Rusty Eddy

Software is Hard

Fri, 22 May 2026 00:00:00 +0000

Why Is Software So Difficult?

Software development projects are one of the most notoriously mis-understood and incorrectly managed of all the common processes used throughout the business world.

There are a number of reasons for software projects being classified as a disaster so often. Software often is solving a complex problem that unfortunately can’t be seen.

Perhaps the worst problem with software projects are the diverging expectations between developers and users.

OttO the Iot Gateway

Thu, 13 Jan 2022 00:00:00 +0000

What Does OG Hub Do?

In a nutshell the Hub gathers environmental data from a network of Collection Stations using the well known MQTT Messaging protocol. The hub feeds the data to the Oraganic Gardner application, streams it real-time to dashboard users via Websockets and caches the data in RAM.

How Does the Hub Work?

The Hub is a small, fast server written in Go with the following dependencies:

Use Cases

Fri, 27 Sep 2024 00:00:00 +0000

Why Use Cases?

Before writing a single line of code, we need to understand what we are building — and more importantly, why someone would use it. Use cases give us that foundation.

A use case is a single, focused story that describes one way a user achieves a specific goal with the system. Keep them in plain language, from the user’s point of view, with no technical jargon. A good use case has a clear success condition: you can observe or measure when it worked.

Use Cases to Tasks

Thu, 26 Dec 2024 00:00:00 +0000

In Use Cases we broke Kelly’s watering system story into a first use case and derived an initial set of requirements and acceptance tests. Now we turn those into actual development work items.

Slicing Use Cases

A single use case is often too large to implement in one sprint. We slice it into thinner, independently deliverable use cases.

Starting from Use Case 1:

Use Case 1: As a gardener, I want my system to periodically measure soil moisture and turn on a water pump when the soil is dry, then turn it off when it gets wet enough.

Organizing Software Projects with Kanban

Fri, 22 May 2026 00:00:00 +0000

Kanban is a visual task management system built around one principle: make the work visible. When every task has a card and every card has a status, anyone who looks at the board knows exactly where the project stands.

The mechanics are intentionally minimal. A board has three columns — Todo, In Progress, and Done. Cards representing tasks move left to right as work advances. That is the entire system. Its power comes from discipline in how tasks are written and how the board is maintained, not from the tool itself.

Version Control Systems

Fri, 22 May 2026 00:00:00 +0000

The first sign of an undisciplined software project is source code managed as a folder of files, with copies passed around by email or shared drives. The inevitable question — which copy has your changes? — is a symptom of a deeper problem: there is no authoritative record of what the software is, what changed, or why.

A version control system solves this. Every change is recorded with who made it, when, and a description of why. The full history of the project lives in the repository, reproducible at any point in time.

Collection Station

Thu, 13 Jan 2022 00:00:00 +0000

Publishing Sensor Data

The idea is pretty simple really: build a network of wireless battery powered devices to gather environmental data such as temprature, moisture, light levels, etc. The collected data will then be published via MQTT wirelessly to the Hub.

Types of Published Data

The planned data types to be published by the system are concerned with the following types of sensors.

Temprature
Humidity
Moisture
Light
Barometric Pressure

Technically any type of data could be published and collected however we are focused on the type of data our OG application will use. Data will be transmitted as either integer or floating point, depending on the sensor and how it collects the data.

Test Driven Software Development

Fri, 22 May 2026 00:00:00 +0000

Testing Unit and Systems

Before any developers new code can be integrated into the mainline production code base, it must be tested, vetted and peer reviewed.

Software Testing has been written about extensively, so I won’t spend time here discussing testing directly, as there are as many ways to test software as there are technologies.

Test Driven Development

Test Driven Development (TDD) is a principle that earns nearly universal agreement in theory and frequent compromise in practice. The discipline of writing tests first is harder than it sounds — not technically, but because it forces you to define precisely what you are building before you start. That clarity is exactly why it is worth the effort.

Peer Reviews

Thu, 21 May 2026 00:00:00 +0000

A peer review is the process of having one or more knowledgeable colleagues examine your code before it merges into the main branch. It is one of the highest-leverage practices in software development: bugs found in review cost a fraction of what they cost after shipping.

