Re: Why is the DVD image so large?

On Mon, 3 Nov 2025 12:31:42 +0100
Tomek CEDRO <tomek@cedro.info> wrote:

> On Mon, Nov 3, 2025 at 10:12 AM Tomoaki AOKI <junchoon@dec.sakura.ne.jp> wrote:
> > Another option (far more difficult, though) would be switching
> > to Blu-ray disks.
> >
> > Why difficutlt? Because it would be strongly expected supports for
> > newer UDF that BD requires, if official BD image is provided,
> > even if the media is actually in ISO 9660. And UDF support on FreeBSD
> > is outdated that cannot mount BD.
> 
> Hmm I have two 5.25" SATA BD recorders (Pioneer and Asus) using them
> for backups with BD-R (25GB) and BD-R DL (50GB) and BD-RE DL (50GB
> rewritable) disks with no problem. Also tested external USB BD
> recorders work fine but a bit more expensive (looks like Pioneer in
> Europe is sold by Verbatim?). These are not that expensive and can
> burn dvd, cd, and mdisk too. Because DVD-RW-DL are hard to find I just
> bought whole bunch of BD-RE DL and use them in cycles no to waste
> plastic. For clients with one time use BD-R and BD-R DL are fine and
> cheaper. I trust Verbatim disks as there are many different types of
> physical medium just marked BD-R* but burner firmware must support
> them to write correctly.

Writing ISO9660 into BD* media on BD drive would be fine
if the drive is actually recognized as "writtable".
I've never succeeded writing anything usign USB BD drive
on FreeBSD yet, while reading ISO9660 and DVD in pre-BD version
of UDF are fine and DVD videl playback is OK on the exact same
USB BD drive.

I had chance to try reading backup BD-R written by BD writer
running on Windows (can read its contents on Windows) on FreeBSD,
without success (too old UDF support).

Maybe newbies who noticed a BD media (even though it's actually
formatted in ISO9660 or old UDF) is accessible on FreeBSD could
think that FreeBSD can at least read every BD disks unless the disk
is encrypted, which is not true for now.


> You just need to create hybrid ISO9660 + UDF (plus -iso-level 3 or 4
> if you have single files over 2GB) with mkisofs and then burn the
> image with cdrecord or just growisofs or k3b or whatever you prefer.
> Then if you mount it with mount_iso9660 files looks a bit weird, but
> if you mount_udf all looks fine. But this does not seem the case for
> FreeBSD installer as it is simple ISO9660 not even UDF nor hybrid :-)
> 
> I also tend to use mdconfig to mount iso and compare files inside iso
> with files to backup before burning just to make sure all landed as
> expected (i.e. sometimes i forget to add -iso-level 3 so big files are
> gone). Then disk verification with iso can be performed after burning.
> 
> I found VENTOY [1] extremely helpful because it allows having many ISO
> files on a single USB drive and choose one from its boot menu, it
> supports BIOS and UEFI boot, adding boot keys, and other utilities..
> so there is no need to have single usb drive per iso anymore just one
> usb drive with many iso :-)
> 
> [1] https://www.ventoy.net/
> 
> ps/2: What I really miss about UDF implementation in FreeBSD is modern
> version support with R/W access so we could just use UDF filesystem as
> standard platform independent disk format (i.e. for pendrive in place
> of fat32 / vfat /ntfs). But other systems also have this support
> varying in version support and on the fly write so this is Universal
> Disk Format only in theory and still mainly used for optical disks :-P
> 
> -- 
> CeDeROM, SQ7MHZ, http://www.tomek.cedro.info

Exactly. It would be wanted, but maybe lower priority than cutting edge
GPUs and WiFis.

Regards.

-- 
Tomoaki AOKI    <junchoon@dec.sakura.ne.jp>