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- id m0tzmzg-0007qxa; Thu, 21 Mar 96 09:13 MST
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- From: Clifford T. Matthews <ctm@ardi.com>
- Newsgroups: comp.emulators.mac.executor
- Subject: Re: Question about Bugs in Executor and what Ardi does about them
- Date: 21 Mar 1996 08:26:10 -0700
- Organization: ARDI
- Lines: 54
- Message-ID: <ufd966zcvh.fsf@ftp.ardi.com>
- References: <314EA718.3FF3@student.utwente.nl>
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- In-reply-to: Andreas Sikkema's message of Tue, 19 Mar 1996 11:22:48 -0100
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-
- >>>>> "Andreas" == Andreas Sikkema <a.t.sikkema@student.utwente.nl> writes:
- In article <314EA718.3FF3@student.utwente.nl> Andreas Sikkema <a.t.sikkema@student.utwente.nl> writes:
-
-
- Andreas> Hi, I'm not that an Executor user, but I have seen it
- Andreas> many times. Still, I'm interested in all this so I read
- Andreas> this newsgroup alot.
-
- We're glad we can hold your interest.
-
- Andreas> My question is, everytime a bug is discovered and Ardi
- Andreas> fixes it, is this bug just removed so that only one
- Andreas> program has been helped or are more structual measures
- Andreas> being taken.
-
- It depends on the nature of the bug. In theory, any time we fix a bug
- the fix could help out other programs. In reality bugs largely fall
- into two categories: application specific and penetrating.
-
- Application specific "bugs" often are due to applications being
- programmed incorrectly, but just happening to work on real Macs. An
- example is a program that calls the OS call "GetTrapAddress" with the
- contents of memory location 0xA198 and then calls GetTrapAddress with
- the contents of memory location 0xA89F and then compares the two
- addresses returned. This is a bug in the program in question -- they
- should be passing the literal values 0xA198 and 0xA89F to the
- GetTrapAddress calls, but instead they are passing the contents of
- these addresses. Memory is laid out on a real Mac in such a way that
- their incorrect calls still yields values that work. Executor has
- been modified so that the right thing happens under it, too. If you
- don't program a Mac, it won't be obvious that what they're doing is a
- bug, but trust me, it is, *and* it's incredibly unlikely that any
- other programs are going to have this same bug.
-
- Penetrating bugs are ones that potentially affect many programs, such
- as Executor using a different algorithm for mapping wdef part codes to
- FindWindow result codes. Once we realize what we were doing wrong we
- make the appropriate change and then all the programs that had
- problems with our old way of doing things will suddenly work.
-
- Andreas> If not structual measures have been taken, Executor
- Andreas> should grow larger than necessary I think.
-
- If I understand what you are saying, you're correct, but we *do* make
- structural changes as appropriate.
-
- Andreas> Thanx and keep up the good work
-
- Thank you for your interest.
-
- Andreas> Andreas Sikkema a.t.sikkema@student.utwente.nl
-
- --Cliff
- ctm@ardi.com
-
-