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emergency boot cdrom

From: Steve Fabac <smfabac@att.net>
Subject: Re: Bootable Recovery CD-Rom
References: <c1a0274c.0301021453.4eaecad4@posting.google.com> 
Date: Mon, 06 Jan 2003 09:08:14 GMT

Brian wrote:
> 
> Does anyone have any information on how to create a Openserver 5.0.5
> bootable CD, that would have both the boot/root floppy images on it. I
> am able to create a bootable CD with the boot floppy (both unix.Z and
> ramdisk.Z are on CD), but when the system asks for the root disk, I do
> not know the proper syntax to tell it how to access the root image
> that is on the CD. There has to be another way. Can anyone help?

Brian, 

I have a UNIX "utility" CD that I maintain with tools (ssh, visionfs,
sendmail, etc.) and software I have developed and collected over the 
years as a directory under /u/cd on my system. As I update my tools,
I burn a new CD for my briefcase. The boot image on the CD consists
of my standard configuration for client systems with additional 
drivers for Mylex and DPT RAID controllers. I can boot all the client
systems that I have set up over the years and some systems that 
I am working on for the first time.

I modified the "fd" script for mkdev to allow it to operate on a ram
disk.  Normally, the script will check for valid /dev/ devices
against an internal look up table. 

Install the modified "fd" in /usr/lib/mkdev (move the existing fd
link out of the way first). 

Edit /etc/rc2.d/8/userdef to setup the ram disk as ram01 then
reboot the system. Note that my userdef sets up a 16M RAM disk
and I just used that for creating the boot image even though 16M is
larger than needed for the 2.88M image. 

Run mkdev fd and choose 2.88M root/boot single floppy. (specify
drive 0 and "no" to format first). 

Size the ram disk image to 2.88M by executing:
dd if=/dev/ram01 of=/cd_root/cdboot.img bs=36b count=160

Run: mkisofs -V "Emergency Root/Boot disk" -b cdboot.img -R -J
/u/cd_root > /u/root.isofs

Then run:

cdrecord -v -v fs=6m speed=12 dev=5,0 /u/root.isofs

Note that dev=5,0  specifies SCSI CD writer on ID5 on default
SCSI controller 0.


The following are my modifications to the fd script shown in
context:

> sselect() {
>         case $1 in
>                 48)     tpi=48 size=720 spt=9 minor=4           
>                         desc="48ds9"                    ;;
>                 96)     tpi=96 size=2400 spt=15 minor=52
>                         desc="96ds15"                   ;;
>             135ds9)     tpi=135 size=1440 spt=9 minor=36        
>                         desc="135ds9"                   ;;
>            135ds18)     tpi=135 size=2880 spt=18 minor=60       
>                         desc="135ds18"                  ;;
>            135ds36)     tpi=135 size=5760 spt=36 minor=44       
>                         desc="135ds36"                  ;;
>            ram01)       tpi=135 size=5760 spt=36 minor=44       
>                         desc="135ds36"                  ;;
>         esac
> }

and 

>  INODES=1024
>         case $dev in
>            *ds15*)        BLKS=5120;;
>            *ram01*|*ds18*|*ds36*) BLKS=6144;;
>         esac

and
>         #Hard code for ram disk, swap comments when building floppy.
>         dev=/dev/ram01
>         rdev=/dev/ram01
> #       dev=/dev/fd${drive}${tpi}ds${spt}
> #       rdev=/dev/rfd${drive}${tpi}ds${spt}   






-- 

                                      Steve Fabac
                                       S.M. Fabac & Associates
                                        816/765-1670
 

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