A. The 4164 is a 64 K DRAM (64 K × 1) whose access time is 100 ns. Its internal organization has 256 × 256 matrix (internally it has two 32 K bit array). If refreshing is done with RAS-only principle, calculate the refresh overhead. Note: Each cell must be refreshed atleast once in 2 ms.
B. The 814400 is a DRAM IC of 1 M × 4. Its parameters are as follows:
(a) Cycle time: 80 hs
(b) Refresh time: 60 hs
(c) Refresh cycle: 1024 cycles; 16.4 ms
Calculate the refresh overhead.