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So, for the exo-kernel, there will be absolutely no FS ( at kernel level). So how can I read data on disk? I need to read sector 2 to parse data, then load next n sectors. Assume that we are working on a floppy disk, all of the data are written continuously at disk create/format time and apps don't have access rights to overwrite it.
EDIT: Oh, I forgot that we also assume that we're working in Realmode.

Where's the problem? In real mode the BIOS can read absolute disk sectors. (int 13h, ah=2)

Make the bootloader load the data by using the BIOS.

Yeah I know. But do I need BPB?

So, for the exo-kernel, there will be absolutely no FS ( at kernel level).

If there is no FS, then why do you need bpb?

Ok. Thank you. Mod, lock this please.

I don't think you entirely understand what a BPB is. It's part of the floppy's first sector and exclusive to FAT volumes. It's not something you drop into a kernel or its drivers. Sure, you can write a struct that lets you access the BPB's values, but you don't hardcode the BPB's values into the kernel.

I know. But BPB is not just exclusive to FAT volumes, but also FAT32, NTFS and maybe others. Anyway, I don't need it.

FAT32 is FAT....

NTFS uses a way different BPB than FAT does, take a peek here: http://www.geocities.com/thestarman3/asm/mbr/NTFSBR.htm. It's also based on the FAT BPB but it adds more and fills up a bunch of bytes with nulls or seemingly random numbers.

Apparently HPFS also uses the BPB (probably in a similar manner as NTFS does), but I'll have to research it.

Troy Martin wrote:FAT32 is FAT....

No, FAT is often used to refer to FAT16/FAT12 (depending on the medium), while FAT32 is used to refer to... FAT32.

I imagine that this concept is what quanganht was using in his post.

pcmattman wrote:

Troy Martin wrote:FAT32 is FAT....

No, FAT is often used to refer to FAT16/FAT12 (depending on the medium), while FAT32 is used to refer to... FAT32.

Troy is still technically correct... I personally refer to FAT as a generalization for all FAT filesystems, which technically includes FAT32.

Sorry, I meant that they're still FAT, but FAT without the numerics is often used when talking about FAT12/FAT16, while FAT32 is always used for FAT32 volumes. The easiest way to see this different naming is when formatting disks in Windows

EDIT: The only reason I brought this up was because of the ambiguity in "FAT and FAT32" in the post in question.

pcmattman wrote:The easiest way to see this different naming is when formatting disks in Windows

Right, good point there. Troy is still technically correct but I cannot answer why they do that in Windows (and alot of other sources.)

The last time I used FAT16 was when I had a copy of Windows 95 OEM. No OSRs.