Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.debian.user > #202971 > unrolled thread

blu-ray recommendations?

Back to article view | Back to linux.debian.user

Contents

  blu-ray recommendations? kjonca@poczta.onet.pl (Kamil Jońca) - 2018-12-02 22:00 +0100
    Re: blu-ray recommendations? "Thomas Schmitt" <scdbackup@gmx.net> - 2018-12-02 22:40 +0100
      Re: blu-ray recommendations? deloptes <deloptes@gmail.com> - 2018-12-03 08:20 +0100
        Re: blu-ray recommendations? "Thomas Schmitt" <scdbackup@gmx.net> - 2018-12-03 09:00 +0100
          Re: blu-ray recommendations? Stefan Monnier <monnier@iro.umontreal.ca> - 2018-12-03 10:40 +0100
            Re: blu-ray recommendations? <tomas@tuxteam.de> - 2018-12-03 12:00 +0100
              Re: blu-ray recommendations? deloptes <deloptes@gmail.com> - 2018-12-03 15:30 +0100
                Re: blu-ray recommendations? Curt <curty@free.fr> - 2018-12-03 16:10 +0100
                Re: blu-ray recommendations? <tomas@tuxteam.de> - 2018-12-03 16:50 +0100
                  Re: blu-ray recommendations? deloptes <deloptes@gmail.com> - 2018-12-03 17:00 +0100
                    Re: blu-ray recommendations? <tomas@tuxteam.de> - 2018-12-03 17:10 +0100
                      Re: blu-ray recommendations? "Thomas Schmitt" <scdbackup@gmx.net> - 2018-12-03 18:10 +0100
                      Re: blu-ray recommendations? Stefan Monnier <monnier@iro.umontreal.ca> - 2018-12-04 20:50 +0100
                        Re: blu-ray recommendations? <tomas@tuxteam.de> - 2018-12-04 21:10 +0100
                  Re: blu-ray recommendations? deloptes <deloptes@gmail.com> - 2018-12-03 17:10 +0100
                Re: blu-ray recommendations? Jonathan Dowland <jmtd@debian.org> - 2018-12-04 10:40 +0100
                  Re: blu-ray recommendations? "Thomas Schmitt" <scdbackup@gmx.net> - 2018-12-04 12:20 +0100
                    Re: blu-ray recommendations? deloptes <deloptes@gmail.com> - 2018-12-05 08:40 +0100
                      Re: blu-ray recommendations? Curt <curty@free.fr> - 2018-12-05 10:20 +0100
                        Re: blu-ray recommendations? deloptes <deloptes@gmail.com> - 2018-12-06 00:50 +0100
                  Re: blu-ray recommendations? "Thomas Schmitt" <scdbackup@gmx.net> - 2018-12-05 10:50 +0100
              Re: blu-ray recommendations? tomas@tuxteam.de - 2018-12-03 15:30 +0100
                Re: blu-ray recommendations? Stefan Monnier <monnier@iro.umontreal.ca> - 2018-12-03 15:40 +0100
                  Re: blu-ray recommendations? <tomas@tuxteam.de> - 2018-12-03 16:40 +0100
                    [OT]Re: blu-ray recommendations? Michael Lange <klappnase@freenet.de> - 2018-12-03 19:50 +0100
                      Re: [OT]Re: blu-ray recommendations? deloptes <deloptes@gmail.com> - 2018-12-03 21:20 +0100
                      Re: [OT]Re: blu-ray recommendations? <tomas@tuxteam.de> - 2018-12-04 10:20 +0100
                    Re: blu-ray recommendations? Stefan Monnier <monnier@IRO.UMontreal.CA> - 2018-12-03 23:00 +0100
              Re: blu-ray recommendations? Stefan Monnier <monnier@IRO.UMontreal.CA> - 2018-12-03 17:20 +0100

Page 2 of 2 — ← Prev page 1 [2]

#203045

Hi,

deloptes wrote:
> the nature of the CD/DVD implies degradation of material.

This is where our experience differs.


If i had such media in hand i would run

  img_buffer=...path.for.emerging.media.image.file...
  sector_map=...path.for.emerging.map.file...

  xorriso -outdev /dev/sr0 \
          -check_media use=outdev \
                       sector_map="$sector_map" \
                       data_to="$img_buffer" \
                       --

This run will try to create a pair of files with retrieved image data
and info about successfully read sectors and yet unreadable sectors.
Repeated runs will only try to retrieve the previously unreadable sectors.

The file pair may be moved to other computers (or accessed via network)
in order to make retrieval attempts with other reader drives.
But it is also worth to make more tries with the same drive, because a
degrading drive tends to retrieve more sectors if it tries reading with
different start sectors.

