Niall McMahon

Search by DuckDuckGo

The Social Network of Wind Energy

2023-03-13

Wind is a key component of our present and future energy supply. Different stories about the technology are told for different reasons.

This draft essay is the basis of a lecture I was scheduled to deliver as part of the MSc in Consumer Psychology at NUIG on March 13th. My own position is, of course, pro-wind.

Read the full post

The Social Experience of the Internet

2023-02-20

In 2023, the internet is shaped by the companies that dominate it, the stories that they tell. Let's tell new stories, to create a better internet built for people.

This is a draft edit of a part of a couple of lectures I put together about the social experience of the internet. It's a complicated thing and not all the fault of corporations. State spying, misinformation and propaganda play their part. Politics also, and crime, of course. At the bottom, maybe self-interest, inequality and greed are behind all of these. As with other problems facing humanity, cf. climate and energy.

Read the full post

History of Computing

2022-09-29

A slightly hit-and-miss collection of links.

There are many super books on this topic. Andrew S. Tanenbaum lists a few - which I haven't read - in his book, Structured Computer Organization, in Section 1.2, Milestones in Computer Architecture.

Pre-1900s

Early Twentieth Century Computing

NASA and Computing

Minicomputers

Unix, C and Unix-like Systems

Universities and Research Institutes

(Selected.)

USA, West Coast

USA, East Coast

UK

Chip Manufacturers

USA

Elsewhere

Personal Computing

Altair

Atari

IBM

Microsoft

Apple

Sinclair

Commodore

Dell

The Internet

Companies

Read the full post

Getting Started with Netflow

2022-07-21

Some notes about getting started with Cisco Netflow.

Netflow

Overview

NetFlow is a feature that was introduced on Cisco routers in the mid-1990s.

Routers and switches that are Netflow enabled can collect IP traffic statistics about interfaces. This Netflow data is forwarded as soon as its generated to a Netflow collector, usually a server running analysis code.

Version 5 is supported across the Cisco router range. In addition, Version 5 uses bandwidth the most efficiently of all Netflow versions.

Flows

A flow is a sequence of similar network packets all going in the same direction. Packets in a flow are similar in that the values for seven important packet descriptors are the same. The seven descriptors make up a tuple - a list of the seven descriptors - that identifies the flow.

The seven descriptors are: (i) the ingress interface, i.e. the SNMP ifIndex, (ii) the source IP address, (iii) the destination IP address, (iv) the IP protocol, (v) the source port for UDP or TCP, or 0 for other protocols, (vi) the destination port for UDP or TCP. Type and code for ICMP and 0 for other protocols, (vii) the IP Type of Service. This is the second byte of the IPV4 header.

IBM has detail on the Version 5 data formats.

Packet Tracer

Cisco's free Packet Tracer software allows you to create a simulated network and to experiment with configuring infrastructure devices (routers, switches etc.) for Netflow logging. You can learn how to set up a Netflow generator that will export Netflow to a collector. This is super.

There are limitations:

Still, Packet Tracer allows you to understand how to set up a network and to get a Netflow collection system working.

Netflow Generator

Netflow Collector

Datasets

Netflow datasets for testing:

References

Read the full post

App Deployment

2022-06-01

Some draft notes for multi-tenant app development and deployment using PostgreSQL, Node.js and Express or Apache.

Be sure to check the latest version of the appropriate documentation if things go wrong - these notes were made using some now out-of-date versions of software.

Read the full post

Dispatch Down is a Problem for Ireland

2021-02-20

Notes about dispatch down in Ireland. Dispatch down means removing a power generator from the grid for good reasons.

Read the full post

Starting in Small Wind

2012-07

Some recommended reading. Updated 2022. Since this note was originally put together, the small wind industry suffered a major reversal and many companies no longer exist.

Begin with Paul Gipe's Wind Works. Paul Gipe, a respected wind worker, journalist and writer, has several good published titles. If you are looking for an introduction to small wind, his Wind Energy Basics will be a sound first investment. (Wind Works has been down for a while now, unfortunately. As of November 2022, Paul Gipe is in the process of rebuilding it.)

Read the full post

See list of posts