Symbols on computers (was: Wang 300 Calc)

Well, I'm not sure about PeeCee's, but I have complained before about the icons used on the MicroVax switches. They don't make too much sense, and simple words would have been MUCH better. I'm sorry, but it's hard to design a picture that means "Halt at the Chevron, don't boot automatically" I know that on early clones, indicators were clearly marked. "POWER", "DISK", etc. Later, cheaper machines went to a little picture of a stack of platters for disk activity. Macintosh computers fairly early on used symbols, and the "Programmer's Switch" option featured some confusing little pictures to represent what should have been labeled "RESET" and "INTERRUPT". We are at a point where the indicator for POWER is universal as being a picture of a zero with a one in it. I don't remember that being used on early machines - the power switch was typically marked with a 1 and a 0 (of course, they were real switches too, none of this soft-power stuff). And pushbuttons were typically labeled with 1/0. Anyone know when this symbol got established? -Ian