Subj : Re: Computer Broken
To   : apam
From : tenser
Date : Mon Sep 15 2025 02:41 am

On 12 Sep 2025 at 05:51a, apam pondered and said...
 
 ap>   Re: Re: Computer Broken
 ap>   By: tenser to apam on Fri Sep 12 2025 11:03 am
 ap> 
 ap>  te> Cool.  USB is hard; for x86_64, it depends: to enter 64-bit long mode
 ap>  te> have to set up virtual memory paging and enable the MMU; if you're al
 ap>  te> doing that for 32-bit, it's not so bad: but if you're using
 ap>  te> x86-segmentation (which I think you are?) it's a lot more challenging
 ap>  te> because a) most of x86 segmentation is ignored in long mode, and b) y
 ap>  te> have to switch to paged virtual memory (with at least 4 level paging)
 ap> 
 ap> no i do have paging with the mmu. I'll look at it.

Ah, cool.  I stand corrected!

 ap> I did go down another
 ap> rabbit holr though, adding fat support via grafting the fatfs driver in,
 ap> its _almost_ working, but having some minor issue that is proving to be
 ap> difficult :)

Oh nice.  What's the problem that you hit?  Possibly you've already
fixed it by now, but I'm curious.

 ap> my goal for adding fat support was to be able to use usb keys which
 ap> would be awesome if i had a usb stack, and able to use limine boot
 ap> loader which i hear is good (and part of a youtube video about porting
 ap> to x86_64) plus having to have an OS that can write minix v3 filesystems
 ap> to prepare my disk images is a bit tricky (debian does still, but most
 ap> linux distros ship kernels with it disabled)

It strikes me that you could probably still use limine regardless
of whether the OS used a different file system format: you'd just
prepare an image with a copy of the kernel in a small FAT
partition, but the system would mostly ignore it once running.

I presume to prepare an image, you attach a file to a pseudo disk
device via a loopback driver and initialize and mount a Minix FS
on it, then just copy files to that.  You could, however, create
a filesystem directly in a disk file and copy files into that; it
would be a fair bit of work, as you'd have to write code to write
the minix3 file structures into that file, versus letting the kernel
do that for you, but it would be very portable.  Of course, using
FAT would be much simpler.

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