🚀 go-pugleaf

Bill Moyer (ttk@rahul.net) wrote:
: In article <wilcafe-2008950222390001@callaghan.coretech.com>,
:  <wilcafe@mail.coretech.com> wrote:
: >I've read through a lot of this thread and noticed a lot of things that
: >just are not true.

: [..snip..]

:   A good article.  I wish more people would follow your example.

: >Myth #1 Copland will have preemptive multitasking.
: >  Apple has decided to phase preemptive multitasking accross 2 major
: >versions of system software. This is to ensure compatability. You will
: >have to wait until Gershwin for completely preemptive multitasking, but by
: >then, all the programs will be writen to take advantage of it and will be
: >instantly compatible.

:   Could someone in the know let me know something?  Why would 
: pre-emptive multitasking break apps made for co-operative 
: multitasking?  Properly done, a process doesnt "know" when 
: it's been pre-empted.  Its state remains the same before and
: after the task switch.
:   Presumably there are MacOS-specific issues I don't know about.
: Perhaps apps diddle with system data structures as they set up
: a co-operative task switch, and you don't want the pre-emptive
: multitasker to interrupt them in the middle of it?

You are close to it.

Also, after they relinquish the CPU, they also expect to recieve a message 
from the OS, and certain data structures in the app and system are restored.


:   Sort of along the same lines, what would an app need to do to
: take advantage of pre-emptive multitasking?  The idea is that 
: the task-switcher will behave exactly the same, regardless of 
: what a process does or doesn't do..  Again, I suspect there are
: MacOS-specific issues I'm ignorant of.
: -- 
: Bill Moyer <ttk@rahul.net>


By removing any voluntary points where they relinquish the CPU cycles and 
recieve messages from the OS.  

I personally don't think it should be hard to rewrite applications.  
Furthermore, there should be a lot of incentive to do PMT apps in a year 
or so, particularly if one is interested to do win32 <-> Unix <-> OS/2 
<-> Copland crossports.

Rgds,

Chris

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