SRE School: No Haunted Forests

You've heard the euphemism tech debt, where like a car loan you hold a recurring obligation in exchange for immediate liquidity. But this is misleading: bad code is not merely overhead, it also reduces optionality for all teams that come in contact with it. Imagine being unable to get indoor plumbing because your neighbor has a mortgage!

Thus a better analogy for bad code is a haunted forest. Bad code negatively affects everything around it, so engineers will write ad-hoc scripts and shims to protect themselves from direct contact with the bad code. After the authors move to other projects, their hard work will join the forest.

Why I Ripped The Same CD 300 Times

I collect music by buying physical CDs, digitizing them with Exact Audio Copy, and scanning the artwork. This is sometimes challenging if the CD was self-published in a limited run in a foreign country ten years ago. It is very challenging if the CDs have an innate defect that renders some tracks unreadable.

“Plumbing the depths of obsession” – Jeff Atwood

Also see the follow-up post Error Beneath the WAVs for more investigation about what exactly is wrong with my discs, and info about which CD drives are capable of reading them.

Error Beneath the WAVs

This is a follow-up to Why I Ripped The Same CD 300 Times. By the end of that page I'd identified a fragment of audio data that could cause read errors even if it was isolated and burned to a fresh CD. This page explores how specific bit patterns named weak sectors can create corrupt physical media by tickling bad encoding logic in a CD burner.

I also explore dusty archives of the early 2000s game piracy scene, which was very concerned about mitigating weak sectors used as copy protection. With the power of a “two-sheep” LTR-40125S drive, I successfully ripped the original discs with bit-exact audio data and a matching AccurateRip report.

UNIX Syscalls

On UNIX-like operating systems, userland processes invoke kernel procedures using syscalls. Each syscall is identified by a unique number and has a short list of parameters, which both can vary betwen operating systems, hardware platforms, and configuration options.

Performing a syscall is usually done via a special assembly instruction, though some platforms use other mechanisms (e.g. a vDSO). This page is a catalog of how to invoke syscalls on different UNIX-like platforms.