gilgalad@zip.eecs.umich.edu (Ralph Seguin) (10/09/90)
Hi. I am curious about how Commodore is going to accomplish resource
tracking (so they can also accomplish a good virtual memory implementation).
I think that this would be an interesting subject for discussion.
Is Commodore going to stick with lightweight processes or going to
go for heavyweight?
I have an interesting idea:
Consider the case where one process creates a screen for itself.
It then passes a message to another process, to indicate that it has
opened a screen. In this message is a pointer to the screen, so that
the other process can do things with the screen as well. Clearly this
is not a very good method of doing things. First, the OS doesn't realize
that there are going to be 2 (or more) processes accessing the screen.
Thus when the process that created the screen gets killed for some reason,
or another, the OS will try to remove the screen. Then the other process
is going to go haywire.
A better method of going about this, would be to create system calls
that allow, a duplicate screen pointer to be accessed by another process.
GetPublicScreenPtr()? In this fashion, the OS can realize that there are
going to be multiple processes accessing the screen, and thus not remove
the screen immediately when process A terminates. This is VERY similar
to links in UNIX.
This scenario is obviously extendable to many other situations. There
are also considerably more things that have to be dealt with in a VM
implementation on the Amiga as far as resource tracking is concerned.
I've just tossed out this hypothetical situation to stimulate
conversation (and waste bandwidth 8-). I think that this should prove
to be an interesting discussion.
Thanks, Ralph
gilgalad@dip.eecs.umich.edu gilgalad@zip.eecs.umich.edu
gilgalad@caen.engin.umich.edu Ralph_Seguin@ub.cc.umich.edu
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