Depending on the drive's effort, unreadable sectors can slow down the
retrieval substantially. By default -check_media will try for 8 hours.
(See -check_media option "time_limit=seconds" in man xorriso.)

If the attempt shall be aborted, then this should be done by touching
file
  /var/opt/xorriso/do_abort_check_media
in order to let the retrieval run store its sector map before ending.
(The file path settable by -check_media option "abort_file=disk_path".)

In case of success, the report text will contain only quality marks "+"
and "0, not "-"'. Subsequent attempts with the same sector_map file will
finish quickly without reading attempts.

  Media checks :        lba ,       size , quality
  Media region :          0 ,    1209009 , + valid
  Media region :    1209009 ,         15 , 0 off_track
  Media region :    1209024 ,      20491 , + valid
  Media region :    1229515 ,         21 , 0 off_track
  Media region :    1229536 ,      21186 , + valid
  ...
  Media region :    1800992 ,      21006 , + valid
  Media region :    1821998 ,         18 , 0 off_track
  Media region :    1822016 ,      21838 , + valid

("off_track" are sectors in the gaps between tracks or sessions.
 With CD-R and DVD-R those gaps can have several MB of size.)

The resulting image file can be read or mounted like the medium.
If the storage format contains own checksums, then this is the state to
verify them.


Curt wrote:
> Here's a decade-old (and a little more) opinion from UNESCO (?)
> [...] data tape and hard disc systems are made reliable because
> technological testing [...]
> No viable automatic testing and management system exists to make
> optical disc reliable [...]

It depends on whom you ask. Of course, owners of LTO robots or giant disk
arrays are not impressed by optical media.

Testing is much a matter of popularity. Insofar tapes are substandard.
(The reason why i began to make my backups on CD was the miserable
 quality delivered by QIC and DAT tapes and drives in conjunction with
 normal users.)

Whether testing needs to be automatical depends on the ratio of people
and data. I am one people and have data for one people.
If you have the money for tape robot or drive array, then you also can
afford a big jukebox for opticals.

Maybe the quoted text also mentions the relevance of ubiquity of reader
drives for old media. If so, then it should also note that optical drives
are still manufactured for all old media types.

I have seen as backup media: removable hard disks, MOs, and various tapes.
They all were unreliable in the hands of $WORK users. Optical media
brought relief twofold: They don't fail as often and the user can be held
responsible for verifying that important data are indeed in the backup.

Optical media cannot really compete with spinning hard disks when it comes
to price and reliability. But the properties of both are so different
that hard disk cannot easily replace all typical backup use cases.


Have a nice day :)

Thomas

[toc] | [prev] | [next] | [standalone]

#202988

[Multipart message — attachments visible in raw view] — view raw

On Mon, Dec 03, 2018 at 09:18:07AM -0500, Stefan Monnier wrote:
> > My hunch is that those chips are fairly expensive, ecologically, but
> > where's the tipping point?
> 
> I remember reading somewhere that back around the turn of the century
> a laptop's RAM chips needed about the same energy to produce as the
> laptop's energy consumption during its lifetime.

"Energy"? Or "environmental externalities confounded?" Energy prices
do vary around the world, but not by a huge factor it seems: witness
the Bitcoin "factories" looking for places with cheap energy access,
as energy costs take a significant part of total costs), while
foundries don't seem to follow that pattern. OTOH other ecological
externalities do vary *a lot* -- rare earth metals being a sobering
example.

>                                                 And AFAIK there are
> precious few studies trying to measure such things, so who knows whee
> things stand now.

Yes, more transparency here would be something, wouldn't it?

> I think it's fair to assume that chips are very expensive ecologically,
> indeed, and optical disks are likely much cheaper in this regard.
> 
> But the same amount of chips as a blu-ray drive probably gives you
> a multi-TB HDD, so the tipping point probably requires use of more
> than a hundred blu-ray disks.

My feeling too...

Cheers
-- t

[toc] | [prev] | [next] | [standalone]

#202990

> "Energy"? Or "environmental externalities confounded?"

I remember it talking specifically about energy.


        Stefan

[toc] | [prev] | [next] | [standalone]

#202995

[Multipart message — attachments visible in raw view] — view raw

On Mon, Dec 03, 2018 at 09:35:28AM -0500, Stefan Monnier wrote:
> > "Energy"? Or "environmental externalities confounded?"
> 
> I remember it talking specifically about energy.

Interesting.

Thanks
-- t

[toc] | [prev] | [next] | [standalone]

#203007 — [OT]Re: blu-ray recommendations?

On Mon, 3 Dec 2018 16:37:22 +0100
<tomas@tuxteam.de> wrote:

> On Mon, Dec 03, 2018 at 09:35:28AM -0500, Stefan Monnier wrote:
> > > "Energy"? Or "environmental externalities confounded?"
> > 
> > I remember it talking specifically about energy.
> 
> Interesting.

