The examples are based on FreeBSD/i386 6.2-RELEASE and Microsoft Windows Small Business Server 2003 R2 Service Pack 2.  For additional background information, see the following web sites:

• Convert FreeBSD ISO image for PXE bootstrap
• PXELINUX and Microsoft RIS
• MEMDISK documentation
• Booting FreeBSD via PXE
• Network-, Memory-, and File-Backed File Systems
  

Limitations

Windows Deployment Services must be running in "Legacy" or "Mixed" mode.

A method for adding the PXELINUX boot loader as a WDS boot image is not known at this time. For instructions on how to configure WDS in one of these modes, see the Windows Deployment Services Update Step-by-Step Guide for Windows Server 2003. Note that this requires the addition of a RISetup image (e.g., Windows XP) to the WDS server via the "Windows Deployment Services Legacy" wizard prior to authorizing and configuring WDS with the "Windows Deployment Services" management console. This image can be removed from server after adding the FreeBSD RISetup image.

Change the default boot program if not using any Windows PE boot images.

If WDS is running in mixed mode and there are no Windows PE boot images, PXE clients will return a "file not found" error because the default boot program "boot\x86\pxeboot.com" is missing.  Either change the default boot program to "OSChooser\i386\startrom.com" in the WDS server properties (which is the legacy RIS boot program), or add a Windows PE boot image (which you can find in the Windows Automated Installation Kit).

FreeBSD's pxeboot should not be used.

The pxeboot loader obtains all of its configuration information from DHCP, conflicts with the DHCP settings required by WDS/RIS.  (It would be nice if pxeboot could be hacked to pass the hostname and domain administrator credentials from the RIS environment to the FreeBSD installer.)

MEMDISK must be called with the "noedd" option.

Enhanced disk device support appears to be incompatible with the FreeBSD boot loader, based on the authors experience (limited to testing the boot code in FreeBSD/i386 6.2-RELEASE).

Proper drive geometry calculations are necessary.

If the correct geometry is not specified when attaching the hard disk image as an md-style block device, fdisk and disklabel may not guess the correct geometry. This will cause these tools to misrepresent the total size of the disk image, which can cause problems for newfs, the boot loader, and MEMDISK.

The hard disk image is not available once FreeBSD boots.

The image, along with the MEMDISK program, its INT 13h and INT 15h BIOS hooks, and the entire PXE/UNDI stack, are deleted from memory once the FreeBSD kernel starts up and transitions to enhanced mode. In order to include additional tools or utilities with the FreeBSD installation program, one must modify the "mfsroot" image (similar to the Linux initrd), which is located inside of the hard disk image.

Modifications to the "RemInst" Share Point

Once RIS or WDS is installed and configured, create the following folders in the "RemInst" share point with commands similar to the following (e.g., German users would have to use "Setup\German\Images\FreeBSD" etc.):

mkdir Setup\English\Images\FreeBSD
mkdir Setup\English\Images\FreeBSD\i386
mkdir Setup\English\Images\FreeBSD\i386\templates
mkdir Setup\English\Images\FreeBSD\i386\pxelinux.cfg

Next, create the file "Setup\English\Images\FreeBSD\i386\templates\freebsd62.sif".  Use the following for its contents:

[RemoteInstall]
Repartition = Yes
UseWholeDisk = Yes

[OSChooser]
Description ="FreeBSD/i386 6.2-RELEASE"
Help ="Automatically installs FreeBSD/i386 6.2-RELEASE without prompting the user for input."
LaunchFile = "%INSTALLPATH%\%MACHINETYPE%\pxelinux.0"
ImageType = Flat
Version = "6.2 (0)"

Scripting the Installation

TBD.

The Hard Disk Image

These instructions create the hard disk image from the boot floppy set included with the FreeBSD release, as this minimizes the image size (and thus minimizing the amount of data that must be transferred during the PXE boot process). The procedure for creating the image is based loosely (and somewhat blindly) on the boot floppy set creation procedure used by the FreeBSD "make release" process. Execute the following Bourne shell commands while logged into the "root" user account on a FreeBSD workstation (or copy the commands to a file and execute them using the Bourne shell).

