Marcel Maatkamp marcelmaatkamp

Uses capped collection, tailable cursors and streams.

What's here?

init.js recreates collection capped collection 'queue' on mongodb.
writer.js spams queue with new messages
worker.js processes all messages saved to queue,
onceWorker.js processes only unprocessed messages, so you can spawn several of them and each of your messages will be processed by only one worker.

Steps

OS X Screencast to animated GIF

This gist shows how to create a GIF screencast using only free OS X tools: QuickTime, ffmpeg, and gifsicle.

Instructions

To capture the video (filesize: 19MB), using the free "QuickTime Player" application:

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

As some of you know, one of my projects is an implementation of Context Free Art in Scheme. It was a part of Abstracting and has been ported to Agave.

The only part of the task that I'd tackled was a core engine which would interpret low-level state machine instructions and a way to render the results of this interpretation. The Scheme versions of the CFDG programs were thus much longer; the flow control of the program was explicit, whereas most of this is implicit in the CFDG language.

	use warnings;
	use Getopt::Std;

	getopt('xytGgwsf',\%opts);

	# pcm file = $opts{f}

	# samples per pixel x
	$xscale = $opts{x} // 1200;

	#!/bin/sh

	########################################################################
	#
	# Usage: via-ssh.sh [-v] [-d] [USER@]SERVER[:PORT]
	#
	# -v Provide verbose output.
	# -d Send all UDP on the DNS port 53 to 127.0.0.1.
	# USER User name to use for SSH; default is current user.
	# SERVER Server to use for SSH.

	# to generate your dhparam.pem file, run in the terminal
	openssl dhparam -out /etc/nginx/ssl/dhparam.pem 2048