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Re: OT: Is there any size limit for ISO's?

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Hi,

Hans wrote:
> does anyone know, if there is a limit of the size an iso may have?

With xorriso: 4 TiB = 4096 GiB.

An ISO 9660 filesystem may have 2 exp 32 data blocks. The usual block
size is 2 exp 11 = 2048 bytes. That would be 2 exp 43 = 8 TiB in total.
But xorriso uses libburn for writing and a poor design decision of
about 20 years ago lets it use signed int for block addresses.
So only 2 exp 31 blocks = 4 TiB are possible with libburn and xorriso.


> Background: I have a selfmade lifefile iso image, which was created by
> bootcdwrite. The size of the imagefile is about 32GB.

Looks like bootcd uses genisoimage for producing the ISO,
(https://tracker.debian.org/media/packages/b/bootcd/control-6.7)

Anyways, 32 GB of size should not be a problem.


> When the stick is booting, first appear the usual text messages,

Can you determine the origin of the last visible messages ?
BIOS/EFI ?
Boot loader (GRUB or ISOLINUX/SYSLINUX) ?
Linux ?
Debian installation software ?


> but then the screen goes blank and the further boot hangs.
> However, when I am booting this file (this iso-image) with Virtualbox,
> everything is working well.

Is Virtualbox using the same BIOS type as the real machine ?
I mean EFI versus Legacy BIOS aka CSM mode.


> Note: In earlier times I had a smaller image (about 8 GB), which booted
> perfectly.

Is the USB stick large enough for the image ?

Can dd read the whole image back from the USB stick ?

  # Set variable blocks to image file size divided by 2048
  blocks=...
  # Set variable stick to device file address of the USB stick
  stick=...

  dd if="$stick" bs=2048 count="$blocks" | md5sum

If no i/o error is reported by dd, compute the MD5 sum of the image file
and compare both.


> So I believe, the size of the image is, what matters. But maybe I am wrong.

It's not impossible. Especially if the stick hardware has problems.
But depending on the origin of the last visible message there is also
a chance that boot loader or Linux derail because of buggy file content
in the elsewise healthy ISO.


Have a nice day :)

Thomas

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Thread

OT: Is there any size limit for ISO's? Hans <hans.ullrich@loop.de> - 2024-01-22 21:10 +0100
  Re: OT: Is there any size limit for ISO's? Marco Moock <mm@dorfdsl.de> - 2024-01-22 21:30 +0100
  Re: OT: Is there any size limit for ISO's? "Thomas Schmitt" <scdbackup@gmx.net> - 2024-01-22 22:00 +0100
    Re: OT: Is there any size limit for ISO's? Hans <hans.ullrich@loop.de> - 2024-01-22 22:40 +0100
      Re: OT: Is there any size limit for ISO's? Stefan Monnier <monnier@iro.umontreal.ca> - 2024-01-22 23:40 +0100
        Re: OT: Is there any size limit for ISO's? Hans <hans.ullrich@loop.de> - 2024-01-23 11:30 +0100
          Re: OT: Is there any size limit for ISO's? Hans <hans.ullrich@loop.de> - 2024-01-24 13:30 +0100
      Re: OT: Is there any size limit for ISO's? gene heskett <gheskett@shentel.net> - 2024-01-23 03:30 +0100
  Encrypted partiotions - which files related? Hans <hans.ullrich@loop.de> - 2024-01-29 11:40 +0100
    Re: Encrypted partiotions - which files related? Arno Lehmann <al@its-lehmann.de> - 2024-01-29 12:20 +0100
      Re: Encrypted partiotions - which files related? Hans <hans.ullrich@loop.de> - 2024-01-29 12:40 +0100
        Re: Encrypted partiotions - which files related? Arno Lehmann <al@its-lehmann.de> - 2024-01-29 13:20 +0100
          Re: Encrypted partiotions - which files related? Hans <hans.ullrich@loop.de> - 2024-01-29 16:20 +0100
            Re: Encrypted partiotions - which files related? David Wright <deblis@lionunicorn.co.uk> - 2024-01-29 21:00 +0100

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