Any body know why they called the Mark VIe redundancy as R, S and T ?
Based on what? is any thing specific for this symbols?
The three processors could have been called anything: 1, 2, 3; A, B, C; X, Y, Z; P1, P2, P3. I think the designers tried to find a logical order of letters/symbols,characters that was simple and somewhat unique yet logical and non-confusing. They did use the 'carets' (< & >) to enclose the letters to make them distinctive, and primarily to designate them as hardware (as opposed to software).
I've never heard of any special reasoning/logic for the choice of "names", nor any special meaning for the characters.
Good question; boring answer. ;)