Beyond bug catching, review serves two other purposes that are easy to overlook. It spreads knowledge — the reviewer learns what changed and why, reducing the bus-factor on any given piece of the codebase. And it enforces consistency, keeping the code readable to everyone on the team, not just the person who wrote it.

Wireframes and Storyboards

Thu, 21 May 2026 00:00:00 +0000

Use cases define what users need. Wireframes and storyboards show how they will interact with it. Done before any code is written, they are among the cheapest ways to discover what you got wrong.

Storyboards

A storyboard is a sequence of rough sketches — one frame per step in a use case — that walks a user through the experience of using the system. Think of it as a comic strip version of your use case.

Release Process

Thu, 21 May 2026 00:00:00 +0000

A release is the moment development work becomes user value. Everything up to this point — use cases, tests, peer review — has been preparation. The release process is what determines whether that preparation pays off cleanly or turns into a crisis.

The goal is to make releases boring. A release that requires careful coordination, manual steps, and nervous engineers is a process waiting to fail. A release that is fully automated and runs dozens of times a week is one nobody worries about.

Panasonic Avionics

Fri, 15 Dec 2023 00:00:00 +0000

Sugo Music Dashboard

Wed, 27 Jan 2021 00:00:00 +0000

Sugo Music is an online Music publishing platform for Artists by artists. It was my responsibility to manage the software process, build and test the backend and manage the front-end development in React.

Go, React, REST API, HTTP, HTML, JavaScript, Webapp, fullstack

University of Southern California ~ MSCS

Tue, 02 Jan 1996 00:00:00 +0000

Sahara Networks

Wed, 27 Jan 2021 00:00:00 +0000

Sahara Networks is building something truley unique, connecting micro-controllers and IoT devics across the network allowing virtual circuits to be created. I help design, develop and lead the design and implementation of the network protocol that delivers high speed digital I/O signals across a “device network”.

Backend, C/C++, nodejs, TCP/IP and Raspberry Pi

Radian Laser

Mon, 01 Jul 2019 00:00:00 +0000

Radian is a small, fast moving startup that sells Laser Engravers and Cutters. I manage five software projects, including two Web Applications for the control and calibration of the Laser system. I am also responsible for the successful delivery and maintanance of the products Firmaware and Fleet Management system.

C/C++, Go & Python, embedded systems and microservices.

Cloud Trek

Sat, 01 Apr 2017 00:00:00 +0000

Alchemy Networks is an indepently owned service provider. I automated the provisioning of their Private Cloud Service offering. I was an individual contributor on this project. I collaborated with another developer.

Ansible, Linux, Python, Websockets, Networking

DirecTV / AT&T

Thu, 01 Dec 2016 00:00:00 +0000

I was hired by DirecTV (and subsequently AT&T) to help lead the new Software Defined Networking (SDN) team. We were tasked with replacing the companies aging production Video Distribution Network with a new modernized design. Project goals included:

Replace aged network with modern SDN solution
Solution to incrementally replace existing production network
Development would build on industry standard OpenSource solutions
Had to be Reliable and Scalable
Linux, OpenFlow, Java and Python

Sierra Hydrographics

Sat, 02 Jan 2010 00:00:00 +0000

Led the design and development of automated data collection for hydrological gauging stations. Data is gathered by pulling data from line of sight telemetry radios and NOAA/LRGS satellite ground stations. Data is fed to timeseries server for hydrological calculations and alert monitoring.

Timeseries database, C/C++, PHP, Python and Java.

Green Hills Software

Thu, 02 Jan 2020 00:00:00 +0000

I worked on a small team that added multicast forwarding to the Integrity RTOS kernal. Modified multicast routing daemon to run on same operating system allowing the product to serve as the foundation for a military grade network switch/router. Added IPv6 Neighbor Discovery to the suite of routing protocols.

C/C++ and Network Routing Protocols; Real Time OS.

The IMS Company

Fri, 21 Sep 2018 00:00:00 +0000

Led a project to replicate entertainment media (music, video and games) from a single media source to hundreds of inflight entertainment units with minimal redundancy. Contributed to the design and development of an inflight entertainment server.

