|
 |
 Glossary |
|
| E11 |
|
| A type E11 error indicates the loss of only one recoverable
data bit. |
| E12 |
|
| A type E12 error indicates the loss of only one recoverable
data bit by the second decoder. |
| E21 |
|
| A type E21 error indicates the loss of two recoverable
data bits. |
| E22 |
|
| A type E22 error indicates the loss of two recoverable
data bits by the second decoder. |
| E31 |
|
| A type E31 error indicates the number of non-recoverable
errors by the first decoding algorithm. |
| E32 |
|
| A type E32 error indicates some irretrievable errors
by the second decoder. A working disc cannot have this type of error. |
| ECC (Error Correction Code) |
|
| An algorithm through which data lost as a result of an
error can be reconstituted. |
| ECC (Eccentricity) |
|
| The difference in the size of the center of the disc
and the center of the spiral. In CDs it is ± 70 µ but should be ±
50 µ in CD-ROMs, as they are read in a much less methodical way than
CD-Rs. |
| EDC (Error Detection Code) |
|
| Error detection algorithm. |
| Electroforming |
|
| Technical procedure for creating a metal or master mask
for continuous production of CDs from a glass matrix. |
| Form1 |
|
| Mode 2 CD-ROM sub-format used for Photo - CDs and electronic
books. |
| Form2 |
|
| Mode 2 CD-ROM sub-format used for applications where
data will not suffer from low correction levels (video, sound). |
| Glass Master |
|
| The first recorded media and used for the CD duplication.
A photosensitive film is applied to the glass master and data is written
with a laser. The film applied to the exposed glass master gives the
master information. |
| Green Book |
|
| The standards applying to CD-I |
| Header field |
|
| 4 bits at the beginning of every CD-ROM sector. The header
gives the sector address amd recording method. |
| High Sierra |
|
| A file organization format on which ISO 9660 is based. |
| IG (Intensity Groove) |
|
| Measure of the percentage of the reflectivity of the
spiral. The figure is obtained by taking measurements at 10 points
in the disc data area (measurements taken before and after recording:
IGa and IGb ). |
| IL (Intensity Land) |
|
| Measure of the percentage of the reflectivity of the
land. The figure is obtained by taking measurements at 10 points on
the surface of the disc (measurements taken before and after recording:
ILa and ILb). |
| Index |
|
| Easily-located points marked on a track. |
| Injection molding |
|
| Polycarbonate discs which form the basis of a CD, are
created by injecting pressurized plastic into a mold. |
| ISO 9660 |
|
| International norm describing computerized file organization
on CDs. |
| ISRC (International Standard Recording
Code) |
|
| An optional unique code assigned to a track. The ISRC
value, situated in the Q channel, identifies a track by the region
of origin (2 ASCII characters), the year of creation (2 numbers),
the owner (3 ASCII characters) and a serial number (5 numbers). |
| Jewel Case |
|
| Plastic storage case for CDs. |
| Jitter (Standard Deviation) |
|
| Jitter is measured on single pits and lands from 3T to
11T. Each pit and land is measured and jitter is calculated statistically
as a standard deviation. |
| Kb (kilobytes) |
|
| 1024 bytes (1024*8 bits). |
| Label |
|
| A print on the upper surface of the CD, which may include
the manufacturer's name, the disc contents, etc. |
| Lacquer coating |
|
| A protective layer on the surface of the CD, applied
on top of the the layers of dye and gold (or silver). |
| Land |
|
| Also called a flat. The part of the spiral (groove) which
is left unburnt by the laser. |
| Lead In Area |
|
| On a CD, the lead-in area is the area containing the
Table of Contents at the beginning of the spiral. The TOC contains
the track listing and location. It is left blank until the session
is closed. This zone uses up to 4500 sectors (about one minute or
9 Mb). If the disc has not been closed, the lead-in area gives the
address of the next writable zone. |
| Lead Out Area |
|
| Zone buffer at the end of the disc after the last track.
It is left empty and and occupies 6750 sectors for the first session
and 2250 sectors thereafter. |
| LECC (Layered Error Correction Code) |
|
| Error-correction code replacing the CIRC when the latter
cannot correct errors. The LECC performs a fresh error-detection and
tries to correct them by using EDCS values and ECCS. |
| Length Deviation |
|
| The length of every pit and every land is measured and
average lengths are compared to the recommended lengths. The recommended
values of pits and lands are defined by the equation nT = n x 231.4,
where n=3 to 11. Deviation is the difference between measured average
and recommended value. |
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