SUMMARY: writing bootable CD

From: lombardi emanuele <lele_at_mantegna.casaccia.enea.it>
Date: Tue, 27 Oct 1998 11:05:06 +0100 (MET)

Dear alphists,

My goal was to boot from CD a system which has all the file systems
(including / and /usr) of type ADVFS. In this way I could avoid to keep
a spare DISK only for emergency boot (when the normal boot disk
crashes).

I had several answers, telling me that in some way it should be
possible to write bootable CD (see later for them),
                        BUT
Tom Blinn <tpb_at_doctor.zk3.dec.com> says:

        Digital UNIX has, at present, NO SUPPORT for booting from an ISO 9660 CD.

        When you use "mkisofs" you are making an ISO 9660 format file system, then
        you are putting it on the CD with the cdrecord software. The CD will not be
        bootable because you don't have a software bootstrap program to support it.

        Note, also, that to be bootable, the CD has to be in a format that can be
        read and understood by the console firmware, not just by software that you
        might put on the CD.

        The way we, Digital, make bootable CDROM media is to put a bootable image on
        an appropriately sized hard drive (one that's either really about the size
        of the CD media, or one that's labelled to be the size of CD media), laid
        out with a UFS file system and with appropriate boot blocks (since we only
        support CDROM drives on SCSI bus or IDE bus through SCSI emulation, we only
        put the SCSI boot blocks on the disk, and we put the UFS format boot blocks
        on the disk using the disklabel command with -t ufs as the option to force
        the disk to have UFS boot blocks). Then once we're sure we can boot and run
        off the disk, we image copy it onto the CD. (You might be able to do this
        using cdrecord, or you might not.)

---> Note that what's on a bootable installation CDROM is NOT what would be on a
---> CD you made with an image copy of your root and /usr file systems. You can
---> make a system disk that has root and /usr in a single partition, that does
---> not depend on mounting /usr as you transition from single user mode to some
---> higher run level. HOWEVER, you can not run the system for long without the
---> knowledge of how to set up writable memory file systems and how to populate
---> them with the things you'd need.

---> In other words, you need to REALLY know how the system runs in order to get
---> this to work. It's not particularly trivial.

---> You could learn a lot by studying what happens during the initial loading of
---> he "standalone system management" environment from the OS installation CD.

---> Have fun.. But don't expect to succeed, unless you have some really very
---> limited goals.


I suppose that making /tmp with mfs it might work, but I don't want to change my job
into another so I gave up making my own bootable CD !!

Anyway thanks to all who replied, whose messages are after my
signature.