Perl, Python, C/C++ and Java

Cisco Systems

Wed, 01 Feb 2006 00:00:00 +0000

Original member of the Multicast Routing team. Team of 12 responsible for the design, implementation and testing the complete suite of Multicast Routing protocols for the Cisco Carrier Routing System (CRS). Worked this project from early design through product launch into maintenance.

Computer Networks, Multicast Routing, C/C++, Real Time, Distributed Systems

California State University, Long Beach

Tue, 02 Jan 1996 00:00:00 +0000

USC ~ ISI

Thu, 20 Sep 2018 00:00:00 +0000

Led the effort to add IGMP/PIM and Multicast Routing Information Base (MRIB) to the Open Source GateD suite of routing protocols. Mentored graduate students and others that would eventually become prominent members of the computer networking community.

Retix

Tue, 01 Aug 1995 00:00:00 +0000

Promoted to lead the team of 6 engineers that developed and automated test plans for L2 switches, OSPF, RIP and BGP

Implemented an automated test framework and led junior engineers in developing the automated test suites. C; C++; Perl; TCL
Provided 3rd level customer support, serious customer problems that could not be resolved by customer support or field engineers became my teams responsibility to diagnose and determine solutions and workarounds was required.

Rockwell, Intl. Space Systems Division

Mon, 03 Jan 1994 00:00:00 +0000

Led a team of 5 Sysadmins responsible for the use and well being of Engineering Departments 300+ UNIX workstations, servers (Sun, HP, DEC) and network.

On a team that Developed a Real Time OS that was embedded in a variety of space and military projects.

California State University ~ Chancelors Office

Tue, 01 Aug 1995 00:00:00 +0000

I was hired to install and manage the departments first AT&T Unix Mini-computers, UUNET connection and write a bulletin board system for California State Educators.

Exposing a Go App as Claude MCP Tools

Fri, 22 May 2026 00:00:00 +0000

The Model Context Protocol (MCP) lets Claude call external tools defined by your application. Instead of pasting data into a chat window or writing one-off scripts to query your system, you define tools with typed schemas, start an MCP server, and Claude can call them directly — in Claude Code, Claude Desktop, or any MCP-compatible client.

The Trader project uses this to expose its Forex trading engine as Claude tools: query your OANDA account, review open trades, run a backtest against historical data, and — when explicitly enabled — place or close orders.

Numeric Types in Financial Software

Fri, 22 May 2026 00:00:00 +0000

Financial software has one rule about numeric types that is not negotiable: never use floating-point for prices or money.

This is not a performance concern or a style preference. It is a correctness requirement. Floats introduce errors that accumulate across calculations, and in financial software those errors translate to real discrepancies — in reported balances, in risk calculations, in trade fills. Understanding why, and what to use instead, is table stakes for anyone writing systems that touch money.

The Strategy Pattern in a Backtesting Engine

Fri, 22 May 2026 00:00:00 +0000

A backtesting engine and a live trading engine solve the same problem: given market data, decide what to do, then do it. The data source changes (history versus a live feed), the broker changes (a simulator versus a real exchange), but the decision logic — the strategy — should not change at all.

This is not obvious when you first build one of these systems. The natural instinct is to write the strategy and the execution engine together, letting the strategy reach directly into the data feed or the broker. That works for a prototype. It makes testing hard, live deployment risky, and strategy comparison unreliable because each strategy is tested against a slightly different engine.

IoT System Architecture Explained: The 5 Essential Layers (and How Otto Supports Them)

Sat, 15 Nov 2025 00:00:00 +0000

A complete, SEO-optimized guide to IoT system architecture. Discover what every IoT product needs—from sensors and protocols to gateways, cloud control planes, and applications—and how Otto ties it all together.

Building an IoT Device Manager in Go - Generics, Interfaces and Concurrency

Sun, 02 Nov 2025 00:00:00 +0000

Introduction

Managing IoT devices becomes exponentially more complex as your network grows. You end up juggling a mix of sensors, actuators, and communication buses each with its own quirks and challenges.

In the OttO Project and companion Devices library, I attempted to develop a mini framework that would have a clear separation of concerns between the hardware layer (GPIO, I2C, serial, ADC, PWN, UART, etc.) and the application layer (messaging, control logic, logging, deployment, etc).

Soil Mosture Sensors Adafruit

Wed, 13 Mar 2024 00:00:00 +0000

Why the Adafruit version?

