On 2025-08-04 19:26, Perry Metzger wrote:
On 8/4/25 12:36, Jason Thorpe wrote:On Aug 4, 2025, at 7:45 AM, Johnny Billquist<bqt%softjar.se@localhost> wrote: I'll just top-post to be lazy. First of all, as you know, MOP is the "native" way to netboot DEC machines from back in the day. And MOP sortof fills the place of both DHCP and TFTP in one. But it's more targeted for the explicit need of netbooting and remote management. But in a sense, for VAXen, it would be great if we had the possibility of getting all the netbooting though MOP and not need DHCP and TFTP. Not sure if that is possible, though.Can MOP supply the IP address to the system? If not, you're not goingto be eliminating DHCP (or BOOTP).Certainly, but it's nice not to have to load boot blocks that then just load the kernel if you can just load the kernel in one step. The OS will use dhclient to get its address.
I'm starting to suspect you don't understand the full process of the booting.
The boot block is a really simple piece of code that resides in the first block(s) of a disk, and the sole purpose of that code is to read in the /boot image.
The /boot image in turn is responsible for reading in the kernel.The boot block never reads in the kernel. It's not advanced enough to be able to deal with that. And it can't be. There are limits on how much code you can stash into the boot block.
If you substitute "/boot" for whenever you say "boot block", then you are more in the right place. And MOP reads in /boot. And the next step from there is reading in the kernel. But at the moment, dhcp is needed here, because boot needs to know which address to fetch the kernel from, as well as what filename to fetch, and some other bits. And then, once the kernel have booted, it will also request what IP address itself should use.
What would be nice would be if /boot, instead of depending on dhcp and tftp, could use MOP as well, to get the kernel, as well as the parameters for getting the kernel and its own configuration parameters. Then you could probably skip tftp altogether, and dhcp would be more for normal operation, and not needed for the initial booting.
Although, since dhcp would probably always be needed/used anyway, there is probably less arguments for trying to remove that dependency.
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
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