What types of devices write CD-R and CD-RW discs?
All CD-R and CD-R/RW recorders write CD-R discs but only CD-R/RW recorders write
both CD-R and CD-RW discs. Many DVD recorders also come combined with CD-R and
CD-RW writing functions but be aware that there are exceptions. If in doubt,
consult with the hardware manufacturer.
Are there audio CD recorders available that connect to
Several manufacturers offer consumer and professional audio CD recorders that
connect, like cassette decks, to conventional stereo systems. Typically, they
will record to CD-R or CD-R and CD-RW discs from either digital (CD, DAT, MD,
etc.) or analog (cassette, vinyl record, radio, etc.) sources.
What do the numbers describing a CD-R or CD-R/RW recorder
Manufacturers typically use a sequence of two, three or four numbers to express
the maximum writing and reading speeds of a recorder. The generally accepted
industry convention for a CD-R recorder has been for the first figure to indicate
CD-R writing speed followed by CD reading speed for CD-R and prerecorded (pressed)
data CDs. For a CD-R/RW recorder the first number usually indicates CD-R writing
speed followed by CD-RW writing speed and then by the CD reading speed. In the
case of a combination recorder a fourth number is included to indicate DVD reading
speed. As examples, 8x12 usually means 8x CD-R write and 12x CD read while 48x12x48
typically indicates 48x CD-R write, 12x CD-RW write and 48x CD read. And for
a combination recorder 24x10x40x12 denotes 24x CD-R write, 10x CD-RW write, 40x
CD read, and 12x DVD read.
What types of CD-R and CD-R/RW recorder configurations
Whether for PC, Mac or UNIX computers in desktop, laptop or notebook form, CD-R
and CD-R/RW recorders are available in a wide variety of configurations to suit
most needs. Several industry standard interfaces are available including SCSI,
EIDE/ATAPI, Parallel, USB and IEEE 1394 for either internal or external recorder
The Enhanced Integrated Drive Electronics/ATA Packet Interface (EIDE/ATAPI) is
the most popular method for connecting CD and DVD-ROM drives and hard disks as
well as CD-R and CD-R/RW recorders to a computer. Since most computers already
have EIDE/ATAPI built-into their motherboards no additional interface card is
necessary. These devices are normally installed internally but many external
recorders are actually EIDE/ATAPI models that use bridge technology to convert
them to SCSI, USB or IEEE 1394 interfaces.
The Small Computer Systems Interface (SCSI) or “scuzzy” interface
is a high performance and flexible method of connecting to a computer many peripherals
including scanners, CD and DVD-ROM and hard drives as well as CD-R and CD-R/RW
recorders. In addition to long cable lengths, SCSI allows for both internal and
external attachments. Some computers already have SCSI built-into their motherboards,
but, more often than not, a SCSI interface card is required. Depending upon the
specific product, a SCSI card may or may not be included with the CD-R/RW recorder
CD-R/RW recorders that make use of a parallel interface connect to the computer
using the same parallel port used by a printer and can only be installed externally.
Depending upon the product, some recorders have pass-through arrangements allowing
both a printer and recorder to be connected to the computer at the same time.
The Universal Serial Bus (USB) is used to connect many types of peripherals to
a computer including joysticks, mice, keyboards, printers, scanners and external
CD-R and CD-R/RW recorders. Since USB is a plug and play interface computers
do not have to be rebooted when a recorder is attached as these devices are automatically
recognized by the system. And USB has been updated several times to accommodate
the demands of increasingly faster peripherals. USB 1.1 interfaces are built
into the motherboards of many systems and generally permit up to 4x CD-R/RW writing
and 6x reading speeds. USB version 2.0 is an updated version of the specification
allowing greater performance but typically requires an additional interface card.
Most USB 2.0 CD-R/RW recorders are backward compatible and can operate at reduced
speed when connected to older USB 1.1 systems.
Popularly known by trade names such as FireWire and i.LINK, IEEE 1394 is a high
performance plug and play interface commonly used to connect computers to external
hard disk drives and CD-R and CD-R/RW recorders as well as consumer electronics
devices like digital camcorders, televisions and game consoles. IEEE 1394 interfaces
come standard on many Macintosh systems and on some brands of PCs but, more often
than not, an interface card is required.
What is buffer underrun?
An important point to remember about CD-R and CD-RW recording is that information
must be written to a blank disc in a continuous stream. To help smooth out the
flow in the data transfer rate from the computer, the recorder employs a memory
buffer which, like a reservoir storing water for use when it is needed, caches
data for when it is required by the recorder. As with a water reservoir, the
key is to always have enough data in the buffer to satisfy the demands of the
recorder, even if, from time to time, the computer can’t supply the needed
amount of information. If the buffer runs dry (a “buffer underrun”)
the disc is ruined.
How can buffer underrun be prevented?
Most current computer recorders incorporate advanced buffer underrun protection
technology to eliminate buffer underruns but for units not so equipped there
are a variety of common sense techniques that can be used to help minimize the
possibility. These include ensuring that the recorder and writing software are
properly configured, defragmenting the operating system and data source hard
disk partitions, disconnecting from any networks, closing all other programs
and disabling background tasks such as power managers and anti-virus software.
In more stubborn cases additional measures to be considered include reducing
writing speed as well as enabling the recording software to build a temporary
image on the hard disk drive before recording.
What is buffer underrun protection?
In order to keep pace with the demands of ultra speed writing, recorder manufacturers
have created new technologies for preventing buffer underruns. A recent innovation
now known by a multitude of different trade names, buffer underrun protection
utilizes a combination of recorder hardware, firmware and writing software to
accomplish its task.
Buffer underrun protection functions by constantly monitoring the amount of
data in the recorder’s buffer during the writing of a disc and suspends recording
if the amount available falls below a predetermined threshold. Once the buffer
again accumulates sufficient data the recorder resumes writing precisely where
it left off. Obviously, it’s critical to leave as small a gap as possible
between the previous and newly recorded sections so as to avoid producing an
unreadable segment on the disc. Generally speaking, the gap length has been
found to be well within the error correction capabilities of CD and DVD-ROM
and players. As the technology matures the gap will continue to shrink.