not access the file system, so one could not do very much, and I think settings did not persist across reboots. But the general idea seemed appealing at the time.
hugelgupf 9y ago
Chances are you don't want to re-flash your firmware on your servers just to change what kernel you run in production. The kernel in flash also has space constraints that will make it a pretty small kernel with a lot of features turned off.
- euyyn 9y ago
  Tannenbaum is spinning in his chair.
- BenjiWiebe 9y ago
  In fact, you'd have to reflash to update Firefox! Oh wait, Firefox won't even fit on the ROM chip. No wonder we don't use the ROM chip as our main storage...
  - hugelgupf 9y ago
    You could have a tiny initramfs that mounts the disk you want with your actual init and then switch_root to that. You'd have the kernel from flash, and init from disk.
mixmastamyk 9y ago
So you have choice of running Windows or BSD, etc.

why boot linux then boot linux again, rather than just booting linux once?

bootstrapping

The current way an x86 platform is booted to linux today uses mostly closed source UEFI DXE drivers, so the current boot flow is really (simplified) like this: UEFI DXE loads disk/network -> Linux We're doing Linux (with commonly used open source drivers)-> Linux It's possible that if your end goal is a Linux system without too many requirements, you could stop at the first Linux system without ever booting the second. However the bios rom memory is pretty small, and we're mostly working with about 4-8mb of free space left not including the ME region or UEFI PEI.

krylon 9y ago
> you could stop at the first Linux system without ever booting the second Someone did that! Well, something like it, anyway.I have an Asus EeeBox sitting on my desk, gathering dust, that has something called "SplashTop" - if I hit the right key during the POST screen, it boots into a minimalistic Linux desktop in about 2 seconds. There is networking and a browser. I haven't used it in ages, but I think the problem was that it could not access the file system, so one could not do very much, and I think settings did not persist across reboots. But the general idea seemed appealing at the time.

hugelgupf 9y ago

Chances are you don't want to re-flash your firmware on your servers just to change what kernel you run in production. The kernel in flash also has space constraints that will make it a pretty small kernel with a lot of features turned off.

euyyn 9y ago
Tannenbaum is spinning in his chair.
BenjiWiebe 9y ago
In fact, you'd have to reflash to update Firefox! Oh wait, Firefox won't even fit on the ROM chip. No wonder we don't use the ROM chip as our main storage...
- hugelgupf 9y ago
  You could have a tiny initramfs that mounts the disk you want with your actual init and then switch_root to that. You'd have the kernel from flash, and init from disk.

mixmastamyk 9y ago

So you have choice of running Windows or BSD, etc.