Li Chen 陈力 li-ch

Software Engineering Philosophy & Development Protocol

1. Global Integrity & Topology

System Awareness: Before implementation, map the dependency graph and system topology. Ensure local changes preserve global invariants and do not trigger "Shotgun Surgery."
Orthogonality: Design for independence. Ensure that changes in one module do not leak side effects into others. Minimize coupling and maximize cohesion.

2. Intent & Abstraction Hierarchy

Intent-Revealing Design: Prioritize human readability and intent over machine cleverness. Use naming that explains "Why" rather than "How."
Single Level of Abstraction (SLA): Adhere strictly to the Single Responsibility Principle (SRP). Each function must operate at a consistent level of abstraction and have exactly one reason to change.

Common Options

-#, --progress-bar Make curl display a simple progress bar instead of the more informational standard meter.

-b, --cookie <name=data> Supply cookie with request. If no =, then specifies the cookie file to use (see -c).

-c, --cookie-jar <file name> File to save response cookies to.

Summary of book "Clean Architecture" by Robert C. Martin

Uncle Bob, the well known author of Clean Code, is coming back to us with a new book called Clean Architecture which wants to take a larger view on how to create software.

Even if Clean Code is one of the major book around OOP and code design (mainly by presenting the SOLID principles), I was not totally impressed by the book.

Clean Architecture leaves me with the same feeling, even if it's pushing the development world to do better, has some good stories and present robust principles to build software.

The book is build around 34 chapters organised in chapters.

`vs` Questions

http://stackoverflow.com/questions/804115 (rebase vs merge).
https://www.atlassian.com/git/tutorials/merging-vs-rebasing (rebase vs merge)
https://www.atlassian.com/git/tutorials/undoing-changes/ (reset vs checkout vs revert)
http://stackoverflow.com/questions/2221658 (HEAD^ vs HEAD~) (See git rev-parse)
http://stackoverflow.com/questions/292357 (pull vs fetch)
http://stackoverflow.com/questions/39651 (stash vs branch)
http://stackoverflow.com/questions/8358035 (reset vs checkout vs revert)

Installation Caffe + NVIDIA CUDA 7 Tools on Ubuntu 14.04 (step by step, including external libraries)

Guide for Ubuntu 16.04 with a 64 bit processor.

Tested on a Dell XPS L421x laptop with a NVIDIA GeForce GT 630m.

This guide is intended to be a (sort of) comprehensive step by step tutorial, including the installation of external dependencies.

This tutorial assumes some decisions about the versions and programs to install, to make it as straightforward to follow as possible, while still having as much advanced features as possible.

Notably:

It uses Anaconda Python (which facilitates installation and has many great feat

#System Design Cheatsheet

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

##Basic Steps

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?

	Latency Comparison Numbers
	--------------------------
	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

	---
	# ^^^ YAML documents must begin with the document separator "---"
	#
	#### Example docblock, I like to put a descriptive comment at the top of my
	#### playbooks.
	#
	# Overview: Playbook to bootstrap a new host for configuration management.
	# Applies to: production
	# Description:
	# Ensures that a host is configured for management with Ansible.

Li Chen 陈 力 li-ch