Furuno GD-3300 Operator's Manual page 108

The track and memory capacity includes current or loaded track and
current or loaded marks.
• Current track: Position input by navigator
• Current mark: Mark input through keyboard
• Loaded track/mark: Track/mark loaded from a memory card
Note: Waypoints loaded from a memory card are erased if they share
the same waypoint numbers as current waypoints.
Postion data
from navigator
Track
Memory
Figure 11-15 Contents of track and mark memories
Track memory
When the track memory becomes full oldest track is deleted.
+
3000 pts
New Track
Current Track
Figure 11-16 How track points are deleted
External event
mark
Memory
card data
Mark
Memory
=
3000 pts
1600 pts
1000 pts
Erased
600 pts of
current track are erased.
Marks entered
thru keyboard
600 pts
11-11