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FWIW, you should be backing up to DVD+Rs instead of DVD-Rs, if you have the option, since DVD+R has better error correction.

More details here.

Its only likely to happen if you buy bad media. This is why I wrote this guide so people don't continually blame CDs for their own error. Oh, and its been featured on Slashdot's front page... twice.

If you're going to use an optical disc format, use DVD+R, not DVD-R. DVD+R has far more robust error correction capabilities. Most DVD burning drives will support it, although you have to watch out for commercial DVD playback decks that won't read it. Do a test.

I found this informative:

http://adterrasperaspera.com/blog/2006/10/30/how-to-choose-cddvd-archival-media

+ really is a better format, though.

http://adterrasperaspera.com/blog/2006/10/30/how-t o-choose-cddvd-archival-media/

Ad Terras Per Aspera (featured on Slashdot three or four times in the past few years) has already discussed Display port here and here.

Ad Terras Per Aspera (featured on Slashdot three or four times in the past few years) has already discussed Display port here and here.

Comming from a guy that tells that on CD and DVD pit codes for "0" and peaks code for "1"....

Who says tht Creative Labs invented the PC analog Joystick connector. (WTF ? It's an IBM PC standart. Creative were only the first to put midi (in a non standart way) on some pins of the port. They even weren't the first to conveniently include it on cheap multifunction cards : multi-IO with serial/parallel/floppy/game connectors were quite popular long before creative decided to make the first joystick/sound card hybrids).

And fails to mention the fundamental topology difference between USB and FireWire. I could pardon him not mentionning it in an article about power over plug-n-play connection, but when he makes an add-up about FireWall, he should mention it with its other technical advantages.

I find him not enough detailled on some part, so I take his description of DVD-R vs +R with a pinch of salt until I have time to check the facts for my self.

Is there really a difference in the error correcting codes written to +R and -R?

Yes.
From http://adterrasperaspera.com/blog/2006/10/30/how-t o-choose-cddvd-archival-media/

As I said earlier, DVD-R sucks for data preservation for three reasons: inferior error correction, inferior 'wobble' tracking, and the fact its data writing methods look like an un-needed halfway point between CD-R and DVD+R. The wobble tracking I shall explain first, then the error corrections method, then the specifics of ATIP/pre-pit/ADIP optimum power settings.

For a CD/DVD burner to track where it is on the disc, it uses three things: the 'wobble' of the data track (where it actually wobbles back and forth instead of in a straight line) to tell where it is in the track, the position of the track to tell where it is on the disc, and some additional information on the disc to tell where the track (singular, as CDs and DVDs only have one track, and it is written in a concentric spiral) begins and ends.

This additional information on a CD-R is called the ATIP (Absolute Time In Pregroove), which contains how long the track is, where it begins, what the maximum and minimum writing speeds are, what formula dye it uses, who actually made it, optimum power control settings, and error correction data. The ATIP is stored as a frequency modulation in the wobble itself.

However, since the wobble changes subtly to encode data, it is impossible to use with the small size of tracks DVD requires, as electric noise in the laser pickup and wobbles introduced by the electric motor spinning the disc, these could easily be read as frequency changes in the real track itself.

On DVD-R, they tried to solve the problem with something called 'pre-pits' where spikes in the amplitude of the wobble appear due to pits fully out of phase with the rest of the track (ie, between two spirals of the track, where there is no data). This can be viewed as a simple improvement over CD-R as it makes it easier to track the wobble (since the wobble is constant except for the easy to detect and remove spikes).

Unfortunately, this method as one flaw: due to electric noise in the laser pickup, it would be very easy to miss the pre-pit (or read one that wasn't actually there) if the disc were damaged or spun at fast speeds. The time to read a pre-pit is 1T (roughly .0000000038th of a second), which even for a computer can be easy to miss. DVD-R traded hard to track frequency changes for hard to read wobble-encoded data.

On a DVD+R, however, they came up with a much better method. Instead of changing the frequency of the wobble, or causing amplitude spikes in the wobble, they use complete phase changes. Where CD-R's and DVD-R's methods make you choose between either easy wobble tracking or easy ATIP reading, DVD+R's method makes it very easy to track the wobble, and also very easy to encode data into the wobble. DVD+R's method is called ADIP (ADdress In Pre-groove), which uses a phase change method.

With ADIPs' phase changes, the direction of the wobble changes and continues on going in the exact opposite direction (ie, counter-clockwise to clockwise, or the reverse). For example, if the wobble was 'going up', the phase change causes it to instantly reverse direction start 'going down' no matter where it in the wobble cycle. The phase change is very easy to detect, and also continues for a set period (in this case, one 32T section of the track, or 32 times longer than the pre-pit method of DVD-R).

The state of the phase change (clockwise or counter-clockwise) encodes the individual bits in each block In essence, with the phase change method, not only do you have an easy way of tracking the wobble, but you now have an easy way of reading wobble-encoded data.

As I mentioned earlier, this wobble-encoded data includes error correction of wobble-en

Ubuntu started shipping Vim 7.0 way back in April or May. Even though I quit Ubuntu, I have to say Ubuntu managed to do something right for once.

If the stats on my website are any indication, there are more Firefox users than MSIE users. Since the beginning of September there have been roughly two times as many Firefox users as MSIE users, over almost 159k visitors.

I'm the guy who wrote the series of critical entries against Rob Levin. Today I have made my final entry.

For nine years I ran Debian. Then, a few people convinced me to switch to Ubuntu. For one year I used Ubuntu, and I hated it, and I switched back. Now I am back on Debian, and I love it. Then, like many people, I decided to blog about it.

I wrote an article like this 6 months ago: The Downfall of Sega Part 1 and Part 2

I wrote an article like this 6 months ago: The Downfall of Sega Part 1 and Part 2