A computer employs RAM chips of 256 x 8 and ROM chips of 1024 x 8. The computer system needs 2K bytes of RAM, 4K bytes of ROM, and four interface units, each with four registers. A memory-mapped I/O configuration is used. The two highest-order bits of the address bus are assigned 00 for RAM, 01 for ROM, and 10 for interface registers. 

a. How many RAM and ROM chips are needed? 

b. Draw a memory-address map for the system. 

c. Give the address range in hexadecimal for RAM, ROM, and interface.