Tag: MacOS

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Installing OpenJDK 11 on MacOS

If you download the .tar.gz for OpenJDK 11 direct from http://jdk.java.net/11/, there’s no obvious install instructions (at least that I can find) either on the OpenJDK website on in the .gz file. If you’ve done any fiddling with different JDK versions on MacOS before, you’ve probably come across the ‘/usr/libexec/java_home’ utility (see here for my previous article about this utility, and answers to this StackOverflow post which includes one of the most extensive and useful guides to running different JDK versions on MacOS that I’ve seen) which does a number of useful things relating to which JDK you’re currently using in your PATH:

/usr/libexec/java_home : shows you were the current JDK home is, eg:

/Library/Java/JavaVirtualMachines/jdk-10.jdk/Contents/Home

/usr/libexec/java_home -V : lists all installed JDKs, e.g.:

$ /usr/libexec/java_home -V
Matching Java Virtual Machines (2):
    10, x86_64:    "Java SE 10"    /Library/Java/JavaVirtualMachines/jdk-10.jdk/Contents/Home
    1.8.0_151, x86_64:    "Java SE 8" /Library/Java/JavaVirtualMachines/jdk1.8.0_151.jdk/Contents/Home

To switch between JDKs, use /usr/libexec/java_home -v version (e.g. 10):

$ /usr/libexec/java_home -v 1.8.0_151
/Library/Java/JavaVirtualMachines/jdk1.8.0_151.jdk/Contents/Home

Knowing that your available JDKs are installed to /Library/Java/JavaVirtualMachines/ by default, moving the contents of the downloaded OpenJDK 11 dir from inside the .gz file to the same location would make sense.

Once you’ve moved it there, java_home -V now shows the new JDK in place:

$ /usr/libexec/java_home -V
Matching Java Virtual Machines (3):
    11, x86_64:    "OpenJDK 11"    /Library/Java/JavaVirtualMachines/jdk-11.jdk/Contents/Home
    10, x86_64:    "Java SE 10"    /Library/Java/JavaVirtualMachines/jdk-10.jdk/Contents/Home
    1.8.0_151, x86_64:    "Java SE 8" /Library/Java/JavaVirtualMachines/jdk1.8.0_151.jdk/Contents/Home

Updating my aliases to quickly switch versions in my .bash_profile, I now have:

alias j11="export JAVA_HOME='/usr/libexec/java_home -v 11'; java -version"
alias j10="export JAVA_HOME=`/usr/libexec/java_home -v 10`; java -version"
alias j8="export JAVA_HOME=`/usr/libexec/java_home -v 1.8`; java -version"

Sourcing the .bash_profile (source .bash_profile) and then running each alias, now I’ve got OpenJDK 11 set up and ready to go!

$ j11
openjdk version "11" 2018-09-25
OpenJDK Runtime Environment 18.9 (build 11+28)
OpenJDK 64-Bit Server VM 18.9 (build 11+28, mixed mode)
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MacOS Mojave spaces gestures stopped working after taking screenshot with Grab

I just took a screenshot with the updated Grab app in MacOS Mojave and my 4-finger swipe to switch Spaces desktops stopped working. I found this post which talks about something similar with multitouch gestures which sounds like it’s a randomly occurring issue with multitouch gestures. A reboot fixed it for me, but it was surprising how much I rely on gestures to switch desktops/apps, and when it’s not working how to you switch?! (Ctrl-Left/Right is also works as a keyboard shortcut).

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Error installing Zappa on MacOS: “error: could not create /Library/Python/2.7/site-packages/requestlogger”

Attempting to install Zappa on MacOS with:

pip install zappa

I get an error:

error: could not create '/Library/Python/2.7/site-packages/requestlogger': Permission denied

Searching for this error I found similar errors installing other packages, and the recommendation seems to be to use the –home option to install to your home dir. So instead, this worked:

pip install --home zappa

 

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Piping audio between applications: Configuring ham radio apps on Mac OS using SoundFlower (virtual audio cables)

You’re running some digital mode software like WSJT-X on your Mac. Normally you would use a physical audio cable between your radio to your Mac, either via a soundcard interface like a Rigblaster, or even a direct USB connection to your Mac and your radio. What happens though if you want to route your audio from one application to another? For example, can you pipe the audio from a Web SDR running in your browser straight into WSJT-X (or any other digital mode software)? What you need are ‘virtual audio cables’.

On Windows you have a product called VB-Cable (the approach for Windows is similar to what’s described here). On MacOS you have a couple of options. There’s a commercial product called Loopback from Rogue Amoeba, or an open source alternative called Soundflower.

Follow the instructions to download and install. Once installed, you’ll find a couple of extra sound devices in your System Preferences:

Think of the Soundflower device as your cable. Instead of configuring Speakers for output and Mic for input, if you configure the input for one app as Soundflower (one end of the virtual cable) and the output for another app also as Soundflower (the other end of the cable), and sound output from one app is now directed into input of the other.

Let’s give this a go to connect the output from a WebSDR with the input to WSJT-X.

First, from System Preferences, select the Output to be Soundflower (shown above).

Start up a browser and pick a Web SDR station from http://websdr.org/

Here’s KFS and we’re tuned in to 7.074Mhz USB to receive some FT8:

Next, start up WSJT-X and go to Preferences, Audio:

Note that with Input = Soundflower we’re routing the Output audio from the WebSDR running in the browser into the Soundflower virtual cable. From WSJT-X we’re then taking the audio from this virtual cable as the input into WSJT-X, effectively routing the audio from the web browser into WSJT-X.

Also note that with Output = Soundflower in WSJT-X, if we transmit on WSJT-X the audio will also go out on the virtual cable. With WebSDR we can’t obviously transmit, but if you have access to a remote rig like remotehamradio.com, you can route the audio from WSJT-X into the remote rig app. More on that coming next.

You might note that with this current configuration there’s no actual audio coming out of your speakers. With some virtual cables you have the option to monitor the audio passing over the virtual cable. On MacOS you also have the ability to create composite audio devices using the Audio MIDI Setup app:

This shows a ‘Multi-Output Device’ comprising both the regular built-in audio (your speakers) and Soundflower. Now you’ve got the best of both worlds. More on this next step, and also configuring to use remotehamradio.com with WSJT-X coming up next.

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