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From: karl@sugar.UUCP (Karl Lehenbauer)
Newsgroups: comp.sys.amiga
Subject: A proposed solution to the resource tracking problem
Message-ID: <636@sugar.UUCP>
Date: Fri, 4-Sep-87 17:43:43 EDT
Article-I.D.: sugar.636
Posted: Fri Sep  4 17:43:43 1987
Date-Received: Wed, 9-Sep-87 05:38:43 EDT
Organization: Sugar Land UNIX - Houston, TX
Lines: 71


The question often comes up on the net, "How can I kill my Amiga tasks?" or
more often, "Why can't I kill my Amiga tasks?".  The problem, of course,
is resource tracking, or more specifically the lack of support for it under
AmigaDOS.

We've been told that there would be too much overhead to implement this.
I think most of us tend to discount that as we end up having to write 
equivalent (and tricky) code in each of our programs anyway.  There is 
a case to be made for the former position, though, as the existing OS 
routines (memory alloc, etc.) are quite speedy and it would undeniably 
increase overhead to add resource tracking.

Anyway, I think any solution should be compatible with existing code
(as much as possible possible), easy to use and would be most likely 
to succeed if it didn't require changing the operating system.

Peter da Silva (sugar!peter) and I were quite surprised recently when
we found out that Mac windows all behave in a manner that is analogous 
to the Amiga's simple refresh windows.  What that means is that every
time your program's window gets resized or has something moved from
in front of it, it has to redraw part or all of the window.  This 
makes even "Hello, world" type programs hard to write.  The Maccians 
get around this by using libraries as a front-end to the toobox calls 
to provide some enhanced capabilities that aren't present in the toolbox 
itself.

We should do that, too.  The memory allocation problem can be solved
by using AllocRemember (Thanks, Peter, for showing me this).
Library routines would front-end calls to create message ports and 
such.  The library routines would keep track of what things need to
be cleaned up on termination and how to do the cleanup in addition 
to making the system calls to perform the specified operations.  The 
_main (for C people) startup code would set up to receive a software 
interrupt on the various control keys.  The interrupt would call the 
code that cleans everything up.  

All a programmer would have to do to use this is to link from the 
new resource-tracking library.  It is even possible for the routines 
in this new library to have the same names as their non-resource-
tracking counterparts.  The existing names, after all, are just the 
names of assembly routines that call an offset to A6 after playing 
with the stack and registers.  You give those routines new names and 
call them, via their new names, from the new resource tracking routines 
that bear the original names.  If one were to do the same for RemTask,
one wouldn't need to explicitly call any special resource tracking code
at all!  (Peter came up with this part.  I think it'll work.)

Yes, it is stinky that the resource tracking code will have to be 
linked into every program that makes use of it rather than just being
part of the OS.  It mightn't neccessarily increase the size of 
programs a whole lot, though, as it could be implemented as a shared, 
reentrant, dynamically-loaded library like the ones in LIBS:.

---

Now I'd like to end my posting, which I hope has provided a positive 
and technical contribution to this newsgroup, with a remark that 
postings about the inappropriateness of other postings, please-don't-
post-about-this postings, postings about the danger to the net posed
by all the garbage postings and so on consume net bandwidth too, 
and often create the destructive meta discussions warned about in 
the netnews new user docs.  

Flaming, also, increases net bandwidth, as few people are going to be 
willing to undergo a thorough, public charcoaling without making some 
sort of public reply.  For most people, to not do so feels like tacit 
surrender to the flamer, with additional scorching caused by the 
provocative language that characterizes such flames.
-- 
...!soma!uhnix1!sugar!karl    "Life is wasted on the living." - Z.B. IV