[ENH] StartUp/ShutDown - less than perfect

Dan Ingalls Dan.Ingalls at disney.com
Fri Jun 2 05:29:47 UTC 2000


Mats Nygren <nygren at sics.se> wrote...
>It seems to be a bad idea to have two separate lists StartUpList,
>ShutDownList for closing and reopening the image. This invites problems:

I agree about this.
I ran into similar problems when getting segment swapping to work:

If Sound was not in use, all the sound code would be swapped out,
but then if you did a quit, it would still try to shut down sound, 
thus swapping in the whole sound segment, just to do an
unnecessary shutDown.

It seemed to me from that experience not so much that there should only be one list, but that the state of the lists should be maintained more dynamically -- ie, Sound would not normally be in the shutDown list, but would be put there if something makes it startUp.  Similarly, if it later shutsDown, then it would not startUp again, unless something makes it do so.

If someone wants to make this work right, it would be a real contribution, but you need to know what you are doing -- order is important, for one thing, and if anything isn't right, you will find yourself with an image that cannot be restarted (because it may try to display a debugger before the Display is installed, or it may try to write an error file before the File system is initialized, etc).

	- Dan






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