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Burn-ProofT vs JustLinkT
http://www.cdrwcentral.com/general/justlinkvburnproof.htm
Updated 18/11/2000

These two new technologies claim to prevent the dreaded buffer underrun. So,
how well do they do it ? Lets take a look at what each does in terms of
preventing a coaster.

The cause of Buffer Under Run Error
In order to make CD-DA/CD-ROM compatible discs, it is required to write the
data constantly on the discs. However, data stream speed is not always
constant, especially when starting up some other applications, such as the
Internet. Further, if an unexpected error occurs in the source disc, this
will create the Buffer Under Run error. These are the typical causes of a
Buffer Under Run Error.

Once a Buffer Under Run Error has occurred, the disc cannot be read by a
CD-ROM or in the worst case, the disc will be useless.

So, here enters two companies that have found a way to prevent this from
happening.

Sanyo's Burn-ProofT
This new technology now enables many CD-R/RW drives to record data
seamlessly between the end of one recorded point and the start of another
recording point, even though data transfer may be suspended due to the
occurrence of a Buffer Under Run Error.

Burn-ProofT technology helps prevent the creation of a useless disc (coaster
disc).
Burn-ProofT technology allows the user to multitask on their PC. Previously,
a user couldn't do any other work on the PC while recording data. With
Burn-ProofT technology you do not have to suspend your work even though you
are recording data.
Lower performance PCs may also perform high-speed recording. Actual
recording speed depends upon the data transfer rate of the PC and the PC's
performance.

When the CD Recorder starts recording, the status of the buffer is
constantly checked. Shortly before a buffer underrun might occur (typically
when the buffer falls below 10% of its maximum capacity), the CD Recorder
will stop recording as of a specific location on the CD.
The CD Recorder continues attempting to receive data from the PC and to
refill the buffer. In the meantime, the Burn-ProofT circuit determines where
the last successful sector is written.
Using the location of the last successful sector, the Burn-ProofT circuit
will position the Optical Pickup. As soon as the buffer has been refilled,
the CD Recorder will start recording again.

Identically Burn-ProofT does not make the overlapped data area and the
data-gap area by suspending and restarting to record. However, the data-gap
will happen by the Auto Power Control Function for the recording laser as
follows.
Example:The length of data-gap (unrecorded area) on the disc will be
approximately 45 um with 12x speeds. (Updated, see below)

The data-gap of around 45 um will be completely corrected by error
correction function. An advanced version of Burn-ProofT has been released,
length gap has been reduced to 2-5�m from 40 - 45�m to compete with JustLink
from Ricoh.
Therefore, the disc created by Burn-ProofT can be handled as the usual
recorded disc.

Burn-ProofT is accomplished by a combination of hardware and firmware that

is resident on the drive control electronics.

Ricoh's JustLinkT
JustLinkT is a new technology developed independently by Ricoh. It
automatically prevents buffer underrun errors by predicting them before they
happen.
This new technology now enables Ricoh's CD-R/RW drives to record data
seamlessly between the end of one recorded point and the start of another
recording point, even though data transfer may be suspended due to the
occurrence of a Buffer Under Run Error.
JustLinkT technology allows the user to multitask on their PC. Previously, a
user couldn't do any other work on the PC while recording data. With
JustLinkT technology you do not have to suspend your work even though you
are recording data.
Lower performance PCs may also perform high-speed recording. Actual
recording speed depends upon the data transfer rate of the PC and the PC's
performance.

JustLinkT works on the following principal
The amount of data, accumulated in the buffer memory, is constantly

monitored during writing.

If, for some reason, data transfer speed from the computer falls below the
writing speed, the amount of data accumulated in the buffer memory falls.

When the amount of data in the buffer memory falls below a certain level
(this level is un-known at this time), and the possibility of a buffer
underrun error is predicted if writing continues, writing is intentionally
suspended for the time being.

During the time that the writing is suspended, data transferred from the
computer accumulates in the buffer memory.

When enough data has accumulated, writing is resumed from the point directly
after the point where it was suspended, and monitoring of the amount of data
in the buffer memory is recommenced.

The link section from Ricoh's JustLinkT being 2�m or under is almost
imperceptible.
The link section from JustLinkT being extremely small at less than 2�m does
not affect the reading quality.

Tests
Tests on Burn-Proof have been carried out here. Burn-ProofT does work as
described.

Tests on JustLinkT have have been carried out here. JustLinkT does work as
described.

Which one is best ?
Well, this is not going to be easy to answer !! Burn-ProofT and JustLinkT
work very well. The Ricoh MP9120A and the drives that have Burn-ProofT that
we have tested to date do work as described, both work in exactly the same
way at preventing a 'coaster', thus not wasting a blank disc. Over the last
few days we have hammered the Ricoh MP9120A and PlexWriter PX-W1210S with
all kinds of tests ranging from heavy internet access via our 10/100Mb/s
internal Network to the Internet Gateway PC here. While this was going on
the drives where set with the task of burning many discs with audio, video
and data, each making a VCD disc, an Audio disc, and a data disc. This was
done with data being taken from another PC within our internal network here.
In most cases, the PC with the CD-RW drives cached the data, that is, the
data was taken from the source and cached in the PC with the drives that are
going to burn this data.

We also tested the drives with PacketCD / DirectCD in much the same way,
this was done by using the PC that had the data that we wanted to save, and
then sending it across the Network to the PC that had the CD-RW drives
(drives need to be shared to do this).

Tests on audio were also carried out to see if we could produce a click in
the sound track while the drives wrote the disc. We forced the drives to
stop recording data by pressing Alt+Ctrl+Del, this froze the PC and in turn
stopped the CD Recorders from writing data to the CDR. Pressing Esc to make
the CD Recorder resume were they left off. We tested this many times with
single tone tracks, the result was that no clicks were detected in any CD's
that we made in this way.

Conclusion
As you can see, Burn-ProofT and JustLinkT work on the same principal, in
fact you could say they are the same, but there could be a difference, but
we are unable to tell this at this time. Based on the information that we
have here, they seem to do the same thing with the buffer on the drives.

Both monitor the buffer in the drive, if the buffer falls below a certain
point with data, the writing process is paused until the buffer on the drive
has been filled with data.

CDR/RW applications will need to be modified to support / use Burn-ProofT
and JustLinkT, as they are not just hardware dependant.

>From all these tests, we have decided that both Burn-ProofT and JustLinkT
are the way to go. If you are looking to buy a drive that has 'Anti-coaster
Technology' built-in, you will not go far wrong with either the Ricoh
MP9120A or any drive that has Burn-ProofT.




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