Posts from May 2021 [ on iamcal.com ]

Posts from May 2021

May 18th: This write up on finding arbitrary code execution in ExifTool is interesting both because it's Perl code that I used almost 20 year ago (and is still the best way to do it!), and that it's a great explanation of finding and exploiting vulnerable code.

May 10th: While researching the different colored bands for bundles of American bank notes, I found this fascinating page about the rules for US currency deposits.

Geography

I thought my geography was reasonable, but I only hit 52 of the 150 largest countries by area. You get a few tries per country.

The harder version has all 193 members of the UN.

May 4th: It's been three and a half months since I got PHP CI working on Travis, so of course it's now broken. Github Actions are the new hotness, so I figured out the right magical config to run multi-version CI for PHP over there instead, and it runs much faster too.

IBM Wiring

I'd seen the photo a few times, but this is the first I'd read about what was actually being wired up. Turns out it's a semi-mechanical pre-computer for accounting and it's even more interesting than it first looked.

About

This is the personal website of Cal Henderson, Slack co-founder & CTO.

I give occasional talks, write code and sometimes articles.

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