Bootable CD-Roms

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11 comments, last by Eight 22 years, 2 months ago
Right, this is my third attempt at phrasing this question so I''ve decided to cut all the waffle and ask things straight. Since modern motherboards have an in-built capability to boot from CD-Rom, it must be possible to write a PC program and burn it to a CD to run without the need for a harddisk or Operating System??? Does anyone know how I''d go about doing this and what version of assembler would be used - is a Pentium III cpu still perfectly compatible with x86 assembler output? Many thanks, E
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I don't quite follow what your're after (sorry), but near as I can tell, you're talking about developing your own cut-down OS. It's possible, and that's about as far as I can help you. I've studied OS design and the underlying tech, but I've never had to work with a PC on that low a level, and to be honest I hope I never do

Sorry if you already know this, but you don't have to do all that. If you make a bootable CD for say, MS-DOS, the CD already contains enough of the OS to run without any need for a hard disk or other gear. Would that be sufficient?

Edited by - NeverSayDie on February 22, 2002 6:17:58 AM
quote:Original post by NeverSayDie
I don''t quite follow what your''re after (sorry), but near as I can tell, you''re talking about developing your own cut-down OS.

Yep - that''s pretty much it I think.

quote:
It''s possible, and that''s about as far as I can help you. I''ve studied OS design and the underlying tech, but I''ve never had to work with a PC on that low a level, and to be honest I hope I never do

I know what you mean - I''m much more familiar with console architecures and they tend to be much nicer.

quote:
Sorry if you already know this, but you don''t have to do all that. If you make a bootable CD for say, MS-DOS, the CD already contains enough of the OS to run without any need for a hard disk or other gear. Would that be sufficient?

I''m trying to keep Bill out of the equation.
When you create an MS-DOS bootable CD then it''s that little piece of OS which is first loaded that I''m really interested in - I guess. Presumably the BIOS interface to the CD drive knows where to look for some code, and I''m assuming it doesn''t have to be a Microsoft product that it finds.

E
what you are asking is how to make your own os
i can help a bit
the first sector of any bootable disc ( eg the fisrt 512 bytes of on plater 0 head 0 is the boot sector ), put some code, but the 511 and 512 byte must = somthing ( dont remember what ) in roder for the BIOS to see that its a bootable volume
look around the net you''ll find some stuff
i av mead my own OS its not to hard, but its hard to make a good one :p
lol

hope that helps some

-Ian
-VBLimitsSorry about the Spelling..
Thanks Ian.

That''s perfect, your comments have helped me find what I was after from google.
No problem
you should post the line :p
LOL i forget all mine, i had over 20 pages that where of good qulity, but i formatted and never back anything up
you know the story
if you need anymore help just post them in this thread, i ll keep an i on it and try and help you out some

-Ian
-VBLimitsSorry about the Spelling..
quote:Original post by VBlimits
No problem
you should post the line :p

The last word of the 512byte header needs to be 0AA55h.

quote:
LOL i forget all mine, i had over 20 pages that where of good qulity, but i formatted and never back anything up
you know the story

Oh yes. I thought I wrote that tale.

Cheers.
quote:Original post by VBlimits
what you are asking is how to make your own os
i can help a bit
the first sector of any bootable disc ( eg the fisrt 512 bytes of on plater 0 head 0 is the boot sector ), put some code, but the 511 and 512 byte must = somthing ( dont remember what ) in roder for the BIOS to see that its a bootable volume
look around the net you''ll find some stuff
i av mead my own OS its not to hard, but its hard to make a good one :p
lol

hope that helps some

-Ian


Sectors don''t exist on a CD, it only has one track and nothing else, no sectors, no nothing.





"And that''s the bottom line cause I said so!"

Cyberdrek

Resist Windows XP''s Invasive Production Activation Technology!

"gitty up" -- Kramer
/(bb|[^b]{2})/ that is the Question -- ThinkGeek.com
Hash Bang Slash bin Slash Bash -- #!/bin/bash
[Cyberdrek | ]
quote:Original post by Eight
Right, this is my third attempt at phrasing this question so I''ve decided to cut all the waffle and ask things straight.

Since modern motherboards have an in-built capability to boot from CD-Rom, it must be possible to write a PC program and burn it to a CD to run without the need for a harddisk or Operating System???

Does anyone know how I''d go about doing this and what version of assembler would be used - is a Pentium III cpu still perfectly compatible with x86 assembler output?

Many thanks,

E


You should actually get a ready made bootstrap loader instead of creating one yourself, it would take some of the load off of your back. Then all you''d need to concentrate on is creating the basic part of your os and then creating a compiler for it, if you plan to create Apps for your OS. Anyhow, hope this helps...

"And that''s the bottom line cause I said so!"

Cyberdrek

Resist Windows XP''s Invasive Production Activation Technology!

"gitty up" -- Kramer
/(bb|[^b]{2})/ that is the Question -- ThinkGeek.com
Hash Bang Slash bin Slash Bash -- #!/bin/bash
[Cyberdrek | ]
quote:
Sectors don''t exist on a CD, it only has one track and nothing else, no sectors, no nothing.

Good point.

I''m currently messing on with the floppy drive but the principal is the same.

E

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