This "gray" or "emobodied" energy is usually being grotesquely
underestimated.
According to
https://www.dw.com/en/ecological-footprint-how-gray-energy-is-totally-underestimated/a-43261811 :

"The production of a laptop's hardware amounts to 1,000 kWh of grey
energy. That's equivalent to 40 days of continuous vacuuming."
and
"For the manufacture, transport, storing, selling and discarding of a
smart phone, 220 kWh of gray energy is needed. With that same energy, you
could charge your phone for 50 years." :)

Also interesting in this context may be this quote from
https://en.wikipedia.org/wiki/Embodied_energy#In_transportation :

"it is striking to note that we consume more embodied energy in our
transportation expenditures than direct energy [...]. Put in other words,
we consume less energy to move around in our personal vehicles than we
consume the energy we need to produce, sell and transport the cars,
trains or buses we use "

Regards

Michael

.-.. .. ...- .   .-.. --- -. --.   .- -. -..   .--. .-. --- ... .--. . .-.

No problem is insoluble.
		-- Dr. Janet Wallace, "The Deadly Years", stardate 3479.4

[toc] | [prev] | [next] | [standalone]

#203011 — Re: [OT]Re: blu-ray recommendations?

Michael Lange wrote:

> This "gray" or "emobodied" energy is usually being grotesquely
> underestimated.
> According to
>
https://www.dw.com/en/ecological-footprint-how-gray-energy-is-totally-underestimated/a-43261811
> :
> 
> "The production of a laptop's hardware amounts to 1,000 kWh of grey
> energy. That's equivalent to 40 days of continuous vacuuming."
> and
> "For the manufacture, transport, storing, selling and discarding of a
> smart phone, 220 kWh of gray energy is needed. With that same energy, you
> could charge your phone for 50 years." :)
> 
> Also interesting in this context may be this quote from
> https://en.wikipedia.org/wiki/Embodied_energy#In_transportation :
> 
> "it is striking to note that we consume more embodied energy in our
> transportation expenditures than direct energy [...]. Put in other words,
> we consume less energy to move around in our personal vehicles than we
> consume the energy we need to produce, sell and transport the cars,
> trains or buses we use "

I now know exactly why globalization looks suspicious, or should I say
globalism

thanks - this was a good story

regards

[toc] | [prev] | [next] | [standalone]

#203021 — Re: [OT]Re: blu-ray recommendations?

[Multipart message — attachments visible in raw view] — view raw

On Mon, Dec 03, 2018 at 07:33:39PM +0100, Michael Lange wrote:
> On Mon, 3 Dec 2018 16:37:22 +0100
> <tomas@tuxteam.de> wrote:
> 
> > On Mon, Dec 03, 2018 at 09:35:28AM -0500, Stefan Monnier wrote:
> > > > "Energy"? Or "environmental externalities confounded?"
> > > 
> > > I remember it talking specifically about energy.
> > 
> > Interesting.
> 
> This "gray" or "emobodied" energy is usually being grotesquely
> underestimated.

Thanks for the links.

Actually I was trying to account for that by assuming that there is
some (non-ridiculous) factor between the energy price as we know it
and the energy price manufacturers, transporters, etc. pay -- so the
energy expended in mfg, packaging, transport... somehow reflects in
the gadget end price.

This may have been an optimist assumption, and I can now test it
against your links :-)

Cheers
-- t

[toc] | [prev] | [next] | [standalone]

#203012

>> > "Energy"? Or "environmental externalities confounded?"
>> I remember it talking specifically about energy.
> Interesting.

Part of the discussion was about it being useless to recycle those
material 'cause most of the damage is in the form of energy used to put
those material in this particular shape.  Only *reuse* (or keep using)
is really beneficial.


        Stefan

[toc] | [prev] | [next] | [standalone]

#203002

> My hunch is that those chips are fairly expensive, ecologically, but
> where's the tipping point?

I remember reading somewhere that back around the turn of the century
a laptop's RAM chips needed about the same energy to produce as the
laptop's energy consumption during its lifetime.  And AFAIK there are
precious few studies trying to measure such things, so who knows whee
things stand now.

I think it's fair to assume that chips are very expensive ecologically,
indeed, and optical disks are likely much cheaper in this regard.

But the same amount of chips as a blu-ray drive probably gives you
a multi-TB HDD, so the tipping point probably requires use of more
than a hundred blu-ray disks.


        Stefan

[toc] | [prev] | [standalone]

Page 2 of 2 — ← Prev page 1 [2]

Back to top | Article view | linux.debian.user

csiph-web