Crime scene forensics has captured the attention of nearly everyone, thanks primarily to the CSI television franchise shows. Fans tune in every week, to all three series, to find out whodunit and, more importantly, how the detectives are going to catch the bad guys. Forensics investigations have progressed past the point of simply blood, hair, and fibers. The television shows routinely show evidence being recovered from digital media that the perpetrators had thought were erased or destroyed. I enjoy the shows, but a lot of what they do with electronic media has seemed like magic. I became a doubter in that kind of recovery technology.
Paul Crowley and Dave Kleiman’s new book CD and DVD Forensics addresses such electronic magic. They formed a company that specializes in recovery of lost or intentionally disrupted data. With their technique and program, they can virtually look into a disc and find out not only what has on it now, but also know what has ever been on it.
We live in an era with rewritable data, and many people mistakenly believe that once they erase something from their computer or put it into the trash bin on their desktop, it’s gone. Even if they delete the file from the computer, the information is not gone. With the advent of the police shows, the general public has learned that files are not erased. They get overwritten, which is vastly different. Overwritten means that parts of that file still exist on a hard drive or a flash drive. Of course, the educated criminal can install a program that will overwrite the whole drive.
CDs and DVDs are the same way. Computers burn images onto the disc surface. Some of the discs are rewritable, but they feature the same logistical programming as hard drives. Information that was previously stored on the disc is merely written over, not erased. Even though a disc has been damaged, or even thought destroyed, information can be recovered from them.
Crowley and Kleiman begin their book with a thorough discussion of what the CD and DVD media are. They explain the makeup and architecture of those discs from the ground up in terms that a generalist can understand. People who are already skilled in knowing CD and DVD composition can probably skip over this section, but I had a very vague idea of how the discs were made and archived. I found the technology fascinating, and again was overwhelmed by how much science and invention we seem to take for granted on a day-to-day basis.
Once a general understanding is achieved, the authors move on into the recovery procedures. They talk about their application, CD/DVD Inspector, and explain at length about how to use the software when recovering information.
The book is well laid out. There are plenty of margins for taking notes and for highlighting the text. Too often technical manuals have a habit of being densely printed and provide no areas in which to work. They’re also hard to read.
The authors use down-to-earth language and provide plenty of illustrations to make their methodology and procedure clear. The book is extremely user-friendly and laid out so that someone who uses this technology often can easily reference the material.
As a writer, I often find myself researching many subjects. Sciences, technologies, histories, and geographies are all part of the usual retinue I have to wade through in order to create a novel. Many of the books that I use are not as generous as this one. This is one of those reference manuals I will keep near my desk.
For fiction purposes, I would have liked more information on how the evidence recovered from the discs was presented in court. How does a recovery expert persuade a jury that he knows what he’s doing? How can he provide a jury a short lesson that will bring them up to speed on the technology being shown? Of course, the authors didn’t write this book to provide that kind of slant with their material. But I can see that law enforcement personnel or private security agencies would want additional training in those fields as well.
CD and DVD Forensics is an excellent book for the layman. Even though I doubt I will ever use the software application, it’s still nice to know that I can recreate it in a fictional setting and have it right.