TrueDisc 1.0.1
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Create damage-resistant disc backups.   Demo ($52.00)
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TrueDisc... If you backup your files to optical disc, you know how fragile those backups really are. Scratches, labels, even age or poor manufacturing can make those discs unreadable within months.

A master copy contains extra information that allows TrueDisc to replace damaged parts of the file. To make a master copy, TrueDisc splits your file up into small parts, called cells. TrueDisc then adds specially-crafted redundant cells. Together, your file's original cells and the redundant cells make up the "master copy."

When you want to copy a file back off disc,
What's New
Version 1.0.1:
    TrueDisc can now burn and restore files larger than 1.875 GB.
  • TrueDisc now handles read errors better, preventing a potential crash.
  • On a restore failure, TrueDisc now removes the partially-restored file.
  • Eliminated Sparkle's 'double dialog' problem on fresh installations of TrueDisc.
Intel/PPC, Mac OS X 10.2.8 or later

*Previously available here

MacUpdate - TrueDisc

TrueDisc User Discussion (Write a Review)
ver. 1.x:
Your rating: Now say why...

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Truedisc (developer) commented on 13 Mar 2007

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]


truthhurts commented on 13 Mar 2007
So... what does this offer that PAR files do not? It certainly sounds like you're implementing a parity-based recovery solution, which quite frankly has been done to death. PAR2 is an especially good implementation, and free for any use. What does TrueDisc bring to the table?
[Version 1.0.1]


Revco commented on 09 Mar 2007
Hi Erich. To quote your previous comment:

"The one file limitation is more of a nuisance than an actual limitation. "

To dismiss this limitation as a nuisance really downplays its severity.

Firstly, in the same registration email I received was the other known limitation:

"Files larger than 1.85 GB are not supported."

Secondly, you've stated that maximum damage recovery is for files 292MB or less for DVD-R.

So, based on the above figures I can burn a 1.85GB image onto a 4.4GB DVD but I won't expect to achieve maximum recoverability because this image is over 292MB. Do you see what I'm getting at?

Also, given I can only use 1.85GB of a 4.4GB DVD why don't I just burn two lots of the same files on the same DVD using Toast? If one file becomes damaged I can always use the other copy.

Speaking from personal experience, I've been stung once or twice by archiving compressed and/or disk images. If the archive becomes corrupted you lose everything. I wouldn't recommend anyone combining all their files in one container for archiving.

At this point in TrueDisc's development it seems to offer limited usefulness and protection. So while it's really pretty to look at I can't actually use TrueDisc. What's your timeline for removing the two known limitations?

In another post here I asked the question what would the storage capacity be for a DVD-DL? The question should read "Once you remove the 1.85GB limitation what would the storage capacity be for a DVD-DL?".

FWIW I'm expecting good things from TrueDisc. Don't let me down :)

[Version 1.0]

2 Replies

Truedisc (developer) replied on 10 Mar 2007
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
PorkPieHat replied on 01 Jun 2011
Hmmm, I'm curious about what happened with this 4 years ago. It seems the dev did get past the 1.875 GB file size limitation in the following week as he said he would, but he did so with version 1.0.1 instead of 1.1. Plus, he seemed just as confident about version 1.2 coming out 2 weeks after penning his last post, but that never materialized either.

So what was it that brought this glass house down?
Truedisc (developer) commented on 09 Mar 2007
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
[Version 1.0]


Revco commented on 08 Mar 2007
I registered yesterday. My registration email came with the following tidbit:

"Known Issues: Only one file can be burned per disc. This will obviously be corrected in an upcoming point release."

This is a pretty big deal. Don't you think this should have been pointed out before users bought the product?

You calling this v1.0 software is, I think, a bit premature. It feels more like a beta or at best a preview. I look forward to the missing capabilities being added soon. Real soon!
[Version 1.0]

Kaielano commented on 04 Mar 2007
I have been waiting for software like this to come along for years! Finally I can feel safe in taking digital photos. As an amatuer photographer, i've always been a bit nervous to shoot in only digital for fear of losing my work, now I have a software that I can be confident in. I love how easy it is to use, and it looks great!
[Version 1.0]

iwans commented on 04 Mar 2007
For developer: Maybe it would be fine to know what amount of data could be burn to CD-R or DVD-R with this technology... It is not 650(700) MB ar 4,7 GB, is it?
[Version 1.0]

2 Replies

Truedisc (developer) replied on 04 Mar 2007
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

Revco replied on 08 Mar 2007
And what is the writeable capacity for a Dual Layer DVD?

NaOH commented on 03 Mar 2007
I would like to know a little more how TrueDisc works.

From the description, it seems to create parity information in a separate area of the disk. This would indeed hold true to the claim of being able to recover the data on the disk, even with missing portions of data. It would also mean the data doesn't need to be saved in a particular format in order to be recoverable.

