Re: Linux M-Disc support

-I bought a Samsung USB drive when m-disks were new and got some media to backup my Windows laptop. I was using Acronis and the boot and restore from USB was a pain; so I have left over unused disks I should use. The disks I did create are still readable on Linux. FWIW, here's output from xorriso -to from two mdisks. One is a Verbatim and the other is Millentia; one was written. These reports are from an LG SATA BD drive.

Drive current: -dev '/dev/sr0'
Drive access : exclusive:unrestricted
Drive type : vendor 'HL-DT-ST' product 'BD-RE WH16NS40' revision '1.02'
Drive id : 'K9AE5EA4251 '
Media current: BD-R sequential recording
Media product: MILLEN/MR1/0 , Millenniata Inc.
Media status : is blank
Media blocks : 0 readable , 12219392 writable , 12219392 overall
Media summary: 0 sessions, 0 data blocks, 0 data, 23.3g free

Drive current: -dev '/dev/sr0'
Drive access : exclusive:unrestricted
Drive type : vendor 'HL-DT-ST' product 'BD-RE WH16NS40' revision '1.02'
Drive id : 'K9AE5EA4251 '
Media current: BD-R sequential recording, Pseudo Overwrite formatted
Media product: VERBAT/IMk/0 , Mitsubishi Kagaku Media Co.
Media status : is unsuitable , is POW formatted
Media blocks : 35185280 readable , 12906880 unused , 48092160 overall
Media summary: unsuitable Pseudo Overwrite formatted BD-R

I will try to burn an m-disk next with xorriso and let you know how it goes.

Paul

On Tue, Jun 28, 2022 at 6:50 AM Thomas Schmitt <scdbackup@gmx.net> wrote:

Hi,

Paul von Behren wrote:
> Can xorriso burn/engrave an M-Disc? Can any other Linux SW?

Yes to both, although rarely tested.
In my mailbox i find libburn user reports only for BD-R M-Discs.

M-Disc is entirely a matter of drive and medium. The burn programs get
the media info from the drive which presents M-Disc as DVD+R or BD-R.
(Verbatim seems to sell M-Disc DVD as "DVD R" omitting the significant
difference between DVD-R and DVD+R. But i remember that DVD+R was
mentioned when the M-Disc technology was announced.)

So if you really want to pay the price difference between M-Disc and
other write-once media, then give it a try with your favorite burn
program for DVD or BD.
I would of course be glad if you choose xorriso or cdrskin.

Please report the outcome.
As said: Reports are rare.

----------------------------------------------------------------------

If the burn run looks successful, consider to run

xorriso -for_backup -indev /dev/sr0 -check_media --

to get an impression of readability.

If you use xorriso to create an ISO 9660 filesystem, then consider to
use -for_backup to equip the data files and the overall filesystem with
MD5 checksums. (With xorriso's mkisofs emulation the option begins by
two dashes: --for_backup.)

A xorriso run with -for_backup ... -check_media will then verify the
overall checksums.
But even without recorded MD5s it will check the readability of all data
blocks of the written area.

If you recorded MD5 and want to check the single file checksums:

xorriso -for_backup -indev /dev/sr0 -check_md5_r sorry / --

This will report on stdout each file which fails to match its recorded
MD5. Informational messages and pacifiers appear on stderr.
The exit status of xorriso will indicate whether all was fine (0) or
whether files failed the test (not 0, actually 32).
This check works only if indeed MD5s were recorded by xorriso.

Consider to repeat this checking regularly to get an impression how your
recorded files are doing.

Have a nice day :)

Thomas