«««< HEAD I have had a hard time with the general Capacitive Soil Moisture sensors that you find readily on the Internet as described in this article about soil moisture sensors. In a nutshell, the ones I bought had the wrong timer chip in them, not that was a total show stopper but I also had problems getting them to work with the esp32 ADC (Analog Digical Converter).

Soil Mosture Sensors

Thu, 15 Feb 2024 00:00:00 +0000

Overview

Seems like I’m not as uniquely clever as I once thought, the idea of creating a self watering garden is probably one of the more popular DIY maker projects on the Internet it seems.

Check out my version of the Self Watering Garden

What makes my project different? Probably not alot, however in this project we treat each of the watering stations as a part of a larger, complete system of the watering stations that can be observed and controlled by a single hub and associated web application. Check out the project, I’d love to hear what you think!

Raspberry Pi Pico Setup

Tue, 13 Feb 2024 00:00:00 +0000

IoT System Architecture (Device to Cloud)

Fri, 13 Jan 2023 00:00:00 +0000

IoT System Architecture (Device to Cloud)

This page provides a diagram-first overview of the IoT architecture used throughout the projects on this site.

The goal is not to present a single “correct” design, but to show a reasonable baseline architecture that scales beyond demos and remains flexible as requirements change.

If you want implementation details, those are covered in linked articles. This page focuses on structure, boundaries, and tradeoffs.

High-Level System Overview

At a high level, the system looks like this:

How to Build a Self Watering Garden

Wed, 25 May 2022 00:00:00 +0000

Why Build this Thing

The typical small irrigation systems today are based on time schedules, where sections of the garden (zones) are watered based on days of the week, a start time and a duration. In otherwords, your garden is watered according to a set schedule regardless of environmental changes.

In reality, the amount of water should be increased during long hot dry days and decreased as the days shorten and get colder. For example, if it rains you probably need to turn your sprinklers completely off and remember to turn them on again when it stops raining.

Using Go timers for MQTT testing

Mon, 02 May 2022 00:00:00 +0000

This article uses a Go timer and the Go select statement to test our MQTT publish and subscribe in a single simple test statement. A quick note on the go testing package: it is much like the JUnit where tests using a particular naming convention TestXXX(t *testing.T) {} will be run automatically with easy to reports having been generated.

The Problem

The following code snippet is directly from the IoTe edge gateway project. One of the primary features of IoTe is the ability to send and receive MQTT messages.

Adding the REST API to IoT Gateway

Wed, 30 Mar 2022 00:00:00 +0000

Previously we have added MQTT to the IoT Gateway as part of the Organic Gardner Project. This gave the gateway the ability to collect and store a lot of environmental data from sensors all over the place.

Now we need to provide a way for others programs, like the IoT Dashboard access that data via a REST API.

Implementing a RESTful API

The RESTful API convention is exteremely popular, well supported and is perfectly suited to providing access to the sensor data that has been collected. REST is ubiquitous these days, most people involved in frontend or backend development most likely have quite a bit of experience with REST.

Adding MQTT to the IoT Gateway

Tue, 29 Mar 2022 00:00:00 +0000

This page marks the beginning of the Organic Gardner (OG) IoT Project Milestone 1 development! If you want to program along but have not yet worked with the Go programming language check this intro: Getting ready to Go.

A Brief About MQTT

MQTT is the messaging protocol that a Collector will use to periodically publish sensor data (like temperature and humidity) to the IoT Gateway. MQTT will also be used to signal when the Control Station or Controller will respond to commands to turn a sprinkler pump on or off.

How to build a private WIFI network for your WebApp

Thu, 22 Jul 2021 00:00:00 +0000

I work with physical computing or devices that have rather sophisticated software that needs to be configured, monitored and controlled.

Building a Private Wifi

Here is the situation, I just plugged a white box into the wall and it has a steady green light. I can see two other lights, one of which is red. The other two lights are off.

This device is pretty cool, it will control the lights in my garage, I have a well lit garage. But I need to configure this thing to set up lighting schedules, basically synchronize with daylight.

A Simple Go Configuration

Fri, 26 Mar 2021 00:00:00 +0000

I use this same configuration structure and supporting functions in most every Go program I work on. It is pretty simple but makes it easy to keep global variables orgranized and configurable.

