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Index > OS Construction > Bootloader,Pascal,Fun OS?

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Embrance



Joined: 14 Mar 2004
Posts: 116
Location: Greece
Embrance
1)Ok,i have seen LOTS of bootloaders.I still dont get how they work or what they do exaclty.I want to make a simple boot loader that will load an image(specific width and height)and load the OS after some seconds...
2)I want to use Pascal as programming language.My problem is how to make the OS/Kernel and bootloader understand the Pascal code.FPC has ASM exporting abilty.Would this help?
3)I want a simple OS,just to play media files.Nothing more(MP@,etc)
Post 14 Jul 2005, 04:23
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Dex4u



Joined: 08 Feb 2005
Posts: 1601
Location: web
Dex4u
Here is a full freepascal OS , i have up loaded to my old site
http://falconrybells.co.uk/AnonymOS.zip

You could also look at bootprog as that can load a mz exe.
http://alexfru.chat.ru/epm.html#bootprog
Post 14 Jul 2005, 10:05
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dieboy



Joined: 30 Dec 2004
Posts: 41
Location: Poland, Elblag
dieboy
Post 14 Jul 2005, 11:19
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Embrance



Joined: 14 Mar 2004
Posts: 116
Location: Greece
Embrance
Delphine is quite dead for llooooonnngg time now.And i doubt (from what i have seen)if it considered a Pascal OS.
Post 14 Jul 2005, 20:50
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THEWizardGenius



Joined: 14 Jan 2005
Posts: 382
Location: California, USA
THEWizardGenius
A bootloader loads a file which contains the rest of the OS into memory off the disk. When the computer starts up, the BIOS loads the first 512 bytes off a disk into memory. That first 512 bytes has to load the rest of the OS. Actually, 2 bytes of it has to be a signature, 55AAh, or BIOS won't load the bootloader after all. So you have 510 bytes to work with, minus the BPB (about 30h bytes if I remember right) if you are using FAT.

BTW, the "rest of the OS" that a bootloader loads is called an image, so your question was slightly confusing (but it's OK, you didn't know).

If you want to load a bitmap or something like that, you should probably use the bootloader to load a file - kernel.img or kernal.bin or something like that - which would load a bitmap file off the disk. If you're using pascal to write your OS, you'll need to make sure it's a plain binary file- NOT a MZ EXE, a PE, an ELF, or anything else. No headers, footers, loading tables, or anything, unless your bootloader knows what to do with it.

You'll probably want to use VESA (hopefully you don't have an integrated graphics card like mine, that is totally incompatible) to access SVGA/XGA high resolution graphics modes.
If so, don't even think about protected mode.

Writing an OS is complex, even a simple OS. You may not understand some of the things I just wrote, so feel free to ask questions. Good luck Wink

_________________
FASM Rules!
OS Dev is fun!
Pepsi tastes nasty!
Some ants toot!
It's over!
Post 14 Jul 2005, 23:27
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simpaticool



Joined: 12 Jan 2005
Posts: 16
Location: Romania
simpaticool
Smile
Fasm rules!

Hello people!
I'm back!
In few days I'll probably come with may OS created in fasm.
And with a lot of questins, of course Smile


BYE!
Post 15 Jul 2005, 10:46
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dieboy



Joined: 30 Dec 2004
Posts: 41
Location: Poland, Elblag
dieboy
Ok, we're waiting Smile.
Post 15 Jul 2005, 15:24
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