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Hello,

I've been digging some more during the last couple of days, as no-one
has yet replied to my original e-mail I guess I'll do so myself.

I've progressed a little, but unfortunately I'm not there yet. At least
by starting out with the mkdiskimage tool I can perfectly convert an
ISO to a "disk image" which will boot the machine *if I put it on a USB
stick*.

My ISO file is 108MB large, so I create a 110MB disk image:
# mkdiskimage -o -M ubcd403.img 110 16 63
32256

Install boot loader:
# /usr/local/syslinux-3.36/unix/syslinux -o 32256 ubcd403.img

Mount ISO and disk image:
# losetup -o 32256 /dev/loop0 ubcd403.img
# mkdir /tmp/iso /tmp/img
# mount -o loop,ro ubcd403.iso /tmp/iso/
# mount /dev/loop0 /tmp/img/

And copy the ISO contents:
# cd /tmp/imag
# cp -R /tmp/iso/* .

Unmount everything and detach disk image from loop device:
# umount /tmp/img/ /tmp/iso
# losetup -d /dev/loop0

So now I've got a nice ubcd403.img file. If I dd it to a flash drive
in /dev/sda I can perfectly boot the "Ultimate Boot CD" from it.

So I tend to think the disk image file itself is okay.

However, making it available through pxelinux as follows doesn't work:

label ubcd
kernel memdisk
append initrd=images/test/ubcd403.img harddisk

The machine just hangs there at "Loading boot sector... booting..."
(See below for full output)


What am I doing wrong?


Best regards,

Pascal Vandeputte


P.S. In my original post, I pointed out that the image couldn't be
transferred if it was 94371840 bytes in size. Apparently a
collegue of mine had swapped out tftpd-hpa for atftpd on our
file server. :((
Grrrr...
At least that problem is fixed now.


P.S. Full output for a 9MB disk image which works on a USB stick:

MEMDISK 3.36 2007-02-10 Copyright 2001-2007 H. Peter Anvin
e820: 0000000000000000 000000000009f400 1
e820: 000000000009f400 0000000000000c00 2
e820: 00000000000dc000 0000000000024000 2
e820: 0000000000100000 0000000005df0000 1
e820: 0000000005ef0000 000000000000f000 3
e820: 0000000005eff000 0000000000001000 4
e820: 0000000005f00000 0000000000100000 1
e820: 00000000fec00000 0000000000010000 2
e820: 00000000fee00000 0000000000001000 2
e820: 00000000fffe0000 0000000000020000 2
Ramdisk at 0x055f4000, length 0x008dc000
command line: initrd=images/test/ubcd403.img harddisk BOOT_IMAGE=memdisk
Disk is hard disk 0, 9072 K, C/H/S = 18/16/63, EDD on
Total size needed = 2412 bytes, allocating 3K
Old dos memory at 0x9f400 (map says 0x9f400), loading at 0x9e800
1588: 0xfff 15E801: 0x3c00 0x045f
INT 13 08: Success, count = 1, BPT = 0000:0000
old: int13 = ebeb25fc int15 = f000f859
new: int13 = 9e800008 int15 = 9e800376
Loading boot sector... booting...





