DVD / DVD+R /DVD-R / DVDRW. Are they all really distinct media formats?

"chrisrushlau" wrote in message
...
If I can jump in that mention of -RW not reading as precisely as +RW: My
Samsung R100 seems to be wearing out after three years, early on used with
lots of dusty disks: it rejects many once-used disks (-RW) as unreadable.
This is progressing, from rarely to occasionally (randomly) to now where
anything but a fresh disk is unreadable. I assume the hardware mechanism
that positions the read-write head gets confused/lost as it navigates the
disk: it wobbles too much or diffracts the signal too much to read it
accurately.


It is not the mechanics that is the problem. Unfortunately, solid state
lasers have a limited life. And the lasers used in CD/DVD drives seem to
have a shorter life than they really ought to do. Three years is about
average for a laser life (and they usually last long enough to survive the 1
year warranty - just). In your drive, the laser has weakened to the point
where it is barely reading the image on the disc.


"M.I.5¾" wrote:


"Bill in Co." wrote in message
...
M.I.5¾ wrote:
"Rahul" wrote in message
48.16...
I'm always confused by DVD terminology when buying media to write on.
There's DVD / DVD+R / DVD-R / DVDRW and I'm not even sure which more!

Are these all really distinct technologies and formats? Or are some
subsets
/ supersets of others? Or maybe its only backward compatibility
issues?
What's the best way to figure out what format my Laptop supports? Do
they
have varied sizes? Does it matter whether I'm writing data or movies
etc.?
I faintly remember there being lead-in / lead-out issues....

I've never faced the problem that I bought some commercial movie etc.
on
a
DVD and my Dell Laptop ( Inspirion E1505)'s inbuilt DVD reader
/writer
couldn't read it. Its a dual boot so are there any Linux-vs-Win
issues
too?

Are these distinctions only relevant when writing disks at home as
opposed
to commercially stamped disks? Or maybe when reading on hardware
other
than
"computers" (etc. DVD players etc.)



First: the easy bit. The 'R' media is write once. The 'RW' media can
be
erased allowing its re-use.

A little more complex is the difference between the '-' discs and '+'
discs.
As far as you the user is concerned, except for some uses there is
little
to
chose. Some older video DVD players will refuse to recognise the
DVD+RW
discs (but will recognise DVD+R). This was the result of a deliberate
attempt by Toshiba to discourage the '+' format. Once rumbled they
had
to
abandon it.

For DVD-R and DVD+R, there is no practical difference other than the
latter
is written faster by some drives.

For DVD-RW and DVD+RW there is a subtle difference in that the former
is
eraseable at the block level only. The latter is eraseable at the
word
level. This means that individual words can be erased and
overwritten.
It
also means that if used for video, more video can be added to the end
of
existing video and the two played through seemlessly. This cannot be
done
with the '-' format.

If you are planning on using packet incemental format (Nero's InCD or
Roxio's Drag-to-disc), then DVD+RW will be much more reliable than
DVD-RW.

Just out of curiosity, why is that? (I don't use the packet writing
format, but am curious, and would have expected the older standard to
be
more compatible in this case, too - seems like (from a hardware
viewpoint)
it might be "simpler" to just erase the whole block, rather than the
individual word - albeit less desireable for the user).


It is because the read/write head when writing a DVD-RW in the drive, can
only locate positions on the disc to within a block of data. As a result
the drive has to leave a 2 block gap between different data block to
avoid
over writing previous data. It is bit hit and miss and consequently it
misses on occasions and overwrites something. If that happens to be part
of
the TOC or FAT, then the disc is corrupt and unreadable.

DVD+RW is a bit more technologically advanced such that the read/write
head
can locate to a word of data and accurately overwrite it. Thus the
potential for overwriting something important, whilst not entirely
removed,
is vastly less likely.

"Bill in Co." wrote in message
...
M.I.5¾ wrote:
"Bill in Co." wrote in message
...
M.I.5¾ wrote:

Name the player and I will look it up.

JVC HR-XVC1U (mentioned above)

Comes up as:

Compatible with DVD-R

Compatible with DVD-RW

Partially compatible with DVD-R9 (Plays layer 0 only)

Compatible with DVD+R.

Allegedly, anyways. More below.

Not compatible with DVD+RW.

Not compatible with DVD+R9.

No information on RW9 discs but unlikely to be compatible.

The DVD mechanism of this machine is made by Toshiba. Apparently it is a
DVD/VHS combo unit and the VHS mechanism is made by JVC themselves.

Interesting.

DVD+RW discs can be made to play by changing the Compatibility ID byte
from
'2' to '0' - there are numerous utilities that do this. It is necessary
to
change it back before erasing and reusing the disc.

It is possible that the particular brand of blank DVD+R discs that you
used
may not have had a good image made when recorded in your burner.

It happened on more than one occasion. In fact, none of the few
DVD+R's that I tried ever worked on my deck. But more on that below.

You could
try burning it at a lower speed (this often works). Alternatively, try a
different brand - they are not all as equal as they should be.

When I did the experiments, I'm pretty sure I was using the same brand of
DVD discs for both (Memorex, IIRC).

I didn't try using a slower than "normal" speed, but then again, the speed
was pretty slow, anyways, since my DVD/CD burner was a bit older (Memorex
True 8X, and rated at that for both +R and -R formats). But the Memorex
DVD discs were also rated at 8X (this was some time ago, when that was
common).

But thanks for the info and looking it up.

