jaeddy

Building a new RStudio Server AMI

The steps below can be followed to create a new AMI for use with Amazon EC2 instances that includes the latest versions of R, RStudio, and RStudio Server. The idea is inspired by the work of Louis Aslett, who creates and hosts his own public AMIs for RStudio. My own goal was to create an AMI with RStudio v1.0.0 or higher, such that I could use the recent R Notebooks feature. However, the instructions should generally apply for whenever you might be impatient accessing the latest version of R-related software on AWS (via an interactive browser interface...).

Getting started

1. Create a new EC2 instance with the latest Ubuntu AMI (should be fine to do with Spot); based on Louis Aslett's AMI, I opted to include a general purpose SSD EBS volume with 10GB of storage space
2. SSH into the instance

Downloading/installing RStudio Server

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