What now?

[shikhin]

Hello All,
I am an beginner in OS'Deving. I just started building my OS, currently named SOS, and have done the following in it:

a) A GDT.
b) Interrupts up and working (IRQ).
c) Keyboard Input.
d) Paging implemented.
e) A working heap.
f) Support for displaying the time. (Pretty cool.. huh?)

Now I wanted to ask what next? I think doing this much is crossing the beginner level in OS Dev, and now I am sort of beginnerish intermediate. So I wanted to ask, according to you guys what all shall I do next, and more importantly some links on the topics you are suggesting, as resources. Also, I have the following question, which I would be grateful, if they are answered.

a) Can you guys tell me, how is an filesystem implemented. I mean I found some pretty good resources, which tell me what an filesystem is, but no one even gives me an hint on how it is implemented.
b) Can you guys tell me, (same format ) how I shall read the CD. I have found some articles on programming the FDC, but none on the CD controler (or whatever, it is called). So any hints?
c)How a executable file is loaded. I ain't picky, so any format such as PE, ELF would work. But it should be simple. This is the least prefered question, as I guess this would come after the above two are done.
d) What is to be done after this stage?
e) What did you all do?

Thats all folks. Too many questions.

EDIT: Preferably I want some discussions on the ISO 9660 filesystem, as that would be used for the CD, I guess.

[Combuster]

I see a few STFW and even FAQ topics flying past...

http://wiki.osdev.org/What_order_should ... ings_in%3F
http://wiki.osdev.org/ATAPI

Also, you can't expect to find a tutorial on every subject imaginable. That's where you can get beyond being a beginner: use manuals and specifications, your knowledge on software architecture and development, to make something that does not yet have to exist.

[shikhin]

Thanks for the response, Combuster. I see my way ahead a little bit. One question though:

Can a CD be formated to some *OTHER* file system? Such as FAT? Because, I wanted to implement FAT first, as from what I have read, its more easier. So can it be? Further more, can grub read off it?

[chibicitiberiu]

But do you have a working driver for the storage device you want to work with? Do you have a CD driver? Floppy? ATA?

[Combuster]

Can a CD be formated to some *OTHER* file system?

Do you want a CD to be formatted to some other filesystem. The standard exists for a reason, so that everybody with a cd can use it. It might work, it probably will not.

A CD uses different booting mechanisms and a different hardware sector size. I doubt you can get GRUB to like a combination that was never intended to exist.

EDIT: and IIRC booting a CD on a PC depends on the ISO9660 filesystem to be present.

[Owen]

It doesn't require an ISO9660 file system (For example, BeOS used to use a BeFS formatted CD). However, you will struggle to get them onto the disk, and there is really no reason not to do so; ISO9660 is very well documented, and in many regards much simpler than FAT.