Sony DDU100E User Manual page 26

When the drive unit's right side is down
To facilitate disc handling, set the disc locks B, C and D into the
locked position, and leave the disc lock A in the unlocked position.
D
A
Top side
Right side
C
B
When the drive unit's left side is down
To facilitate disc handling, set the disc locks A, C and D into the
locked position, and leave the disc lock B in the unlocked position.
C
B
Top side
Left side
D A
26
Operating the Drive