DVDs are worse than CDs

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"Error posting message: 441 Article rejected by Spamassassin"
said Alpine but I am not trying to spam.

I recently made a webpage, i.e.
HTTPS://Gloucester.Insomnia247.NL/media/media.HTML

I copied and pasted from it to a submission to the USENET but Spamassassin=
=20
does not like that. So I removed parts. If you are interested, then it may=
=20
be sensible to read this webpage instead of just these excerpts on USENET.

"Which medium is good?
An SSD (Solid-State Drive) is better than a Hard-Disk Drive (HDD). Cf. a=20
webpage by excellent Adaist Jeremy Grosser's Legitimate Data Company LLC:=
=20
HTTPS://DiskPricing.com/faq and HTTPS://WWW.StorageReview.com/ssd-vs-hdd

SSDs and internal hard disks are preferable to DVDs and CDs.

Avoid USB flash sticks and USB external hard disks. Operating systems are=
=20
buggy and USB ports do not always remain properly powered (especially=20
lapstops old computers' and notebook old computers' USB ports). Files'=20
names on USB external hard disks and on USB flash sticks tend to become=20
destroyed. Writing to a flash memory destroys a flash memory. Using a=20
hard disk destroys a hard disk. Using a USB product destroys a USB=20
product.

A DVD is worse than a CD. Cf. "There are some anecdotal reports that=20
DVD=C2=B1Rs have separated due to adhesive failure or that the metal layers=
=20
have corroded due to the chemical reactivity of the adhesive. An=20
accelerated aging study looking at the stability of DVD formats found=20
this to be potentially an issue, at least under elevated temperature and=20
RH conditions (Iraci 2011)." says=20
HTTPS://WWW.Canada.Ca/en/conservation-institute/services/conservation-prese=
rvation-publications/canadian-conservation-institute-notes/longevity-record=
able-cds-dvds.html=20
(Cf. "Newer doesn't mean better. Newer means newer!" said a physicist at=20
Spain.)

HTTPS://WWW.Canada.Ca/en/conservation-institute/services/conservation-prese=
rvation-publications/canadian-conservation-institute-notes/longevity-record=
able-cds-dvds.html=20
said that a gold CD-R is better than a silver(-alloy) CD-R.=20
HTTPS://WWW.Canada.Ca/en/conservation-institute/services/conservation-prese=
rvation-publications/canadian-conservation-institute-notes/longevity-record=
able-cds-dvds.html=20
gave me the impression that a "phthalocyanine" CD-R is better than an=20
"azo" CD-R. The DVD+R Double Layer company that is called Verbatim=20
advertises that it made a DVD+R DL with "AZO recording layers". Is "azo"=20
"AZO"?

A "multi-layer format" is worse than a "single-layer recordable DVD"=20
according to=20
HTTPS://WWW.Canada.Ca/en/conservation-institute/services/conservation-prese=
rvation-publications/canadian-conservation-institute-notes/longevity-record=
able-cds-dvds.html

A gold DVD-R is less bad than a non-gold non-CD-R, according to=20
HTTPS://WWW.Canada.Ca/en/conservation-institute/services/conservation-prese=
rvation-publications/canadian-conservation-institute-notes/longevity-record=
able-cds-dvds.html

A DVD-RW is much worse than a CD-RW, according to=20
HTTPS://WWW.Canada.Ca/en/conservation-institute/services/conservation-prese=
rvation-publications/canadian-conservation-institute-notes/longevity-record=
able-cds-dvds.html

Do not write to a CD or a DVD or a flash medium more than a few times.=20
Write to a DVD or a CD preferably approximately 1 time.

"Store the discs properly: in a standard-size jewel case without=20
additional materials in the case" says=20
HTTPS://WWW.Canada.Ca/en/conservation-institute/services/conservation-prese=
rvation-publications/canadian-conservation-institute-notes/longevity-record=
able-cds-dvds.html

A DVD+R is worse than a DVD-R according to=20
HTTPS://WWW.Canada.Ca/en/conservation-institute/services/conservation-prese=
rvation-publications/canadian-conservation-institute-notes/longevity-record=
able-cds-dvds.html=20
(Cf. "Newer doesn't mean better. Newer means newer!" said a physicist at=20
Spain.)

A BD-R has "poor stability compared to" a CD or a DVD according to=20
HTTPS://WWW.Canada.Ca/en/conservation-institute/services/conservation-prese=
rvation-publications/canadian-conservation-institute-notes/longevity-record=
able-cds-dvds.html=20
(Cf. "Newer doesn't mean better. Newer means newer!" said a physicist at=20
Spain.)

A CD-RW is much worse than a CD-R, according to=20
HTTPS://WWW.Canada.Ca/en/conservation-institute/services/conservation-prese=
rvation-publications/canadian-conservation-institute-notes/longevity-record=
able-cds-dvds.html

The best technique to maintain a CD or a DVD is not clear to me.
I am a computer scientist. No lecture and no class note and no textbook=20
for my computer-science degree is about CDs or DVDs. Many computers from=20
my computer-science degree do not have even a CD drive. I do not know=20
each thing about a CD or a DVD.

I interpret this picture of (pressed (i.e. not burnt)) orthogonal DVDs to=
=20
show Mork & Mindy to be horizontal with a pressed "surface face down" and=
=20
Transformers to be "vertical". (Am I mistaken?)

The DVD-R company that is called Kompact says: "store the disc in a case=20
with recording surface face down."