Here is what I do:

Create a type config struct
Every configurable variable for the program becomes a Member field of the Configuration structure.
Register every field of the Configuration Structure with go’s builtin flags package such that the flags are parsed when the program starts we can use our configuration variable.

WPE an Excellerated Raspberry Pi Kiosk

Fri, 25 Dec 2020 00:00:00 +0000

The WPE project allows you to create a hardware accelerated web viewing_ experience with an embedded system and inexpenive display.

For example a Raspberry Pi with an 7inch tftp touch screen has my brain racing with ideas for applications.

About WPE

WPE creates a cool hardware accelerated kiosk, just point at a URL and the app displays the application takes over the screen.

It is awesome! But, it has one major drawback.!.

Golang timers to remove stale sensor stations

Tue, 03 Nov 2020 00:00:00 +0000

This articles introduces Go (Golang) Timers as the mechanism the the IoTa gateway uses to identify stale IoT stations. Modifying the Station with with a new Go timestamp field will allow IoTe to determine how long it has been since the last time it has heard from a given Station.

If the last refresh time for a particular station has been longer than the timeout period the Station will be marked as stale.

Proof of Concept vs. Production

Sat, 11 Apr 2020 00:00:00 +0000

A POC is taking a conceptAnd demonstrating that it can actually be done in hardware and/or software. And implementation is takingApproving POC And turning it into something usable To somebody other than the developer.

Embrace this fact, And projecting software Development times and cost Become much less mysterious.

Was it Rodney Brooks that Said Plan on Throwing away your first version. Because you will anyway.

I Believe the motive behind this was simplyThe fact that Software development takes on to very different Trajectories Depending on whether you are buildingA known entity, Or are exploringA new development or concept.

Get Ready to Go

Wed, 01 Apr 2020 00:00:00 +0000

Get Ready To Go

The IoT Gateway was written in the Go programming language. I won’t get into the reasons why Go is an excellent choice of programming language for this project other than to point out two advantages this project will benefit from right away:

Go is Compiled and easy to distribute

First, Go is a compiled language making the resulting executable self contained with no external libraries or run time environment to rebuild, just copy a single binary, that is it.

Paradise Aint Perfect

Mon, 03 Feb 2020 00:00:00 +0000

Paradise Ain’t Perfect

Or maybe there is so much conflict that Hawaii doesn’t look like it is really everybodies paradise.

The point to all of this, a little bit of drilling down to all of the passangers, the captiain and crew as well as the owner of the boat would have all had better results.

If it was discovered before hand, that “Going to Hawaii”, really consisted of two groups: one going to Maui and one going to Kaui.

Career Summary

Thu, 02 Jan 2020 00:00:00 +0000

I am a Software Engineer and Contract Programmer living in Huntington Beach, CA with my family. I build micro-services and work on micro-controllers, usually with Go, C/C++, Python and JavaScript (among other techs).

Skills and Interests

Thu, 02 Jan 2020 00:00:00 +0000

Go, C/C++, Python and JavaScript (and many others..)
Computer Networks, Multicast Video Distribution
Distributed systems and realtime communications
DevOps, cloud automation and continuous delivery
Fullstack software development, reactive front-ends with VueJS
MicroServices: REST APIs, Websockets, etc.
Linux Systems and OpenSource Software

Using Vue to Develop Webapps

Wed, 25 Dec 2019 00:00:00 +0000

Every piece of software that exists has to speak to the external world in some manner. It might be programattically through messaging or an API call. It could be a human clicking through an GUI on our laptop or phone.

I think it is clear that web apps are taking over the world. It is a powerful notion that they can pretty much run on any computing devices that support a browser, which is almost everything with a screen.

Bootstrap makes WebUI look great!

Fri, 20 Dec 2019 00:00:00 +0000

Bootstrap is a great way to get your ugly little fledgling website into something respectable in no time. Do not waste time futzing with silly formating directives, focuse on the site itself!

Software is Iterative

Wed, 23 Oct 2019 00:00:00 +0000

Good Software is Continually Improved

The greater the success software Is directly proportionate to The number of features that are requested As well as the number of bugs that are found.

