Re: Archiving content of a directory on a DVD-R.

["Thomas Schmitt" <scdbackup@gmx.net>]

Hi,

peter@easthope.ca wrote:
> Drive type   : vendor 'PLEXTOR' product 'DVDR PX-708A' revision '1.06'

How old is it ?
I find this model mentioned as early as 2003. DVD burning was a novelty
back then.


> https://www.londondrugs.com/verbatim-dvd-rw---30-pack/L7011505.html

Says "You have been blocked".

Guessing from the URL: DVD-RW media.
I would avoid DVD-RW with an old DVD burner. After DVD+R DL this is the
next type of DVD which fails when the burner's sight becomes blurred by
age.

The internet says that PX-708A does DVD-R, DVD-RW, and DVD+RW.

You may ask it by

  xorriso -outdev /dev/sr0 -list_profiles out

A modern DVD burner is supposed to reply something like

  Profile      : 0x0012 (DVD-RAM)
  Profile      : 0x0011 (DVD-R sequential recording)
  Profile      : 0x0015 (DVD-R/DL sequential recording)
  Profile      : 0x0016 (DVD-R/DL layer jump recording)
  Profile      : 0x0014 (DVD-RW sequential recording)
  Profile      : 0x0013 (DVD-RW restricted overwrite)
  Profile      : 0x001A (DVD+RW)
  Profile      : 0x001B (DVD+R)
  Profile      : 0x002B (DVD+R/DL)
  Profile      : 0x0010 (DVD-ROM)
  Profile      : 0x0009 (CD-R)
  Profile      : 0x000A (CD-RW)
  Profile      : 0x0008 (CD-ROM)
  Profile      : 0x0002 (Removable disk)

Yours might omit some of those lines.
A profile is a set of features. It describes a media role. Most of them
are about writing particular media types. Some are about reading.


> Not clear which medium is suitable for weekly backups.

DVD-R and DVD+RW should both be ok. DVD-R can store up to 99 sessions
with several MB wasted between each session. DVD+RW get their sessions
emulated by xorriso with no more than 64 MB waste between sessions.
In case that the drive announces to support DVD+R: 153 sessions with
4 MB waste between sessions.

If you cannot avoid DVD-RW then format them (if profile 0x0013 is
announced):

  xorriso -outdev /dev/sr0 -format as_needed

This makes them similar to DVD+RW.

DVD+RW and DVD-RW can be re-used. But xorriso will not be willing to
overwrite them from scratch unless you explicitely tell it to invalidate
the existing ISO 9660 filesystem (or other filesystem formats):

  xorriso -outdev /dev/sr0 -blank as_needed


Have a nice day :)

Thomas