I am having a trouble with this quoted paragraph of=20
HTTPS://WWW.Canada.Ca/en/conservation-institute/services/conservation-prese=
rvation-publications/canadian-conservation-institute-notes/longevity-record=
able-cds-dvds.html=20
- "Store discs vertically in standard-sized jewel cases. Paper or plastic=
=20
sleeves are not recommended as they provide little physical protection,=20
they may interact chemically with the disc". Do I misinterpret this=20
quoted paragraph by the Canadian Conservation Institute? To me it seems=20
to contradict Kompact saying: "store the disc [. . .] with recording=20
surface face down." What are "jewel cases"? An Oxford dictionary failed=20
to inform me. A Merriam-Webster website explains that they are plastic.=20
Why are "plastic sleeves [. . .] not recommended" but "jewel cases" are=20
recommended? If "plastic sleeves" and "jewel cases" are plastic, then are=
=20
they equally dangerous of interacting "chemically with the disc" and=20
scratching?

What are "standard-sized jewel cases"? Many a jewel case for a DVD is=20
much bigger than a DVD as with this picture of Mork & Mindy and=20
Transformers, but many a jewel case for a CD is almost as small as a CD.

HTTPS://WWW.Canada.Ca/en/conservation-institute/services/conservation-prese=
rvation-publications/canadian-conservation-institute-notes/longevity-record=
able-cds-dvds.html=20
is about media which are recorded onto via lasers. Is it also applicable=20
to pressed CDs; DVDs; and Blu-ray discs?

Slowly burn.
HTTPS://WWW.Canada.Ca/en/conservation-institute/services/conservation-prese=
rvation-publications/canadian-conservation-institute-notes/longevity-record=
able-cds-dvds.html=20
recommends to record slowly.

water
"In humid tropical climates, care must be taken to find discs that stand=20
up to the weather. One user reported that the data layer on [. . .] discs=
=20
began cracking after a couple of months in an otherwise sheltered=20
environment (e.g. no direct sunlight).;" said CDRFAQ.org.

Do not permit relative humidity to be higher than 50% according to=20
HTTPS://WWW.Canada.Ca/en/conservation-institute/services/conservation-prese=
rvation-publications/canadian-conservation-institute-notes/longevity-record=
able-cds-dvds.html

Alas it is difficult to permanently maintain relative humidity at below=20
64%! (I used to succeed at a humid place during days to reduce relative=20
humidity to below 50%, but during nights relative humidity is badly big.)

"Do not leave the [grey] disc [. . .] in [. . .] excessive moisture" said=
=20
Capcom(R) Classics Collection Vol.1 without an explanation as to what=20
"excessive moisture" is.

A page for a TDK 2x DVD-RW shows"10~90%": is this a warning to stay=20
within circa 10% - circa 90% relative humidity?

A page for a Verbatim 8x DVD+R DL shows"6-85%": is this a warning to stay=
=20
within 6% - 85% relative humidity?

A page for a Verbatim CD-R shows"10-80%": is this a warning to stay=20
within 10% - 80% relative humidity?

LASERs can not be maintained forever.
"Subject: [5-27] Will the laser in my drive wear out?
(2002/12/02)
Yes, eventually. Depending on a number of factors, though, it's quite=20
possible that your device will suffer mechanical breakdown or simply=20
become obsolete before that happens.

There are many different ways to construct a laser diode. Different=20
approaches result in different wavelengths, maximum power levels, and=20
lifetimes. The lifetime of a laser is usually measured as MTTF (Mean Time=
=20
To Failure) at a particular power level and ambient temperature (e.g.=20
10,000 hours at 5mW and 50 degrees Celsius).

Higher power levels mean higher heat dissipation -- the optical=20
conversion efficiency of a laser diode is around 30% -- and in the=20
semiconductor world, more heat usually equates to shorter lifetime.=20
Recording for an hour at high speed will take a greater toll on the laser=
=20
than playing a CD for an hour.

[. . .]

Laser diodes can suffer catastrophic failure (they suddenly stop working)=
=20
or gradual degradation (reduced optical power for a given input power=20
level). [. . .] However, if the laser's efficiency is reduced, more DC=20
power must be supplied, more heat is generated, and the likelihood of=20
failure increases." said HTTPS://WWW.CDRFAQ.org/faq05.html#S5-27

E.g. Mike Swaine recommends to back up frequently, but backing up=20
frequently can destroy a backing-up LASER!

I used to use the same LASER to record (more than) the discs like which=20
are reported by this table. Almost each of these discs is almost full=20
(e.g. almost 702 MB for a normal CD and almost 4.7 GB for a normal singly=
=20
layered DVD.

[HTML table . . .]
I never detect a problem with a disc from this drive.

"Subject: [5-2] How long do CD recorders last?
(1998/04/06)
The MTBF (Mean Time Between Failures) on these drives is typically 50,000=
=20
to 100,000 hours, and they come with a 1 year warranty. Compare that to=20
hard drives rated at between 500,000 and 1,000,000 hours with a 3 or 5=20
year warranty and that should give you some idea.

Most of the drives available today weren't meant for mass production of=20
CD-Rs. [. . .]

Incidentally, MTBF is not an estimate of how long the drive will last.=20
Rather, it's an estimate of the failure rate of the drives during the=20
expected lifetime of the device. Once you exceed the expected lifetime,=20
which is often on the order of a couple of years, the anticipated failure=
=20
rate increases. If you have new drives with an MTBF of 25,000 hours, and=20
you run 1000 units for 100 hours, you can expect to see four of them=20
fail. It does NOT mean you can expect them to run for 2.8 years and then=20
all fail at once." said HTTPS://WWW.CDRFAQ.org/faq05.html#S5-2
"
says
HTTPS://Gloucester.Insomnia247.NL/media/media.HTML
by me. If I made a mistake, then please consider warning me!
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