TRUEDISC DEVELOPER  Hi E_COMMERCE,

I like PAR, just not for optical discs. For that, I use TrueDisc. I would never advocate using TrueDisc's algorithms to replace PAR files on file-sharing networks such as BitTorrent or Usenet; in those scenarios, PAR is a MUCH better choice (and it's what I use).

PAR is a file-based approach with no specific support for optical media. TrueDisc employes a real-time, streaming, block-level systematic code designed specifically for optical media (where seeking is slow, among other things). TrueDisc can do damage-recovery in real-time scenarios like video playback. That's simply not possible with PAR on optical discs--by design.

In addition, because PAR is so generic, it has to do a lot of work to implement ECC that is wasted (or duplicate work) on optical discs. For this reason, PAR is much less efficient (in time and space) than TrueDisc is on optical media.

To reiterate, I like PAR, just not for optical media. TrueDisc is superior to PAR on optical media because it was designed to be used *only* on optical media. If the team that designed PAR had the same design goals as TrueDisc, PAR would no-doubt be more competitive on optical discs.

I also think TrueDisc is much easier to use than PAR, but I'm biased. :-)  
(Version 1.0.1)

TRUEDISC DEVELOPER  My apologies for making light of the current limitations of TrueDisc. The 1.875GB limitation will be removed in TrueDisc 1.1, due next week, and multiple files will appear in TrueDisc 1.2, due the following week (assuming no hiccups with testing).

Once the 1.875GB limitation is removed, you'll be able to burn files up to the maximum file size supported by the format itself (less 7% space for redundancy).

Best, Erich  
(Version 1.0)

TRUEDISC DEVELOPER  The one file limitation is more of a nuisance than an actual limitation, since you can easily zip up a collection of files into one file and burn that to disc, or do the same thing with a disk image.

Nevertheless, multi-file support is high on my priority list.

Best, Erich

Erich Ocean

Founder

TrueDisc  
(Version 1.0)

TRUEDISC DEVELOPER  TrueDisc supports variable-rate damage-resistance, so it will use whatever disc space is left on the disc for redundancy information. Less original data == more damage-resistance.

The maximum file size for CD-R is 600MB and for DVD-R is 4.1 GB. Maximum damage recovery is currently achieved for files 80MB or less for CD-R, and 292MB or less for DVD-R. We have had very good results in our labs with files between 40% and 80% of the size of the disc.

(TrueDisc 1.0 has a maximum file size of 1.875GB; this will be removed very shortly.)

Hope this helps!

Best, Erich

Erich Ocean

Founder

TrueDisc  
(Version 1.0)

TRUEDISC DEVELOPER  NaOH,

We don't add parity information, but the technique is similar in spirit and comes out of cryptography. We'll soon have a much better description of the TrueDIsc technology on our website, hopefully within the next week. For now, the application does a reasonably good job of visualizing what TrueDisc does when you do a burn. It shows the major stages TrueDisc goes through with your file, what TrueDisc adds to the disc, and how that data is ultimately distributed on the disc.

We've also got some really cool animations for the Restore phase that weren't ready for the 1.0 release. We're hoping to get them out soon in a point release update. It's really cool to watch TrueDisc skip bad parts of the disc, reconstruct the data, and keep on going.

TrueDisc was originally designed for real-time data reconstruction in Blu-ray and HD-DVD video formats. (The target application was childrens DVDs and DVD rental services like Netflix, which receive a lot of DVD abuse. TrueDisc can virtually eliminate "bad" DVDs in these applications.) TrueDisc can be hardware accelerated in those formats, and in older formats (CD-R, DVD-R), with driver updates.

However, no special hardware (optical discs, burners, etc.) is required to use TrueDisc. In fact, TrueDisc works GREAT with cheap CD-Rs that drop sectors here and there without warning. With TrueDIsc, you can basically eliminate all of the usual "testing" that goes on when picking a batch of CD-Rs or DVD-Rs to use, and just use whatever's cheapest, letting TrueDisc get the data off correctly.

Thanks for your interest!  
(Version 1.0)