Octalink was a passing standard Shimano sold to OEM factories for quite a few years , others adopted it to be compatible .
ISIS was a spline system that at that same time, was outside the Shimano Patented Corral ..
so at this Point You have 2 choices A) Buy 2 new chainrings for the 2 larger sizes , & a new chain
3rd inner looks like you didn't do a lot of Pass Hunting so is still OK.
Or B) a whole New Crankset and BB as the Shimano company went on to start another 'standard' that others had to emulate to get some Market Share..
Square Taper stuff , 110-74 seems to stay pretty Future Proof.
Last edited by fietsbob; 04-06-15 at 10:50 AM.