[229] in java-interest
Re: Threads vs New White Paper
daemon@ATHENA.MIT.EDU (Patrick Doane)
Wed Jun 7 23:52:44 1995
Date: Wed, 7 Jun 1995 23:42:36 -0400
To: java-interest@java.Eng.Sun.COM
From: pdoane@pcnet.com (Patrick Doane)
>The underlying implementation is guaranteed to be preemtive. On platforms
>that do not support thread preemtion (like the Mac), we'll make sure that
>the thread is rescheduled on the next opportunity. In our Mac port we
>check for this on every branch and method call. This "poor-mans" preemtion
>provides you with similar semantics as true preemption.
Pre-emptive threads are supported on the Macintosh, but only on 68k based
machines. I don't know if Sun is only planning on supporting the PowerPC
architecture, which at this time, currently doesn't support pre-emptive
threads.
I'm interested as to why the "poor-mans" approach was taken here to
provide the pre-emptive model. Why not write a custom thread manager for
the Macintosh Java implementation. I'm fairly sure that the OS support that
exists is just using the Time Manager or some variant thereof. It seems to
me that placing a yield() into every branch or method call would could
cause the program to slow down considerably.
I have been unable to see or use Java yet since I work almost exclusively
on a Macintosh but I am extremely interested in it. I'm wondering what the
compiler environment is like. Is there automatic support for projects or do
you have to create your own make file? Any information I could get on it
would be greatly appreciated.
Patrick
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