holmanb

#!/bin/sh
# https://gist.github.com/smoser/14df5f0cd621e10d2282d7c90345e322
# This is /etc/schroot/setup.d/91smoser
# I use it to apply local updates to schroots.
# make sure it is executable (chmod +x).
# Things it does:
#   a.) sets proxy inside.  If apt proxy is configured outside, it will
#       apply that inside.
#   b.) uses a portion of 'apt-go-fast'
#       https://gist.github.com/smoser/5823699/

holmanb

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

holmanb

Code is clean if it can be understood easily – by everyone on the team. Clean code can be read and enhanced by a developer other than its original author. With understandability comes readability, changeability, extensibility and maintainability.

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General rules

1. Follow standard conventions.
2. Keep it simple stupid. Simpler is always better. Reduce complexity as much as possible.
3. Boy scout rule. Leave the campground cleaner than you found it.
4. Always find root cause. Always look for the root cause of a problem.

Design rules