[syslinux] memdisk : booting OpenBSD and NetBSD

Mon Apr 5 15:31:05 PDT 2004

I had a similar problem (with OpenBSD). In my case, I couldn't even get 
to the boot prompt.

My current work around (as suggested by somebody), is to tell ISOLinux 
to boot the image use BIOS emulation.

i.e. "kernel floppy34.img" in your isolinux.cfg file or "floppy34.img" 
on the boot prompt. This solves the problem.
However if your machine has an older BIOS (and hence probably buggy) 
then this may not help.

- Murali

Benjamin Pineau wrote:

>hi there.
>
>I'm trying to boot several OSes floppy images from a cdrom via memdisk.
>
>Actually, Linux and FreeBSD boots fine, but, while i'm using the same method,
>I couldn't get into booting netbsd nor openbsd.
>
>The boot process seems to hang up, in those two cases, when the second stage
>native bootloader try to load the kernel (i'm not absolutely sure about this).
>The native first stage bootloader works fine in both case.
>
>So I supect a bug in memdisk (well, something that makes it differs from a bios
>in the os viewpoint, shouldn't happen...).
>
>I use the standard netbsd's 'rescue-tiny.fs' floppy image (you can try it at:
>ftp://ftp.netbsd.org/pub/NetBSD/NetBSD-1.6.2/i386/installation/floppy/rescue-tiny.fs)
>and the standard openbsd's 'floppy35.fs' image from
>ftp://ftp.openbsd.org/pub/OpenBSD/snapshots/i386/floppy35.fs
>Both boots fine when they're loaded straigth from the bios (eg: when installed
>on a floppy without syslinux/memdisk and booted from there). Tried with two
>differents bios. I also tried with different floppy and hard drive images.
>
>Here, more infos:
>------------- menu.lst -------------------
>#I use grub to load memdisk
>title FreeBSD rescue disk (works fine)
>kernel /boot/memdisk
>initrd=/boot/boot.flp
>title OpenBSD rescue disk (not yet functional)
>kernel /boot/memdisk
>initrd=/boot/floppy35.fs
>title NetBSD rescue disk (not yet functional)
>kernel /boot/memdisk
>initrd=/boot/rescue-tiny.fs
>-------------------------------------------
>note: following outputs copied by hand, hope without errors
>
>------------ sample output, netbsd: -------
>[...]
>INT 13 08: Success, count = 2 BPT = 0000:0000
>old: int13 = ec6a40bd int15 = f000f859
>new: int13 = 9f000008 int15 = 9f00027c
>Loading boot sectore... booting...
>
> >> NetBSD/i386 BIOS Boot, Revision 2.13
> >> (autobuild at tgm.netbsd.org, Tue Feb 10 21:25:10 UTC 2004)
> >> Memory: 636/127776 k
> Press return to boot now, any other key for boot menu
> booting hd0a:netbsd - starting in 0
> 978496-
>-------------------------------------------
>
>The 'starting in 0' is just a counter that decrease from 5 to 0 seconds.
>The '978496' is a sort of counter (dunno what) that grows when (i thing) 
>the NetBSD  kernel is loaded. Everything freezes here, I don't know if
>it's while loading the kernel in memory, or while trying to amorce it or 
>something else...
>
>
>-------------------------------------------
>- sample output, openbsd:
>[...]
>command line: mem=131072K
>Disk is floppy, 1440 k, C/H/S = 80/2/18 
>Total size needed = 1509 bytes, allocating 2k
>Old dos memory at 0x9f800 (map says 0x9f800), loading at 0x9f000
>1588: 0xffff 15E801: 0x3c00 0x06d8
>INT 13 08: Success, count = 2 BPT = f000:85d0
>old: int13 = ec6a40bd int15 = f000f859
>new: int13 = 9f000008 int15 = 9f00027c
>Loading boot sector... booting...
>
>  Loading;...........
>  probing: pc0 com0 com1 apm mem[632k 124M 1024k a20=on]
>  disk: fd0 fd1 hd0+*
>  >> OpenBSD/i386 BOOT 2.06
>  boot> 
>  booting fd0a:/bsd: 3281040_
>
>-------------------------------------------
>
>Then it freezes (the ' booting fd0a:/bsd' indicates that we are actually
>loading the openbsd kernel). In normal case, the output should seems like:
>this: "booting hd0a:/bsd 4464500+838332 [58+204240+181750]=0x56cfd0".
>
>Running on vmware, I got this at this point (only with openbsd, not netbsd):
>
>*** Virtual machine kernel stack fault (hardware reset) ***
>The virtual machine just suffered a stack fault in kernel mode. On a real
>computer, this would amount to a reset of the processor. It can be caused by
>an incorrect configuration of the virtual machine, a bug in the operating
>system, or a problem in the VMware Workstation software. Press OK to reboot
>virtual machine or Cancel to shut it down.
>
>
>The openbsd boot process is described here:
>http://www.openbsd.org/faq/faq14.html#Boot386
>and there:
>http://www.openbsd.org/cgi-bin/man.cgi?query=boot&sektion=8&arch=i386&apropos=0&manpath=OpenBSD+Current
>
>Does anyone there have an idea about booting one of thoses os from memdisk ?
>or an idea of the reason that make it so difficult ?
>
>
>
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