On Wednesday, February 9, 2011 10:52:17 PM UTC-6, catcalls wrote:
> Hi TNK,
>=20
> To use Fat 16, it requires rewriting the boot loader. Just attempted
> to get Fat 16 working, and it loads, then hangs. So, no to Fat 16.
>=20
> Also, I've tried all last night to get Fat 12 working on USB stick,
> basically I cannot do it. Dunno why tho?

When I was developing my 32-bit operating system, all we had were floppy di=
sks to easily write to from DOS and boot back into upon reset.  For my test=
ing, I wrote my own real-mode debugger, which allowed me to step through my=
 boot code by loading the known sectors from the disk to a known location i=
n memory and redirecting the INT1 and INT3 interrupts there.

It let me have disassembly, test values in memory, step through code line b=
y line to test everything.  Huge time saver.  Of course, it required the de=
bugger itself to be basically perfect in a non-DOS environment, which took =
special programming care for the wrapper, but was most doable.

- Rick C. Hodgin

On Feb 10, 6:59=A0am, "Rick C. Hodgin"
<foxmuldrs...@nospicedham.gmail.com> wrote:
> On Wednesday, February 9, 2011 10:52:17 PM UTC-6, catcalls wrote:
> > Hi TNK,
>
> > To use Fat 16, it requires rewriting the boot loader. Just attempted
> > to get Fat 16 working, and it loads, then hangs. So, no to Fat 16.
>
> > Also, I've tried all last night to get Fat 12 working on USB stick,
> > basically I cannot do it. Dunno why tho?
>
> When I was developing my 32-bit operating system, all we had were floppy =
disks to easily write to from DOS and boot back into upon reset. =A0For my =
testing, I wrote my own real-mode debugger, which allowed me to step throug=
h my boot code by loading the known sectors from the disk to a known locati=
on in memory and redirecting the INT1 and INT3 interrupts there.
>
> It let me have disassembly, test values in memory, step through code line=
 by line to test everything. =A0Huge time saver. =A0Of course, it required =
the debugger itself to be basically perfect in a non-DOS environment, which=
 took special programming care for the wrapper, but was most doable.
>
> - Rick C. Hodgin

Hi R.C. Hodgin,

Interesting stuff. I use a Virtual Machine (VMWare) for testing my OS.
That way, I can test new code with a shell script to assemble the
floppy image and then just reboot the VM to see the results.

I'd like to take a look at Mike's code for booting from USB. In fact,
I'm a big boot sector buff! This obsession with boot loaders goes back
to the 1980's, when I first heard about them. :)

I dreamt of being able to become 'independent' of the OS. And last
year, that dream became a reality. A friend provided me with some
FAT12 boot loader code, enabling me to access a specific file off the
floppy disk and load it into RAM, then execute the code.

Amazed is not a powerful enough word for how I felt. Ecstatic, maybe?

So, ever since then, I've been developing my OS. GDT, LDT, and IDT
later...it is looking good. And has been loads of FUN!

Linus Torvalds was right when he said OS dev. is/should be fun. :)

Thanks for writing,

Catcalls

catcalls said (in part):
....
|I dreamt of being able to become 'independent' of the OS. And last
|year, that dream became a reality. A friend provided me with some
|FAT12 boot loader code, enabling me to access a specific file off the
|floppy disk and load it into RAM, then execute the code.

As I figured for myself several decades ago:
The only way of beeing 'independent' from any OS is to take over all
functionality and this just means: "write our own OS" from scratch.

|Amazed is not a powerful enough word for how I felt. Ecstatic, maybe?

ask me, I still feel very good with my own OS, but a bit tired too.

|So, ever since then, I've been developing my OS. GDT, LDT, and IDT
|later...it is looking good. And has been loads of FUN!

|Linus Torvalds was right when he said OS dev. is/should be fun. :)

Sure, there is a large fun factor in being creative ...
for me neither Loonix nor windoze cheating found in hackers community
gave me a feeling of satisfaction, so I decided to "do it my way".

Ok Alex Obrzut (if this is your true name) I can see you are
at the startpoint of a very long road yet.
This road looks steep, dirty, hideous and by far too long ... that long
that you can't even see its end ...

You didn't make your first step so far, but at least you moved towards it.

meouh! (I try to call the cat yet).
__
wolfgang