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Re: Having trouble booting from CD?
Posted: Thu Jun 11, 2015 4:44 pm
by zehawk
Combuster wrote:For all your booting problems, try it in a virtual machine or emulator first.
Only the truly ancient BIOSes can't boot from CD. In fact, no-emulation El-Torito is better supported than no-emulation which is generally better supported than USB boot. But each mechanism is different, and you can't simply use code for one method to do the other. However, test cycles using a CD are pretty much the slowest option available - from experience they are worse than floppies.
I have a working external CD drive that can be booted from - I even installed my computer with it.
If you want to do the CD way, your best bet is to make the .iso using mkisofs/genisoimage and specifying the bootcode properly. You can then also post that command for scrutiny if either the VM or real hardware doesn't grok it.
Yeah, been using emulators so far. My biggest problem with them is that, for example, even VirtualBox just accepted an iso and ran with it despite the glaring issues people pointed out in my source code earlier. Thinking external hard drive is just a much more simple way to do it. And it also will help me understand how the underlying file systems work as I will have to implement that eventually. And burning a cd every time i want to test it? Pass. xD
gerryg400 wrote:kiznit wrote:zehawk wrote:I'm assuming
When programming, never assume. Verify.
This is poor advice. Assumptions are important in all forms of engineering. Without making assumptions, often no progress can be reasonably made. As long as assumptions are considered and stated they should present no problem.
I can see where he's coming from, but I agree. I used the words 'I assume' knowing that someone would correct me if I'm wrong. I'd look stupid if I said things with conviction and they weren't accurate. But you raise a very valid point as well!
Re: Having trouble booting from CD?
Posted: Thu Jun 11, 2015 4:45 pm
by kzinti
gerryg400 wrote:kiznit wrote:zehawk wrote:I'm assuming
When programming, never assume. Verify.
This is poor advice. Assumptions are important in all forms of engineering. Without making assumptions, often no progress can be reasonably made. As long as assumptions are considered and stated they should present no problem.
Yes, taking a sentence out of context allows one to easily contradict it.
I was replying to the OP's assumption that DS and ES are 0. Do you still want to claim that this statement from OP doesn't present any problems because it was stated?
Re: Having trouble booting from CD?
Posted: Thu Jun 11, 2015 4:48 pm
by zehawk
kiznit wrote:gerryg400 wrote:kiznit wrote:
When programming, never assume. Verify.
This is poor advice. Assumptions are important in all forms of engineering. Without making assumptions, often no progress can be reasonably made. As long as assumptions are considered and stated they should present no problem.
Yes, taking a sentence out of context allows one to easily contradict it.
I was replying to the OP's assumption that DS and ES are 0. Do you still want to claim that this statement from OP doesn't present any problems because it was stated?
You are right, assuming that DS and ES are 0 is an awful idea. But i did originally mean I assume I should set them to 0. Either way, lesson learned. And hey, that's why we're are part of this community, right? To learn!
Re: Having trouble booting from CD?
Posted: Thu Jun 11, 2015 8:39 pm
by zehawk
FORGET ALL MY PREVIOUS QUESTIONS. I successfully got my OS to boot from a USB! Thank you guys so much for your help!
Re: Having trouble booting from CD?
Posted: Fri Jun 12, 2015 10:07 am
by kzinti
zehawk wrote:FORGET ALL MY PREVIOUS QUESTIONS. I successfully got my OS to boot from a USB! Thank you guys so much for your help!
Congrats!