Pascal Vandeputte wrote:
> Hi,
>
> I am aware that it is impossible to netboot ISO files through
> pxelinux/memdisk and that there are multiple reasons for not
> even attempting it (like the operating system which will try
> to access a physical optical drive through its own drivers
> anyway, BIOS issues etc.).
>
> When people ask questions regarding ISO support in
> pxelinux/memdisk, they're mostly told to convert the ISO into
> a "disk image" and boot it that way. We usually don't hear back
> from these people. Either they find it obvious how to do this
> and everything always works, or they don't even bother to try
> it.
>
> Unfortunately I don't find it that obvious at all. As far as I
> know it should be relatively straightforward if you can create
> a sufficiently large file, partition it, create the right
> filesystem, modify some OS config files and the bootloader. And
> create an MBR in that file while you're at it. Simple.
>
> A few days ago I needed to convert an ISO for installing FreeBSD
> on a lot of 1U boxes without an optical drive. For many Linux
> distros you can find a PXE version of the installer ready to
> download, but for FreeBSD converting the ISO seemed to be the
> easiest way to get started, as these are my first BSD steps.
>
> After a lot of googling and forum browsing, the only information I
> could find which effectively got the job done was an e-mail by Shaun
> Reitan on this mailing list:
> http://syslinux.zytor.com/archives/2005-October/006076.html
> And even then it's a little hard to swallow if you're only used to
> Linux.
>
> I thought it would be a good idea to rewrite Shauns command listing
> into something which slightly resembles a howto and post it to this
> list. See below.
> Maybe the SYSLINUX project home page isn't the right place for howtos
> like this, but I feel that it should at least contain a pointer to
> a few examples.
>
> Enthousiastic about this first success, I'm eager to try it another
> time, now with a different ISO namely the "Ultimate Boot CD" which is
> even using ISOLINUX.
> I'm stuck however. I create a file with dd, attach it to loop0 with
> losetup, partition it (W95 FAT16 LBA?), re-attach it with the right
> offset for the first partition, format it (mkdosfs/mkfs.vfat), mount
> it and copy all files. But then I'm stuck. I need to write an MBR
> without ruining the partition table but I don't know how, and I
> probably need to do something with the isolinux.cfg file as well. But
> what?
>
> Does a howto, similar to the one below, exist?
>
> Another problem I get is that pxelinux doesn't find the disk image
> file as soon as it's 94371840 bytes large. 94370816 bytes is fine. The
> amount of allocated memory in VMWare doesn't seem to affect this.
>
>
> Best regards,
>
> Pascal Vandeputte
>
>
>
>
> ***********************************************************************
>
> How to create a PXE-bootable disk image of the FreeBSD "bootonly"
> install ISO
> =======================================================================
> Based on an e-mail by Shaun Reitan on the SYSLINUX mailing list in
> October 2005.
> http://syslinux.zytor.com/archives/2005-October/006076.html
>
>
> The general idea:
> -----------------
> - transform the small "bootonly" ISO (which is intended to fetch all OS
> files over the network) into a PXE-bootable harddisk image
> - make the first installation CD available on the network e.g. through NFS
>
> This howto only explains how to create the PXE-bootable image.
>
>
> - Download the "bootonly" installation ISO (about 25MB for FreeBSD 6.2)
> e.g.
> ftp://ftp.freebsd.org/pub/FreeBSD/releases/i386/ISO-IMAGES/6.2/6.2-RELEASE-i386-bootonly.iso
>
> - If case you haven't got a FreeBSD system running already, install BSD
> somewhere temporarily using the first installation ISO (e.g. in VMWare).
>
> - Copy the "bootonly" ISO to your BSD system, e.g. using scp or WinSCP.
>
> - Find out how large you need to create your disk image:
>
> # ls -al *.iso
> -rw-r--r-- 1 root wheel 25444352 Apr 16 15:44
> 6.2-RELEASE-i386-bootonly.iso
>
> - Create a file of the appropriate size (make it a little larger to
> account for differences in block size, file system overhead etc.):
>
> # dd if=/dev/zero of=6.2-RELEASE-i386-bootonly.img bs=1k count=26000
> 26000+0 records in
> 26000+0 records out
> 26624000 bytes transferred in 1.404435 secs (18957091 bytes/sec)
>
> # ls -al *.iso *.img
> -rw-r--r-- 1 root wheel 26624000 Apr 27 03:28
> 6.2-RELEASE-i386-bootonly.img
> -rw-r--r-- 1 root wheel 25444352 Apr 16 15:44
> 6.2-RELEASE-i386-bootonly.iso
>
> - Attach this image file as a memory disk:
>
> # mdconfig -a -t vnode -f 6.2-RELEASE-i386-bootonly.img -u 0
>
> - Write a BSD label with boot code to it:
>
> # bsdlabel -w -B md0 auto
>
> - And create a filesystem on it (BSD uses ufs):
>
> # newfs -m 0 md0a
> Warning: changing optimization to space because minfree is less than 8%
> /dev/md0a: 25.4MB (51984 sectors) block size 16384, fragment size 2048
> using 4 cylinder groups of 6.36MB, 407 blks, 832 inodes.
> super-block backups (for fsck -b #) at:
> 160, 13184, 26208, 39232
>
> - Create a mount point and mount this "memory disk" device (attached to the
> image file):
>
> # mkdir /tmp/img
> # mount /dev/md0a /tmp/img
> # df /tmp/img
> Filesystem 1K-blocks Used Avail Capacity Mounted on
> /dev/md0a 24950 4 24946 0% /tmp/img
>
> - Create another mount point and mount the ISO file on it through another md
> device:
>
> # mkdir /tmp/iso
> # mdconfig -a -t vnode -f 6.2-RELEASE-i386-bootonly.iso -u 1
> # mount_cd9660 /dev/md1 /tmp/iso
> # df /tmp/iso
> Filesystem 1K-blocks Used Avail Capacity Mounted on
> /dev/md1 24848 24848 0 100% /tmp/iso
>
> - Copy the ISO contents to the new disk image file:
>
> # cd /tmp/img/
> # cp -r /tmp/iso/* .
> # ls -al
> total 12
> drwxr-xr-x 4 root wheel 512 Apr 27 03:40 .
> drwxrwxrwt 8 root wheel 512 Apr 27 03:36 ..
> drwxrwxr-x 2 root operator 512 Apr 27 03:35 .snap
> dr-xr-xr-x 5 root wheel 512 Apr 27 03:40 boot
> -r--r--r-- 1 root wheel 2048 Apr 27 03:40 boot.catalog
> -r--r--r-- 1 root wheel 25 Apr 27 03:40 cdrom.inf
>
> - Unmount and detach all md devices:
>
> # cd
> # umount /tmp/img /tmp/iso
> # mdconfig -d -u 0
> # mdconfig -d -u 1
>
> - We're done. Copy the .img file to your tftp server.
>
> # ls -al *.img *.iso
> -rw-r--r-- 1 root wheel 26624000 Apr 27 03:41
> 6.2-RELEASE-i386-bootonly.img
> -rw-r--r-- 1 root wheel 25444352 Apr 16 15:44
> 6.2-RELEASE-i386-bootonly.iso
>
> - And add something similar to this to your pxelinux.cfg/default file:
>
> label freebsd62
> kernel memdisk
> append initrd=images/freebsd/6.2-RELEASE-i386-bootonly.img harddisk
>
> _______________________________________________
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Op 30-04-2007 om 19:45 schreef Pascal Vandeputte:
>
> Hi,
>
<bigsnip/>
>
> I thought it would be a good idea to rewrite Shauns command listing into
> something which slightly resembles a howto and post it to this list.
> Maybe the SYSLINUX project home page isn't the right place for howtos like
> this, but I feel that it should at least contain a pointer to a few examples.