Download the boot floppy set using commands similar to the following (change ARCH, RELEASE, or BASE as appropriate):

ARCH=$1; shift;    if [ "x${ARCH}" = "x" ];    then ARCH="`uname -m`";    fi
RELEASE=$1; shift; if [ "x${RELEASE}" = "x" ]; then RELEASE="`uname -r`"; fi
BASE="ftp://ftp.freebsd.org/pub/FreeBSD/releases/${ARCH}/${RELEASE}/floppies"
fetch "${BASE}/boot.flp"
i=1; while (fetch "${BASE}/kern${i}.flp"); do i=`expr $i + 1`; done

Extract the contents of the boot floppy set using the following commands:

## create some working directories
mkdir data
mkdir mnt

## extract contents of boot floppy
MD=`mdconfig -a -t vnode -f boot.flp`
mount /dev/${MD} mnt
cp -R mnt/* data
umount /dev/${MD}
mdconfig -d -u ${MD}

## extract contents of kernel floppies
i=1
while ([ -e "kern${i}.flp" ])
do
  MD=`mdconfig -a -t vnode -f "kern${i}.flp`
  mount /dev/${MD} mnt
  cp -R mnt/* data
  umount /dev/${MD}
  mdconfig -d -u ${MD}
  i=`expr ${i} + 1`
done

Reconstruct the split kernel image with the following commands:

cat data/kernel.gz.boot data/kernel.gz.?? > data/kernel.gz
rm data/kernel.gz.*

Remove the diskette prompt prior to loading the "acpi.ko" module with the following commands:

grep -v acpi_before data/boot/loader.conf > loader.conf.new
mv loader.conf.new data/boot/loader.conf

Optional: Add the customized installation script (plus any supporting files) to the "mfsroot" image with the following commands:

TBD.

Calculate the size of the new hard disk image, being careful to round up to align with cylinder/track/sector boundaries:

FLPSIZ=`du -sk data | awk '{print $1}'`
FLPSIZ=`expr ${FLPSIZ} \* 1024`
IMGSIZ=0
i=0
while ([ ${FLPSIZ} -gt ${IMGSIZ} ])
do
  i=`expr ${i} + 2`
  IMGSIZ=`expr ${i} \* 16 \* 63 \* 512`
done
CYL=${i}
TRK=16                # heads per cylinder
SEC=63                # sectors per head
SECSIZ=512            # bytes per sector

Also calculate the number of inodes needed in the new file system with the following commands:

NUMFILES=`find data | wc -l`
NUMINODS=`expr ${FLPSIZ} \/ ${NUMFILES}`

Create and mount the new hard disk image with the following commands:

dd if=/dev/zero of=pxeboot.img bs=${IMGSIZ} count=1
MD=`mdconfig -a -t vnode -f pxeboot.img -y ${TRK} -x ${SEC} -S ${SECSIZ}`
fdisk -BIv /dev/${MD}
disklabel -w -B /dev/${MD} auto
newfs -O1 -i ${NUMINODS} -b 4096 -f 512 -o space -m 0 -n /dev/${MD}a
mount /dev/${MD}a mnt

Copy the boot files over to the image with the following command:

cp -R data/* mnt

Dismount and compress the image with the following commands:

umount mnt
mdconfig -d -u ${MD}
gzip -9 pxeboot.img

Copy the file "pxeboot.img.gz" to the directory "Setup\English\FreeBSD\i386" on the RIS/WDS server.

PXELINUX and MEMDISK

PXELINUX downloads MEMDISK plus the hard disk image created above, loads them both together into memory, and runs MEMDISK.  MEMDISK hooks BIOS interrupts 13h (disk access) and 15h (memory info) and uses the image to emulate the first BIOS floppy drive or hard disk drive, as appropriate.  Then it runs the contents of the image's boot sector.  The real-mode boot program uses the BIOS I/O routines to continue loading itself from what it thinks is a real hard disk image, before transitioning to the operating system kernel.  In this example, the boot program is the FreeBSD BTX loader, and the kernel is FreeBSD/i386 6.2-RELEASE.

To complete the configuration of the RIS/WDS boot image, install SYSLINUX.  First, download the latest version of SYSLINUX (which includes PXELINUX and MEMDISK) from www.kernel.org (version 3.36 at the time this was written).  Next, extract the files "pxelinux.0" and "memdisk\memdisk", and copy them to the directory "Setup\English\Images\FreeBSD\i386" on the RIS/WDS server.  Finally, create the file "Setup\English\Images\FreeBSD\i386\pxelinux.cfg\default".  Use the following for its contents:

DEFAULT memdisk initrd=pxeboot.img.gz harddisk noedd
PROMPT 0
NOESCAPE 1

Testing

At this point, you should be able to perform a PXE boot from another server or workstation, select "FreeBSD/i386 6.2-RELEASE" from the RIS boot menu, and launch the FreeBSD sysinstall program (or your scripted installation).  Bear in mind that this will reset the domain account of that server or workstation.