The disk “your disk” wasn’t ejected because one or more programs may be using it

This error message has come up on a number of occasions and I’m sure many people have wondered what is the best way to deal with this. This is for macOS, OSX, Macintosh operating system. For historical sake, I’m currently running High Sierra.

I have found a few main things that cause this error on my machine…

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NagiosTV for Nagios 4

Here is the first release of NagiosTV for Nagios 4.

NagiosTV is an alternate user interface (UI) for the Nagios open source monitoring system.

This UI is designed to be viewed on a TV or on your desktop to quickly see if all your services are up or down. This is not meant to be a replacement for the Nagios web interface.

This version adds Flynn, the character from the game Doom. This is just a bit of added fun to bring some emotion to server monitoring. The more services are down, the more angry Flynn gets.
When I walk into my office in the morning, I take a look over at Flynn and see if he is happy or angry. If he is angry then you can fix whatever needs fixing to make him happy again.

Included is a Node.js server which can be used to serve the NagiosTV web interface, and to optionally proxy connections to your Nagios server.

Open Source on GitHub:

Achieving high frame rate with a Raspberry Pi camera system

When you read about using Raspberry Pi cameras as part of your home security system, most of the information you will find will point you in the direction of running motion which is the de-facto standard for doing video motion detection on Linux. There are also variants of motion such as MotionEye or motionEyeOS which provide a nicer UI on top of motion.

Motion requires some horsepower to handle the video processing to detect motion, and also to run the web server and other features. On the modest hardware on the Raspberry Pi, I was only able to reliably achieve 4-10 frames-per-second at 800×600, depending on the Raspberry Pi model in use.

Using this technique below, my camera system is now able to get the full resolution for each Raspberry Pi camera which is 1920×1080 at 30 frames per second.

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Create a bootable OS X El Capitan installer

This is how to create a OS X El Capitan installer on a flash disk or external disk.

Download OS X El Capitan from the App Store. When it finishes downloading, quit the installer. The “Install OS X El Capitan” application should be in your /Applications folder. On a side note even if you do not create a bootable installer, it’s a good idea to get a backup of this installer before running it. After upgrading your system, the installer will remove itself.

Format a flash stick Mac OS Extended (Journaled) with GUID Partition Table

Name the disk “Untitled”. Simply because the command below references the disk by the “Untitled” name.

In Terminal, run:

sudo /Applications/Install\ OS\ X\ El\ –volume /Volumes/Untitled –applicationpath /Applications/Install\ OS\ X\ El\ –nointeraction