As it stands, the product description is a bit too full of 'marketing speak' for me to get a clear idea of what it actually does.

For a while I was wondering if it required me to buy special media, in order to use the software, rather than conventional CDs, DVDs or Blu-Ray disks.

If the product does work as I postulated above, then it is a very nice and easy way to allow recovery from optical media.

In any event, I think the software makers could make a little more technical information available to potential customers. Maybe on the website. That way we can make informed decisions about what we are actually buying.
[Version 1.0]

2 Replies

Truedisc (developer) replied on 03 Mar 2007

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!

MacUpdate-Lon replied on 07 Mar 2007
We've posted a link to the developer's blog on the MacUpdate product page for TrueDisc, near the top of the page in the 'Editor's Notes' section.

sartin77 reviewed on 03 Mar 2007
Great interface! I tried it out and it worked. I put a photo on the disc and then scratched it up. I was still able to get the pic off the disc with no trouble. I added more scratches three times before I had any issue and these were significant scratches! Even after the final set of scratches I was able to get the picture off the disc, but I had to do a bit of a work around by opening TrueDisc directly instead of using the TrueDisc File Restore on the Disc, which I must have damaged too much to open, the little pop up window didn't even show up for a few seconds.

It would be nice if TrueDisc started up automatically when I put in the disc, a few extra features like this would make the app better in my opinion.

Cool app and very useful! Seems like it would definitely be useful for professional photographers who need to archive their work.
[Version 1.0]

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Version Downloads:1,987
Type:Utilities : Backup
Date:12 Mar 2007
Platform:PPC 32 / Intel 32 / OS X
Price: $52.00
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TrueDisc... If you backup your files to optical disc, you know how fragile those backups really are. Scratches, labels, even age or poor manufacturing can make those discs unreadable within months.

A master copy contains extra information that allows TrueDisc to replace damaged parts of the file. To make a master copy, TrueDisc splits your file up into small parts, called cells. TrueDisc then adds specially-crafted redundant cells. Together, your file's original cells and the redundant cells make up the "master copy."

When you want to copy a file back off disc, TrueDisc reads the master copy. If any of the original cells stored in the master copy cannot be read, TrueDisc replaces them with one of the redundant cells. In this way, TrueDisc can make a perfect copy of your original file, even when the disc becomes damaged.

The specially-crafted redundant cells created by TrueDisc are not mere copies of your data. Instead, like "stem cells" in the human body, they can be transformed into whatever original cells are missing. To get the same level of damage-protection TrueDisc provides by burning copies to multiple discs yourself, you'd need to burn as many as 16 discs for each file you wanted to protect. Even then, you'd have to write special software to recover the data and you still may not be able to recover the entire file, depending on how the discs themselves were damaged.

TrueDisc is smart when it comes to creating redundant cells. TrueDisc will automatically use any available space on the disc, so you always get the maximum possible damage-resistance. When you burn less amounts of data to disc, lots of redundant cells can be added. When you burn a lot of data to disc, less redundant cells will be available for TrueDisc to substitute later if there's file damage. Either way, TrueDisc provides the best damage-protection possible. The TrueDisc format supports burning up to 600MB of data to CD and up to 4.1 GB of data to DVD.

TrueDisc creates CD-Rs and DVD-Rs that are compatible with every major operating sytem. Since TrueDisc stores master copies in the standard CD-ROM and DVD-ROM filesystems, you don't have to use TrueDisc to read the master copies, or even have TrueDisc installed on your computer. TrueDisc's file format is an open specification, so any software can read a master copy and recover your file's original cells. But remember, only TrueDisc can correct disc damage, so you should always use TrueDisc to restore your files whenever damage is suspected.

With TrueDisc, there's no special hardware or media to buy; it works great with the burner and blank discs you already own. And to make it easy for you to share your TrueDiscs with friends and family, a free copy of the damage-correcting TrueDisc reader is automatically included on every disc you burn.

Key Features:
  • The world's only damage-resistant optical storage format - The TrueDisc format can withstand disc damage as high as 90% and still recover the original data.
  • A gorgeous, transparent interface - TrueDisc works hand-in-glove with your Mac to make creating "master copies" drop dead easy.
  • A non-proprietary file format - TrueDisc's optical storage format stores at least one identical copy of your data on disc in the industry standard ISO 9660 filesystem, so you don't have to use TrueDisc to get your data back off.
  • Super space-efficient - TrueDisc's patent-pending layout and reconstruction algorithms deliver enhanced data protection with theoretically-optimal space usage. Simply put, there's no better way to make optical storage work for you. TrueDisc requires as little as 7% of your disc to add damage resistance.

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