Closed/Open Knuckle...Full/Semi Floaters...

[alice@domain.elided]

Hello,
A few questions ...some related ...well, most related.  I seem to 
have received a number of conflicting 4WD opinions lately.  I am 
kinda' new to all this stuff (remember, I mostly read the paper in
my topless Scout with Volvo seats ...sometimes I take a nap 
there too), so...

Old Land Rovers have a closed knuckle front axle.  They tend to leak, 
the swivel balls pit and the semi-contained oil relys on a seal.  
Please tell me what the advantage is of this design.  There may be 
other vehicles with this design (perhaps IHC products).  I understand 
that turning radius is affected.  These vehicles also offer a "full 
floating rear hub" whereas, I am told, theIH Scout2 Dana 44 (which I 
have) is a "semi floating" type.  What does this mean?  Are my Dana 
44 axles prone to fatigue and catastrophic failure?  The Land Rover, 
as I am told, has a weak axle designed in as a "fuse" so as to not 
destroy other drivetrain components.  Does this make any sense?
I mean, are mechanical fuses, such as this, common?  If my Dana axle 
breaks while going down the highway at 70 mph, will my wheel depart 
for whereabouts unknown?  This is a scary thought.  Is there an 
inspection procedure to determine axle fatigue?  Is axle replacement 
a periodic maintenance I should be doing?  I drive relatively few 
miles, mostly on paved roads, mostly in 2WD.  The Scout body rusts 
...not as nice as an aluminium, but I think steel is easier to 
repair.  I am told it is more difficult to MIG weld aluminium.

I appreciate your comments.  If your response is tending off topic, 
feel free to email me direct.  Mark