Drawing styles
We will now see the different representations available for
the I/O subsystem.
Round

Data area.
Swap area.
Blocks requested from the data area.
Blocks requested from the swap area.
Reader head.
Current placement of the reader head.
Route
This style, pretends to clearly show the trajectory which
will follow the reader head to access all requested blocks
depending on the selected algorithm.

Requested Blocks.
Trajectory between block reads.