[rahen]

I'm uncertain about the 'A' in KA, it might suggest that it was the initial release.

'I' stands for 'Integrated', as it was the first PDP-10 CPU to utilize ICs, and 'L' stands for 'LSI'.

There was also the ill-fated KC-10, which was unfortunately killed for various reasons, both technical and strategic as it was competing with the 11/780. It was to use integrated NAND chips like the 11/750 (or even the Cray 1). I'm not sure what the 'C' stood for.

Oh, I should also mention the small KS-10, which had a mini form factor (the DEC10-20 was a mainframe). I guess you can figure what the 'S' stood for.