Category Archives: Uncategorized

VMware Disconnection Caused by Network Manager Connectivity Check

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A Windows virtual machine running under VMware 17 Pro was freezing several times a day, seemingly due to a brief network outage. The cause was found to be a Network Manager setting on the host computer, a laptop running Linux Mint 21.2. As explained below, the fix was to disable connectivity checking in the NM configuration, which is on by default, while noting the side effect of disabling captive portals.

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Install and Optimize Linux Mint 21

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This article is about installing and optimizing Linux Mint. The focus is on Mint 21, but it’s relevant to all versions. The best disk layout is discussed at the end of the article.

Install vs Update

If Mint is already installed on your system, then updating to the latest version is an option. I would recommend updating between minor versions, but for major versions, a fresh install is better.

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USB Disk Errors on Mint 19 VMware Guest

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Connecting a physical USB device to a virtual machine is sometimes tricky. Virtual machines are not really designed for physical interaction. In this case, it was necessary to mount a 1 TB external USB disk to a VMware virtual machine running Linux Mint 19.3. USB errors were seen and the disk would not connect. The fix was very simple.

Connecting the Disk

A USB disk was connected to a Linux laptop running VMware Workstation 15.5.1, and hosting a Linux Min 19.3 guest. When the connection “button” (at the bottom right of the VMware window) was pressed, these errors appeared in the guest’s kernel log:

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Bash Script Behaves Differently When Called From Cron

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Unix users and administrators will be familiar with the cron, unix’s built in job scheduler. It is a good way of running regular jobs eg backups, system monitoring programs or housekeeping scripts. The configuration of cron is quite particular and care is needed when setting up a new job. Your well tested script can behave differently when it is called from cron. Sometimes the differences won’t matter. But sometimes they do, and finding the cause can be tricky.

This brief article describes how many such problems can be tracked down simply by capturing the standard error output properly. In short, make sure your troublesome cron job is not quietly discarding the very information you need to fix it. Continue reading →

How to Convert a Website from HTTP to HTTPS

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An http website is not encrypted. That is to say, the data comprising the site is not encrypted as it flows from the web server to the device (pc, phone, tablet) on which the user is viewing the page. Anyone able to “listen in” on the network could read that data, which is a security risk. An https web site is different. Data is encrypted. The web server encrypts each web page before transmission, and the user’s browser decrypts it, providing end-to-end protection from eavesdropping.

This article explains how to convert an existing basic website to https by obtaining a free digital certificate from Let’s Encrypt. It is based on a Raspberry Pi running the “Apache” web server, but will also work on other Linux systems. It is intended for home users and people running small-scale web sites, and as a learning aid. Continue reading →