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Network Booting

It saves time during development to boot the kernel and use a networked rootfs from the developer’s machine. It also allows for editing on the host files used live on the target

Two variants: with/without PXE

The device can be statically configured in the boot loader to know it’s IP address and what files to download and how to boot them. OR you can configure a DHCP server to tell the device those steps. The latter is preferred as it moves more of the configuration to the developer’s machine and requires less interaction with U-Boot on the device over the console.

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Same Network for Multiple docker-compose files

The A file creates the network. The B file connects to it.

Run

docker-compose -f docker-compose-A.yaml up -d
docker-compose -f docker-compose-B.yaml up -d

Testing what names Docker puts into DNS:

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/* Test:
 *     gcc -o atoi atoi.c
 *     ./atoi 12345 123465
 * Output:
 *     Number: 12345          Reverse:           54321           54321           54321
 *     Number: 123456         Reverse:          654321          654321          654321
 */

#include <stdio.h>
#include <stdlib.h>

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#!/usr/bin/env python3

import time
import urllib.parse
import base64
import hmac
import types


# https://en.wikipedia.org/wiki/Time-based_One-time_Password_algorithm

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// https://www.codewars.com/kata/how-much-wood/train/javascript
//
// Written for node v8.1.3
//
// nvm install v8.1.3
// nvm use v8.1.3
// node woodLength.js
//

function woodLength(dimensions) {

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# set sysroot /opt/poky/2.3.1/sysroots/corei7-64-poky-linux
directory /opt/poky/2.3.1/sysroots/corei7-64-poky-linux
set breakpoint pending on
file /work/build-mxencoder-Poky-Debug/mxencoder-test/mxencoder-test
target remote | ssh -T root@192.168.4.52 gdbserver - /opt/mxencoder-test/bin/mxencoder-test
b mxencoder-test.cpp:67

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static GstEncodingProfile* create_encoding_profile()
{
    // At some point, we might want to allow multiple formats etc.
    // FIXME: hook up Configure() parameters here
    GstEncodingContainerProfile *container;
    GstEncodingVideoProfile *video;
    GstCaps *caps, *restr;

    caps = gst_caps_new_simple("video/quicktime", "variant", G_TYPE_STRING, "iso", NULL);
    container = gst_encoding_container_profile_new(NULL, NULL, caps, NULL);

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gst-launch-1.0 -e v4l2src ! video/x-raw,width=3840,height=2160,format=YV12 \
    ! vaapih264enc bitrate=20000 rate-control=2 ! queue \
    ! mpegtsmux ! filesink location=file.mp4

gst-launch-1.0 -e v4l2src ! video/x-raw,width=1280,height=720 ! queue ! xvimagesink

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def luhn(cc, debug=False):
    double = True
    sum = 0
    doubled = [0, 2, 4, 6, 8, 1, 3, 5, 7, 9]
    if debug:
        print('{:15}{:15}{:15}{}'.format('digit', 'sum digit', 'sum', 'double'))
    for n in (int(c) for c in reversed(cc.replace(' ', ''))):
        value = doubled[n] if double else n
        if debug:
            print('{:<15}{:<15}{:<15}{}'.format(n, value, sum, double))

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#!/bin/bash

# Don't forget to read the SECURITY WARNING below, and then don't
# say you didn't know.

#######
## Description
#
# tl;dr -- Type `e filename` on a remote host via ssh and your local
#          emacs will open the remote file. Don't have the `e` function