Try a lower burn speed. If 4x doesn't work then try 2x (might be 2.4x on
your burner (don't ask)). It is also possible that the laser on your video
player is dying as it is not a particularly recent model (they have a very
limited life).

Thank you, Walter. My lesson here is I had a week of anxiety about my DVD
recorder ("Is Samsung the worst in the industry?" was one Google hit that
fueled my anxieties), found some information (mostly this MS community
discussion), you responded to my precise query (off the track of this
discussion), and I'm back on dry land, as it were, or back breathing the free
air of the city, where people look out for each other.
"Walter Wall" wrote:


"chrisrushlau" wrote in message
...
If I can jump in that mention of -RW not reading as precisely as +RW: My
Samsung R100 seems to be wearing out after three years, early on used with
lots of dusty disks: it rejects many once-used disks (-RW) as unreadable.
This is progressing, from rarely to occasionally (randomly) to now where
anything but a fresh disk is unreadable. I assume the hardware mechanism
that positions the read-write head gets confused/lost as it navigates the
disk: it wobbles too much or diffracts the signal too much to read it
accurately.


It is not the mechanics that is the problem. Unfortunately, solid state
lasers have a limited life. And the lasers used in CD/DVD drives seem to
have a shorter life than they really ought to do. Three years is about
average for a laser life (and they usually last long enough to survive the 1
year warranty - just). In your drive, the laser has weakened to the point
where it is barely reading the image on the disc.


"M.I.5¾" wrote:


"Bill in Co." wrote in message
...
M.I.5¾ wrote:
"Rahul" wrote in message
48.16...
I'm always confused by DVD terminology when buying media to write on.
There's DVD / DVD+R / DVD-R / DVDRW and I'm not even sure which more!

Are these all really distinct technologies and formats? Or are some
subsets
/ supersets of others? Or maybe its only backward compatibility
issues?
What's the best way to figure out what format my Laptop supports? Do
they
have varied sizes? Does it matter whether I'm writing data or movies
etc.?
I faintly remember there being lead-in / lead-out issues....

I've never faced the problem that I bought some commercial movie etc.
on
a
DVD and my Dell Laptop ( Inspirion E1505)'s inbuilt DVD reader
/writer
couldn't read it. Its a dual boot so are there any Linux-vs-Win
issues
too?

Are these distinctions only relevant when writing disks at home as
opposed
to commercially stamped disks? Or maybe when reading on hardware
other
than
"computers" (etc. DVD players etc.)



First: the easy bit. The 'R' media is write once. The 'RW' media can
be
erased allowing its re-use.

A little more complex is the difference between the '-' discs and '+'
discs.
As far as you the user is concerned, except for some uses there is
little
to
chose. Some older video DVD players will refuse to recognise the
DVD+RW
discs (but will recognise DVD+R). This was the result of a deliberate
attempt by Toshiba to discourage the '+' format. Once rumbled they
had
to
abandon it.

For DVD-R and DVD+R, there is no practical difference other than the
latter
is written faster by some drives.

For DVD-RW and DVD+RW there is a subtle difference in that the former
is
eraseable at the block level only. The latter is eraseable at the
word
level. This means that individual words can be erased and
overwritten.
It
also means that if used for video, more video can be added to the end
of
existing video and the two played through seemlessly. This cannot be
done
with the '-' format.

If you are planning on using packet incemental format (Nero's InCD or
Roxio's Drag-to-disc), then DVD+RW will be much more reliable than
DVD-RW.

Just out of curiosity, why is that? (I don't use the packet writing
format, but am curious, and would have expected the older standard to
be
more compatible in this case, too - seems like (from a hardware
viewpoint)
it might be "simpler" to just erase the whole block, rather than the
individual word - albeit less desireable for the user).


It is because the read/write head when writing a DVD-RW in the drive, can
only locate positions on the disc to within a block of data. As a result
the drive has to leave a 2 block gap between different data block to
avoid
over writing previous data. It is bit hit and miss and consequently it
misses on occasions and overwrites something. If that happens to be part
of
the TOC or FAT, then the disc is corrupt and unreadable.

DVD+RW is a bit more technologically advanced such that the read/write
head
can locate to a word of data and accurately overwrite it. Thus the
potential for overwriting something important, whilst not entirely
removed,
is vastly less likely.

Rahul wrote:
I'm always confused by DVD terminology when buying media to write on.
There's DVD / DVD+R / DVD-R / DVDRW and I'm not even sure which more!

Wikipedia is your friend ! You'll find more there than you'll probably
want to know, and links to even more.

In general DVD+R is "more robust" than DVD-R. It's worth the few extra
pennies per disk.

The age of your equipment for writing and playing back **does** matter.
Some older DVD players have problems with some brands of blanks. Buy
a small quantity of blanks and try them on all of your burners and
players is the only sure bet.

Jack Patteeuw wrote:
Rahul wrote:
I'm always confused by DVD terminology when buying media to write on.
There's DVD / DVD+R / DVD-R / DVDRW and I'm not even sure which more!

Wikipedia is your friend ! You'll find more there than you'll probably
want to know, and links to even more.

In general DVD+R is "more robust" than DVD-R. It's worth the few extra
pennies per disk.

Might depend on how you define "robust", so I'm not so sure about that.
Cites?

The age of your equipment for writing and playing back **does** matter.
Some older DVD players have problems with some brands of blanks.

Yup. And I've found the older DVD-R to be a bit more compatible, in my
albeit limited tests.

Buy a small quantity of blanks and try them on all of your burners and
players is the only sure bet.

True enough.