Bug reports means your softwar is getting used.!.

That is obvious if people are happy using a software That they might have some requests that would flow in from time to time.

What might seem counterintuitive is the fact that, Even well done successful software will have bugs. Period. Good teams understand and embrace that… The Bugs will be fixed And the customers will be even happier

Why Choose the Go programming Language for your Project?

Sun, 22 Sep 2019 00:00:00 +0000

Go is simple

Go is easy to learn to program with and it is free! Go is much easier to maintain and deploy than Java.

Go does not have weird virtual environments of Python or npm, gulp, grunt, yarn, webpack (what’s next?) convuluted and complex build environments.

Go is Fast

It smokes most other languages, except the grand mother of Unix programming C. The Go programming language is almost as fast (performant geeky folks like to say) as C.

Red Eye Video Server

Fri, 24 May 2019 00:00:00 +0000

The Red Eye project is a service definition rapper around inexpensive cameras attached to inexpesive micro-controllers that take pretty good video.

The video streams are built using the GStreamer library. The camera native capabilities are used to extract as high quailty, realtime images possible.

The video streams will be consumed by one or more sinks, including but not limited to Files, cloud storage, High Def Display and Computer Vision libraries.

Skid Steering

Wed, 15 May 2019 00:00:00 +0000

Skid steering basics

Based on fixed direction wheels[1] or tracks
There are two groups or sides of wheels: left and right
All wheels in a group MUST always point in the same direction
All wheels in a group MUST always rotate at the same rate
Direction is determined by the speed of the two wheel groups
- To move straight all motors rotate at the same rate
- Forward and Reverse are determined by positive and negative values
- Turning is achieved by varying the throttle on the right and left

Example

The Skidder class has the following API, as you can see all of the movements we desire can be accomplished with a single API call skidder.set_throttle(left_throttle, right_throttle), does not get much simpler than this!

Raspberry Pi Motor Control Software

Tue, 14 May 2019 00:00:00 +0000

This software adds a Skid Steer motor control software to the Raspberry Pi Device Server device server. RPID adds motor controls accessible via both MQTT and REST APIs, as well as directly with the Skidder python library.

MQTT For Controllor Communication

Fri, 03 May 2019 00:00:00 +0000

The MQTT message bus is a simple but critical element of our MBR software design. MQTT provides what is known as a publish/suscribe or pubsub communications model. This model of machine to machine communication has some attractive benefits for realtime driving algorithms that we will discuss in this post.

Streaming Video is Complicated

Mon, 29 Apr 2019 00:00:00 +0000

I need to stream live video from a moving vehical with a connected camera and a possibly connected wifi.

Live High Resolution Video

Video will stream from the vehicle to be picked up by video consumers and processed as required. Examples of consumers are Live Video Display on our (Webapp), OpenCV for vision algoritms.

High Demand For Low Resolution

It turns out that computer vision alogrithms typically run quite a bit faster on lower resolution images, the additional information from these hi-res images can slow down the type of algorithms we are interested in by many factors.

The ESP32

Thu, 25 Apr 2019 00:00:00 +0000

You need to push the RESET button to get them to write flash.

A power packed chip that I have just started playing with. Give some quick specs here: and compare with other well known options (arduino’s, stm32 or Raspberry Pi.

Standout Features

Builtin Wifi & BT and others
Dual Core
Powerful esp-idf
FreeRTOS (Arduino optional)
Great Feature Set!

Usage

Interactive Console over UART

This demonstrates using the serial port for an interactive console while ESP is running other things. During this console session we can do a number of things including:

Streaming Video Tools

Tue, 23 Apr 2019 00:00:00 +0000

The grandparents of streaming video, and snapshots, read, writing and transcoding video and single frame images are ffmpeg, vlc and gstreamer.

Other platforms, such as the wildly cool and inexpensive Raspberry Pi and attached CSI Camera (Raspberry Pi Camera) have thier own set of utilities: like raspivid. Or the NVidia Nano with it’s gst-streamer plugins and nvgst-capture/nvgst-playback utilies.

These notes were originally written in March 2019

GStreamer Complex, Flexible, Future Proof

GStreamer really complex pipelines but insanely flexible.

