On the back of the envelope

by reestheskin on 01/06/2020

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The famous nuclear physicist, Enrico Fermi, was said to be fond of coming up with surprisingly useful numerical answers on topics where he possessed little prior expert knowledge. ‘How many piano tuners are there is New York?’ is one example. The ever excellent Jean-Louis Gassée in the Monday Note joins in, allowing us all to marvel at modern logistics. BTW, if you follow the link you will see that he does not ignore the fact that such marvels require a human calculus, too.

In the next Xmas quarter, Apple will need to produce 80 million iPhones — that’s about the number Apple disclosed before it decided to no longer give out units data. Given 8 million seconds in a quarter (90 days * 24hrs * 60mins * 60 seconds = 7,776,000 seconds), this yields a nicely rounded production requirement of 10 iPhones per second — 24 hours a day!

How many production lines are needed to create that many devices? Let’s say the assembly, test, and pack process for one iPhone takes 10 minutes (600 seconds). This means a single production pipe can output 1/600th of an iPhone per second. If you trust my math, producing 10 iPhones per second would require 6000 assembly/test/pack pipes working in parallel.

$12B TSMC US Plant: What Problem Does It Solve? – Monday Note