Ontrack Data Recovery

CD-ROM/DVD-ROM Recoveries


CD-ROMs and DVD-ROMs seem so permanent, yet if you have ever made CD-ROMs you know that sometimes you can mistakenly make a whole set of drink coasters without knowing why. Today most computers have a CD-Burner as standard equipment. Being able to store 600+MB worth of data on CD-ROMs, or storing 5+GB of data on DVD-ROMs is becoming the norm for many users.

This month's technical article will discuss CD-ROM/DVD-ROMs, some common data loss scenarios, and Ontrack's recovery efforts.

Levels of Complexity

As with other aspects of computer hardware, the CD-ROM/DVD-ROM storage medium is a unique and complex technology. It is easy to take for granted the manufactured CD-ROM that holds data or music, or the movie DVDs that we buy, however, the result of years of research and testing lies beneath the surface of that shiny disk. There are a few levels of complexity with CD-ROM/DVD-ROM. The first level starts with the physical disk itself, the next level is the physical blocks, and finally there is the file system level—this provides structure to the written data. As with other storage media, there has to be a logical file system that maps out where the data physically resides. There are a handful of file systems that have been specifically designed for the CD-ROM/DVD-ROM media.

Along with the music or data that is on the disc, there are also low-level error correction and data decoding schemes. This is by design to preserve data quality and integrity.

Data Loss Scenarios

CD-ROM/DVD-ROMs are susceptible to media damage or corruption as well as file system corruption. What is the difference between media damage and media corruption? As the name implies, media damage is when something is physically wrong with the media itself. Media damage includes scratches on one side of the disk, warping, or something that has damaged the plastic disk. Media corruption can mean the dye used in CDR/Ws has failed or the pits in a manufactured CD-ROM/DVD-ROM have somehow become incapable of representing the binary bits.

Finally, the file system can be corrupted due to a variety of reasons. Everything from software bugs to hardware issues can produce corrupted CD-ROM/DVD-ROMs. This is quite unlikely for manufactured disks because they go through strict quality assurance controls. Personal burners and 3rd party software have the potential to corrupt the file system of the CD-ROM/DVD-ROM.

Here are some tips to ensure quality CD/DVD recording

  1. Use reputable 3rd party CD-Burning software. Make sure that the software is kept up to date with service packs and versions.
  2. Take care in recording multiple data formats on CD/DVD. If you choose to have multiple formats, make sure that the software you are using supports this option.
  3. Use blank CDR/W and DVD-R/W disks that are recommended by the CD/DVD recorder manufacturer.
  4. When closing out a recording session, make sure that the software is completely done with the process before removing the disk.
  5. Make it a practice to verify ALL data written to CDs or DVDs. If data is to be archived to CD-ROM/DVD-ROM, it is critical to verify that the CD/DVD can be accessed and that the information can be opened—BEFORE—erasing the original files.
  6. Perform regular file system checks on the host machine and keep the volumes defragmented. This can speed up the CD burning process as well as prevent corrupted data from being backed up.

Ontrack Data Recovery Leadership

Ontrack Data Recovery's goal is to be your complete data recovery solution. From CD-ROM/DVD-ROM recovery to patented Remote Data Recovery™, Ontrack proves day after day its commitment to successful recoveries. Ontrack's large developmental staff works to provide a complete suite of software tools for all sorts of data loss situations. While other data recovery companies rely on a few primary recovery tools, Ontrack specifies, designs and tests all of the recovery tools used by its labs throughout the world.

What does this mean for you? It means that you are getting the very best in data recovery technology and techniques. In the case of CD-ROM/DVD-ROM recoveries, Ontrack Data Recovery uses a suite of tools specially designed for those recoveries. In addition to the development of software that will read a disk properly, supplemental tools are also created and implemented to traverse the logical file system. In many CD recoveries, senior engineers work by hand to put the file system back in order. In one recent case, a senior data recovery engineer spent hours putting the file system together by hand. The end result: 100% recovery.