It it now also at
http://syslinux.zytor.com/wiki/index.php/DiskImageCreation


HtH
GSt

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Op 02-05-2007 om 18:25 schreef Pascal Vandeputte:
>
> Hello,
>
> I've been digging some more during the last couple of days, as no-one
> has yet replied to my original e-mail I guess I'll do so myself.
>
> I've progressed a little, but unfortunately I'm not there yet. At least
> by starting out with the mkdiskimage tool I can perfectly convert an
> ISO to a "disk image" which will boot the machine *if I put it on a USB
> stick*.
>
> My ISO file is 108MB large, so I create a 110MB disk image:
> # mkdiskimage -o -M ubcd403.img 110 16 63
> 32256
>
> Install boot loader:
> # /usr/local/syslinux-3.36/unix/syslinux -o 32256 ubcd403.img
>
> Mount ISO and disk image:
> # losetup -o 32256 /dev/loop0 ubcd403.img
> # mkdir /tmp/iso /tmp/img
> # mount -o loop,ro ubcd403.iso /tmp/iso/
> # mount /dev/loop0 /tmp/img/
>
> And copy the ISO contents:
> # cd /tmp/imag
> # cp -R /tmp/iso/* .
>
> Unmount everything and detach disk image from loop device:
> # umount /tmp/img/ /tmp/iso
> # losetup -d /dev/loop0
>
> So now I've got a nice ubcd403.img file. If I dd it to a flash drive
> in /dev/sda I can perfectly boot the "Ultimate Boot CD" from it.
>
> So I tend to think the disk image file itself is okay.
>
> However, making it available through pxelinux as follows doesn't work:
>
> label ubcd
> kernel memdisk
> append initrd=images/test/ubcd403.img harddisk
>
> The machine just hangs there at "Loading boot sector... booting..."
>
>
> What am I doing wrong?

:-)


Several things, one is asking "What am I doing wrong?"

<preach>
Make the challenge a common challenge by avoiding 'I'.

Wrong is the wrong word, there is nothing wrong with a expriment.
If an expriment does learn you something, it is good expriment.
</preach>


The missing knowlegde ( in fact the missing imagination ) :

Syslinux is started from ROM and loads a kernel or program from floppy
or other FAT filesystem and starts it.

Isolinux is started from ROM and loads a kernel or program from CD
and starts it.

PXElinux is started from ROM and loads a kernel or program from the
network and starts it.



What your expriment proves, is that you have started PXElinux starting
a syslinux that can't do it's job.


> Best regards,
>
> Pascal Vandeputte


Cheers
Geert Stappers
--
For better logical thinking: Allow reading in the order as it was discussed.
So please reply below the original text.

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Geert Stappers wrote:
> Op 02-05-2007 om 18:25 schreef Pascal Vandeputte:
>> Hello,
>>
>> I've been digging some more during the last couple of days [...]
>>
>> <snip...>
>>
>> So now I've got a nice ubcd403.img file. If I dd it to a flash drive
>> in /dev/sda I can perfectly boot the "Ultimate Boot CD" from it.
>>
>> So I tend to think the disk image file itself is okay.
>>
>> However, making it available through pxelinux as follows doesn't work:
>>
>> label ubcd
>> kernel memdisk
>> append initrd=images/test/ubcd403.img harddisk
>>
>> The machine just hangs there at "Loading boot sector... booting..."
>>
>>
>> What am I doing wrong?
>
> :-)
>
>
> Several things, one is asking "What am I doing wrong?"
>
> <preach>
> Make the challenge a common challenge by avoiding 'I'.
>
> Wrong is the wrong word, there is nothing wrong with a expriment.
> If an expriment does learn you something, it is good expriment.
> </preach>

Hmm... Maybe this is the wrong mailing list... :^)

I learnt a lot, but Murphy surely has a hand in this...
atftpd is now swapped out for tftpd-hpa, and other netboot options
(Knoppix terminal server etc) still work perfectly, but all of a sudden
the FreeBSD disk image doesn't work anymore! What gives? TFTP'ing a file
is TFTP'ing a file, isn't it? Instead of seeing the FreeBSD boot loader
appear there's now only a "Read error" after "Loading boot sector...
booting...". This should be the BSD boot code speaking.
MEMDISK complains "Image seems to have fractional end cylinder", but
maybe it did so before already.


