Optimizing Boot Times

Each system has its own set of boot time requirements to meet. Depending on your goals, there are a number of ways you can optimize the startup of the system. By implementing some simple techniques at various points in the boot sequence you can make the OS and applications load, initialize, and launch more quickly. For the QNX CAR platform, you can optimize startup times in three distinct areas:

To optimize:	See these sections in this guide for details:
The loading and launching of OS itself	Optimize the bootloader Reduce the size of the startup program Remove unnecessary debug printing Reduce the size of the IFS Generate the IPL to skip the image scan Enable fast reading in the SD card Use compression strategies
The platform application stack	Make careful use of the default build script Consider the placement of `waitfor` statements Reorder the startup program
The HMI	Optimize the HMI Create modular applications Statically link libraries

In the QNX CAR platform, boot time optimization has been done using many of the techniques discussed in this chapter. These optimizations were focused on the following goals:

Early splash screen and camera—meeting this goal required loading the IFS and getting to the build script as soon as possible, and then running the Screen Graphics Subsystem and the graphical app as early as possible (see Optimize the bootloader, Reduce the size of the IFS, and Reorder the startup program).
Early audio—used the same techniques as early splash screen and camera, but starting audio as early as possible.
Early HMI display (within 10 seconds)—used and benefited from the same techniques as above, but required additional work to reduce the HMI's dependencies down to what was strictly necessary. This led to the development of Boot Manager, which allows the HMI to come up before all the apps are instantiated.
Last audio playing within 10 seconds—required the invention of a new multimedia service that saves its state at shutdown and restores it at power-up. This also required careful management of this service's dependencies and placement in the SLM configuration.