ASUS CRW-5224A: CDR's Reach The End of the Line

Features

Most of the features found on the CRW-5224A were similar to the features on the CRW-4012A-U we reviewed previously.  The two more prominent features were FlextraLink and FlextraSpeed.  For a full explanation of both of these technologies, please refer to the ASUS drive review we did last month. 

The 5224A burns at 52x, a whopping 7800KB/s.  Do not get too excited though, since the drive barely obtains speeds that high.  Simply, the drive will obtain a speed of 52x when it reaches the most outreaches of the disk.  The diagram below provides a visual explanation of constant angular velocity CD burning.

The CD rotates at a constant velocity while the CDRW head moves out from the center of the disk at a constant velocity as well.  A little math shows that the circumference of a circular path is two times pi times the radius.  In simplified terms, the innermost rings are shorter than the rings on the outside of the disk.  Since the disk is spinning at a constant rate, at the beginning of the burn the CDRW head is exposed to less of the disk surface at the beginning of the burn than at the end.  In order for the CD to burn at a constant 52x, the CD would have to start spinning at a very fast velocity and then gradually slow down as the CDRW head moves outward.  Unfortunately, the CD would melt if it were to spin that fast.

One solution to this problem is instead of a CAV (constant angular velocity), the writer burns at Z-CLV, or zone-constant linear velocity.  Basically, the CD slows down while the CD head moves out, but only for short periods of time.  Once the head gets to a certain point in the CD, the drive spins up again and the process repeats. The last ASUS drive we reviewed, the CRW-4012A-U used this method of burning instead of CAV.

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We were a little critical about the CRW-4012A-U not supporting Mount Rainier.  Fortunately, the 5224A drive is CD-MRW ready.  For those of you not familiar with CD-MRW, it is basically a protocol similar to Roxio's DirectCD where the disk can be written to on the fly, essentially transparent.  The protocol allows for background CD-RW formatting, no disk finalizing, fault management and 2K (rather than 64K) packet writing.  All CD-MRW operations are carried out on regular CD-RW disks, and right now natively supported in Windows XP.  In time, this may also be extended to other operating systems.