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@vasanthk
vasanthk / System Design.md
Last active Sep 17, 2021
System Design Cheatsheet
View System Design.md

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

  1. Clarify and agree on the scope of the system
  • User cases (description of sequences of events that, taken together, lead to a system doing something useful)
    • Who is going to use it?
    • How are they going to use it?
View ffmpeg.md

ffmpeg

Converting Audio into Different Formats / Sample Rates

Minimal example: transcode from MP3 to WMA:
ffmpeg -i input.mp3 output.wma

You can get the list of supported formats with:
ffmpeg -formats

You can get the list of installed codecs with:

@ogrrd
ogrrd / dnsmasq OS X.md
Last active Sep 12, 2021
Setup dnsmasq on OS X
View dnsmasq OS X.md

Never touch your local /etc/hosts file in OS X again

To setup your computer to work with *.test domains, e.g. project.test, awesome.test and so on, without having to add to your hosts file each time.

Requirements

Install

@adamawolf
adamawolf / Apple_mobile_device_types.txt
Last active Sep 17, 2021
List of Apple's mobile device codes types a.k.a. machine ids (e.g. `iPhone1,1`, `Watch1,1`, etc.) and their matching product names
View Apple_mobile_device_types.txt
i386 : iPhone Simulator
x86_64 : iPhone Simulator
arm64 : iPhone Simulator
iPhone1,1 : iPhone
iPhone1,2 : iPhone 3G
iPhone2,1 : iPhone 3GS
iPhone3,1 : iPhone 4
iPhone3,2 : iPhone 4 GSM Rev A
iPhone3,3 : iPhone 4 CDMA
iPhone4,1 : iPhone 4S
View tmux-cheatsheet.markdown

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname
@hellerbarde
hellerbarde / latency.markdown
Created May 31, 2012 — forked from jboner/latency.txt
Latency numbers every programmer should know
View latency.markdown

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs
Read 1 MB sequentially from memory ..... 250,000 ns  = 250 µs
@jboner
jboner / latency.txt
Last active Sep 17, 2021
Latency Numbers Every Programmer Should Know
View latency.txt
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