Final answer:
The decoder size required for a 64x128 ROM memory bank is 64x128, with 13 address lines (bits) needed to access its memory locations. To access row 12, we need the binary representation of the decimal number 12, which is 001100.
Step-by-step explanation:
To determine the size of decoder required for addressing a 64x128 ROM memory bank, and the number of address lines needed, we must consider the total number of memory locations in the ROM. The ROM is organized as 64 rows by 128 columns, which equals 8192 memory locations (64 * 128 = 8192).
To address 8192 locations, we need to calculate the number of bits required to represent that number in binary. The formula for this is 2n = number of memory locations, where n is the number of bits. For 8192, we find that n is 13 because 213 = 8192. Therefore, a 13-bit address is required, with 6 bits to select among the 64 rows (26 = 64) and 7 bits to select among the 128 columns (27 = 128).
To access row 12, we need to convert the decimal number 12 to binary, and this will be the input to the decoder for row selection. The binary equivalent of 12 is 001100, which is 6 bits corresponding to the number of bits required to address 64 different rows.
The correct answer is therefore: a) 64x128, 13 bits, Row 12 (expressed as the binary value for the 12th row).