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yingxuan
18-09-2003, 11:28 AM
I was wondering that how many times can a dvd rw disc can be erased and copied.The laser touches the laser head only unlike tapes which actually pulls and touches the tape.How does dvds actually looses its quality?

brucea
18-09-2003, 11:37 AM
I would assume its the same as CD-RW,
ie can be written 1,000 times.,

[insert plug for my business]

Dvd writers are coming down in price at the moment, and there are a number of good deals all over the place.

With writers under $500 with 10dvd-r 's included, they are getting very cheap.

But be warey of the formats.. ie DVD-R & DVD+R, make sure if the formats are supported by any tasks you need them for (ie for playing in a dvd player.)


-Bruce
Manager, Air2000

Steve Askew
18-09-2003, 11:37 AM
Most manufacturers claim you can Re-use RW discs up to 1000 times.
I've never counted my self

Cheers Steve

godfather
18-09-2003, 02:02 PM
Its only as good as the stability of the dye used in the substrate.
It changes colur (=reflectivity) when written to, and changes back again (hopefully) when erased at a higher intensity of laser beam.

The life will be determined by how well the dye makes the transition from one reflectivity to the other, and back again. I assume there will be some degredation in each use, so the life will be a function of this, plus the output power of the laser.

Steve_L
18-09-2003, 05:19 PM
WHY would anyone want a DVD writer anyhow?

OK, I know this may be a stupid Q, and will admit that I am ignorant about DVD usage. I do know that DVDs hold about 4 times as much as a CD, but DVD movies cannot be copied and besides blank DVDs are expensive at around $8 each.....correct?

When DVD writers and blank DVDs come way down in price, maybe it would be useful to use DVDs as backing up data, photos, etc, but it seems to expensive now.

Comments welcome to end my ignorance. Thanks.

Steve_L

metla
18-09-2003, 05:49 PM
dvd's cant be copied?...of course they can.

As to what other uses they have?....Many people do digital editing on their computers and the cd format is far too small.

Or huge collections of photo's,I cant see someint that can hold 4.7gb as being expevsive compared to a 700mb cd...And its doesnt take a huge amout of large photos to fill a cd.

Or want to do a complete back up to dvd.

Susan B
18-09-2003, 05:52 PM
I would find a DVD writer handy for backing up my hard drive after Ghosting it. It takes two or three CDs for a bare-bones installation of Win XP and my essential programs and double that if I include my data as well.

Another use would be putting home videos onto DVD discs as they take up lots of room.

The price of the writers and discs are too expensive for me now, but they have been steadily dropping in price over the past couple of years so they will eventually be as affordable as CD writers.


> DVD movies cannot be copied

Do you mean physically or legally?? :D

Susan B
18-09-2003, 06:01 PM
> It takes two or three CDs for a bare-bones installation of Win XP and my essential programs and double that if I include my data as well.


Better clarify myself a bit......

It takes two or three CDs for a bare-bones installation of Win XP and my essential programs and double that if I include my data as well, but I could fit all that on one DVD and still have room to spare.

Steve_L
18-09-2003, 11:34 PM
Hello Susan, et. al.,

> Do you mean physically or legally??

Physically..... I thought there was a block that prevented copying, but maybe that is for DVD to VHS tape??? BTW, I suppose there would be an electronic gizmo that WOULD allow copying DVD movies to VHS tape, but I have not searched for it.

Thanks for all comments as to why DVD writers can be useful. I don't feel so ignorant anymore.

Steve_L

godfather
18-09-2003, 11:41 PM
You are thinking of Macrovision protection, which prevents a DVD movie being dubbed to VHS tape (or DVD-R) as an example.

Many of the low cost stand-alone DVD players available in NZ have the ability to disable the protection system.