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I found a web page that suggests one can read the .iso images kept on
a disk and use them to do an upgrade without copying them to a cd
first. This is exactly what I want to do.

Here: http://www.linuxquestions.org/questions/history/341506

I've been following the steps outlined there, but ran into a problem
(fairly quickly). Here are the exact steps I took. (The text here
was entered by hand, since I cannot connect the laptop to the network
without switching it to XP due to the firewalls etc. at the palce that
I work. Note, however, that I took these steps just as I composed
this message, so the steps are as complete and accurate as I could
make them.)

I went to my linux laptop and logged in as root.

I created a mount point directory and made it world writeable.

mkdir /mnt/isoxxx
chmod 777 /mnt/isoxxx

I mounted the iso I wanted to read from on this mount point:

mount -o loop /home/CentOs-4.1-i386-bin1of4.iso /mnt/isoxxx

I made that my working directory and checked that the file I wanted to
copy was there.

cd /mnt/isoxxx
ls -la
total 4549
dr-xr-xr-x 2 root root 2040 Jun 11 09:48 ./
....
-r--r--r-- 4 root root 1429017 Jun 11 09:44 vmlinuz

I then tried to copy the file vmlinuz to where I wanted it (on my boot
partition):

cp vmlinuz /boot/iso-vmlinuz
cp: reading: vmlinuz: Input/output error

Since, that failed, I tried just cat'ing the file:
cat vmlinuz
cat: vmlinuz: Input/output error

I don't know why the contents of the .iso file could be unreadable in
this fashion (and what this rather non-descriptive error message is
trying to tell me). Note, that I have no problem reading and writing
to the partition which contains the .iso file that I mounted.

(I have the feeling that the reason I couldn't make a bootable cd is
related to being unable to read from this .iso file when mounted as a
partition.)

What step should I take next??? For example, how do I calculate the
checksum on the .iso file and compare it to what it should be? Maybe
the inital download of the file was botched.

Thanks,
-Chris

Chris F Clark wrote:
> I found a web page that suggests one can read the .iso images kept on
> a disk and use them to do an upgrade without copying them to a cd
> first. This is exactly what I want to do.
>
> Here: http://www.linuxquestions.org/questions/history/341506
>
> I've been following the steps outlined there, but ran into a problem
> (fairly quickly). Here are the exact steps I took. (The text here
> was entered by hand, since I cannot connect the laptop to the network
> without switching it to XP due to the firewalls etc. at the palce that
> I work. Note, however, that I took these steps just as I composed
> this message, so the steps are as complete and accurate as I could
> make them.)
>
> I went to my linux laptop and logged in as root.
>
> I created a mount point directory and made it world writeable.
>
> mkdir /mnt/isoxxx
> chmod 777 /mnt/isoxxx
>
> I mounted the iso I wanted to read from on this mount point:
>
> mount -o loop /home/CentOs-4.1-i386-bin1of4.iso /mnt/isoxxx
>
> I made that my working directory and checked that the file I wanted to
> copy was there.
>
> cd /mnt/isoxxx
> ls -la
> total 4549
> dr-xr-xr-x 2 root root 2040 Jun 11 09:48 ./
> ...
> -r--r--r-- 4 root root 1429017 Jun 11 09:44 vmlinuz
>
> I then tried to copy the file vmlinuz to where I wanted it (on my boot
> partition):
>
> cp vmlinuz /boot/iso-vmlinuz
> cp: reading: vmlinuz: Input/output error
>
> Since, that failed, I tried just cat'ing the file:
> cat vmlinuz
> cat: vmlinuz: Input/output error
>
> I don't know why the contents of the .iso file could be unreadable in
> this fashion (and what this rather non-descriptive error message is
> trying to tell me). Note, that I have no problem reading and writing
> to the partition which contains the .iso file that I mounted.
>
> (I have the feeling that the reason I couldn't make a bootable cd is
> related to being unable to read from this .iso file when mounted as a
> partition.)
>
> What step should I take next??? For example, how do I calculate the
> checksum on the .iso file and compare it to what it should be? Maybe
> the inital download of the file was botched.
>
> Thanks,
> -Chris

It's very likely the iso is corrupted. Try

ms5sum /home/CentOs-4.1-i386-bin1of4.iso

and compare the md5sum to what it should be (which
can be found on the website you got the iso from)

/dan

Chris F Clark <cfc@shell01.theworld.com> wrote:
> I found a web page that suggests one can read the .iso images kept on
> a disk and use them to do an upgrade without copying them to a cd

Upgrade? What do you mean? Sure you can use the isos - that's obvious.
No magic required. Just mount 'em.

> I mounted the iso I wanted to read from on this mount point:

> mount -o loop /home/CentOs-4.1-i386-bin1of4.iso /mnt/isoxxx

Fine.

> I then tried to copy the file vmlinuz to where I wanted it (on my boot
> partition):

> cp vmlinuz /boot/iso-vmlinuz
> cp: reading: vmlinuz: Input/output error

Well, you have an media error or such. Check the kernel error mesages.

