ISO file size in bytes?

[Jerry Williams]

Would it be possible to list the iso file size in bytes in the SHA1SUM file?

The reason that I ask it is that I had a DVD with Fedora 7 on it and needed
a copy of the iso file.  So I did a dd on the DVD, but the file ended up
being bigger than the original iso file.  I had to know the size so I could
enter the number of blocks to copy.

It is much quicker to do an ls -l than it is to run sha1sum on a file.
If the size is right then run the sha1sum.

Or is the size listed on some web page some place?
Everywhere I have looked I end up with an estimate.

Thanks!
Jerry

[Matt Domsch]

On Wed, Oct 24, 2007 at 09:03:45PM -0600, Jerry Williams wrote:
>  Would it be possible to list the iso file size in bytes in the
> SHA1SUM file?
>  
>  The reason that I ask it is that I had a DVD with Fedora 7 on it and needed
>  a copy of the iso file.  So I did a dd on the DVD, but the file ended up
>  being bigger than the original iso file.  I had to know the size so I could
>  enter the number of blocks to copy.
>  
>  It is much quicker to do an ls -l than it is to run sha1sum on a file.
>  If the size is right then run the sha1sum.
>  
>  Or is the size listed on some web page some place?
>  Everywhere I have looked I end up with an estimate. 
When reading a the file itself with isoinfo, it'll tell you:

$ isoinfo -d -i F-7-x86_64-DVD.iso 
...
Logical block size is: 2048
Volume size is: 1683582
...


If you're reading a physical CD or DVD, you can do the same thing.
Here's a little script I use all the time for getting the size right.
It prompts you for the name of the ISO you want to create, then reads
the media using dd; repeat until Ctrl-C.

IIRC there was something about using -pad when writing media, but I
haven't had to do that for a while...

Thanks,
Matt

-- 
Matt Domsch
Linux Technology Strategist, Dell Office of the CTO
linux.dell.com & www.dell.com/linux


#!/bin/bash

DEVICE=/dev/cdrom

let i=0

while [ 1 ]; do

echo "Please insert a disc.  What do you want it named?"
read FILENAME
BLOCKS=`isoinfo -d -i ${DEVICE} | grep "Volume size" | awk '{print
$4}'`

dd if=${DEVICE} of=${FILENAME} bs=2k count=${BLOCKS}
md5sum ${FILENAME}
done

[Jon Masters]

On Wed, 2007-10-24 at 22:29 -0500, Matt Domsch wrote:
>  On Wed, Oct 24, 2007 at 09:03:45PM -0600, Jerry Williams wrote:
>  > Would it be possible to list the iso file size in bytes in the SHA1SUM file?
>  > 
>  > The reason that I ask it is that I had a DVD with Fedora 7 on it and needed
>  > a copy of the iso file.  So I did a dd on the DVD, but the file ended up
>  > being bigger than the original iso file.  I had to know the size so I could
>  > enter the number of blocks to copy.
>  > 
>  > It is much quicker to do an ls -l than it is to run sha1sum on a file.
>  > If the size is right then run the sha1sum.
>  > 
>  > Or is the size listed on some web page some place?
>  > Everywhere I have looked I end up with an estimate.
>  
>  When reading a the file itself with isoinfo, it'll tell you:
>  
>  $ isoinfo -d -i F-7-x86_64-DVD.iso 
>  ...
>  Logical block size is: 2048
>  Volume size is: 1683582
>  ... 
Right, but I think what he's saying is that he *didn't* have the ISO
file to hand - but did have a DVD he could dd from - and he wanted a way
to find out how big the image should have been without downloading it.

Jon.

[Todd Zullinger]

Jon Masters wrote:
>  Right, but I think what he's saying is that he *didn't* have
> the ISO
>  file to hand - but did have a DVD he could dd from - and he wanted a
>  way to find out how big the image should have been without
>  downloading it. 
And the very next part of Matt's mail said:

>  If you're reading a physical CD or DVD, you can do the same
> thing.
>  Here's a little script I use all the time for getting the size
>  right.  It prompts you for the name of the ISO you want to create,
>  then reads the media using dd; repeat until Ctrl-C. 
He even provided a short script to do the job.  You can't be much more
helpful than that. ;)

-- 
Todd        OpenPGP -> KeyID: 0xBEAF0CE3 | URL: www.pobox.com/~tmz/pgp
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
You're not drunk if you can lie on the floor without holding on.
    -- Dean Martin

[Matt Domsch]

On Wed, Oct 24, 2007 at 11:44:08PM -0400, Jon Masters wrote:
>  
>  Right, but I think what he's saying is that he *didn't* have the ISO
>  file to hand - but did have a DVD he could dd from - and he wanted a way
>  to find out how big the image should have been without downloading it. 
Go to bed Jon, you didn't read far enough. :-)  You would have seen
the appended script do:

BLOCKS=`isoinfo -d -i ${DEVICE} | grep "Volume size" | awk '{print
$4}'`
dd if=${DEVICE} of=${FILENAME} bs=2k count=${BLOCKS}

where DEVICE=/dev/cdrom  or whatever device had the media.


