Comment by shadowgovt

Back in the day, because the architecture was shared memory and cooperative multitasking, this is how MacOS applications declared their memory constraints.

Apps had a (recommended and then user-configurable) "Minimum memory" and "Preferred memory." The app would not launch if the OS couldn't give it the minimum. It would then give the app up to the preferred amount, if available, exclusively... This was in the era before virtual memory and paging, so there was no easy way to share memory across an application boundary.

This mean that savvy users with high-resource tasks knew you had to launch your apps in a certain order to get the architecture into the configuration to do their work.