Sony DRU-840A detail information

DVD-RAM writing performance

The Sony DRU-840A is a so-called Multi DVD Drive; meaning is also supports writing and reading the DVD-RAM format. Writing at 12X and reading at 12X.  

This drive is one of few drives that also supports the DVD-RAM format, lets us look at the recording side of the disc, and as you can see it has differences from the other DVD+R/W/R9 DL and DVD-R/W discs.

We can see a very fascinating pattern of darker spots. These tick marks are "address information" ("Pre-mastered Pit Header Field") which is embedded onto the disc. This is header information in front of data sector area, and is the same format as HDD and MO.

A DVD-RAM’s disc can be formatted in the following formats:

• FAT32
• UDF 1.02
• UDF 1.50
• UDF 2.00
• UDF 2.01
• UDF 2.50

By formatting a DVD-RAM disc with FAT32 it will act like a removable hard drive and all writing will be done as “background processes”. Meaning you do not have to wait for it to finish, you can start or work with other applications while the DVD-RAM is working without noticing any “hangs” or CPU slowdowns.

DVD-RAM has error correction, but also has error replacement to spare sectors as a "defect management" function. This gives higher reliability than other DVD format.

Another advantage with DVD-RAM is that the discs can be formatted/erased/written at over 100.000 times before it will/can cause/report any errors. Let’s try to read back the 2 discs that we wrote:

Lets us take a look how the drive performs:

Writing the Maxell 12X without verification

Writing the Maxell 12X with verification

Transfer Rate Test

For those of you who are not familiar with DVD-RAM, you may probably think that something went wrong during the write process with the verification turned on, since the 12x media was written at 5x. But don’t worry, that is pretty normal for DVD-RAM discs. The reason for the lower writing speed is the drive constantly reads back the data after writing it to verify that it’s written correctly. We can also call it a “bullet proof” writing/verify technique, with no data loss/errors.

Summary

The Sony DRU-840A was able to read and write our tested media without any problems.

DVD R DL writing performance

Advanced Tests