-- 
Matt Domsch
Linux Technology Strategist, Dell Office of the CTO
linux.dell.com & www.dell.com/linux

[Jon Masters]

On Wed, 2007-10-24 at 22:56 -0500, Matt Domsch wrote:
>  On Wed, Oct 24, 2007 at 11:44:08PM -0400, Jon Masters wrote:
>  > 
>  > Right, but I think what he's saying is that he *didn't* have the ISO
>  > file to hand - but did have a DVD he could dd from - and he wanted a way
>  > to find out how big the image should have been without downloading it.
>  
>  Go to bed Jon, you didn't read far enough. :-)  You would have seen
>  the appended script do:
>  
>  BLOCKS=`isoinfo -d -i ${DEVICE} | grep "Volume size" | awk '{print
> $4}'`
>  dd if=${DEVICE} of=${FILENAME} bs=2k count=${BLOCKS}
>  
>  where DEVICE=/dev/cdrom  or whatever device had the media. 
Yeah. I suck. Too much Red Sox and coffee, not enough reading...sorry
Matt - sooner or later I'll learn :-)

Jon.

[Jon Masters]

On Wed, 2007-10-24 at 22:29 -0500, Matt Domsch wrote:

>  If you're reading a physical CD or DVD, you can do the same
> thing.
>  Here's a little script I use all the time for getting the size right.
>  It prompts you for the name of the ISO you want to create, then reads
>  the media using dd; repeat until Ctrl-C. 
Right. But if you end up reading more from the disk than you planned,
this will only flag that up (the MD5SUM generated) - it won't tell you
what it should be. So my point from before is somehow semi valid ;-)

>  IIRC there was something about using -pad when writing media, but I
>  haven't had to do that for a while... 
It's down to the size of the ISO image. I haven't had to use pad in a
while, which suggests that most of the ISOs are created in the right
multiples of 2.whatever K or tools like growisofs are handling it.

CDs are fascinating little things. I've got a book on the multiple stage
error correction process somewhere here I used to use for bedtime
reading...these days, coffee is all that's required.

Jon.

[Jon Masters]

On Thu, 2007-10-25 at 01:14 -0400, Jon Masters wrote:
>  On Wed, 2007-10-24 at 22:29 -0500, Matt Domsch wrote:
>  
>  > If you're reading a physical CD or DVD, you can do the same thing.
>  > Here's a little script I use all the time for getting the size right.
>  > It prompts you for the name of the ISO you want to create, then reads
>  > the media using dd; repeat until Ctrl-C.
>  
>  Right. But if you end up reading more from the disk than you planned,
>  this will only flag that up (the MD5SUM generated) - it won't tell you
>  what it should be. So my point from before is somehow semi valid ;-) 
No, I'm wrong, because isoinfo is going to get that from the TOC. So
clearly I'm way too Red Soxed for one evening and should just shut up.

Ignore me... :-)

Jon.

[Tony Nelson]

At 10:29 PM -0500 10/24/07, Matt Domsch wrote:
> On Wed, Oct 24, 2007 at 09:03:45PM -0600, Jerry Williams wrote:
> > Would it be possible to list the iso file size in bytes in the SHA1SUM file?
> >
> > The reason that I ask it is that I had a DVD with Fedora 7 on it and needed
> > a copy of the iso file.  So I did a dd on the DVD, but the file ended up
> > being bigger than the original iso file.  I had to know the size so I could
> > enter the number of blocks to copy.
> >
> > It is much quicker to do an ls -l than it is to run sha1sum on a file.
> > If the size is right then run the sha1sum.
> >
> > Or is the size listed on some web page some place?
> > Everywhere I have looked I end up with an estimate.
>
> When reading a the file itself with isoinfo, it'll tell you:
>
> $ isoinfo -d -i F-7-x86_64-DVD.iso
> ...
> Logical block size is: 2048
> Volume size is: 1683582
> ... 
I find isosize less AWKward, as it puts out the size directly and will also
do the math:

    $ isosize Fedora-7.92-i386-DVD.iso
    3000535040
    $ isosize -d 2048 Fedora-7.92-i386-DVD.iso
    1465105
-- 
____________________________________________________________________
TonyN.:'                       <mailto:[e-mail]>
      '                              <http://www.georgeanelson.com/>