4 ms·
> the rest is just reading up some documentation about what you are going to load That documentation is usually.... lacking > You can't fit a filesystem parse
by gravypod 10y ago
> the rest is just reading up some documentation about what you are going to load
That documentation is usually.... lacking
> You can't fit a filesystem parser into 1 sector and have anything other sensible in there
You don't use a single sector. You use a 2 stage bootloader that uses a reserved FAT sector. In FAT12 (at least) you can specifiy how many reserved secotrs on formatting. A reserved sector comes directly after the first sector. You can do a full FAT12 implementation in assembly in two sectors.
> using bios generally (on x86 atleast). and you can understand how to do it from this tutorial.
You're going to need to do a lot more reading. Even just looking up the interrupts you need is a task. I've found nothign that does a good job explaining the 1, 2, and 3s of how to get all the way to booting from a formated disk.
- johnnycarcin 10y agoYou sound pretty well versed in this area, would you be interested in writing something up? Don't take this as a dig, I know the value of free time and how much that free time is lacking for most of us, I just thought I'd toss it out there.
- gravypod 10y agoThe best I can do is load up a second stage. Searching for the COM file is where I get lost. I've also been trying to do it in C for months and I haven't been able to finish for various reasons.
- sigjuice 10y agoYou're going to need to do a lot more reading. Even just looking up the interrupts you need is a task. I've found nothign that does a good job explaining the 1, 2, and 3s of how to get all the way to booting from a formated disk. There is unlikely to be a single thorough body of documentation on this sort of thing. IMHO, the best resource would be the numerous open source bootloaders that are available.
- upofadown 10y agoThere isn't a lot there to document. At this point it counts as a part of our civilization. It's even on Wikipedia: * https://en.wikipedia.org/wiki/Master_boot_record https://en.wikipedia.org/wiki/Master_boot_record * https://en.wikipedia.org/wiki/BIOS_interrupt_call https://en.wikipedia.org/wiki/BIOS_interrupt_call There isn't much call for FAT12 these days...