Philips RWDV2010K/00, RWDV1610B/00, PCRW4012K/00, PCRW1208K/00, JR12CDRWK/05 User Manual

A new addition to the Philips “intelligent drive” features,

Seamless Link acts to manage and minimise

the effects of buffer under run (BUR), a common cause

of wasted discs during the CD writing process.

INTRODUCTION

Today, burning discs with a CD writer has become a common method of storing and
distributing data, text, video and audio files for PC users. With advances in writer speeds
and performance, greater ease of use, improved writing application software with
“drag-and-drop” functionality, and simple Graphical User Interfaces (GUI),
users today require less time and hassle when burning their first disc.

Other advances in CD writing are related to write integrity, and ensuring optimal writing
on nearly all media, as example, with Philips Thermo Balanced Writing (TBW) and Self
Learning strategies.

However, even with exponential strides in ease of use, and a mainstream place in new PC
systems for CD writers, users, especially those with older systems, still face an occasional
buffer under run error message. A less frequent error for users of new PC systems,
BUR is still an annoying problem.

™

While first addressing the problem via a software solution (“Ultra-Buffer
with AHEAD), Philips now takes the solution a step further, by placing the solution

“on board” the CD writer. For both users of new and older systems, Philips Seamless Link
“on board” offers an excellent management solution for BUR without tying users to a

specific application software provider.

” in co-operation

ABOUT BUFFER UNDER RUN (BUR)

Buffer under run can occur when the users’ PC or a host PC cannot supply a steady and uninterrupted flow
of data from the data source, typically a CD ROM or HDD, to the internal DRAM buffer of the CD writer
(writer buffer) (Fig. 1). If this transfer of data to the drive writer buffer is interrupted, then the buffer is not
kept full (Fig. 2). If the interuption is long enough, the "writer buffer" gets empty, the writing process stops
and the disc is ruined (Fig. 3). Buffer under run occurs most frequently when users are writing to a CD-R or
CD-RW disc in either Track-at-Once (TAO) or Disc-at-Once (DAO) mode.

The causes of BUR have been numerous and are related to the PC system, the system configuration or set up,
and the CD writer itself. Most sources of BUR have been reduced in newer PC systems (with faster CPUs
and HDDs with transparent Thermal Recalibration), and by improvements in both
CD writer and the application software.

Fig. 1, Typical CD writing process: The data that needs to be written on the disc is transferred from the
source over the system bus, and is put into the DRAM buffer of the CD writer. From this buffer, the data
is put onto a disc in the writing process.

CD writer

Internal DRAM buffer, “writer buffer”
compensates for
in the data stream

short interruptions

PAGE 2

Fig. 2, Typical CD writing process: Short interruptions in the transfer of the data over the IDE bus will cause
the writer buffer level to drop.

CD writer

If the data stream is interrupted, the speed at which
the data is sent to the writer is lower than the speed
at which the data is written to the CD
=> the level of the writer buffer
will drop.

After the interruption, the writer
buffer level will rise again