Alcatraz Megademo 3

[extralife]

Hi guys I'm going through alot of a500 demos now, since my a1200 just blew its sounds so now I got some time to look at the "real" demos of the past anyways I was looking at Alcatraz Megademo 3 and I can't seem to find a good dump of this one (i think) it keeps making these weird scratchy noises in the fourth part of the demo (the one after mickey ) I have tried many places, but all of the dumps seem the same, maybe it doesn't exist, maybe one of u collecters out there have it ?
I should say that i run this on ocs chipped amiga500, kick1.2 and with some 512k ram expansion, but i dont think the expansion is causing the problem, coz when i try the exact same dumps on winuae, it does the same noises. Hope someone can help or at least let me know, if this is the only known dump that exist. thx and happy new years all

[Frog]

i don't know if you check this link : http://ftp.amigascne.org/pub/amiga/G...-Megademo3.dms

Worth to check http://kestra.exotica.org.uk/ but database problem atm.

[extralife]

yea I think I tried that link aswell, anyways, I downloaded from your link, just to be sure and it the same deal anyways I can tell u that the scratching is happening in part 4 right where the bottom scroller says greetings and just before the tune turns into the IK+ cover . Oh well its not that important, I just like to keep my democollection in top shape that's all.
Oh yea I allso dug out my dusty scene archieves cd's and that dump is even worse, it simply skips the entire part lol, so it seems that the one u linked is the best of them, so I'm keeping that and moving on thx m8

[Asle]

hi,

works fine : http://bitworld.bitfellas.org/demo.php?id=3252
I'll add the zik links later today.

Cya
Sylvain

[extralife]

Sorry for the late reply, needed sleep lol, yea I checked it and works the same as above, but as I said, it's probly the best dump, maybe I have a hardware problem, coz sounds of gnome is the same, both red and blue version (yep one boots in red from amigascne) except the red doesnt slow down like a heavy pc game does your windooze machine and acme's megademo in first part have same weird scratch, seems im the only one with that problem so maybe i need to replace some chips anyways thx for your time m8's

[Toni Wilen]

Very late answer but I was just debugging this thing..

There are 2 other problems with this megademo:

- 4th part requires OCS Agnus. Note that this is not the standard modulo error (see Eliminator & first Double Dragon 2 release) but I think DDFSTRT/STOP combination enabling "too long" bitplane DMA scanline (DDFSTRT=0x32, OCS sees 0x30, DDFSTOP=0xD4. I think this means final end position will be 0xE2 which is also position of first refresh slot) which probably confuses some Agnus' internal DMA state machines. (this is not emulated)

-5th part, "green alien" dualplayfield bitplane priority is inverted. This part only works correctly if demo disk is inserted after Amiga asks for bootable disk. ("insert disk" screen = second copper list initialized -> demo sets wrong BPLCON2, KS copper list fixes it..)

[Photon]

He's running it on A500, not A500+, so OCS Agnus is not a problem

And WinUAE is not used.

So the dump is the problem here? Or what.

[Skope]

I'm gonna go ahead and guess that it's not entirely ks1.2 compatible, but rather needs ks1.3. It wouldn't be the first demo I've run in to that crashes under 1.2, I know for a fact that Phenomena's Megademo crashes about halfway through unless you have 1.3. The link posted by Asle works like a charm here, but the amigascne.org link points to a dms which is ~250 bytes large. Would definately say something is wrong with that dump. (: