Each bit here (the 8 digits) refers to specific chips on the motherboard of the Iic. The right-most bit represents the RAM chip closest to the front of the computer, MRD0, while the left-most is MRD7. So this particular error would indicate that the chip at MRD2 is faulty. If you dig into the computer, you will see that there are actually 16 RAM chips on the motherboard. The frontmost 8 are main memory (labeled MRDx) and the next 8 are auxiliary memory (labeled ARDx). If the fault was in auxiliary memory, then it would be indicated with an asterix instead of a 1.