Showing posts from August, 2020


(This post originally appeared at Swarajya magazine here )  During the 1990s, computing faced a unique ‘ memory wall problem ’ due to increasing processor clock speeds but relatively slow memory speeds. While processor speeds increased at 50% year on year (Moore’s law) memory speeds increased only by 10%. Imagine a talented and quick chef bogged down by a slow assistant, who takes longer than usual to fetch ingredients from the pantry. The solution was found by using a ‘cache’, a smaller but faster memory placed nearer to the processor, thus avoiding multiple trips to the larger and slower main memory. This was like the chef getting a shelf that stocked all recently used or frequently used ingredients closer to his table. Today we have multiple caches at multiple levels in any given computer. Similar problem of earth-size arose when digital contents were to be served to multiple users across the globe. Imagine Netflix maintaining data centers only at US and trying to service the users