BL460c G7 Blade Cannot see NC542m Mezzanine Card

This post explains how to install the mlx4 driver into ESXi 5.1 in order that it can see and communicate with the NC542m 2-port Ethernet adapter card.  The card was fairly new (at the time) and ESXi 5.1 could not see it by default. Continue reading

How to Rename the Default Raspberry Pi User

NOTE: The article below applies only to Raspian distributions published before April 2022. At that point, the default “pi” user was dropped, for sound security reasons. Subsequent releases include an alternative, and more secure, process for creating a user of your choice (detailed at the above link).

The rest of this article remains online for historical reasons only, and should no longer be used. (author, 6/7/24).

Historical Article

The Raspberry Pi comes with a default user called “pi”, whose initial password is also set to a well known default. While this makes it easy to use the system, it is not very secure. Anyone with physical access to your Pi could login with these widely known credentials. Furthermore, if you have enabled the SSH server, users on the local network could do the same.

Even if you have changed the “pi” user password, just having a user name that is universally known is still a security risk. The following article explains how to safely rename the “pi” user to something more secure.  This article was last updated on 31st May 2020 and tested with Raspbian (Raspios) Buster release 27/5/2020. Continue reading

How to Delete a Route in Red Hat 6.6

Deleting a route from the routing table in Linux should be simple. However, the syntax of the route command can be a little fussy.

I wanted to remove the first entry in the routing table shown below: Continue reading

List Virtual Machines on ESXi

ESXi is popular hypervisor product from VMware. It comes with several management GUIs including Vsphere and VCenter. Command line tools are also bundled, though they are used more rarely. This article describes a short script to list all virtual machines on the system.

The script is below. It is intended to run under the Busybox shell, the default environment when you ssh directly into the system hosting ESXi. Continue reading

Some Raspberry Pi 2 Benchmarks

This article presents a few informal benchmarks comparing the Raspberry Pi to the Raspberry Pi 2. The original Pi has a single core ARM v6 processor. The Pi 2 is quad core, ARM v7, and clocked faster than the Pi 1. But is it really six times as fast, as the makers claim ? Short answer: yes it is. And then some. Continue reading

Simple Owncloud Installation on Raspberry Pi 2

The Raspberry Pi’s low power consumption makes it well suited to the role of always-on server. This post describes how to install Owncloud onto the Pi. Owncloud is an open source software package providing remote file sharing services, similar to Dropbox. But with Owncloud, you retain ownership, security and control of the shared data. Owncloud works well on a Pi 2 and Pi 3 but will run very slowly on a Pi 1.

Update 20th November 2016 – There is a newer version of this article. Please see Simple Nextcloud Installation on Raspberry Pi. Nextcloud was forked from ownCloud in June 2016. It now seems to have become the natural successor to Owncloud. I recommend using Nextcloud rather than Owncloud. This article remains on line because it might be helpful to existing Owncloud users, particularly the parts about upgrading and using external USB media.

UPDATE 16th July 2016 – Nextcloud was forked from Owncloud in June 2016. The procedure below can be used both for Owncloud and the initial release of Nextcloud (version 9.0.52). Thanks to Dan for this information.

My Raspberry Pi 2 was purchased from RS Components in the UK. It was installed with Raspbian “Jessie” (Debian 8) by applying the image “2016-02-09-raspbian-jessie.img” downloaded from the raspberrypi.org downloads page. The following procedure was then performed without any further pre-work (other than enabling ssh in the basic setup). Continue reading

Enable Outgoing Mail on Raspberry Pi

This article explains how to send email from the Raspberry Pi. It is a generic procedure and also works on other Debian distributions. This is not for receiving mail, only for sending it. (Receiving email on the Pi is a much more involved process, requiring your Pi to perform the role of a full mail server).

The ability to send mail across the Internet is useful. It enables scripts and applications to send you email about system events or the sending data such as pictures from a webcam.

This article was updated in December 2019 and has been successfully tested on Raspbian Stretch, Jessie and Buster/Debian 10.

Continue reading

Picture Frames and Captions with ImageMagick

This article discusses some of the caption and border effects available with the ImageMagick image processing package. ImageMagick is freely available for Linux and Windows. It offers a huge number of image processing options, so many in fact, that using the program can be a little tricky.

The following examples were evolved from the ImageMagick online documentation, plus a good deal of trial and error to get the details right. I used Linux, but the same commands should work under Windows. Continue reading

Simple Picture Gallery on Raspberry Pi

The Raspberry Pi is a small Linux computer designed to help children learn programming. Being a full Linux System, it can also be used as a server or as the basis for various projects. The Pi’s low power consumption makes it particularly suited to the role of always-on web server.

This post describes how to create a simple photo gallery on the Pi, which can be shared over the internet with or without password protection. While not as polished as Flickr, Smugmug or similar services, it allows you to retain ownetship, control and security of the shared images. Continue reading