3. CD-ROM (COMPACT DISK)
&
DVD-ROM

4.  5 ¼ inch (12 cm) diameter
 SILVER OR GOLD LAYER IS USED
 THIN LAYER ON THE TOP REFLECTIVE SURFACE
 SPACE (650 MB --- 700MB)
 DISKS ( 120 mm 74/80 min) having also 650 MB --- 700MB
 80 mm 21 min DISK HAVING 184 MB
 MINI DISKS ARE AVAILABLE IN DIFFERENT SHAPES
 CD-ROM DISKS ARE CALLED (ISO9660)
INTERNATIONAL STANDARED ORGANIZATION

5. Different shapes

6. TYPES OF DISKS
 DVD (Digital Video Disc)
 WORM DISK (CD-R)
 CD read/write (CD-RW)

7. A.
A polycarbonate disc layer has the
data encoded by using lands and pits.
B.
A reflective layer reflects the laser
back.
C.
A lacquer layer is used to prevent
oxidation
D.
Artwork is screen printed on the
top of the disc.
E.
A laser beam reads the
polycarbonate disc, is reflected
back, and read by the player.

8. CAPACITY