Ah, I see what's happening (was quadra system bloat)

Martin Baxter martin at atwork.bdx.co.uk
Tue Mar 19 18:52:01 CST 2002


>"Ken Norris (dialup)" <pixelbird at interisland.net> wrote:
>
>on 3/19/02 9:26 AM, Martin Baxter at martin at atwork.bdx.co.uk wrote:
>
>> I've concluded that what's happening on the quadra, and I think the
>> screenshot clearly shows this, is that revolution isn't using its own
>> application memory partition for documents and data and instead is loading
>> them into the operating system's memory partition, at any rate that's how
>> it appears to the mac Finder.
>----------
>I would think you're right, but I'm not sure. It certainly shouldn't install
>itself into the system folder at all,

Ken,

Hey man, now, did I actually say anything about the system folder or
installation or disks? No, I did not. You misunderstood what I'm talking
about. I completely forgive you though;) after all it's probably because
I'm not communicating very well, so let me try and be very clear.

I'm simply talking about RAM - that is *memory*.
I realise you understand the definition that follows, but I thought it best
to include it in the hope of clarifying the terms I'm using.....

In the Classic Mac the available RAM is divided up into *partitions*.
Each partition belongs to an application that is running and whatever RAM
is left over outside of those is what the operating *system* (the OS) uses
for itself.
The idea is that each application program is supposed to stick to keeping
it's own data in it's own partition.

So to the situation I'm trying to explain;
1) The system (the OS) is of course already loaded into RAM
2) I launch Revolution by double-clicking it
3) A partition is created in RAM for Revolution to put all its stuff in
     (there are now in effect 2 partitions in RAM, revolution's and the
system's)
4) The revolution application is loaded into the revolution RAM partition
by the Finder (that's normal)
5) Revolution begins running and starts loading its various stacks *into
the System's RAM partition* (that's not normal at all, revolution should
put them in its own partition.)
6) Revolution keeps loading stacks into the system's RAM partition until
the system's RAM partition is full.
7) Once the system's RAM is full, the computer crashes (with no warning
whatever) because the system has absolutely no RAM to work in anymore - all
the RAM it ought to have available is now full of Revolution stacks.
8) This is despite the fact that there is actually loads of RAM unused in
Revolution's own partition, because it has never put anything there.

By increasing the RAM available (physical or virtual, the type isn't
relevant to this issue) all we are doing is delaying the time when the
system's RAM partition gets filled up and the mac unceremoniously crashes.
If you give it a large enough amount of RAM, or only load a few small
stacks, you may be able to get away with working for a fairly long time
without a crash happening, fine I suppose if you don't mind the risk to the
other data on your computer from random crashes, but the underlying problem
has not in any way been solved, it's still an inherently unstable situation
because an application is writing data into a part of RAM that it has no
right to use.

Do you see what I'm saying now Ken ?

martin =)

martin baxter Cambridge UK





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