Peter

On Thu, 06 Oct 2005 19:04:20 +0200, Chris F Clark <cfc@shell01.TheWorld.com> wrote:

> I found a web page that suggests one can read the .iso images kept on
> a disk and use them to do an upgrade without copying them to a cd
> first. This is exactly what I want to do.
>
> Here: http://www.linuxquestions.org/questions/history/341506
>
> I've been following the steps outlined there, but ran into a problem
> (fairly quickly). Here are the exact steps I took. (The text here
> was entered by hand, since I cannot connect the laptop to the network
> without switching it to XP due to the firewalls etc. at the palce that
> I work. Note, however, that I took these steps just as I composed
> this message, so the steps are as complete and accurate as I could
> make them.)
>
> I went to my linux laptop and logged in as root.
>
> I created a mount point directory and made it world writeable.
>
> mkdir /mnt/isoxxx
> chmod 777 /mnt/isoxxx

The mode of the mount point should not matter. Once something else
is mounted, it's the access bits of the root directory of the mounted
file system that are consulted. (Except if you do ls .., you need
search permission on the underlying mount point to look up the inode
number of "..".)

> I mounted the iso I wanted to read from on this mount point:
>
> mount -o loop /home/CentOs-4.1-i386-bin1of4.iso /mnt/isoxxx

You probably need "ro" in the options, or else the kernel will try
to update the inodes to reflect the last access time.

mount -t iso9660 -o loop,ro /home/CentOs-4.1-i386-bin1of4.iso /mnt/isoxx

Perhaps it does not matter, I haven't checked what the kernel does
if the file system type lacks the appropriate write functions in its
file_ops or inode_ops tables, but you could try and see if it helps.


> I made that my working directory and checked that the file I wanted to
> copy was there.
>
> cd /mnt/isoxxx
> ls -la
> total 4549
> dr-xr-xr-x 2 root root 2040 Jun 11 09:48 ./
> ...
> -r--r--r-- 4 root root 1429017 Jun 11 09:44 vmlinuz
>
> I then tried to copy the file vmlinuz to where I wanted it (on my boot
> partition):
>
> cp vmlinuz /boot/iso-vmlinuz
> cp: reading: vmlinuz: Input/output error

I don't think it's a media error, since it would have to be a harddisk
media error. A format error is rather likely to go undetected, in the
sense that the kernel very seldom double checks anything. A format error
could make the kernel think a file is larger or smaller or has blocks
that do not really exist... OK, that one could give I/O error, but I think
it would rather give a panic.

> Since, that failed, I tried just cat'ing the file:
> cat vmlinuz
> cat: vmlinuz: Input/output error
>
> I don't know why the contents of the .iso file could be unreadable in
> this fashion (and what this rather non-descriptive error message is
> trying to tell me). Note, that I have no problem reading and writing
> to the partition which contains the .iso file that I mounted.

If the "ro" mount option does not help, you could check if you can read
the very blocks that this iso file occupies:

cp /home/CentOs-4.1-i386-bin1of4.iso /dev/null && echo OK || echo $?, ouch!

-Enrique

"Enrique Perez-Terron" <enrio@online.no> wrote in message
newsp.sx8pe5awnxtvbs@apeiron.home.lan...

>> I mounted the iso I wanted to read from on this mount point:
>>
>> mount -o loop /home/CentOs-4.1-i386-bin1of4.iso /mnt/isoxxx
>
> You probably need "ro" in the options, or else the kernel will try
> to update the inodes to reflect the last access time.

With an iso image filesystem, which will automatically be mounted as type
iso9660? I don't think so, and that should be auto-detected. I've just
double-checked that on a Fedora installation.


>> Since, that failed, I tried just cat'ing the file:
>> cat vmlinuz
>> cat: vmlinuz: Input/output error
>>
>> I don't know why the contents of the .iso file could be unreadable in
>> this fashion (and what this rather non-descriptive error message is
>> trying to tell me). Note, that I have no problem reading and writing
>> to the partition which contains the .iso file that I mounted.
>
> If the "ro" mount option does not help, you could check if you can read
> the very blocks that this iso file occupies:
>
> cp /home/CentOs-4.1-i386-bin1of4.iso /dev/null && echo OK || echo $?,
> ouch!

If the ISO is corrupt, why not simply redownload it?

Daniel Ganek <ganek@comcast.net> writes:

> It's very likely the iso is corrupted. Try
>
> md5sum /home/CentOs-4.1-i386-bin1of4.iso

Thanks. 3 of the 4 iso's I downloaded were corrupt. I am downloading
them again. At least, now I know why the cd wouldn't boot--gigo.

-Chris

Thanks to all who have helped. I finally got a copy of the iso's that
report the correct md5sum (well parts 1, 2, and 4 only so far, but
part 1 is the critical part). It took 8 times of pulling part 1 over
to get one which did so.

Anyway, now that I have one with the correct md5sum, I can read the
files inside. Curious how that works out, huh?....

In any case, I can now do the upgrade and see if that fixes my "linux"
mouse problem.

Ever hopeful,
-Chris

I would just like to thank all the people who helpd me get my laptop
upgraded. It is now running CentOS 4.1 and that fixes my "mouse"
problem, which is how this all started. (Yes, I do have a few minor
glitches due to things changing (and some of those I have already
fixed), but all-in-all the process has come to a successful
conclusion.) I can now go back to being mostly a Linux user and not a
system installer. That makes me happy.

Again, thanks to all.
-Chris

BTW, anyone who contributed and happens to be in the Boston/Worcester
area and wants a beer, drop me a line, I will gladly oblidge.