5 ms·

Honest question: who is still using BIOS (or I guess CSM mode) and why? I was a BIOS holdout, and even I switched to pure-UEFI _years_ ago.

by teach 2y ago

nightski 2y ago
I use UEFI but I am going to be honest I kind of hate it. I miss the simplicity of BIOS, UEFI is so over-engineered.
- yjftsjthsd-h 2y ago
  UEFI might be too complex, but I think BIOS was too simple. I do not miss having to dd over the front of the disk to make it bootable; placing a file (or multiple! It's not exclusive!) on a FAT partition is so much lower stress.
Delomomonl 2y ago
I booted my arch Linux Kernel straight from UEFI 9 years ago :)
ChocolateGod 2y ago
I still see it used commonly for VMs.
- yjftsjthsd-h 2y ago
  Yeah, what's up with that? Like, I don't mind qemu defaulting to BIOS, but why is UEFI booting a VM so convoluted?
  - lostmsu 2y ago
    Just use Hyper-V. It does UEFI, TPM, GPU passthrough and partitioning and everything else you need by default /ms
Paianni 2y ago
All of my PCs except an old MacBook Pro have a BIOS, not UEFI. Two are from 2010, one from 2008, one from 1996.
- doener 2y ago
  Do you use a modern graphics card in any of them?
  - Paianni 2y ago
    The main one, and the one I'm using now, has a Radeon Pro WX 5100 which is a Polaris card from about 8 years ago.
  - hadlock 2y ago
    I have a 4070 plugged into an intel haswell era (2013?) as my personal desktop machine. it runs most midrange games pretty ok, although helldivers 2 (AAA title) is a bit of a dog even at low resolutions. For personal desktop tasks I haven't had much need to upgrade past that. Probably just about ready to buy a new motherboard/cpu combo for it for another dozen years or so.
    - KeplerBoy 2y ago
      Pretty sure most has well boards come with UEFI. At least my ivy ridge Z77 board at the time did. God, those were the days, one could buy a proper motherboard for like 80$.
      - wtallis 2y ago
        They did use UEFI back then, but the BIOS CSM was on by default so it was pretty easy to accidentally end up taking the legacy boot path.
HankB99 2y ago
I have an old server motherboard that does not support UEFI. Otherwise it still runs fine. I came here to ask why it matters to the GPU how the host boots. Does it need to load some drivers or firmware before the host OS? The only thing I found in the article was "... may lose access to important and necessary features of your motherboard,"
- wmf 2y ago
  Resizable BAR (which doesn't exist on old pre-UEFI hardware anyway).
- toast0 2y ago
  > I came here to ask why it matters to the GPU how the host boots. Does it need to load some drivers or firmware before the host OS? Only if you want some display output before the host OS starts. Like maybe firmware menus, or boot prompts. Generally, this functionality is enabled by a ROM with code for the system firmware to call into: VGA BIOS for CSM and the UEFI GOP for UEFI. I think all of the IBM video standards involve semi-fixed memory and i/o addresses, so a video card operating in CSM mode needs to listen on those addresses or CSM software is unlikely to work.
- sunshowers 2y ago
  Yeah, boot menus and UEFI configuration as the sibling suggests. This is actually a huge problem with DDR5 memory training. Since memory training must happen before the GPU is brought up, the screen stays blank for that duration (which can take several minutes). The only indication that it's happening is in debug LEDs if your motherboard has them.
  - chronid 2y ago
    The fact boot codes displays are getting pushed to always more expensive motherboards - and there is no standard way to get them otherwise - drives me crazy.
    - hakfoo 2y ago
diego_sandoval 2y ago
I used to use CSM mode because I didn't understand how UEFI worked, specifically the Boot Manager. My Boot Manager always ended up full of old entries of OSes that I had already deleted, and it caused some issues. This was not a problem in compatibility mode. But then I read an article [1] and learned how to manage the Boot Manager. Then I made a video [2] summarizing what I learned from the article. But to this day, I defend the point that UEFI is not a drop-in replacement for BIOS, because if you install and delete OSs frequently, you need to know how to manage the Boot Manager to avoid ending up with a mess. [1] https://www.happyassassin.net/posts/2014/01/25/uefi-boot-how-does-that-actually-work-then/ https://www.happyassassin.net/posts/2014/01/25/uefi-boot-how... [2] https://www.youtube.com/watch?v=-V3VhP-MUwE https://www.youtube.com/watch?v=-V3VhP-MUwE
- hnuser123456 2y ago
  Nice, thank you! I stopped experimenting with OSes right around the time UEFI took over so I never would've known.
toast0 2y ago
My hobby OS runs in BIOS because I want to use VGA text mode. Some of my computers around the house boot in BIOS because it was easier at the time, and there's no benefit to UEFI for them (afaik), so why bother; especially if I've moved the disks around from machine to machine.
