GRUB

If you find that grub-mkrescue -o os.ios is not working ... install xorriso

Good HTML5 video

https://www.youtube.com/watch?v=WqV5kqaFRDU

The guy talks about reading and writing files in JS.

Also - mentioned indexdb - which is the persistence solution for webapp

CORS - cross origin resource sharing
EasyXDM  - cross domain messaging  - uses iframe

Creating a bootable HD image using grub

It is nicely documented here - http://tomermargalit.wordpress.com/tag/create-grub2-bootable-image-over-loopback-device/

#!/bin/sh -x

dd if=/dev/zero of=out.img seek=8MB count=1k bs=1

outlo=`sudo losetup -f --show out.img`

parted -s ${outlo} mklabel msdos

parted  ${outlo} mkpart primary ext2 32k 100% -a minimal

parted ${outlo} set 1 boot on

partx -a ${outlo}

mke2fs ${outlo}p1

mkdir -p /mnt/out

mount -t ext2 ${outlo}p1 /mnt/out

grub-install --boot-directory=/mnt/out/boot/ --modules="ext2 part_msdos" ${outlo}

#####

umount /mnt/out

partx -d ${outlo}p1

losetup -d ${outlo}

Starting a network service on Ubuntu 14.04 at boot

I run an Ubuntu 14.04 VM on my Mac Mini with Yosemite. For some reason I cant get "bridged" network to work so I have to stick to NAT. What I needed was for the VM to start a Remote Port forwarding onto the host Mac at boot - so that I could simply use ssh to log into my VM. I needed answers to the following questions for this -


1. How do I get my networking to start at boot?
I am not sure of this I had to do this - add

auto eth0

iface eth0 inet dhcp

into /etc/network/interfaces

2. Add a cron job to ssh into my mac -

#!/bin/sh

x=`ps -Aef |grep 2222:localhost:22  | grep -v grep`

logfile="/home/kashyap/Desktop/log.txt"

if [ "$x" = "" ]

then

echo "Started the service" > $logfile

date >> $logfile 

ssh -N -i /home/kashyap/.ssh/id_rsa -R 2222:localhost:22 10.0.2.2 &

else

echo "Service already running" > $logfile

echo "$x" >> $logfile

date >> $logfile

fi                     

Sonic Pi

A nice program for Raspberry Pi- works on regular machines to -

A nice video introduction by the creator -

https://skillsmatter.com/skillscasts/5809-live-coding-in-the-classroom


Sam talks about a couple of things here -


1. Why's programming guide to Ruby - I think it is this - http://mislav.uniqpath.com/poignant-guide/book/

2. live_loop :loop_name do
   end

3. Examples in sonic pi are cool

midi in clojure

It was a pleasant surprise for me to learn that core java ships with midi support. Mix that with clojure and one can have some music up and running really quickly

(ns music.core)

(import 'javax.sound.midi.MidiSystem)

(def synth (. MidiSystem getSynthesizer))

(. synth open)

(def mc (. synth getChannels))

(def instr (. (. synth getDefaultSoundbank) getInstruments))

(def yy (. synth loadInstrument (aget instr 0)))

(defn dhun [c f] (. (aget mc c) noteOn f 40))

(defn tune [f]

  (new Thread (fn [] (loop [] (f) (recur)))))

(def beats (tune (fn [] (dhun 9 40) (Thread/sleep 500))))

(def lead (tune (fn [] (dhun 0 40) (Thread/sleep 500))))

Emacs24 on ubuntu 12.04 LTS

http://devajava.blogspot.in/2012/08/emacs-24-on-ubuntu-1204.html

To add this PPA:
$ sudo add-apt-repository ppa:cassou/emacs
$ sudo apt-get update

Then, for emacs-snapshot:
$ sudo apt-get install emacs-snapshot-el emacs-snapshot-gtk emacs-snapshot

*Or*, for emacs24:
$ sudo apt-get install emacs24 emacs24-el

Getting started with clojure on emacs

I found this link to be the most useful -
http://www.kedrovsky.com/blog/clojure-emacs-nrepl-and-leiningen

You need the following things installed -

1. leiningen - http://leiningen.org/
2. emacs - http://ftp.gnu.org/gnu/emacs/windows/

(require 'package) (add-to-list 'package-archives '("marmalade" . "http://marmalade-repo.org/packages/")) (package-initialize) (when (not package-archive-contents) (package-refresh-contents)) (defvar my-packages '(clojure-mode nrepl)) (dolist (p my-packages) (when (not (package-installed-p p)) (package-install p)))

And after that
M-x nrepl-jack-in