Started 60-day system design curriculum with latency measurement labs
By RepoJournal , from @anurag629's public GitHub activity
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Anurag launched a structured eight-week system design course in anurag629/system-design-60-days with hands-on labs measuring real hardware performance across the storage hierarchy.
The curriculum spans from ground-truth estimation through storage, caching, async, distributed systems, AI systems, and production concerns [1]. Day 1 includes a scaffolded Python lab that measures RAM, SSD, localhost, and internet round trips on the reader's own machine.
Anurag spent the day fixing measurement bugs that were skewing the results. The internet latency probe was using www.mit.edu and www.unimelb.edu.au, both of which resolve to CDN edges rather than their labeled regions, so he replaced them with AWS regional endpoints [2]. The socket layer was also performing a DNS lookup on every connection attempt, timing "DNS + handshake" instead of a pure round trip, so he resolved hostnames once and reused them [2].
The SSD measurement was reporting memory latency instead of disk latency because the test file was cached in RAM. Anurag set F_NOCACHE on both the write and read handles and added an fsync before closing to ensure bytes reached the device [3]. Day 1 measurements showed "SSD random 4 KB read 84.7 us" and "localhost TCP round trip 19.5 us", revealing that the network beat the disk by 4.3x [4].
He also mapped free resources to each of the eight weeks [5] and added verified resource links to each day, week, and a master resource list, checking that all 200 links resolve [6].
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References
- [1] Start 60-day system design plan: week 1 and day 1 anurag629/system-design-60-days
- [2] Fix internet latency probe: honest hosts, resolve DNS once anurag629/system-design-60-days
- [3] Fix SSD measurement: keep the test file out of the page cache anurag629/system-design-60-days
- [4] Day 1 results, and Day 2: estimation vs reality anurag629/system-design-60-days
- [5] Add free resource list, mapped to the eight weeks anurag629/system-design-60-days
- [6] Add verified resource links to each day, week, and the resource list anurag629/system-design-60-days
