Relaunching the same app after quitting it causes a crash

[jantoman]

Hi. Thanks a lot for all your work: SheepShaver still gives me so much fun after many years. Can't stop using those old games
There's an issue that's always been there, as far as I remember: every time I launch an app that I just quit, an alert window pops in saying that the app crashed and it's better to restart the computer (type 3 error, most of the times). As far as I remember, it happens with Strategic Conquest 3 and Civilization I. Is there a workaround to solve this?
Thanks in advance.

[Ronald P. Regensburg]

The little application "Apple Error Codes '89" explains:

ID=03 Illegal Instruction
The computer has a specific vocabulary of machine language instructions it can understand. If a computer tries to execute an instruction that isn't in its vocabulary, you see this error code. It's less likely than error 02, but still very common.

Did you try enabling "Ignore Illegal Instructions" in SheepShaver preferences (or GUi, depending on your host system)?

Does the error also happen when you wait a longer time before Launching the app again?

[jantoman]

Did you try enabling "Ignore Illegal Instructions" in SheepShaver preferences (or GUi, depending on your host system)?

Yes. "Ignore Illegal Memory Accesses" is enabled as well.
Also other apps refuse to launch after I quit one of those games. But that could be a graphic issue, many old games need different resolutions.

Does the error also happen when you wait a longer time before Launching the app again?

I never waited more than a few seconds because most of the times the system crashes as well.

[jantoman]

Update: almost all the application fail to launch after quitting one.
Once I even got a full strike of System Errors in Finder: 2000, 11, 10 and 41... Bingo

I found out that when I change the monitor resolution after I quit, i.e. switching back and forth from 256 to thousand colors, chances are that crash doesn't happens (around 50%). When it does, the screen becomes a mess of colors and the system hangs. Guess I found the culprit.

MacBook Air i7 1,7 Ghz, 8 Gb RAM, 512 Gb SSD, Intel HD Graphics 5000 1536 MB. SheepShaver is updated to the last notarized version.

[24bit]

I do recall such behaviour - from real Macs and emulated ones.
My guess is that some apps do not free the system resources upon quitting as they should, lazy programming may be one reason.
At second start there are remains in RAM the app wants to allocate again - dang.

There is a small app to flush RAM on vintage Macs which helped somewhat, though not in all cases.
https://macintoshgarden.org/apps/mac-os-purge
Some versions of TechTool may also be used to flush RAM.

[Ronald P. Regensburg]

Launching and quitting apps in the old Mac OS leaves RAM memory fragmented. In the old days I made it a habit to quit all running applications and wait half a minute before starting again with a new combination of applications.

Still, it was not unusual to have to restart my Mac a couple of times a day, especially with the 7.5.X and 8.X OS versions.

[jantoman]

In the meantime I found out that some apps - i.e Civilization I - don't like OpenGL, QuickDraw and other graphic-related extensions. I made a couple of custom sets with Extensions Manager and I've been able to minimize the issue. I'm still experimenting different configurations, but I guess every app has its own preferred settings.

[adespoton]

Please add those to https://docs.google.com/spreadsheets/d/ ... beZg39Q9A/ with the correct config settings