> The missing knowlegde ( in fact the missing imagination ) :
>
> Syslinux is started from ROM and loads a kernel or program from floppy
> or other FAT filesystem and starts it.
>
> Isolinux is started from ROM and loads a kernel or program from CD
> and starts it.
>
> PXElinux is started from ROM and loads a kernel or program from the
> network and starts it.

Well... When the FreeBSD image is booted (back in the days when it
worked :( ), this should be what was going on:

PC BIOS -> NIC PXE BIOS -> pxelinux.0 -> memdisk & freebsd.img
memdisk accesses the MBR in freebsd.img which contains some boot code
which loads the BSD loader (/boot/loader) which loads the kernel from
the first partition. (see
http://www.khmere.com/freebsd_book/html/ch02.html for way more details
on this)
And it works! (or at least it did with atftpd yesterday...)
And it works on a flash stick too!

So when attempting the same with the Ultimate Boot CD:
PC BIOS -> NIC PXE BIOS -> pxelinux.0 -> memdisk & ubcd403.img
memdisk accesses the MBR in ubcd403.img which contains some SYSLINUX
boot code which loads the SYSLINUX boot loader (ldlinux.sys) which loads
whatever it's told to load in syslinux.cfg (i.e. the UBCD menu).

So that boils down to almost the same thing. And the image works on a
flash stick too. As long as memdisk (the "kernel or program from the
network" you refer to) finds and starts the right MBR code, what's the
difference?


> What your expriment proves, is that you have started PXElinux starting
> a syslinux that can't do it's job.

SYSLINUX seems to do it's job just fine from a flash drive, just like
the BSD loader can, but the same image won't work when memdisk emulates
it, while the BSD one works (or better: worked... sigh).


Best regards,

Pascal Vandeputte

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Pascal Vandeputte wrote:
[...]
> I learnt a lot, but Murphy surely has a hand in this...
> atftpd is now swapped out for tftpd-hpa, and other netboot options
> (Knoppix terminal server etc) still work perfectly, but all of a sudden
> the FreeBSD disk image doesn't work anymore! What gives? TFTP'ing a file
> is TFTP'ing a file, isn't it? Instead of seeing the FreeBSD boot loader
> appear there's now only a "Read error" after "Loading boot sector...
> booting...". This should be the BSD boot code speaking.
> MEMDISK complains "Image seems to have fractional end cylinder", but
> maybe it did so before already.

After rebuilding that FreeBSD image a few times while double-checking
everything, the solution to this enigma emerged:

=> I was still using memdisk version 3.07 while testing with the FreeBSD
image and only upgraded to 3.36 to be sure I wasn't wrestling with an
issue which was already fixed, prior to mailing to the maillist.

So a FreeBSD image works with memdisk 3.07 but NOT with 3.36.
Interesting, don't you think?

Now if we try the very same UBCD image once more, we get some SYSLINUX
output:

"Could not find kernel image: linux"

It's not much, but it's something.


Greetings,

Pascal Vandeputte

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Pascal Vandeputte wrote:
>
> After rebuilding that FreeBSD image a few times while double-checking
> everything, the solution to this enigma emerged:
>
> => I was still using memdisk version 3.07 while testing with the FreeBSD
> image and only upgraded to 3.36 to be sure I wasn't wrestling with an
> issue which was already fixed, prior to mailing to the maillist.
>
> So a FreeBSD image works with memdisk 3.07 but NOT with 3.36.
> Interesting, don't you think?
>
> Now if we try the very same UBCD image once more, we get some SYSLINUX
> output:
>
> "Could not find kernel image: linux"
>

Could you try 3.50-pre6?

-hpa

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H. Peter Anvin wrote:
> Pascal Vandeputte wrote:
>> After rebuilding that FreeBSD image a few times while double-checking
>> everything, the solution to this enigma emerged:
>>
>> => I was still using memdisk version 3.07 while testing with the FreeBSD
>> image and only upgraded to 3.36 to be sure I wasn't wrestling with an
>> issue which was already fixed, prior to mailing to the maillist.
>>
>> So a FreeBSD image works with memdisk 3.07 but NOT with 3.36.
>> Interesting, don't you think?
>>
>> Now if we try the very same UBCD image once more, we get some SYSLINUX
>> output:
>>
>> "Could not find kernel image: linux"
>>
>
> Could you try 3.50-pre6?
>
> -hpa

Assuming you are aiming at the memdisk issue: unfortunately 3.50-pre6
cannot start the FreeBSD image either.

After going through some versions prior to 3.36 it appears that the
change occurred between 3.31 (working) and 3.35 (not working). Currently
testing the "Testing/Obsolete" versions and it seems the fatal change
was done going from 3.32-pre2 to 3.32-pre3.

If you're interested I can supply you with the disk image file for testing.

Greetings,

Pascal Vandeputte

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Pascal Vandeputte wrote:
>
> If you're interested I can supply you with the disk image file for testing.
>

Sure. I did get a bug report for that, but I thought it had been
"fixed" (as in, worked around their bug...)

-hpa

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Pascal Vandeputte wrote:
>
> After going through some versions prior to 3.36 it appears that the
> change occurred between 3.31 (working) and 3.35 (not working). Currently
> testing the "Testing/Obsolete" versions and it seems the fatal change
> was done going from 3.32-pre2 to 3.32-pre3.
>

Could you try it with the "noedd" option?

