DOS/Linux boot partition possible?

[orthorim]

I have been told that Macs cannot boot Windows or anything except OS X from an external USB device.

However, Macs can boot Windows from a boot camp partition. So I created a boot camp partition, but I want to boot some DOS version from it. The partition is on the internal HD.

My problem is that I removed the CD ROM drive from my MacBook Pro and replaced it with a second hard drive. But now I got an ISO image for a CD for updating the Intel SSD firmware - Intel claims that Intel Macs will simply boot from that CD when inserted, it will start some sort of free DOS, then proceed to update the SSD firmware. I copied the ISO to a USB stick, and was able to boot from it on Windows laptop. But on the Mac, that doesn't work, the USB stick isn't recognized as bootable.

So I copied the entire contents to my boot camp partition on my internal HD, and tried to boot from it - but it doesn't show up in Startup Disk, and it doesn't appear as option when I restart and hold down the option key.

Any ideas what magic I must invoke to make OS X recognize the boot camp partition with DOS on it?

 

[maflynn]

Dos? You're kidding right?

I think I saw somewhere that you can have a DOS virtual machine setup but not under boot camp. The DOS os is just too old to even think it would work.

Linux on the other hand is easy to install. Ubuntu is the most popular distro and probably the easiest to install on the MBP. I have fedora 12 on mine and it took a little more work to get the video drivers installed and configured correctly. (the default drivers included in F12 work but not in a dual monitor configuration)

 

[balamw]

IMHO DOS is far too reliant on BIOS/MBR to be "safe" on a modern EFI/GPT Mac.

It doesn't sound like you were much of a DOS user or you would know that you can't just copy files and expect it to work. You need to run SYS http://www.computerhope.com/syshlp.htm to make a DOS partition bootable. (Which of course requires that you have a working DOS system to run sys from). And, you would have to mark the partition as active with FDISK.

It may also just be a boot loader issue that you can get around with rEFIt to get it to launch the code.

Personally, I think it would just be easier for you to hook up the Superdrive you pulled out temporarily (if need be hang your second HDD off of USB) and boot from that as planned. Bootable CDs are a different beast as they have certain standards for the kinds of bootable images they will allow, and some amount of BIOS emulation is required.

B

 

[orthorim]

Ok all in all it sounds a bit like Mission Impossible. Too many magic tricks required to make stuff bootable.

I never knew that a CD could boot an intel Mac into DOS, actually.

I did all the magic for the USB stick I tested the boot from, and this one worked. But of course I didn't do this on the internal partition so that's likely where the problem lies. The USB doesn't boot because it's USB, the internal one doesn't because - for starters - I didn't mark the partition "active". I guess I could get this to work if I installed Windows 7, then made another partition to be my DOS boot partition, then booted into Win7 and did all the magic to make the DOS partition bootable. Maybe. But it's a lot of effort. Probably easier to boot from CD

I guess what I don't understand is:

- When holding down option at boot, how does the Mac decide which partitions are bootable? What's the criteria? That's my first hurdle.

- Once it's recognized a partition as bootable, when or how does it load the BIOS emulation layer drivers that allow us to boot a BIOS based system

- At what stage in the boot process does the firmware hand over control to the operating system?

I am sure it would all make sense if I just got answers to these questions. At the moment it's all magic mysteries, and I couldn't find a proper writeup on Google either.

 

[balamw]

I never knew that a CD could boot an intel Mac into DOS, actually.

I've tried it on my iMac and it seemed to go OK. What's even funnier is that it does so by emulating a floppy drive via a floppy image on the CD.

EDIT: Did you read this: http://refit.sourceforge.net/info/boot_process.html

B