installing embedded os

I meant 16 bit PC BIOS compatible gcc runtime.

Once your are in 32 bit, you can't call 16 bit BIOS functions.

Reply to
linnix
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True, that's why you call all your BIOS stuff while still in 16 bit mode. Things like printing out some startup messages, finding out how much memory there is, and what kind of disks are attached, and possibly loading the rest of the kernel from disk.

When you're done with the BIOS, you enable the A20 gate, setup idt/gdt and jump to 32 bit mode. After that, you'll need native drivers to access the hardware directly.

Of course, it's easier to just use a modern bootloader.

Reply to
Arlet

Bootloaders would be useful here to pass the important parameters to the OS kernel/executive. But this may mean that you'd need a bootloader that supports USB. I'm sure there are linux distros out there that boots from thumb drives so I think such things exist. The usual suspects lilo and grub may even do this already but I'm not sure.

He's writing his own "simple" OS. He's on his own anyway. Besides, most modern OS I know ignores the BIOS. And since he already manages to execute his OS as a userspace task in Linux I don't think his OS cares about the BIOS after boot.

Read mike's posts carefully.

Reply to
slebetman

Everyone knows how fat , everything is , today . And all the closed doors .

USBh can not communicate with USBh ! That was the first need , for 2 PC's to talk to each other . The old RS232 could talk to another computer .

What happened ?! Has the world gone mad !!

Are you being paid well , to keep these doors closed , so people can't get useful work from the hardware !!

It wont be much longer . It will be much less work , to obsolete all the old software .

C/C++ , Linux , Unix , MicroSoft , Intel , MicroChip , Zilog , Atmel , Rabbit .

All obsolete , gone .

It has been shown that you dont need 200 MegaFlops , to do any job . You just cant do it on a Pentium .

Reality check , toss your 70 Watt Pentiums , now .

A Forth programmer can code an app in minutes , what takes C++ , weeks .

Linux will not do your task correctly . Nor will WXP , C.E. 5.0 et al . MPG and JPG are hated .... why ?

MP3 will easily be replaced Its not a breakthru , its only a copyright .

No more math . You will see images and charts to guide you thru the learning of its replacement s/w . You will move a joy-stick and the music pattern changes , showing you , rather than telling you : "the inverse DCT is integrated over the interval of 3 years and then convoluted to the 3rd derivative of Pie . Then Object oriented to Taiwan , and defined to the linked output of the input file.

I find programming very easy at low levels . Because i write the disassembler first , but i do it the easy way , by simply defining where and what bits , then Forth writes the "logic" !!

Can your C++ , write the logic !!

NO !

I do everything the easy way , thus i avoid

C++ , and Linux , and Win32API , et al .

Reply to
werty

I have no clue whatsoever, but given the position of the BSS, before the stack, but after initialized data, I do not think it would be unreasonable to say that it stands for Base-of-Stack-Segment or Before- Stack-Segment. But again, I have no idea.

-Le Chaud Lapin-

Reply to
Le Chaud Lapin

It will not be simple dealing with USB.

And he is not using USB yet.

Reply to
linnix

But he didn't say he wants to deal with USB. He just wants to boot from a USB drive. After booting he may or may not care (since the OP specifically say his OS is "simple" I'm betting that he doesn't deal with USB at all after boot).

Again I urge you to read the OP's post carefully, not your own posts, not Arlet's posts, not my posts, the OP's post, before answering the OP. If you're not answering the OP but answering simply to me then fine, it will not be simple dealing with USB. But *I* don't care anyway since I don't have a custom OS that I need to boot.

My guess is he's not going to be using USB after boot. He just wants to know how to boot a custom OS from a USB/flash drive.

Now, after all this, nobody here have yet answered mike's question of how a boot process "really" works at the low level so that he can boot his OS.

Reply to
slebetman

If he is not reading or writing any file, then fine.

"Arlet" already told you how it works. You are not listening.

I already said he can boot his os from DOS.

Reply to
linnix

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