- dwattttt 2y ago
  It's even easier to produce a hobby OS targeting UEFI these days; less direct ASM required (maybe not any?), and the firmware can provide lots of things for you, assuming you're willing to stay in boot services mode. Browsing https://uefi.org/specs/UEFI/2.10/index.html https://uefi.org/specs/UEFI/2.10/index.html, I see console text mode, loadable modules, compression, networking... the list goes on.
  - toast0 2y ago
    Yeah, but most of those cool things go away when you leave boot services mode, and I think boot services also limits you to single core? My hobby OS doesn't have that much assembly. My one asm file [1] is 888 lines, but there's a lot of lazy repetion for my interrupt and error handlers, so I can get the interrupt/error number as a parameter in the C function. If I was lazier and had interrupts go directly to c functions, there wouldn't be that much left in assembly: setting up the stack and stuff for C which isn't that much code, really, task switching bits that were too weird to write in C, stack setup for new threads, trampolines for starting the non-boot processors. There's some inline assembly in the kernel too, but I don't think you'd be able to get rid of that. [1] https://github.com/russor/crazierl/blob/main/kernel_src/start.s https://github.com/russor/crazierl/blob/main/kernel_src/star...
    - dwattttt 2y ago
      I don't think there's any particular reason for you to jump out of boot services mode if you're just having fun. Runtime mode means the firmware gives up control of devices etc, because you're meant to take over them. As far as the rest of the cores go, I don't think UEFI has much to say about them; you're expected to start them yourself once you've switched to runtime mode, so I expect that means they're just hanging out before then, e.g. during boot services time... you could just start them then.
offmycloud 2y ago
Laptops that use Coreboot with the SeaBIOS payload to load Linux are being produced today by privacy/security oriented vendors. Most of them have integrated graphics, but BIOS is certainly not dead yet. Edit: Also Heads [1] secure boot firmware can use Linux in firmware to load the OS and does not need any UEFI services. 1. https://osresearch.net/ https://osresearch.net/
- yjftsjthsd-h 2y ago
  Coreboot can run tianocore just fine. I don't think my corebooted Chromebook even has BIOS. Heads isn't BIOS or UEFI.
bryanlarsen 2y ago
It was only ~2 years ago that I switched. Kept using it for a long time because the boot disk came from an older PC and didn't want to reformat it.
Am4TIfIsER0ppos 2y ago
I dislike uefi because I have to install and update the boot loader into the motherboard instead of the motherboard/cpu just running what's on disk. Not portable in the slightest. Some hardware failure preventing boot? You need another system and OS ready to go or download and burn a usb boot disk. Somehow that works but I can't just do that for my m.2 disk. What does it get me? A fancier "bios" menu that supports a mouse. Big whoop.
- NekkoDroid 2y ago
  > I dislike uefi because I have to install and update the boot loader into the motherboard instead of the motherboard/cpu just running what's on disk. Not portable in the slightest. UEFI by default also looks in the ESP (EFI System Partition) under /EFI/BOOT/BOOTX64.EFI for any PE binary (usually the bootloader). systemd-boot for example installs itself there when you ask it to and you don't have to register anything.
- toast0 2y ago
  > What does it get me? A fancier "bios" menu that supports a mouse. Big whoop. My compaq pentium 75 had bios setup that looked like windows 3. Mouse support in bios wasn't cool or necessary then, and it isn't now. :p
- homebrewer 2y ago
  Sometimes the ability to boot an efi-capable image from any efi partition is useful. For example, I used it to install multiple operating systems (including Windows) without a flash drive — you simply create a sufficiently large efi partition on any disk in the system, unpack the iso on it, and pick the new option from the menu. Then wipe the partition when it's no longer needed. It even works if you have only one disk — the firmware is supposed to support many efi partitions on the same disk, and although I'm sure some of them don't, I haven't personally seen any.
eviks 2y ago
People with old hardware abandoned by vendors, who don't provide new uefi drivers. "Why" - because that's how it was set up when they bought it And you're not "even", most users don't even only about such a choice
waych 2y ago
CSM is required for tools that aren't UEFI enabled. memtest86+ for example can't use a UEFI GOP and requires a BIOS capable VGA. Can't be used with a UEFI-only video card (e.g. recent ryzen igpu). Also, there is still plenty of hardware out there that only comes with BIOS-capable option roms. These still require CSM if you want them to be be visible at boot.

