Re: Loading a Second Kernel
On Tuesday 17 April 2007 11:33, Jon Steel wrote: Hi Im trying to find a way to do a sort of very soft reboot. For example I want to boot up the computer into a kernel on one drive, and then after saying reboot, the computer loads up a kernel from a second drive. I have gotten this to work with the use of a file to pass information between boots, but that is not an ideal solution. What I really want is either a way to pass a parameter to the BIOS so that it can pass it to boot upon restarting, or a way to reload the boot loader into memory and then execute it. It would even be fine to use another operating system on the first boot. So it boots up into say Gentoo, and then when Im done with that, I want to load OpenBSD. Does anybody have an idea how I can approach this? Thanks Jonathan Steel man 8 boot You can do all sorts of cool things while booting and with /etc/boot.conf, including what you want (assuming your are booting instances of OpenBSD on each drive). The ``image'' is a combination of a device and a file name. You can also change your boot device on some i386 systems through your CMOS settings or your SCSI controller settings. Other archs are much better at this (Sun, PARISC, Alpha, ...), and you don't need to fiddle with stuff. Of course you can also net-boot, and make the desired change from one kernel/config to another at the server. Kind Regards, JCR
Re: Loading a Second Kernel
In article [EMAIL PROTECTED], Jon Steel wrote: I have gotten this to work with the use of a file to pass information between boots, but that is not an ideal solution. What I really want is either a way to pass a parameter to the BIOS so that it can pass it to boot upon restarting, or a way to reload the boot loader into memory and then execute it. This is not really possible on the PC architecture. The only way to currently do this is to hack things. Either by putting some stuff into RAM, with checksums and all, and have /boot search for it, and if it find it, execute it. This may or may not work. Some BIOS clear memory on reboot, others don't. Another way is to do some hacking to the unused parts of the NVRAM on PCs, and check for that in /boot again, modifying the boot process as you want. It would even be fine to use another operating system on the first boot. So it boots up into say Gentoo, and then when Im done with that, I want to load OpenBSD. If that is the case, run vmware with a windows/linux host. You can then boot different root disks for example. Does anybody have an idea how I can approach this? Bug Dell and other big consortium PC makers to have a BIOS API defined to store things and retrieve things from NVRAM. Hell to document what the BIOS will use to configure console redirection, boot ordering, etc, so that we can store and use the information in a compatible manner from userland. Oh, while you're at it, have them define a simple way to do a putc(3) and getc(3) through the bios as well (from 16-bit and 32-bit applications), that will respect console redirections of course. Lalalaa, -- [100~Plax]sb16i0A2172656B63616820636420726568746F6E61207473754A[dZ1!=b]salax
Re: Loading a Second Kernel
On 4/17/07, Jon Steel [EMAIL PROTECTED] wrote: Im trying to find a way to do a sort of very soft reboot. For example I want to boot up the computer into a kernel on one drive, and then after saying reboot, the computer loads up a kernel from a second drive. This sounds very similar to the Linux kexec api. Whether it actually is, and whether this can be ported to OpenBSD is left as an exercise. :) http://www-128.ibm.com/developerworks/linux/library/l-kexec.html -- ach
Re: Loading a Second Kernel
On Tue, 2007-04-17 at 14:33 -0400, Jon Steel wrote: Hi Im trying to find a way to do a sort of very soft reboot. For example I want to boot up the computer into a kernel on one drive, and then after saying reboot, the computer loads up a kernel from a second drive. I have gotten this to work with the use of a file to pass information between boots, but that is not an ideal solution. What I really want is either a way to pass a parameter to the BIOS so that it can pass it to boot upon restarting, or a way to reload the boot loader into memory and then execute it. It would even be fine to use another operating system on the first boot. So it boots up into say Gentoo, and then when Im done with that, I want to load OpenBSD. Does anybody have an idea how I can approach this? You could install a bootloader that uses a conf file, and have a script that edits that and then reboots into your chosen OS. Of course, down that road may lie much frustration as a badly-written script can cause you to reboot with a ramdisk or some such and edit by hand. Thanks Jonathan Steel
Re: Loading a Second Kernel
Hi Hi Im trying to find a way to do a sort of very soft reboot. For example I want to boot up the computer into a kernel on one drive, and then after saying reboot, the computer loads up a kernel from a second drive. forget about pc then move onto Sun and the like eeprom boot-device diskN where your os resides I have gotten this to work with the use of a file to pass information between boots, but that is not an ideal solution. What I really want is either a way to pass a parameter to the BIOS so that it can pass it to boot upon restarting, or a way to reload the boot loader into memory and then execute it. eeprom boot-file mykernel It would even be fine to use another operating system on the first boot. So it boots up into say Gentoo, and then when Im done with that, I want to load OpenBSD. Does anybody have an idea how I can approach this? Not on a pc ...
