Former Microsoft engineer Dave Plummer reflected on software performance challenges during the '90s, specifically the limitations of machines with 12 MB of RAM. He discussed the Basic Block Tool (BBT), which optimized software binaries by reorganizing their structures to enhance execution speed. A typical binary contained around 10 MB of code, but only about 300 KB was necessary for startup. If this essential code was scattered, it led to performance degradation due to excessive page access. BBT defragmented binaries, grouping related code to streamline access and improve user experience, particularly for large products like Windows and Office. Modern tools like BOLT and HP's Dynamo continue to optimize binary layouts and runtime code, but Plummer cautioned about the risks of manipulating binaries. He noted that while computational power has increased, modern software faces similar performance challenges, with larger binaries and complex dependency graphs. He emphasized the importance of locality in software design, advising to keep hot data and code together to enhance performance.