Honest question: who is still using BIOS (or I guess CSM mode) and why? I was a BIOS holdout, and even I switched to pure-UEFI _years_ ago.

by teach 2y ago

Honest question: who is still using BIOS (or I guess CSM mode) and why? I was a BIOS holdout, and even I switched to pure-UEFI _years_ ago.

nightski 2y ago

I use UEFI but I am going to be honest I kind of hate it. I miss the simplicity of BIOS, UEFI is so over-engineered.

yjftsjthsd-h 2y ago
UEFI might be too complex, but I think BIOS was too simple. I do not miss having to dd over the front of the disk to make it bootable; placing a file (or multiple! It's not exclusive!) on a FAT partition is so much lower stress.

Delomomonl 2y ago

I booted my arch Linux Kernel straight from UEFI 9 years ago :)

ChocolateGod 2y ago

I still see it used commonly for VMs.

yjftsjthsd-h 2y ago
Yeah, what's up with that? Like, I don't mind qemu defaulting to BIOS, but why is UEFI booting a VM so convoluted?
- lostmsu 2y ago
  Just use Hyper-V. It does UEFI, TPM, GPU passthrough and partitioning and everything else you need by default /ms

Paianni 2y ago

All of my PCs except an old MacBook Pro have a BIOS, not UEFI. Two are from 2010, one from 2008, one from 1996.

doener 2y ago
Do you use a modern graphics card in any of them?
- Paianni 2y ago
  The main one, and the one I'm using now, has a Radeon Pro WX 5100 which is a Polaris card from about 8 years ago.
- hadlock 2y ago
  I have a 4070 plugged into an intel haswell era (2013?) as my personal desktop machine. it runs most midrange games pretty ok, although helldivers 2 (AAA title) is a bit of a dog even at low resolutions. For personal desktop tasks I haven't had much need to upgrade past that. Probably just about ready to buy a new motherboard/cpu combo for it for another dozen years or so.
  - KeplerBoy 2y ago
    Pretty sure most has well boards come with UEFI. At least my ivy ridge Z77 board at the time did. God, those were the days, one could buy a proper motherboard for like 80$.
    - wtallis 2y ago
      They did use UEFI back then, but the BIOS CSM was on by default so it was pretty easy to accidentally end up taking the legacy boot path.

HankB99 2y ago

I have an old server motherboard that does not support UEFI. Otherwise it still runs fine. I came here to ask why it matters to the GPU how the host boots. Does it need to load some drivers or firmware before the host OS? The only thing I found in the article was "... may lose access to important and necessary features of your motherboard,"

wmf 2y ago
Resizable BAR (which doesn't exist on old pre-UEFI hardware anyway).
toast0 2y ago
> I came here to ask why it matters to the GPU how the host boots. Does it need to load some drivers or firmware before the host OS? Only if you want some display output before the host OS starts. Like maybe firmware menus, or boot prompts. Generally, this functionality is enabled by a ROM with code for the system firmware to call into: VGA BIOS for CSM and the UEFI GOP for UEFI. I think all of the IBM video standards involve semi-fixed memory and i/o addresses, so a video card operating in CSM mode needs to listen on those addresses or CSM software is unlikely to work.
sunshowers 2y ago
Yeah, boot menus and UEFI configuration as the sibling suggests. This is actually a huge problem with DDR5 memory training. Since memory training must happen before the GPU is brought up, the screen stays blank for that duration (which can take several minutes). The only indication that it's happening is in debug LEDs if your motherboard has them.
- chronid 2y ago
  The fact boot codes displays are getting pushed to always more expensive motherboards - and there is no standard way to get them otherwise - drives me crazy.
  - hakfoo 2y ago

diego_sandoval 2y ago

I used to use CSM mode because I didn't understand how UEFI worked, specifically the Boot Manager. My Boot Manager always ended up full of old entries of OSes that I had already deleted, and it caused some issues. This was not a problem in compatibility mode. But then I read an article [1] and learned how to manage the Boot Manager. Then I made a video [2] summarizing what I learned from the article. But to this day, I defend the point that UEFI is not a drop-in replacement for BIOS, because if you install and delete OSs frequently, you need to know how to manage the Boot Manager to avoid ending up with a mess. [1] https://www.happyassassin.net/posts/2014/01/25/uefi-boot-how-does-that-actually-work-then/ https://www.happyassassin.net/posts/2014/01/25/uefi-boot-how... [2] https://www.youtube.com/watch?v=-V3VhP-MUwE https://www.youtube.com/watch?v=-V3VhP-MUwE

hnuser123456 2y ago
Nice, thank you! I stopped experimenting with OSes right around the time UEFI took over so I never would've known.

