Re: Why is the DVD image so large?

On Mon, Nov 3, 2025 at 2:00 PM Tomoaki AOKI <junchoon@dec.sakura.ne.jp> wrote:
> 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 is outdated that cannot mount BD.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.

Hmm, this update to at least mount and read modern UDF filesystem
commonly used on the BlyRay disks sounds like a task for LDWG (Laptop
Dekstop Work Group). Forwarding :-)

-- 
CeDeROM, SQ7MHZ, http://www.tomek.cedro.info