If you use ImgLab on a multiprocessor machine this option just starts ImgLab as single threaded process. This option helps to save memory. This option allows to specify the number of IL processes. This feature is valuable on computers where the hardware support seems unreliable. If you change the parameters of an operator you have to wait until all connected displays have been redrawn.
User interactions have no effect until the redraw of the images is completed.
Asynchronous rendering allows to continue working with ImgLab although a display recomputes an image. This option sets the number of IL processes to 2 if option -mp was not used. Suppress loading from any of the given dso paths. This feature is mainly used if ImgLab is extended by user-defined operators. Refer to chapter Extending ImgLab for further details.