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What Writer Wrote This Disc?

March 12, 2015
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A common question that comes up in many different ways is the idea that it is possible to tell what computer or disc writer created a specific disc.  There are some common misconceptions about this that can be cleared up and some interesting information for both users and forensic professionals.

Almost 20 years ago there was some discussion about “RID” or Recorder IDentification.  This mostly came from the introduction of stand-alone music recorder devices which could, in theory, be used to make copies of music discs and to record onto CD-R discs music from the radio and other sources.  This was the same level of concern that was introduced with DAT recorders.  The outgrowth of this concern led to a new category of CD-R discs, the “Music CD-R” and the requirement that all stand-alone recorders label discs with the device that created them.

As we can see today, most of this fuss was for nothing.  Stand-alone music recorders exist, but they are expensive and not all that much fun to use.  Yes, you have to buy special discs for them which hasn’t helped their adoption either.  Just like DAT recorders, they are a niche product and not used for piracy.

Well some manufacturers decided to implement RID-labeling of data discs as well for computer peripheral drives.  In our collection at InfinaDyne I believe we have two such drives out of around 50.  It wasn’t a popular thing to do and it wasn’t done in a consistent manner by manufacturers.

When DVD-R recorders finally made it to the consumer market, there was a standard in place to allow drives to mark the discs they wrote to in the Recording Management Data or RMD.  This was much better than the situation with CD recorders because at least from the beginning there would be only one implementation.  This standard was not mandatory, so different manufacturers were free to implement or not implement the marking of discs with the recorder that wrote them.  Just like with CD recorders, not very many manufacturers chose to mark discs with this identification.

The situation with DVDs is much like that with CDs in that the identification that is put on the disc has a drive serial number, but this is an internal, electronic serial number not the one that is printed on the outside of the writer itself.  There may or may not be a simple translation between the external serial number and the electronic serial number.  About the only way to make sure that a given writer identifies itself by a given number is to ask the writer what its serial number is and compare that to what is found on the disc.

What this means to the average consumer is that if they write a CD or DVD it is highly unlikely that there is any identification of the drive that wrote to the disc embedded in the disc itself.  If there is a serial number, it isn’t necessarily one that might be registered with the manufacturer, so even if this information is present on a disc, there may not be any way to track this back to the original owner of the writer – assuming the serial number was registered for warranty purposes.

CD/DVD Inspector today does not search CD-R discs for RID markings.  There are at least three different locations where RID information might be written and some of these cannot be easily retrieved – some drives will read these locations but others will not.  With DVD discs, the situation is quite different.  If the recorder identification is present in RMD field 1, it is displayed by CD/DVD Inspector’s Analysis tool.  If you aren’t using CD/DVD Inspector you may be able to find other tools which read and display RMD field 1 so you can determine if the writer is identified.

For forensic purposes, RID is extremely valuable when it is present on a DVD.  Unfortunately, most drives do not label the discs they wrote, so this helpful bit of information is not available.

Update: running through a sample of 103 DVDs 18 of these had Recorder Identification in RMD field 1.  The writers that were shown were Lite-On, Pioneer, Plextor, and Sony.  This is by no means an exhaustive test but it does tend to indicate that DVD RID marking is more prevalent than CD-R marking was.  There is some evidence that this is under software control as well as the writer, so some writing software may not follow the correct DVD writing process resulting in no RID marking.


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