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Land or Pits. Mass produced
CD-ROM are a stamped media
with indentations physically
stamped into the recording
layer of the media which is
then covered by a hard clear
plastic. A laser beam focused at
these indentations reflects
differently than the parts of the
media that are not indented.
The indentations are called
"Pits." "Land" is the area that
is not indented. Rather than
use actual Pits and Land CD-R
and CD-RW use heat to alter
the reflectivity of the chemical
of the recording layer. A laser
optical device can read the
difference in reflectivity of
different states of these
chemicals, much like reading
the difference in reflectivity of
the Land and Pits in a stamped
CD.
Lead in. Session information
written at the beginning of a
session.
Lead out. Session information
written at the end of a session.
LED. Light Emitting Diode. A
light device that is designed to
not burn out.
Mb. Megabyte. Basically
means one million bytes, but is
actually 1024 kilobytes or 1024
X 1024 bytes which is 1,048,576
bytes.
Mb/s. Megabytes per second.
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Means of measuring
throughput.
Megabyte. see Mb.
Multi-Read. The ability for
CD-ROM, CD-R, CD-RW, and
DVD-ROM drives to read CD-
ROM, CD-R and CD-RW
media.
Multi-Session. Multi-Session
means several sessions can be
written to, and read from CD-
ROM, CD-R or CD-RW media.
PC. Personal Computer.
Sometimes also a term for IBM
PC or Windows Compatible
PC. In this user's guide the
term "PC" means Windows or
Windows NT compatible PC,
as opposed to Macintosh, or a
UNIX based computer.
Phase Change. The ability of a
substance to change states and
then be stable in the new state.
In CD-RW media the recording
layer can change from an
amorphous state which does
not reflect strongly to a
crystalline state which does
reflect strongly. See
Reflectivity.
Pits or Land. See Land or Pits.
CRX160E User's Guide
Record a CD. Burn a CD,
Writing a CD. Uses special CD-
Recordable discs which can be
altered by the laser in a CD-R
drive.
Reflectivity. In the sense of
laser optical devices,
differences in reflectivity can
be read as 0 and 1 bits. The
intensity of a laser will reflect
differently from a crystalline,
glass like state, than an
amorphous, or non-crystalline,
state. Much like a flashlight
will reflect more brightly from
a mirror than from a white
painted wall.
Session. Data written to CD-R
media at one time.
Source drive. The drive which
contains information that will
be written somewhere else. In
CD recording the source drive
contains the information that
will be written to the CD
Recorder.
Sustained transfer. The rate
which data can be transferred
from one device to another.
This rate is an average over a
longer period of time than a
burst transfer rate. Because the
sustained transfer test is
longer, it means the testing
will take into account both
reading or writing from the
storage device's buffer, as well
as from the media. Reading
CRX160E User's Guide
and Writing from the media is
a much slower operation, so
the sustained transfer test is
usually a much better test for
determining the usability of a
device in a real application,
such as recording a CD.
System Intensive. An
operation that requires the
greatest speed from the
computer system. If other
programs are running at the
same time or in the
background they may slow the
overall speed of the computer,
so that the system intensive
operation will fail.
WORM. Write Once Read
Many. Sometimes drives using
CD-ROM and CD-R media are
called WORM drives because
once data is written to media,
the data cannot be erased or
altered.
Write Once. Media that can
only be written to once.
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