toast0 2y ago

My hobby OS runs in BIOS because I want to use VGA text mode. Some of my computers around the house boot in BIOS because it was easier at the time, and there's no benefit to UEFI for them (afaik), so why bother; especially if I've moved the disks around from machine to machine.

dwattttt 2y ago
It's even easier to produce a hobby OS targeting UEFI these days; less direct ASM required (maybe not any?), and the firmware can provide lots of things for you, assuming you're willing to stay in boot services mode. Browsing https://uefi.org/specs/UEFI/2.10/index.html https://uefi.org/specs/UEFI/2.10/index.html, I see console text mode, loadable modules, compression, networking... the list goes on.
- toast0 2y ago
  Yeah, but most of those cool things go away when you leave boot services mode, and I think boot services also limits you to single core? My hobby OS doesn't have that much assembly. My one asm file [1] is 888 lines, but there's a lot of lazy repetion for my interrupt and error handlers, so I can get the interrupt/error number as a parameter in the C function. If I was lazier and had interrupts go directly to c functions, there wouldn't be that much left in assembly: setting up the stack and stuff for C which isn't that much code, really, task switching bits that were too weird to write in C, stack setup for new threads, trampolines for starting the non-boot processors. There's some inline assembly in the kernel too, but I don't think you'd be able to get rid of that. [1] https://github.com/russor/crazierl/blob/main/kernel_src/start.s https://github.com/russor/crazierl/blob/main/kernel_src/star...
  - dwattttt 2y ago
    I don't think there's any particular reason for you to jump out of boot services mode if you're just having fun. Runtime mode means the firmware gives up control of devices etc, because you're meant to take over them. As far as the rest of the cores go, I don't think UEFI has much to say about them; you're expected to start them yourself once you've switched to runtime mode, so I expect that means they're just hanging out before then, e.g. during boot services time... you could just start them then.

offmycloud 2y ago

Laptops that use Coreboot with the SeaBIOS payload to load Linux are being produced today by privacy/security oriented vendors. Most of them have integrated graphics, but BIOS is certainly not dead yet. Edit: Also Heads [1] secure boot firmware can use Linux in firmware to load the OS and does not need any UEFI services. 1. https://osresearch.net/ https://osresearch.net/

yjftsjthsd-h 2y ago
Coreboot can run tianocore just fine. I don't think my corebooted Chromebook even has BIOS. Heads isn't BIOS or UEFI.

bryanlarsen 2y ago

It was only ~2 years ago that I switched. Kept using it for a long time because the boot disk came from an older PC and didn't want to reformat it.

Am4TIfIsER0ppos 2y ago

I dislike uefi because I have to install and update the boot loader into the motherboard instead of the motherboard/cpu just running what's on disk. Not portable in the slightest. Some hardware failure preventing boot? You need another system and OS ready to go or download and burn a usb boot disk. Somehow that works but I can't just do that for my m.2 disk. What does it get me? A fancier "bios" menu that supports a mouse. Big whoop.

NekkoDroid 2y ago
> I dislike uefi because I have to install and update the boot loader into the motherboard instead of the motherboard/cpu just running what's on disk. Not portable in the slightest. UEFI by default also looks in the ESP (EFI System Partition) under /EFI/BOOT/BOOTX64.EFI for any PE binary (usually the bootloader). systemd-boot for example installs itself there when you ask it to and you don't have to register anything.
toast0 2y ago
> What does it get me? A fancier "bios" menu that supports a mouse. Big whoop. My compaq pentium 75 had bios setup that looked like windows 3. Mouse support in bios wasn't cool or necessary then, and it isn't now. :p
homebrewer 2y ago
Sometimes the ability to boot an efi-capable image from any efi partition is useful. For example, I used it to install multiple operating systems (including Windows) without a flash drive — you simply create a sufficiently large efi partition on any disk in the system, unpack the iso on it, and pick the new option from the menu. Then wipe the partition when it's no longer needed. It even works if you have only one disk — the firmware is supposed to support many efi partitions on the same disk, and although I'm sure some of them don't, I haven't personally seen any.

eviks 2y ago

People with old hardware abandoned by vendors, who don't provide new uefi drivers. "Why" - because that's how it was set up when they bought it And you're not "even", most users don't even only about such a choice

waych 2y ago

CSM is required for tools that aren't UEFI enabled. memtest86+ for example can't use a UEFI GOP and requires a BIOS capable VGA. Can't be used with a UEFI-only video card (e.g. recent ryzen igpu). Also, there is still plenty of hardware out there that only comes with BIOS-capable option roms. These still require CSM if you want them to be be visible at boot.