On Sat, 05 Jan 2019 20:48:01 +0000, Jim
wrote:

Oh dear this thread is not going the way i wanted.
I have read elsewhere about problems like this so may stay with DVD for
a little while longer and look at HDD in about 6 months when my new
build will start

DVDs used to be rated. There's special software to read the embedded
codes, normally inaccessible, a given Pacific Rim factory uses for
product identities.

That's the initial and prime source. Where it gets interesting is the
middle or "jobber" stage, for brand distribution purposes. First bear
in mind not all identities are equal: some discs may exhibit
substandard or uncharacteristic errors. What happens is that major
brandnames will buy such discs, indiscriminately and falsely to
advertise them within whatever "graded tier" product they choose.

You buy x-brand's Ultra disc one day, by way of example, turn around
the next, and a superior disc lot may have been substituted, as the
same Ultra-disc grade, by an inferior "coded" disc during the jobber
stage.

And then there's the writers, themselves, their firmware support,
based for these codes, at presumably some consequent optimal write
adjustment to account different branded discs.

The name of the game, briefly to "cut to the chase", is you need a
reference, specific to those factory codes, for known test results;-
you go to the store, then, buy your brand based on your research, open
the package and immediately determine the factory origin code: If the
ID codes do not match for predetermined test results, the discs are
false and a return trip for your money back is indicated. Repeat as
necessary or buy from a trusted source that's reputable.

The burner units are less tedious because there's only a three or four
brands to consider for their integrity, i.e., a closer focus on
testing means a narrower and discrete band of determinable results.

The sources for optical media reliance may not be now as contained, as
when optical media was in during its prime, although a market is still
there, and grade-test result should still be obtainable.

For many, whatever is in the Microsoft organizational scheme of a GUI
OS -- My Pictures directory -- is just fine and peachy for endeavoring
laser-writing skills. Much less a My Cat, or Dog, subdirectory, or
multiples of gigabytes in excess of a single 4G DVD, a 600-megabyte
"boot CD" to supplant a 1.44 floppy or BIOS boot-dependencies. All of
which were significantly supplanted, anyway, by *nix Android
derivatives -- a photocentric cloud media dependency to handheld
devices -- when the Microsoft "OS market" [to emulate these trends]
turned stagnantly south a few years back.

It may seem borrowed time, but it's still time computing on optical
media computer hardware, nonetheless. You have a choice, either to
write effectively to rust with the magic of magnetism, or a layer of
dye beneath plastic from a laser. Both are unique according to their
applications.