In "The Datacenter as a Computer" there was an interesting diagram sketching a datacenter memory hierarchy latency and capacity and bandwidth to access RAM, SSD

In "The Datacenter as a Computer" there was an interesting diagram sketching a datacenter memory hierarchy latency and capacity and bandwidth to access RAM, SSD, and HDD in the same machine, the same rack, and a larger cluster. It's page 72 of https://www.morganclaypool.com/doi/pdf/10.2200/S00874ED3V01Y201809CAC046 https://www.morganclaypool.com/doi/pdf/10.2200/S00874ED3V01Y... and with luck https://books.google.com/books?id=Td51DwAAQBAJ&pg=PA72 https://books.google.com/books?id=Td51DwAAQBAJ&pg=PA72 will get you to the page. The numbers have changed (commodity SSDs have markedly improved!) but the idea still makes sense. Fun to consider that boxes under one top-of-rack switch can hold dozens of TB of RAM and hundreds of TB of Flash with latency measured in µs between them. There's legitimately interesting space in between writing code for a single machine and code for huge, spread-out clusters of thousands of boxes.