Off-Topic > Off-Topic - Tiny Core Lounge

isohybrid identification

(1/2) > >>

SamK:
Is there a command that will identify and report that an ISO has been produced via the syslinux isohybrid program?
   

curaga:
Not that I know of. File sees them as isos. "qemu -hda /path/to/iso" will tell the difference though ;)

Rich:
Hi SamK
If I understand it correctly, an ISOhybrid basically just has a MBR added to it. Try the following:

--- Code: --- hexdump -n 2 -s 510 -x -v filename.iso
--- End code ---
If I'm correct, a standard ISO will return

--- Quote ---00001fe    0000                                                       
0000200

--- End quote ---
while an ISOhybrid should return

--- Quote ---00001fe    aa55                                                       
0000200

--- End quote ---
If that's the case, couple that with  grep  and you'll probably have what you are looking for.

SamK:
Hi Rich
Thanks for the idea.

--- Quote from: Rich on December 04, 2011, 11:11:59 AM ---If I understand it correctly, an ISOhybrid basically just has a MBR added to it.

--- End quote ---
I have looked a ISOhybrid only superficially.  On a test ISO I created the following was observed:

ISO - Pre ISOhybrid
Size reported by the ls command=29,126,656

ISO - Post ISOhybrid
Size reported by the ls command=29,360,128

Perhaps there is something else going on in addition to the MBR?


I have decided against pursuing ISOhybrid at this time. 

The principal reason for this is the way in which mnttool reports it.  The attached screen shot was taken on a machine booted from a USB flash drive created from Multicore v4.0.2 as the Core team produced it in ISOhybrid form.  The USB drive is sdc.  Both sdc and sdc1 are displayed by mnttool.  Either may be mounted independently, but both cannot be mounted concurrently.

For the purpose I had in mind, these may lead to confusion, hence a non ISOhybrid ISO will be used.

Rich:
Hi SamK
At least satisfy my curiosity and tell me if the hexdump command produced the expected results.

--- Quote ---Perhaps there is something else going on in addition to the MBR?
--- End quote ---
I seem to remember reading something about one of the formats being able to boot from a partition
and the other requiring a drive.

Navigation

[0] Message Index

[#] Next page