Control Station Display

Mon, 22 Apr 2019 00:00:00 +0000

We are going to build a simple control station that begins with a Raspberry Pi and connected 7 inch touchscreen tablet. I have it setup in “kiosk mode”, which is basically full page chrome without the tabs and tool bars etc.

TLV the Type Length Vector Protocol

Wed, 17 Apr 2019 00:00:00 +0000

TLV is a very simple communication protocol that can be used to send messages around a complex, distributed system.

Sync vs. Async, Blocking vs. Non-blocking

Sun, 03 Mar 2019 00:00:00 +0000

Synchronous vs. Asynchronous

Blocking and Non-Blocking

A pratical example of asynchronous is a “blocking” call vs. non-blocking call. For example you are going to call a web service to gather a lot of data, it will take a long time. You can:

Make a blocking call (synchronous) that pauses (blocks) the program from doing anything else until you receive a reply (or error).
Make a non-blocking (asynchronous) call that requests the data from the remote server, after sending the request the program continues to run even though the response from the server has not yet been returned.

Streaming Live Video on a Local Lan Vs. Internet

Sun, 23 Dec 2018 00:00:00 +0000

differences in local vs. internet and streaming video
live stream vs. video on demand
what does real time mean?
what to do with late packets?
UDP vs. TCP in the local network
RTP and UDP
RTP and RTCP
RTP and RTSP
RTP and Multicast
Tools used

RTSP is a good option for streaming video in a local setup up, where minimal delay is the highest priority. However, RTSP does not typically do very well over the Internet due to the nature of RTP/UDP.

website

Tue, 04 Dec 2018 00:00:00 +0000

Websites

According to the W3.org (official web people), modern websites may consist of, i.e. modern browsers must support 3 things:

HTML for basic website structure and other things
CSS for style
JavaScript for all things dynamic.

The most basic of all websites is a single text file containing some content wrapped in some HTML markup. For example here is a working, but incomplete example of HTML snippet attempting to display a level 1 header with the words Hello, world!.:

Publications

Fri, 21 Sep 2018 00:00:00 +0000

Ramesh Govindan, et el. “An Architecture for Stable, Analyzable Internet Routing”, IEEE Network Magazine, Jan-Feb 1999.

Rusty Eddy, Ramesh Govindan, “Testing Protocol Implementations with pkt”, Networld+Interop 99 Engineers Conference Proceedings, June 1999

Rusty Eddy, “Emulating Multicast Routing Protocols in a Software Defined Networking (SDN) Controller”, AT&T 2016 Software Symposium

Rusty Eddy, “Testing Multicast SDN Networks in a Container”, AT&T 2016 Software Symposium

Inexpensive Motor Controllers for Arduino and Raspberry Pi

Wed, 22 Aug 2018 00:00:00 +0000

I prefer to use an Arduino with a Motor Controller over say a Raspberry Pi with a motor-controller. I believe the Arudino has better support for dedicated Real-time software vs. the Raspberry Pi and as a superior platform for general computing including running Control Software. This is how we do it on the West side …

Control System Design

Sat, 05 May 2018 00:00:00 +0000

Early in the process of building the first set of mobile robots I discovered that I was not going to settle on a single micro controller.

The first two obvious choices being the Arduino or Raspberry Pi, for which I tried both with a modest level of success. I quickly realized that I would not be providing my sole focus on either platform, neither was sufficient for my grand plans for a number of reasons.

Comparing the Arduino and Raspberry Pi

Wed, 14 Mar 2018 00:00:00 +0000

Arduino vs. Raspberry Pi in Control Systems

I believe the Arudino has better hardware support, a real-time clock and due to itself simplicity creates a better platform to interact with external hardware in real-time.

The Raspberry Pi, however has a much more powerful set of processors, more memory and a general purpose operating system making it a more suitable choice for general purpose, sophisticated software, such as communicaitons and control software.

IP Multicast the basics

Sat, 03 Feb 2018 00:00:00 +0000

IP Multicast addresses

The typical IP addresses used by computers networking today are known as unicast addresses, meaning that every unicast address as a single (physical or logical) end point.

Most all computer networking is point to point between two specific IP addresses, you name it: web browsing, email exchange, transfer files and so much more.

However, there are other more specific forms on communication available and occasionally used: Broadcast and Multicast.