Evolution of file and memory management
Mahadev Satyanarayanan · 2015
Mahadev Satyanarayanan (Satya) presented his thoughts on "The Evolution of Memory and File Systems". He observed that over a 60-year period, there have been four drivers of progress: the quests for scale, performance, transparency, and robustness. At the dawn of computing, the quest for scale was dominant. Easing the memory limitations of early computers was crucial to the growth of computing and the creation of new applications, because memory was so scarce and so expensive. That quest has been phenomenally successful. On a cost per bit basis, volatile and persistent memory technologies have improved by nearly 13 orders of magnitude. The quest for performance has been dominated by the growing gap between processor performance and memory performance. This gap has been most apparent since the use of DRAM technology by the early 1980s, but it was already a serious issue 20 years before that in the era of core memory. Over time, memory hierarchies of increasing depth have improved average case performance by exploiting temporal and spatial locality. These have been crucial in overcoming the processor-memory performance gap, with clever prefetching and write-back techniques also playing important roles.