-hpa

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H. Peter Anvin wrote:
> Pascal Vandeputte wrote:
>
>> If you're interested I can supply you with the disk image file for testing.
>>
>>
>
> Sure. I did get a bug report for that, but I thought it had been
> "fixed" (as in, worked around their bug...)
>
> -hpa
>

You can find the disk image here:
http://users.atlantis.ugent.be/pvdputte/6.2-RELEASE-i386-bootonly.img.gz

I'll try that "noedd" option tomorrow morning (it is now almost midnight
over here, just got home from work, time to get some sleep. :)

Good night,

Pascal Vandeputte

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H. Peter Anvin wrote:
> Pascal Vandeputte wrote:
>> After going through some versions prior to 3.36 it appears that the
>> change occurred between 3.31 (working) and 3.35 (not working). Currently
>> testing the "Testing/Obsolete" versions and it seems the fatal change
>> was done going from 3.32-pre2 to 3.32-pre3.
>>
>
> Could you try it with the "noedd" option?

Hi,

The "noedd" option indeed fixes the problem. Works now with 3.36 and
3.50-pre6. But you probably want it working with EDD as well?

Thanks you for your time,

Pascal Vandeputte

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Pascal Vandeputte wrote:
> H. Peter Anvin wrote:
>> Pascal Vandeputte wrote:
>>> After going through some versions prior to 3.36 it appears that the
>>> change occurred between 3.31 (working) and 3.35 (not working). Currently
>>> testing the "Testing/Obsolete" versions and it seems the fatal change
>>> was done going from 3.32-pre2 to 3.32-pre3.
>>>
>> Could you try it with the "noedd" option?
>
> Hi,
>
> The "noedd" option indeed fixes the problem. Works now with 3.36 and
> 3.50-pre6. But you probably want it working with EDD as well?

Well, it's hard to know if it's memdisk that's at fault or FreeBSD. In
3.36 I changed it so floppy images have EDD off by default, but yours is
apparently a hard disk image?

Anyway, it's a pretty low priority at the moment...

-hpa

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H. Peter Anvin wrote:
> Pascal Vandeputte wrote:
>> H. Peter Anvin wrote:
>>> Pascal Vandeputte wrote:
>>>> After going through some versions prior to 3.36 it appears that the
>>>> change occurred between 3.31 (working) and 3.35 (not working). Currently
>>>> testing the "Testing/Obsolete" versions and it seems the fatal change
>>>> was done going from 3.32-pre2 to 3.32-pre3.
>>>>
>>> Could you try it with the "noedd" option?
>> Hi,
>>
>> The "noedd" option indeed fixes the problem. Works now with 3.36 and
>> 3.50-pre6. But you probably want it working with EDD as well?
>
> Well, it's hard to know if it's memdisk that's at fault or FreeBSD. In
> 3.36 I changed it so floppy images have EDD off by default, but yours is
> apparently a hard disk image?
>
> Anyway, it's a pretty low priority at the moment...
>
> -hpa


Well, I just managed to get the Ultimate Boot CD ISO converted into a
PXE-bootable hard disk image, and the behaviour is identical: if I use
3.07 it works, 3.36 doesn't, 3.36 + "noedd" works fine.

The UBCD has nothing to do with FreeBSD as far as I know, it starts the
menu.c32 menu which offers many options.

I could pass you that image as well if you wish. I'll mail details on
how to create it in a later mail. (short on time right now)

Best regards,

Pascal Vandeputte

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On Fri, 2007-05-04 at 18:37 +0200, Pascal Vandeputte wrote:
> H. Peter Anvin wrote:
> > Pascal Vandeputte wrote:
> >> H. Peter Anvin wrote:
> >>> Pascal Vandeputte wrote:
> >>>> After going through some versions prior to 3.36 it appears that the
> >>>> change occurred between 3.31 (working) and 3.35 (not working). Currently
> >>>> testing the "Testing/Obsolete" versions and it seems the fatal change
> >>>> was done going from 3.32-pre2 to 3.32-pre3.
> >>>>
> >>> Could you try it with the "noedd" option?
> >> Hi,
> >>
> >> The "noedd" option indeed fixes the problem. Works now with 3.36 and
> >> 3.50-pre6. But you probably want it working with EDD as well?
> >
> > Well, it's hard to know if it's memdisk that's at fault or FreeBSD. In
> > 3.36 I changed it so floppy images have EDD off by default, but yours is
> > apparently a hard disk image?
> >
> > Anyway, it's a pretty low priority at the moment...
> >
> > -hpa
>
>
> Well, I just managed to get the Ultimate Boot CD ISO converted into a
> PXE-bootable hard disk image, and the behaviour is identical: if I use
> 3.07 it works, 3.36 doesn't, 3.36 + "noedd" works fine.
>
> The UBCD has nothing to do with FreeBSD as far as I know, it starts the
> menu.c32 menu which offers many options.
>
> I could pass you that image as well if you wish. I'll mail details on
> how to create it in a later mail. (short on time right now)
>

Not to toot my own horn but if your just trying to duplicate most of the
resources on UBCD you might want to look at http://pxeknife.erebor.org
as it will work fine with all of the syslinux family. UBCD however will
not as it makes a LOT of assumptions about how it works, where it can
get things and which utilities and what not it uses to load it's images
(it's not limited to syslinux). So the problems you might be seeing in
getting UBCD to work may not be related to your image or syslinux, it
may be related to the fact UBCD can't really be converted.

