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The topic is interesting but it seems to be targeted for my grandmother.
Earlier quoted context omitted.
It's not a dependency for Linux boot at all. You can do well with serial port alone, as anyone who brought up eg. an ARM SoC in Linux will attest to. Also it's not very interesting either. At simplest, Linux just needs to take a pointer to a beginning of a framebuffer and some metadata, and will write to the framebuffer whenever there's something to update.
Maybe not linux specifically, but POST requires a video device software (BIOS Option ROM or UEFI GOP Drivers) of some sort does it not? That's been my experience with all PCs for 30 years. But maybe there are cases where it doesn't? edit : Apparently it's a desktop motherboard firmware thing. Ubiquitous but not technically a requirement for POSTing a computer.
Earlier quoted context omitted.
> When power stabilizes, the CPU resets itself to a tiny, old‑fashioned mode called real mode. Real mode dates back to the original 8086 chip. The rules are simple on purpose. Memory addresses are built from two values the CPU keeps in special fast storage called registers. You combine a segment and an offset like this: physical_address = (segment Your grandmother sounds unusually proficient with this sort of thing.
I dont know, i just don't like the tone. This is a complex subject where the target audience should probably already know what is an hexadecimal number or an interrupt and the explanation of a cpu register ought to be better than: "A register is a tiny slot inside the CPU. It holds a number the CPU is using right now." If the subject interest you, you deserve better.
These blog posts really annoy me because I feel like with 20% more effort you could have something worth reading.
Funny how those three posts are in hacker news top 5 now. I guess today is the low level appreciation day. * The Linux Boot Process: From Power Button to Kernel * The Journey Before main() * How programs get run: ELF binaries (2015) (lwn.net) edit: format
> Hex is base 16
i would argue that someone that understand bases (in the first place), understands what the 16 is, doesn't exist. this is the kind of haphazard approach of this article i'm talking about. even the author's name, 0xkato, is an example of this.
as to the content, i wish it had touched on TPM, PCRs, UEFI secure boot, and ME pre-boot.
i'm forgiving all the actual errors since it is a pretty broad overview.
i'm guessing first-year uni student.
rather amazed a post like this can make it to the #1 spot.
Video device initialization is intimately intertwined and a dependency for all this early boot stuff. I was hoping to learn more but it's not even mentioned. Still, neat.
It's not a dependency for Linux boot at all. You can do well with serial port alone, as anyone who brought up eg. an ARM SoC in Linux will attest to. Also it's not very interesting either. At simplest, Linux just needs to take a pointer to a beginning of a framebuffer and some metadata, and will write to the framebuffer whenever there's something to update.
Also, in 2000 when Windows crashed you could get a serial debugger. Wonder if they still do that?