On Aug 21, 2005, at 6:21 PM, Rogério Brito wrote:
On Aug 20 2005, Rick Thomas wrote:NewWorld Macs can boot off of CDs, so these boot floppies are only necessary for OldWorld PowerMacs, which, being out of production, have a fixed unchanging set of devices.That is false, as you can obviously upgrade your box with other devices and even the way of booting (e.g., by using a Tempo Trio card, which supports using IDE instead of the SCSI commonly found in OldWorld macs).
You are, of course, correct in the larger context. But this was in the context of installation boot floppies, not general-purpose kernels.
For a boot floppy kernel (or, if you prefer, "second stage boot loader") all you need is the ability to talk to the console (serial and/or video) and keyboard, and read a floppy disk to get a driver module for the device you want to extract the installation kernel and initial ramdisk from. This make things somewhat easier. The APIs for the serial console, on-board video-frame-buffer, and floppy disk drive are unlikely to change given that Apple is not developing this kind of machine anymore.
Of course, someone will need to write the driver modules for all the new hardware that can be hung off a PCI bus, but that's a different problem. Also, it's not as big a problem as writing a general-purpose driver for a new device. All the loadable driver module has to be able to do is read the kernel and initial ramdisk. It's the new kernel that gets stuck with all the heavy lifting or running the installation process.
Of course, as Sven pointed out, you also need to have code to switch out one kernel and switch in another, which doesn't exist at this point in time.
In any case, Sven didn't like the idea and I haven't got the time or expertise to do it myself, so it's not going to happen.
There is current discussion on the lkml discussing which kernels oneshould use with small systems (like old 486s and such) and the consensusseems to be that one should use either a 2.6 kernel (perhaps using some of the linux-tiny patches) or use a really ancient kernel. I would say that if more of the linux-tiny patches were incorporated in the mainline kernel, then it would be a really nice addition.
I'm not aware of "linux-tiny". Where can I learn more about it? Enjoy! Rick