Antonio Diaz Diaz, the developer behind GNU DDRescue, took the time to answer a few questions for Blue GNU regarding the GNU data recovery utility and how it compares to other projects.

When and why was DDRescue started?
I started ddrescue in the summer of 2004 because I wanted to recover data from a failing CD-ROM and the tools available weren't appropiate for the task. If you try to rescue a failing CD-ROM with dd, it may break your CD drive by excessive seeking.

Who are your primary users?
I think ddrescue has two types of users. The casual users, who happen to have a disk drive with errors on it and want to read the recoverable data from it, and the expert users, who use ddrescue in creative ways like using ddrescue to erase all the good sectors of a failing drive before returning it to the manufacturer without overwriting the bad sectors.

Where does the project stand at this point?
The project is mature and stable. Stability is very important for a program like ddrescue. You really want a stable program when rescuing important data. As far as I know, no user has ever lost a single byte because of a bug in ddrescue.

Ddrescue does what it should, and does it well, but there is always room for improvement. I am currently working on some minor new features and small efficiency improvements, but I do not plan any major changes in ddrescue for the foreseeable future.

How many active developers currently work on DDRescue?
I am the only developer of ddrescue. Ddrescue is a somewhat complex but small project, so no more than one developer is needed.

How does DDRescue compare (in your view) to other projects?
GNU ddrescue is far better than any other similar project I know of because it manages efficiently the status of the rescue in progress and rescues more data in less time, maximizing the amount of data recovered.

The standard utility dd does a linear read of the drive, so it can take a long time or even fry the drive without rescueing anything if the errors are at the beginning of the drive.

Kurt Garloff's dd_rescue does basically the same thing as dd, only more efficiently.

LAB Valentin's dd_rhelp is a complex shell script that runs Garloff's dd_rescue many times, trying to be strategic about copying the drive, but it is very inefficient.

But please, don't believe me. you can find many reviews and comparisons of ddrescue in the net. See for example the John Gilmore's page, Pat Patterson's blog or the comments in the Freshmeat page for ddrescue.

Can you give me any idea of how big and/or active the DDRescue user community is?
There is an active user community around the ddrescue mailing list http://lists.gnu.org/mailman/listinfo/bug-ddrescue where expert users not only help new users, but also suggest the improvements that make ddrescue the best data rescue program out there.

Most GNU/Linux distros include a package named ddrescue, but not all such packages correspond to GNU ddrescue. Some of them correspond to the older and more limited dd_rescue program. Debian for example includes dd_rescue as "ddrescue", and GNU ddrescue as "gddrescue".

What needs to be accomplished before the next release of DDRescue?
Not much. As I said before, ddrescue is mature and stable. I need to sort out some minor issues about how the new option "--fill" have to work, and then implement it.

What are the biggest obstacles the DDRescue team faces in development?
None, apart from lack of time. As most free sofware developers I develop ddrescue in my spare time.