# @(#)README.sparcboot	1.1 99/12/12 joerg
#
The sparc boot feature does allow you to create your own Sun sparc boot disk.
This will allow you to create modified Solaris install disks or to create
installation CD's for other OS that run on sparc systems.

A CD that is bootable on a Sun sparc system has a Sun disk label on sector 0
and some Sun sparc disk partitions behind the ISO-9660 filesystem image.

The layout of a sparc boot CD:

----------------------------------------------------------------------------------------------------
|Sun disk label| Iso 9660 filesystem |Generic sun4 boot|sun4c boot|sun4m boot|sun4d boot|sun4e boot|
----------------------------------------------------------------------------------------------------

On older system CD's all boot partition contain a full UFS miniroot filesystem.
On newer CD's the images on slice 2 and above only contain boot redirects to
slice 1.

To create a CD that is bootable on Sun sparc systems you need to have the
boot images for the apropriate sparc architecture.

A boot image file usually is a UFS filesystem image that contains the 
primary boot image at byte offset 512 ... 8191.

You may get such boot images by extracting partitions 1..5 from a Sun Solaris install CD,
but any bootable image should work.

Here is an expample how to do this with the Solaris 7 install CD.

dd if=/vol/dev/dsk/c0t6/sol_7_sparc_sun_srvr/s1 of=sun4
dd if=/vol/dev/dsk/c0t6/sol_7_sparc_sun_srvr/s2 of=sun4c
dd if=/vol/dev/dsk/c0t6/sol_7_sparc_sun_srvr/s3 of=sun4m
dd if=/vol/dev/dsk/c0t6/sol_7_sparc_sun_srvr/s4 of=sun4d
dd if=/vol/dev/dsk/c0t6/sol_7_sparc_sun_srvr/s5 of=sun4e


mkisofs -R -sparc-boot sun4,sun4c,sun4m,sun4d,sun4e -o boot.img /mnt/install

Will create the bootable image in boot.img.

If you like to make the boot images smaller, you may call 'fstyp -v'
on the images and use the 'size' value to get the needed minimal 
boot image size in kB.

The result for the S7 boot CD is:

ufs
magic   11954   format  dynamic time    Wed Oct  7 00:00:30 1998
sblkno  8       cblkno  12      iblkno  16      dblkno  252
sbsize  2048    cgsize  2048    cgoffset 20     cgmask  0xfffffff0
ncg     7       size    25704   blocks  23987
			^^^^^
			This is the number of interest.
bsize   8192    shift   13      mask    0xffffe000
fsize   2048    shift   11      mask    0xfffff800
frag    4       shift   2       fsbtodb 2
minfree 10%     maxbpg  2048    optim   time
maxcontig 256   rotdelay 0ms    rps     90
csaddr  252     cssize  2048    shift   9       mask    0xfffffe00
ntrak   14      nsect   72      spc     1008    ncyl    102
cpg     16      bpg     1008    fpg     4032    ipg     3776
nindir  2048    inopb   64      nspf    4
nbfree  1768    ndir    667     nifree  24329   nffree  9
cgrotor 2       fmod    0       ronly   0

So you should call:

dd if=/vol/dev/dsk/c0t6/sol_7_sparc_sun_srvr/s1 of=sun4 bs=1k count=25704

To modify this filesystem, you can mount it using the fbk driver:

chmod +t ./sun4		# Need to do this to avoid vm cache aliasing problems

mount -F fbk -o rw,type=ufs /dev/fbk0:sun4 /mnt