Medium Optical Disk (RW551/RW552) Library
6–32
EK–MOL80–SV. B01
Table 6–5 Technical Comparisons of 1X, 2X, and 4X Optical Drives
Item
1X
2X
4X
bytes per sector
1,024 (512)
1,024 (512)
1,024 (512)
track pitch
1.60
1.39
1.15
spiral direction
outward
outward
inward
data encoding
(2, 7) RLL
(2, 7) RLL
(1, 7) RLL
channel bits per byte
16
16
12
raw bytes per sector
1,360 (746)
1,360 (746)
1,410 (799)
headers aligned
yes
no
yes
sectors per revolution ID
17 (31)
20.1 (36.7)
33 (58)
sectors per revolution OD
17 (31)
40.3 (73.5)
66 (116)
modulation method
PPM
PPM
PWM
bit density ID (bpi)
24.9K
29.5K
48.7K
(49.1K)
bit density OD (bpi)
12.5K
29.5K
50.9K
(50.9K)
sectors per logical track
17 (31)
17 (31)
17 (31)
number of user bands
1
16
34 (30)
physical tracks per band
18,751
1,350
765 (868)
physical tracks per user zone
18,751
21,600
26,010
(26,040)
logical tracks per user zone
18,751
37,473
(37,527)
75,732
(73,077)
logical tracks per band ID
1.600
1,485
(1,624)
logical tracks per band OD
3,100
2,970
(3,248)
number of sectors for spares
4,096
2,057
(2,077)
5,287
(6,479)
number of buffer/test sectors
0
0
9,112
(16,616)
number of sectors for DMAs
102 (186)
102 (186)
170 (310)
usable capacity per disk (GB)
0.644 (0.591)
1.300
(1.189)
2.607
(2.296)