macos_appnap_howto

Desktop Application Launchers for fldigi, flrig, etc.

MacOS does not provide an easy way to have multiple, identifiable application launchers, for example an fldigi for HF and a separate fldigi for VHF, both possibly running at the same time. This is an easy to implement solution that also provides protection from the OS intruder "appnap" on a running fldigi or flrig. appnap is designed to save energy, but has the adverse effect of denying fldigi, flrig, etc. access to system services such as audio, serial or network. This has been known to cause fldigi to become unresponsive. Zealous Apple OS developers trying to earn Green credits!!

Create a desktop launcher

This procedure will be performed from a terminal window. It will create an fldigi app laucher specific to working the HF bands. It is based on the latest fldigi version 4.1.14. Modify the version number to apply to your installation.

$ cd
$ cd Desktop
$ cp -r /Applications/fldigi-4.1.14.app HF.app
$ cd HF.app/Contents/MacOS
$ rm fldigi
$ touch fldigi
$ nano fldigi

from within the nano editor, enter these two lines. Control-O to save the text, Control-X to exit nano.

#! /bin/sh
/Applications/fldigi-4.1.14.app/Contents/MacOS/fldigi --config-dir $HOME/HF.files

Note: In the Unix / Linux world the geeks refer to the #! combination as "sha-bang". The #! /bin/sh line is the key to preventing the OS from applying app nap to the new application. It tells the OS to start the default shel" which runs in the background. The shell interprets and executes the next line, the fldigi binary. The OS normally prevents appnap from interfering with the shell and that attribute is inherited by it's child process.

Make the script file "fldigi" executable

$ chmod a+x fldigi

The fldigi lauched by this script will use the directory /home/<user>/HF.files for all of it's configuration items. If the --config-dir $HOME/HF.files were omitted then the default files directory would be used.

Repeat for flrig or another application that you want to run with specified command line parameters.

Update the launcher for new fldigi install

Modify the file

/home/<user>/Desktop/HF.app/Contents/MacOS/fldigi

to correctly point to the newly installed fldigi binary.

Note: The desktop icon can be moved anywhere like any other app icon including to the launch bar. It may also be renamed like any other icon. If you move or delete the original app in /Applications the launcher will not work.

Preventing App Nap with 64 bit applications

MacOS does not provide an easy way to disable App Nap for 64 bit applications. fldigi, flrig etc are all built as 64 bit binaries.

The same procedure can be used to create an application launcher that the OS appnap ignores. This works because appnap does not interfere with a terminal application, which is the method being used in the desktop launcher.