Re: Why is the DVD image so large?

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 is outdated that cannot mount BD.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.

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