- John 'Warthog9' Hawley

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Pascal Vandeputte wrote:
>
> Well, I just managed to get the Ultimate Boot CD ISO converted into a
> PXE-bootable hard disk image, and the behaviour is identical: if I use
> 3.07 it works, 3.36 doesn't, 3.36 + "noedd" works fine.
>
> The UBCD has nothing to do with FreeBSD as far as I know, it starts the
> menu.c32 menu which offers many options.
>
> I could pass you that image as well if you wish. I'll mail details on
> how to create it in a later mail. (short on time right now)
>

Sure. If there really is a bug in the EDD code, I need to find it.

-hpa

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On Fri, May 04, 2007 at 09:49:41AM -0700, J.H. wrote:
> Not to toot my own horn but if your just trying to duplicate most of the
> resources on UBCD you might want to look at http://pxeknife.erebor.org
> as it will work fine with all of the syslinux family. UBCD however will
> not as it makes a LOT of assumptions about how it works, where it can
> get things and which utilities and what not it uses to load it's images
> (it's not limited to syslinux). So the problems you might be seeing in
> getting UBCD to work may not be related to your image or syslinux, it
> may be related to the fact UBCD can't really be converted.

Actually, UBCD uses syslinux/isolinux, so the conversion is easy. The
attached script fixes it if you have it in /ubcd in a dos image.

--
lfr
0/0

On Fri, 2007-05-04 at 18:27 +0100, Luciano Miguel Ferreira Rocha wrote:
> On Fri, May 04, 2007 at 09:49:41AM -0700, J.H. wrote:
> > Not to toot my own horn but if your just trying to duplicate most of the
> > resources on UBCD you might want to look at http://pxeknife.erebor.org
> > as it will work fine with all of the syslinux family. UBCD however will
> > not as it makes a LOT of assumptions about how it works, where it can
> > get things and which utilities and what not it uses to load it's images
> > (it's not limited to syslinux). So the problems you might be seeing in
> > getting UBCD to work may not be related to your image or syslinux, it
> > may be related to the fact UBCD can't really be converted.
>
> Actually, UBCD uses syslinux/isolinux, so the conversion is easy. The
> attached script fixes it if you have it in /ubcd in a dos image.

When I last looked at UBCD not all of it used syslinux. It has it's own
menuing system (that isn't based on syslinux) or at least was - looking
at their website they apparently have changed this and I'll have to look
back into how they have things setup now.

- John

>
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J.H. wrote:
>
> Not to toot my own horn but if your just trying to duplicate most of the
> resources on UBCD you might want to look at http://pxeknife.erebor.org
> as it will work fine with all of the syslinux family. UBCD however will
> not as it makes a LOT of assumptions about how it works, where it can
> get things and which utilities and what not it uses to load it's images
> (it's not limited to syslinux). So the problems you might be seeing in
> getting UBCD to work may not be related to your image or syslinux, it
> may be related to the fact UBCD can't really be converted.
>
> - John 'Warthog9' Hawley


Yes, I had read about pxeknife before and found it very interesting
(pity the "free for personal use" stuff can't be included).

The primary reason for trying UBCD though was that it's isolinux-based
and it was the first one that crossed my mind.

Greetings,

Pascal Vandeputte

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Geert Stappers wrote:
> Op 02-05-2007 om 18:25 schreef Pascal Vandeputte:
>> Hello,
>>
>> I've been digging some more during the last couple of days [...]
>>
>> So now I've got a nice ubcd403.img file. If I dd it to a flash drive
>> in /dev/sda I can perfectly boot the "Ultimate Boot CD" from it.
>>
>> So I tend to think the disk image file itself is okay.
>>
>> However, making it available through pxelinux as follows doesn't work:
>>
>> label ubcd
>> kernel memdisk
>> append initrd=images/test/ubcd403.img harddisk
>>
>> The machine just hangs there at "Loading boot sector... booting..."
>>
>>
>> What am I doing wrong?
>
> :-)
>
>
> Several things, one is asking "What am I doing wrong?"
>
> <preach>
> Make the challenge a common challenge by avoiding 'I'.
>
> Wrong is the wrong word, there is nothing wrong with a expriment.
> If an expriment does learn you something, it is good expriment.
> </preach>
>
>
> The missing knowlegde ( in fact the missing imagination ) :
>
> Syslinux is started from ROM and loads a kernel or program from floppy
> or other FAT filesystem and starts it.
>
> Isolinux is started from ROM and loads a kernel or program from CD
> and starts it.
>
> PXElinux is started from ROM and loads a kernel or program from the
> network and starts it.
>
>
>
> What your expriment proves, is that you have started PXElinux starting
> a syslinux that can't do it's job.


