Messages in this thread | | | Subject | Re: [RFC] x86 ELF bootable kernels/Linux booting Linux/LinuxBIOS | From | (Eric W. Biederman) | Date | 02 Feb 2002 09:17:40 -0700 |
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"H. Peter Anvin" <hpa@zytor.com> writes:
> Eric W. Biederman wrote: > > > What is magic about interactivity? What makes this a different > > problem? We approach booting from totally different perspectives, > > which makes communicating clearly hard. If you spell out individual problems > > I will show you how I would solve > > them. > > > > > It makes it a very different problem because YOU DON'T KNOW WHAT YOU'RE BOOTING > UNTIL THE USER TELLS YOU. > > In fact, depending on just exactly what you're doing, you might not even know > what you're booting until you have already gotten several items downloaded > (consider, for example, a device-probing bootloader.) > > Therefore, the bootloader must be able to obtain boot medium services not just > once and for all, but on a back-and-forth basis. There needs to be an API > between the boot loader and the firmware, and just "stuffing it into memory" > doesn't count.
If you are correct, then there a fundamental design problem with my Linux Booting Linux code. Because that is exactly what I do. I stuff the kernel in memory and jump to it. Once the new kernel starts there is no back and forth. _Please_ help me understand why this back and forth is needed.
Here is my experience. Non-interactive etherboot, doesn't know what it is booting, or where it is booting from until the DHCP server tells it. Then it gets a file from a TFTP server and boots that.
When booting the Linux kernel it never attempts to do a back and forth via the firmware to the boot medium. Instead someone has a clue about what the boot medium was and it mounts that medium using it's own drivers. Booting a rescue cd is a good example.
_Please_ help me find the flaw in my understanding.
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