CD and DVD Burners

[imported_smeg]

CD and DVD burner s/w now has some form of buffer under write protection. My question is will a burner with a 2 meg buffer be slower than one with 8 meg? My thought is that the buffer under run s/w will result in a good burn but does a 2 meg buffer cause the s/w to slow down the write speed more than if the buffer was 8 meg. It looks like most newer burners only have 2 meg (probably to save costs). I don't know of any burner tests that compare burners with different buffer sizes.

 

[EeyoreX]

If the drive has a buffer underrun protection scheme of some sort, cache size is irrelevent. The 8MB cache drives are mostly a way to make more money.

Marketting team: "If you add more cache, you can add more cost!!"

If you set your burner to burn at 4x, it will burn at 4x regardless of cache size (dependant of course on media, etc. The size of the cache won't affect anything other than price).

\Dan

 

[imported_smeg]

But doesn't the buffer under run protection slow down the actual write times so that the buffer does not go empty? My thinking is that a 2 meg buffer will empty more often than 8 meg and this will make the under run prtection slow the writing down more than if there was a 8 meg buffer.

 

[BlueWeasel]

Originally posted by: smeg
But doesn't the buffer under run protection slow down the actual write times so that the buffer does not go empty? My thinking is that a 2 meg buffer will empty more often than 8 meg and this will make the under run prtection slow the writing down more than if there was a 8 meg buffer.

In a single word....NO

I don't think the Buffer protection doesn't slow down the speed of the burn. In the early days of CD-RW, before buffer protection, it was easy to burn a coaster if the drive had to wait on the information. The buffer simply provides the information to the drive at the desired speed, even at 52x.

 

[imported_smeg]

If the under run s/w doesn't slow down the write speed, how does it prevent buffer under run?

 

[EeyoreX]

Link. A Google search turned this up as the first result. It will explain how the technology works.

\Dan

 

[imported_smeg]

Yes, when the buffer runs low, the buffer under run s/w suspends the writing process until the buffer fills again. This would lower the net write speed. So that if you set the writing speed at, say, 40x for CD or 4x for DVD, the buffer under run s/w would be suspending the writing a number of times . The net effect is that that effective write times could be lowered to say 30x and 2x. If the buffer was 8 meg rather than 2 meg, the buffer would not run empty as often and the under run s/w would not suspend the writing operation as often and net (effective) record speed would be higher. I think that this is a given. My question is: "how much difference is there? Is it significant (say 10x) or insignificant (say 0.5x)?

 

[Peter]

Large buffers offset OCCASIONAL slowness of the feeding PC. If the PC's sustained average speed is too low for the speed you chose, neither the large buffer nor some buffer underrun plan B will help it.

If you do get a buffer underrun and the drive doesn't have any recovery strategy, you get a coaster. With buffer underrun recovery (whatever the "brand" name for it), the writer drive tries to continue the recording with as little seam as possible. This is fine for data disks, but audio player devices might hiccup on such a spot.

In a nutshell, if you regularly get buffer underruns, then do something to speed up the system, or choose an adequately lower write speed. Underrun protection avoids coasters if it does happen anyhow. The best protection though is a fast HDD on a reasonably fast system.