Well, to make a long story short:
- my first attempts were to do it similar to what worked with FreeBSD:
dd + fdisk + mkdosfs etc, but this was leading nowhere.
- before mailing to the list I upgraded from 3.07 to 3.36 which
actually made matters worse (see other mails in this thread).
- then I started using mkdiskimage which was effectively the correct
way to do it, but because of the bug in 3.36 it still wouldn't work.
- last but not least, the "syslinux" package in Debian Sarge was no
good either (still 2.11, "can't find linux image").



So let's summarize a few pitfalls to avoid when converting
ISOLINUX-based ISO images/cd-roms to disk images for PXE booting:

- Use the "mkdiskimage" script (from the syslinux package) to create
an empty disk image.
Do NOT try to do the same thing with dd + fdisk + mkdosfs/vfat,
it will not work easily because of the boot code in the MBR.

- Never use the syslinux package which is available through the
package management of your GNU/Linux distribution, as it is bound
to be outdated (e.g. the 2.11 in Debian Sarge was no good match
for UBCD403).

- Don't use atftpd for serving files, but use tftpd-hpa instead.
atftpd bails out when files get larger than 90MB, which is not much
these days.
Even if you think you're using tftpd-hpa, double-check it anyway,
you never know if someone changed a few things without informing
you. :/

- Don't assume that newer SYSLINUX releases are always better. If
you're following a howto and it won't work, try to use the same
software versions as the author of the howto. (if available)



Howto coming up...


Greetings,

Pascal Vandeputte

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Pascal Vandeputte wrote:
> [...] I'll mail details on
> how to create it in a later mail. (short on time right now)



Hello,

What follows is a howto on converting ISOLINUX ISO's into
PXE-bootable disk images.

I hope the provided information is correct and that this can be added
to the SYSLINUX wiki, just like the FreeBSD boot image howto earlier in
this thread.



Pascal Vandeputte's blood-and-tears-and-sleepless-nights howto
for creating a disk image of an ISOLINUX-based bootable ISO file/cd-rom
=======================================================================
But hindsight is 100%... so now it's not that hard at all :-)

We use the "Ultimate Boot CD" as an example of an ISOLINUX-based
bootable cd-rom. See www.ultimatebootcd.com
Versions used: UBCD 4.03
SYSLINUX 3.36
tftp-hpa 0.40-4.1 (Debian Sarge)
Date: 2007-05-06

1. Download the UBCD ISO file to a Linux box as well as the latest
version of SYSLINUX (see http://syslinux.zytor.com/download.php):

# cd /tmp && wget
http://www.kernel.org/pub/linux/utils/boot/syslinux/syslinux-3.36.tar.bz2
# cd /usr/local && tar jxf /tmp/syslinux-3.36.tar.bz2

# ls -alh /tmp | grep iso
-rw-r--r-- 1 root root 108M 2007-04-11 20:19 ubcd403.iso

If there's a SYSLINUX package available in the package manager of
your GNU/Linux distro, you'd better NOT use it because it's
likely to be outdated.

2. The ISO file is 108MB large, so we use the mkdiskimage tool to
create a disk image file which is slightly larger, 110MB:

# cd /tmp
# /usr/local/syslinux-3.36/mkdiskimage -o -M ubcd403.img 110 64 32
16384

The -M option makes mkdiskimage interpret the "cylinder count"
parameter (the "110") as the desired image size in MB instead, and
mkdiskimage will figure out the cylinder count by itself, given the
number of heads (64) and sectors (32).

So we use 64 heads and 32 sectors/track (= sectors/cylinder) (with
512 bytes/sector) and vary the number of cylinders to achieve a
certain disk image size. Some people use 16 heads and 63 sectors
per track which seems to work equally well but you end up with a
higher cylinder count.

We need the offset (16384) to be able to access the FAT partition
inside. See steps 3 and 4.

mkdiskimage has created a disk image with a partition table and a
single FAT16-formatted partition.

# ls -al *.iso *.img
-rw-r--r-- 1 root root 115343360 2007-05-04 16:09 ubcd403.img
-rw-r--r-- 1 root root 113141760 2007-04-11 20:19 ubcd403.iso

# fdisk -l -u ubcd403.img
You must set cylinders.
You can do this from the extra functions menu.

Disk ubcd403.img: 0 MB, 0 bytes
64 heads, 32 sectors/track, 0 cylinders, total 0 sectors
Units = sectors of 1 * 512 = 512 bytes

Device Boot Start End Blocks Id System
ubcd403.img1 * 32 225279 112624 6 FAT16

Note the start of the partition: sector 32 * 512 bytes = 16384, the
offset reported earlier.

The image already contains MBR boot code as well.

# file ubcd403.img
ubcd403.img: x86 boot sector

3. Install the SYSLINUX boot loader:

# /usr/local/syslinux-3.36/unix/syslinux -o 16384 ubcd403.img

syslinux must be pointed at a FAT partition, which is why we need to
specify the right offset here.

4. Attach the image file to a loop device, with the offset reported
by mkdiskimage in step 2. This is the only way to access the
FAT file system inside.

