nicuveo

{-# LANGUAGE TemplateHaskell #-}

import Control.Lens
import Control.Lens.TH


--------------------------------------------------------------------------------
-- Characters
--
-- Some of the fields are only relevant to some characters, but are

mohanpedala

Table of Contents

• set -e, -u, -x, -o pipefail
• set -e
• set -x
• set -u
• set -o pipefail
• Setting IFS
• Original Reference

set -e, -u, -x, -o pipefail

Kalinovcic

//
// Author:   Jonathan Blow
// Version:  1
// Date:     31 August, 2018
//
// This code is released under the MIT license, which you can find at
//
//          https://opensource.org/licenses/MIT
//
//

mikesmullin

Mike's x86-64 Assembly (ASM) Notes

Assembling Binary Machine Code

Operating Modes:

These determine the assumed/default size of instruction operands, and restricts which opcodes are available, and how they are used.

Modern operating systems, booted inside Real mode,

hellerbarde

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

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

jcasimir

Sessions and Conversations

HTTP is a stateless protocol. Sessions allow us to chain multiple requests together into a conversation between client and server.

Sessions should be an option of last resort. If there's no where else that the data can possibly go to achieve the desired functionality, only then should it be stored in the session. Sessions can be vulnerable to security threats from third parties, malicious users, and can cause scaling problems.

That doesn't mean we can't use sessions, but we should only use them where necessary.

Adding, Accessing, and Removing Data