VOGONS


First post, by mr_zen256

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So, I know Magic Carpet 2 has a reputation for being a bit shakey when it comes to stability, even back in the day using hardware it was designed to run on. Regardless of this, I can't seem to get MC2 running very stable under DosBox at all. Speed isnt an issue, it runs brilliantly smooth.

Usually what happens is after an extended play period (30mins plus), strange graphic anomalies will appear when casting the fireball spell. The bitmap gets replaced with a glitchy, garbled like image. This is usually a sign that the game is about to crash or freeze in the next few minutes.

Sometimes the game just crashes within a few mins.

I have attached the current config file. Any tips would be appreciated!

Reply 2 of 11, by mr_zen256

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Tried running without sound by disabling it in the MC2 setup but the program still crashes after a while. Image attached.

I have tried using the official 0.74 release and a few different 0.74 SVNs but keep getting the same error. Are there previous versions of DosBox are known to be more stable with MC2?

Reply 4 of 11, by mr_zen256

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I just tried a fixed cycle count of 100000 and didnt experience any crashes after a good chunk of gameplay. I'm going to try increasing the cycles since the game ran pretty sluggish but other than that, seems all good!

Thanks for the help Qbix!

Reply 5 of 11, by sliderider

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If a game is known not to run correctly on the original hardware it was created to run on, then it's doubtful that running it under DOSBox is going to fix that. It sounds like bad programming by the game author rather than bad emulation. The programmer probably used some kludge-y code that barely works on the original hardware but DOSBox is unable to cope with.

Reply 6 of 11, by wd

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It has already been debugged in-depth and these are plain programming bugs that occur under certain circumstances
related to sound and processor speed/gameplay time which is why Qbix's recommendations usually give at least
some more stability under dosbox.

Reply 7 of 11, by mr_zen256

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Oh ya! I totally agree the problem lies with MC2 and not with DosBox. MC2 was notorious for being bugged when it was first released. Just a matter of finding the perfect operating conditions for the game under DosBox! Havent had a chance to up the cycles to see if it holds stable yet but 100000 definitely extended the playtime (granted sound was disabled).

Reply 8 of 11, by h-a-l-9000

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cycles=auto/max can be a problem though since the CPU speed wouldn't change on real computers.

1+1=10

Reply 9 of 11, by Qbix

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True,

but the game reads the high and low bit of the dma controller in a wrong way with a too large time in between.

Water flows down the stream
How to ask questions the smart way!

Reply 10 of 11, by Jorpho

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Would replacing DOS4GW with DOS32a be a good idea?

Reply 11 of 11, by wd

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Won't help, and in general things tend to be much more stable under their own dos4gw instance (still swapping them with newer ones or dos32a doesn't hurt for testing).