• We’re currently investigating an issue related to the forum theme and styling that is impacting page layout and visual formatting. The problem has been identified, and we are actively working on a resolution. There is no impact to user data or functionality, this is strictly a front-end display issue. We’ll post an update once the fix has been deployed. Thanks for your patience while we get this sorted.

Does Sony DVD-ROM 16x/40x only have 165ms CD access time? Isn' t that very slow?!..

D

Dance123

Senior member
Hi,

Does the Sony DVD-ROM 16x/40x only have an access time of 165ms for CD? Just go here http://sony.storagesupport.com/dvdrw/downloads/ddu1621/DDU1621DataSheet.pdf to see for yourself (goto page 2 where it is mentioned in the specs!). There I read "165ms (typical) (CD)" in the specs. I thought that for CD the access time is mostly around 85ms. Strange enough the access time they give for DVD is 80-220ms, where I thought that DVD access times would be higher then CD. They also mention "full stroke". Anybody know what that is?

Anyway, I would really appreciate it if somebody would check out the link above and explain what this is all about, because I want to be sure if this is correct or not before I would consider buying this drive! A CD access time of only 165ms seems very slow to me!

Anybody who could please clarify this?! Thanks very much!

Mike.
 
The overall seek time depends on what order you access data on the disc. For random (aka Typical) seeks anywhere from 110 to 170ms is normal here. Once again it just depends on the access pattern. The "full stroke" time refers to how long it takes the laser to move from one end of the disc to the other. 140ms and higher is typical here.....

On a DVD the data is packed much closer together than a CD. Because of this the laser will always have to move so far to seek to different files. But once again this depends on the access pattern,


All the times on that page look normal, very much like all other optical drives out there.
 
You say that typical access times between 110 to 170 are normal for CD, but how comes then that the specs of the Asus DVD-ROM 16x/48x drive say following:

"Fast random access time DVD: 105 ms vs. CD:85 ms typical"

So with the Asus drive the typical random access time is 85ms for CD which is much lower then the 110-170 of the Sony drive, so does that mean the Asus is faster then the Sony drive or am I seeing it wrong? I don't get it as I thought "typical" was a standard and the same on all current drives?!..
 
All drive mechinisms vary. Some are faster than others. And I will say it again the access time is completely dependent on the access pattern. Manufactuers ALWAYS post best case access times. The drive will NOT always get 85ms. Most likely it will be around 105 to 110ms for normal access patterns.

The seek times ONLY matter when the laser head is actually seeking to a different spot on the disc.


Really, you are obcessing over something so small. Just buy a drive already!
 
Doesn't matter much anyhow, since random access isn't what you should be doing with a CD or DVD drive. These are about linear streaming of large files.
 
You must log in or register to reply here.

TRENDING THREADS

Back
Top