sticilface

Guide to PROGMEM on ESP8266 and Arduino IDE

Intro

On low memory devices like the arduino and esp8266 you do not want strings to be stored in RAM. This occurs by default on these systems. Declare a string const char * xyz = "this is a string" and it will use up RAM.

The solution on these devices is to allow strings to be stored in read only memory, in Arduino this is the PROGMEM macro. Most of my experience is with the ESP8266 which is a 32bit micros controller. This device stores PROGMEM data in flash. The macro PROGMEM on ESP8266 is simply

#define PROGMEM   ICACHE_RODATA_ATTR

mlconnor

Session Management in an Autoscaling Environment

Problem Statement

User sessions in J2EE and LAMP stacks have traditionally been handled in memory by the application server handling the user request. Because of that, load balancers have been configured to use sticky sessions. By sticky sessions we mean that once the user has visited the site, they will be assigned an app server and will return to that server for subsequent requests. The load balancers typically handle that by referencing the users session cookie.

Elastic cloud environments differ from traditional server configurations in that they have a variable number of servers based on traffic loads whereas traditional configurations had a fixed number of servers. When traffic volumes decline it is necessary to vaporize servers. In doing so, we would lose user sessions (essentially forcing a logout) unless we come up with a new strategy for session management.

A new approach

After much research, it is clear that the best

teslamint

#!/bin/bash
 
# Pass the firmware image file to be flashed as the first and only
# command line argument.
#
# The second curl call will time out, but it is expected. Once the
# script exits, you can unplug the ethernet cable and proceed to the
# next router, but do KEEP each router ON POWER until the new image is
# fully written! When flashing is done the router reboots
# automatically (as shown by all the leds flashing once).

travelton

<?php

require 'vendor/autoload.php';
use Mailgun\Mailgun;
use Sabre\VObject;

// Instantiate the Mailgun Client
$mg = new Mailgun("MG-API-KEY");
$domain = "Your Domain";