Practice Problem 6.1

                                                   Practice Problem 6.1 Solved

In the following, let r be the number of rows in a DRAM array, c the number of columns, br the number of bits needed to address the rows, and bc the number of bits needed to address the columns. For each of the following DRAMs, determine the power-of-2 array dimensions that minimize max(br, bc), the maximum number of bits needed to address the rows or columns of the array.

                    

Transcribed Image Text from this Question:

16 17 4 Organization 16 x 1 16 x 4 max(br, bc) 22128 x 8 512 x 4 1,024 x 4 25 29 31 13 32 15 

                                                      Solution

The idea here is to minimize the number of address bits by minimizing the aspect ratio max (r, c)/ min (r, c). In other words, the squarer the array, the fewer the address bits.

Organization	r	c	br	bc	Max (br, bc)
16 × 1	4	4	2	2	2
16 × 4	4	4	2	2	2
128 × 8	16	8	4	3	4
512 × 4	32	16	5	4	5
1024 × 4	32	32	5	5	6

 

Book:

Computer Systems

A Programmer’s Perspective

Second Edition(2nd Edition) 

By:-

Randal E. Bryant

Carnegie Mellon University

David R. O’Hallaron

Carnegie Mellon University and Intel Labs