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How do CD's record information?
CD-Recordable disks are made like this, from top to bottom:
- [optional] label
- [optional] scratch-resistant
and/or printable coating
- UV-cured lacquer
- Reflective layer (24K gold
or a silver-colored alloy)
- Organic polymer dye
- Polycarbonate substrate
(the clear plastic part)
A pressed CD has raised and
lowered areas, referred to as "lands" and "pits",
respectively. A laser in the CD recorder creates marks in the disc's dye
layer that have the same reflective properties. The pattern of pits and
lands on the disc encodes the information and allows it to be retrieved
on an audio or computer CD player.
Discs are written from the
inside of the disc outward. On a CD-R you can verify this by looking at
the disc after you've written to it. The spiral track makes 22,188 revolutions
around the CD, with roughly 600 track revolutions per millimeter as you
move outward. If you "unwound" the spiral, it would be about
3.5 miles long.
What is CD "burning?"
Burning is just another word for recording. The "R" in CD-R
stands for recording. It is a much more "technical" sounding
word, so many computer enthusiasts use the word "burning" to
sound cool to their friends; but you can use recording and burning interchangeably.
What do I need to burn CD's?
From Microsoft (http://www.microsoft.com/windows2000/techenthusiast/features/cdr.asp):
CD burning is an intricate
technology. But millions of Windows 9x, Windows Me, and Windows 2000
enthusiasts are creating their own CDs simply and successfully for work,
home, and entertainment every day. The PCs available from retail stores
and online vendors today include CD-RW drives more often than not. For
most users, setup is as simple as plugging in the device, loading the
software and following the instructions. Most software programs have
simple user interface designs that make CD burning appear similar to
copying a file to floppy disk.
Adding CD-burning capability
to your Windows-based computer requires:
- A CD-RW or CD-R drive
compatible with your version of Windows. Many drive kits include software,
adapter card, and cables. Cost, depending on features, is about $200.
- Blank CDs. Rewritable
disks are just over $1 each, CD-R disks just under $1. There are several
brands and colors. Dye formulas are patented, and some disk makers
claim the color determines durability: platinum disks may last longer
than green, up to 200 years, for example. Not all CD-ROM drives read
CD-RW disks. But if your CD-R disks will not play in other devices,
try other brands and colors.
- Compatible CD-burning
software.
To set up your drive and
burn CDs, you should follow the instructions provided with your device
and software. In addition, the following tips may help you successfully
burn CDs:
What is the difference between
CD-R and CD-RW disks?
CD-R (CD-Recordable) is the cheapest and most widespread. These discs
can be bought for under a dollar, and can only be burned one time. CDRW,
or CD-ReWriteable -- is a relatively new standard that allows you to erase
discs and reuse them. Most of the new recorders support both CD-R and
CD-RW CD-RW is economical if you need to routinely save and delete large
chunks of data. But, if the data is important enough to back up, you probably
want to keep it for a while. Also remember that older CD-ROM readers will
not recognize CDRW discs. So, in general, CDR is the best bet.
What
software do I need to burn CD's? Where do I get it at SMU?
If your CD drive was purchased separate from your computer (PC), it probably
came with a version of the program "Easy CD Creator." This is
a very easy-to-learn program. If your computer has a CD-Rewritable drive,
but you do not have Easy CD creator, contact the Help Desk (x7800 or 800-635-5987,
ext. 7800) for information on installing CD burning software on office
computers.
Do
I have to burn a CD all at once?
No. You just need to burn the CD in Track-At-Once-Mode. When you burn
a CD in Easy CD Creator, click the advanced tab to select track-at-once.
With track-at-once, the burning process can be interrupted for any length
of time after the burning of each track. In addition, you are also able
to take the CD-R out of the drive. You can even finish the CD-R in a completely
different CD-burner.
What is a "buffer underrun"
and how can I avoid it?
If you've had problems burning CD's, you may have encountered the dreaded
"buffer underrun" error message. Remember that burning a CD
is a sustained process: The laser turns on, writes data, and turns off.
During the writing portion, the computer must supply data to the laser
at a consistent, steady pace. This data is held in a memory buffer and
fed to the laser. If the computer gets interrupted and has no data for
the laser, the process fails and a buffer underrun occurs. This means
your blank CD is now useless -- or, a trendy mirror for your cubicle.
Your choice.
One of the biggest factors
in avoiding the "buffer underrun" is the speed of your computer
and amount of RAM on your machine. While most drives suggest at least
32 MB of RAM, it's better to have at least 64 MB. For other types errors,
software and discs you use can make a difference. Buy several brands of
discs and see which ones your drive likes the best. For music, a good
test is the car stereo: If you can skip through the tracks easily, you've
got a good burn.
If you have no control over
the hardware on your office computer, another solution is to create a
"CD image" before you burn your CD. This creates a copy of the
CD on your hard disk and is much easier on your computer during the burning
process. In Easy CD Creator, select "Create Disk Image" from
the file menu to make the image, and then "Create CD from Disk Image"
to burn the CD.
How do I use Easy CD Creator?
Gateway has an excellent tutorial on
Easy CD Creator at this web address:
http://support.gateway.com/support/faq/c-drives/adaptec/CDCreator5/music_cd.htm#1044603
Where can I go to get more
help with burning CD's?
You may contact the help desk at x7800 or 800-635-5987, ext. 7800. As
CD burning is becoming a common practice, colleagues and students will
probably be very happy to provide assistance also.
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