Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!caen!kuhub.cc.ukans.edu!2fmlhiccup
From: 2fmlhiccup@kuhub.cc.ukans.edu
Newsgroups: comp.sys.amiga.programmer
Subject: Multitasking
Message-ID: <1991May4.174645.30385@kuhub.cc.ukans.edu>
Date: 4 May 91 17:46:45 CDT
Organization: University of Kansas Academic Computing Services
Lines: 15

I never thought it was possible to have a multitasking environment that
did not allow one task to prevent others from running.  If not you would not
be allowed to access shared data structures and the like.  Even if the 
'lock' is reduced to one bit, you still have to lock access to it when
someone wants to try to claim that bit.   It seems possible to have a task
make a copy of a data structure and then use the OS to pass it to another
task and make locks not required, but at the expense of an incredible loss
in performance.  At the bottom level, every singls OS routine would have
to prevent any other task from running in this system.   In other words, 
in a multitasking environment, it is givent that you have to halt other
tasks when accessing shared memory, or if you use locks, you still have to
halt other tasks when you want to claim the lock...
 
Jason Wilson