Greetings from Italy,
Emanuele

-- 
 Emanuele Lombardi
 mail:  AMB-GEM-CLIM ENEA Casaccia
        I-00060 S.M. di Galeria (RM)  ITALY
 mailto:lele_at_mantegna.casaccia.enea.it
 tel	+39 6 30483366 fax	+39 6 30483591
     This transmission was made possible by 100% recycled electrons.
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From: "Martin Mokrejs" <mmokrejs_at_natur.cuni.cz>
Hello,
 look for my SUMMARY: on the archive of this list. 
Here are some my current bookmarks on thsi topic:
<DT><A HREF="http://sunsite.unc.edu/LDP/HOWTO/CD-Writing-HOWTO.html" ADD_DATE="877350794" LAST_VISIT="905053339" LAST_MODIFIED="87
7350791">CD-Writing HOWTO</A>
<DT><A HREF="ftp://sunsite.unc.edu/pub/Linux/utils/disk-management/" ADD_DATE="887563271" LAST_VISIT="893707137" LAST_MODIFIED="88
7563238">Directory of /pub/Linux/utils/disk-management</A>
<DT><A HREF="http://sunsite.unc.edu/LDP/HOWTO/CD-Writing-HOWTO-2.html" ADD_DATE="887558875" LAST_VISIT="893707150" LAST_MODIFIED="
887558868">CD-Writing HOWTO: Prepare your Linux-box for writing CD-ROMs</A>
<DT><A HREF="http://incolor.inetnebr.com/guardian/boot-cd.shtml" ADD_DATE="887657054" LAST_VISIT="888436350" LAST_MODIFIED="887656
904">BOOT CD FAQ & INFO BY SETH</A>
<DT><A HREF="http://www.cd-info.com/CDIC/Technology/CD-R/FAQ.html" ADD_DATE="887655235" LAST_VISIT="887655130" LAST_MODIFIED="8876
55130">CD-R FAQ</A>
Hope this helps
Martin
Hello,
 someone suggest's to do:
disklabel -p rz0 > /tmp/disk.params
disklabel -R -r -t advfs rz0 /tmp/disk.params /mdec/rzboot.advfs /mdec/bootrz.advfs
see man disklabel.
;-)
I have no time to experiment with it now, but it's doable. 
Martin
P.S.: I hope you wanted UFS bootdisk. ;-)
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From: "Dwight L. Hubbard" <dlhubbar_at_collins.rockwell.com>
Here are the basics.  You need to create a ufs filesystem image and then use cdrecord to
burn it to CD.  The steps go somethings like this:
1. Zero out the disklabel of a spare drive (in this example the spare drives is rz6)
    disklabel -z /dev/rrz6a
2. Create a bootable ufs disk on the spare drive
    disklabel -rw -t ufs /dev/rrz6a
3. Edit the disklabel for the spare disk and set up the partitions the way you want.  All
the partitions must be in the first 640MB of the disk.  I am also assuming the a partition
starts at 0.
    disklabel -e /dev/rrz6a
4. Write the disk image to a CD-Rom (in this example I assume the CD is device 4 on the
first scsi controller).  I've haven't tried this step under Digital Unix, I've always booted
into Linux to use cdrecord before, but this command should work with the cdrecord for
Digital Unix that was just announced.
    cdrecord -v dev=4,0 /dev/rrz6a
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From: David Warren <warren_at_atmos.washington.edu>
I would try writing / and /usr onto either a C partition or an A partition of a
drive. Make sure it has the correct boot blocks and then dd the drive onto the
CD. I don't know how you take care of /var though.
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From: "Serguei Patchkovskii" <patchkov_at_ucalgary.ca>
I do not think DU bootable CD ROMs are in the ISO format, so that mkisofs
won't be of much use for you. If you desperately need to create a bootable
CD ROM, one approach which is likely to work is to make a bootable hard
drive using the standard tools, and record the *image* of that hard drive,
disk label and all, onto your CD (cdrecord supports recording from raw
devices). This obviously requires that all partitions on you hard drive
fit on a single CD. 
It may be a good idea to start from the image of an existing bootable
CD ROM and customize it - this way, you are more likely to get something
which will actually boot...
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From: Thomas Leitner <tom_at_finwds01.tu-graz.ac.at>
Hi Emanuele,
Just two quick notes:
1.) I think, that Digital Unix binaries are *not* on:
    http://www.fokus.gmd.de/research/cc/glone/employees/joerg.schilling/private/cdrecord.html
    They are only on my FTP server:
    ftp://finwds01.tu-graz.ac.at/pub/cdrecord	
2.) If you want to get just *some* bootable CD, you could copy the
    Digital Unix Installation CD with:
    dd if=/dev/rrz6c of=cd.iso ibs=64k obs=64k
    cdrecord -dev 5,0 -speed 2 cd.iso
3.) If you want to make your own bootable CD, I think that you're pretty
    out of luck because this is non-standard and not supported by mkisofs.
    I managed to make a Linux/Sparc bootable CD some time ago with
    mkisofs and cdrecord. This involved creating the CD image, mounting
    it in a loopback filesystem and running a special program which
    writes a special boot record.
I'm afraid that there's no standard way to do it. You'd need to 
hack something together yourself.
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Received on Tue Oct 27 1998 - 10:08:23 NZDT