# losetup -o 16384 /dev/loop0 ubcd403.img

(on Ubuntu this may be /dev/loop/0 instead)

5. Mount the ISO file and the FAT file system in the disk image.

# mkdir /tmp/iso /tmp/img
# mount -o loop,ro ubcd403.iso /tmp/iso/
# mount /dev/loop0 /tmp/img/

There should be a file "ldlinux.sys" in the disk image already.
This is the bootloader. If it's missing in action, that means that
the syslinux command in step 3 was unsuccessful.

# cd /tmp/img/
# ls -al
total 27
drwxr-xr-x 2 root root 16384 1970-01-01 01:00 .
drwxrwxrwt 12 root root 1024 2007-05-02 16:48 ..
-r-xr-xr-x 1 root root 10092 2007-05-02 16:47 ldlinux.sys

6. Copy the ISO contents to the disk image (we're still in /tmp/img):

# cp -R /tmp/iso/* .
# ls -al
total 63
drwxr-xr-x 11 root root 16384 2007-05-04 18:07 .
drwxrwxrwt 6 root root 1024 2007-05-04 18:06 ..
-rwxr-xr-x 1 root root 59 2007-05-04 18:07 autorun.inf
drwxr-xr-x 2 root root 2048 2007-05-04 18:07 boot
-rwxr-xr-x 1 root root 2048 2007-05-04 18:07 boot.catalog
drwxr-xr-x 2 root root 2048 2007-05-04 18:07 custom
drwxr-xr-x 73 root root 6144 2007-05-04 18:07 dosapps
drwxr-xr-x 2 root root 4096 2007-05-04 18:07 images
drwxr-xr-x 2 root root 2048 2007-05-04 18:07 isolinux
-r-xr-xr-x 1 root root 10092 2007-05-04 18:06 ldlinux.sys
drwxr-xr-x 2 root root 2048 2007-05-04 18:07 menus
drwxr-xr-x 2 root root 2048 2007-05-04 18:07 syslinux
drwxr-xr-x 4 root root 2048 2007-05-04 18:07 tools
-rwxr-xr-x 1 root root 4382 2007-05-04 18:07 ubcd.ico
drwxr-xr-x 4 root root 4096 2007-05-04 18:07 website

The UBCD ISO already contains the "syslinux" folder with the boot
loader configuration file, no further action is required.
If there's no "syslinux" folder in your ISO, you probably need to
adapt the configuration you find in the "isolinux" folder or the
"isolinux.cfg" file in the root of the ISO. Just renaming the folder
and the file could be enough.

7. That's it. Unmount everything and detach the loop device from the
disk image file.

# cd ..
# umount /tmp/img/ /tmp/iso
# losetup -d /dev/loop0

8. Optional: you can test your image by writing it to a USB flash
drive:

# dd if=/tmp/ubcd403.img of=/dev/sda

And then try to boot from it. If this works, the image itself is
probably okay.

9. To netboot, put the file on your TFTP server and add something like
this to pxelinux.cfg/default (setting up a dhcp + tftp-hpa server
for network booting is not within the scope of this document):

label ubcd
kernel memdisk
append initrd=images/test/ubcd403.img harddisk noedd

The "noedd" option is needed for memdisk version 3.32 up to at
least 3.36, because of a bug which will probably be fixed in future
releases. Without that option the boot process will hang at
"Loading boot sector... booting...".

10. If you get a message that ubcd403.img cannot be found, while you're
absolutely certain that it's in the right location, check that you
are really using tftp-hpa and not aftpd as a TFTP service. The
latter chokes on files larger than 90MB.


Happy netbooting,

Pascal Vandeputte

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H. Peter Anvin wrote:
> Pascal Vandeputte wrote:
>> Well, I just managed to get the Ultimate Boot CD ISO converted into a
>> PXE-bootable hard disk image, and the behaviour is identical: if I use
>> 3.07 it works, 3.36 doesn't, 3.36 + "noedd" works fine.
>>
>> The UBCD has nothing to do with FreeBSD as far as I know, it starts the
>> menu.c32 menu which offers many options.
>>
>> I could pass you that image as well if you wish. I'll mail details on
>> how to create it in a later mail. (short on time right now)
>>
>
> Sure. If there really is a bug in the EDD code, I need to find it.
>
> -hpa


Here it is:

http://users.atlantis.ugent.be/pvdputte/ubcd403.img.gz

Thanks a lot for all the effort put in this project.


Pascal Vandeputte

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Op 06-05-2007 om 18:32 schreef Pascal Vandeputte:
> Pascal Vandeputte wrote:
> > [...] I'll mail details on
> > how to create it in a later mail. (short on time right now)
>
> Hello,
>
> What follows is a howto on converting ISOLINUX ISO's into
> PXE-bootable disk images.
>
> I hope the provided information is correct and that this can be added
> to the SYSLINUX wiki, just like the FreeBSD boot image howto earlier in
> this thread.

The syslinux wiki is (still (sadly)) a hidden wiki,
but for those who can find it, it is free available.

Next hurdle is from where to link a new page.
I propose: http://syslinux.zytor.com/wiki/index.php/SpinOff


The same message in other words:

Link from somewhere in http://syslinux.zytor.com to the wiki
and
make the spin-off page a "top page" in the left margin navigation links


Cheers
Geert Stappers

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