Re: Make Linux CDs

[Tony Nugent <Tony Nugent usq edu au>]

On Thu Oct 01 1998 00:00, David_M_Morgan rsh net wrote:

[ stuff about trying to create RedHat installation CDROMs ]

> >So two questions then;
> >
> >1. Can you make a good Linux CD in either of the above 3 formats (ISO
> >Level 1 or 3, or Joliet)?

As I mentioned in another reply to this message, Joliet is useful - but it
is NOT essential.  RockRidge is essential.

I'm not familiar with exactly what ISO levels 1 or 3 are... if either of
them are RockRidge by another name, then that's what is needed.

> >2. Why didn't the hard drive install work? I used the same directory
> >structure as the Redhat directories on Sunsite.

Don't rely on what's on Sunsite.  I haven't had a good look at how things
are laid out there, but I strongly suspect that what they have mirrored
there is selective and incomplete for installation purposes.

> The true answer is what kernel are you using on your boot disk> If I recall
> right it should be using 2.0.34 with the modules for the Joliet CD

Wowowa!  Stop!  Yes, what you are saying is true... not until the 2.0.34
kernel did linux understand Joliet extensions on a cdrom.

But this is irrelevant.

I've been creating working RedHat install disks with the 2.0.32 kernel
until only just recently.

And there have been RedHat install disks about a long time before the linux
kernels understood Joliet (and well before mickyslop ever invented it as a
kludge for looz95 to be able to read long filenames on cdroms).

What is important how the IMAGE itself is created.  That's where the
mkisofs utility is vitally important, and it can create CDROMS with all
sorts of options.  (See below).

> extenions, so what ever you read or who ever told you the Linux can't read
> the Joliet extensions is a liar and you should seek advise else where. As
> for your failer with the hard drive I would have to ask, what does your
> directory structure look like. Root directory of an install CD should look
> something like the following...
> 
> TRANS.TBL       RedHat     updates    boot     contrib
> and inside the RedHat should look like this
> TRANS.TBL    i386 etc.

Sorry, but you are wrong, or misleading at best.

I have been creating working install disks WITHOUT those ugly ugly UGLY
"TRANS.TBL" files for a while now.

(I "accidently" discovered that they are not really needed when I burned an
image that was created without the "-T" switch to mkisofs, and they worked
fine.

For the cdrom to be readable by a windows box, you need to have Joliet
extensions or long filenames in the image (a mkisofs issue).

Linux doesn't care less, as long as the RockRidge extensions are there.

Let me repeat that... you need to use the RockRidge extensions when
creating iso9660 images that contain unix filesystems.

You are right in that the RedHat/ directory (and its contents) is vital,
But it can exist as a symbolic link to a subdirectory that exists somewhere
else on the cdrom (true...  I've done this and it works just fine).

None of the other directories in the root directory of the cdrom are
essential for RedHat.

> if it doesn't then there's part or all of your problem. If it does and you
> find it to be the kernel and I'm wrong on it having the Joliet extensions
> for modules, check the updates on the redhat ftp site for a new boot disk,
> or have someone make one for you.

It seems that linux does a much better job of creating unix filesystems on
cdroms than winloose software.

This is an example of a command line used for creating a bootable ISO9660 image
for a RedHat installation cdrom:

mkisofs -a -r -N -L -d -J -o redhat.img -b /image/images/boot.img -x /images/lost+found /image 

Explaination:

 -a	include all files (don't ignore ~ and #)
 	I use this, but it is handy not to use it if you don't want such files included.
 -N	omit iso9660 version numbers with filenames (violates the standard, but it works)
 -L	allow dot files (don't replace with underscore)
 -d	omit trailing periods from filenames [not essential, but I use it)
 -x	files/directories to omit from the image
	(you DON'T need a /lost+found directory on a cdrom, especially on a
	read-only disk)
-b boot_image
	the path/filename of the boot image to be used when making an "El
	Torito" bootable CD.  (This is VERY cool! :-)
 -v	verbose output
 -o	output filename to write the image to
 -l	enable long filenames (32 chars)  [not used above, but it could be]
 -J	Joliet extenstion for m$loose (64 characters) [instead of -l]
 -r	Rock Ridge (-R) but with:
	       	uig.gid = 0.0 on all files	(good)
		unset write bits		(sensible on a read-only filesystem)
		set all read bits		(also good)
		set all execute bits (if any)	(good for directories on executable files)
		clear all special bits
 -T	generate TRANS.TBL files in each directory
 	I don't use this any more - they are UGLY and only needed for a few
	(irrelevant) operating systems to be able to use long filenames

(Quickly done from the mkisofs man page... I might also use the -D option
to prevent "deep directory reallocation" which otherwise results in the
creation of ugly "rr_moved" directories in the base directory of the
cdrom).

This isn't how RedHat has been creating their cdroms (they have TRANS.TBL
files, etc).  Whatever.  What I have been doing works (so does theirs).

The issue is whether to use (a) RockRidge (b) long filenames, and/or (c) Joliet.

(a) RockRidge
	Absolutely essential for creating images of unix filesystems (to
	preserve permissions, ownerships, symbolic links).  Linux needs
	this.

(b) long filenames
(c) Joliet extensions

	Please yourself.  Linux doesn't care, but windoze does.
	
	If you don't use either of these when creating the image, windows
	will have trouble looking at filenames, which is a real hassle when
	you have things like web pages on it (it can't understand case or
	anything other than 8.3 filenames).

	For a RedHat cdrom, who really cares if windows has trouble with
	it?  :-)  Note that RedHat have been careful is making the html
	version of its install manual on the cdrom 8.3 filename compliant.

	If you use long filenames, windows can read it, but only up to 32
	characters before the names are truncated. (Case is understood).

	If you use Joliet, the filenames (and case) is preserved up to 64
	characters.  And you'll probably need a post 2.0.34 kernel for
	linux to read it (although I haven't experimented with this to
	confirm if there are any problems in this regard).

Then there's the issue of how to layout the CDROM so that it works as a
RedHat install disk, and then how to customise it.

Hell, if you are going to burn a RedHat cdrom, then you will want to put
all the updates into the install image, no?  Well, this can be done very
easily (if you know what needs to be done to get this to work correctly).
But as I've explained this in another message, I won't elaborate here.

(I really should put all this up on a web page!  This message is sure to
get lost very quickly in this email list...)

Cheers
Tony
 -=*#*=-=*#*=-=*#*=-=*#*=-=*#*=-=*#*=-=*#*=-=*#*=-=*#*=-=*#*=-=*#*=-
  Tony Nugent <Tony Nugent usq edu au>           <linux usq edu au>
  Computer Support Officer                       Faculty of Science
  University of Southern Queensland, Toowoomba Oueensland Australia
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