Currently RunInUAE sets-up E-UAE to behave like an A500 (ECS) with 1MB chip RAM and 3 external floppy drives. After some discussions with someone, we wondered:

1. Whether adding an extra 0.5MB RAM expansion would improve or degrade A500 game compatibility (overall).

2. Whether 3 extra floppy drives was significantly degrading A500 game compatibility, due to the extra memory they use... and whether adding that extra 0.5MB of RAM would solve this.

Please post your opinions here but I am also adding a poll to "crowd source" an answer (which I shall take with a pinch of salt!).

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@ChrisH

I found that the most compatible installation is using 512kb + 512kb expansion. That works on every game i tried on my a500. On the other hand, i remember having problems with certain games using 1mb chip under winuae.

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@ChrisH

0.5MB extra RAM I think it's ok. But I remember having problems with external floppy drives. Even most software companies tend to tell you to disconnect any external floppy disk drives before running the game.

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Remembering Lotus Esprit 1 when booting did tell "no externals" and it was true.
0.5 + 0.5 was probably the best choice overall.

@Phantom

As I recall, this was only a problem where memory was a factor, since each drive used around 30KB. Since a large portion of A500 owners had 2MB in total (using a 1.5MB upgrade) normally giving themselves 1MB chip and 1MB fast, the number of extra drives shouldn't be an issue (although there is generally little point in having more than just DF0: and DF1:).

More irritating was games that ignore extra drives completely, always asking for the disk to be inserted into DF0:

Extra ram should not impact on compatibility usually - many newer titles relied on the extra ram (Alien Breed for example)

@ChrisH

I know what you mean about the incompatibilities.
True A500 would be KICK1.3 OCS 512MB CHIP and an A501 RAM expansion


cpu_type=68000
cpu_compatible=false
cpu_speed=real
chipset=ocs
chipmem_size=1
bogomem_size=2
fastmem_size=0

1MB CHIP & ECS was A500+ / A600


cpu_type=68000
cpu_compatible=false
cpu_speed=real
chipset=ecs
chipmem_size=2
bogomem_size=0
fastmem_size=0

--Edit--

Thanks to olegil for pointing out my typo.

Last edited by JurassicC on 23-Jun-2012 at 11:52 AM.

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@JurassicC

You got the O (original) and E (enhanced) chipsets mixed up there.

I've had numerous games that never worked unless any slow mem was turned off, but can't say if extra chipmem ever bothered anyone.

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Quote:

_Steve_ wrote: @Phantom As I recall, this was only a problem where memory was a factor, since each drive used around 30KB. Since a large portion of A500 owners had 2MB in total (using a 1.5MB upgrade) normally giving themselves 1MB chip and 1MB fast, the number of extra drives shouldn't be an issue (although there is generally little point in having more than just DF0: and DF1:).

Good point, thanks. But I think 2MB in total as you say, might be not the most compatible method when it comes to games.

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@olegil

I tend to use OCS and 1MB chip and 3 floppies for my A500 config.

Games like cannonfodder, worms, jurassic park, lemmings 2 and walker benefit from the extra drives, so you can stick one adf in each drive so to speak.

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@all
Since there seems to be some disagreement over what does (or does not) affect compatibility, it's looking like the only way to solve this is to empirically measure compatibility using a lot of games (which of course takes a lot of time & I'd rather avoid that if possible).

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@ChrisH

There where a few games that only worked whit older kickstarts, I remember having to soft downgrade or, disable extra 0.5mb fast, its a shame I don't remember what games or demos that did not work.

Most games work fin whit 0.5mb fast, and some games need the extra 0.5mb.
0.5 chip+0.5 fast is the best option for a A500 i think.

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@ChrisH

I had 1 MB chip ram on my Amiga 500. I think this is the most compatible memory expansion for Amiga 500. Those games that didnt work with the usual "512kB chip + 512kB pseudo-fast" were working because all RAM is custom chip accessible. On the other hand there were few games (at least Utopia) that didnt detect 1MB chip and claimed I had only 512 kB configuration. But I never had to disable RAM expansion to get games working like my friends had to with certain games.

In my opinion the best configuration would be Amiga 500 (OCS) with 1MB chip ram and Kickstart 1.2 with 4 floppy drives. I dont think anyone want more ram than that.

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@_Steve_

Quote:

Extra ram should not impact on compatibility usually - many newer titles relied on the extra ram (Alien Breed for example)

It does. Original Amigas only had chip ram and therefore all memory was accessible by custom chips. When extra ram was added it was fast or pseudo-fast ram that was not accessible by custom chips but only CPU. Many early developers didnt consider that and data was loaded to wrong type of memory.

Then another problem is how games detect extra ram. It may be ignored if it is not seen exactly like pseudo-fast is seen on Amiga 500.

(Edit: fixed quote)

Last edited by itix on 23-Jun-2012 at 06:20 PM.
Last edited by itix on 23-Jun-2012 at 06:19 PM.

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@ChrisH
I think OCS 512KB chip + 512KB slow and KS1.3 is the most compatible configuration. ECS&1MB chip caused me problems when I had to replace my original a500 motherboard by an a500+ one with KS1.3.

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@All

To know which setting should be the default, another idea would be to emulate the Amiga that was sold the most. I think it's the A500. No?

In that case, it would be 512KB + 512KB

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@itix

I have two A500s, both had ram expansions, I believe both are 1.3 KS and ECS machines. One definitely has a 1.5MB ram expansion configured as 512K chip and 1MB fast.

Both computers worked flawlessly with every single game we own (and my brother and I owned a lot). None required the expansions to be disabled.

In fact I had more problems with a ram expansion for the 1200 than I ever had with the A500 (the microbiotics cards generated a random level 7 interrupt which caused loads of things to either break or malfunction randomly).

@_Steve_

Believe me, there are games that do not work with non-chip ram expansion.

@Crumb

ECS can mean newer Amiga 500 revision with Fat Agnus (without extended display modes or 2MB chip ram support) or full Amiga 500+/Amiga 600 configuration with extended display modes and 2MB chip ram support.

My Amiga 500 was an ECS model but it only supported 320x256 and 640x256 (+ interlaced) display modes.

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@ChrisH

There are some old games that only accept OCS machines with pure Chip-RAM. The coders thought Amigas will only have Chip RAM and accessed their GFX with the Blitter directly without thinking about the possibility it might be located in Fast RAM.

This is one of the main reasosn why a Fast RAM expansion could cause trouble.

Mabye you might also run into troubles if your Amiga has other chipsets than the original one, this is very common if you expand your chipram beyond 512MB but other ECS/OCS games needed 1MB Chipram, so you will be always in trouble with original 512MB Chipram yes or no.

So the most compatible Amiga for old games is an unexpanded A500, additional floppy did IMR not effect compatibility.

There are some software patches patching the Amiga or the game for better compatibility best one is WHDL ( http://www.whdload.de/ ) bust this is a solution for bigger Amigas with HD and acellarators.

@_Steve_
Try this http://www.lemonamiga.com/games/details.php?id=2256 I knew Matthias, he did not care about Fast RAM and old the Kickstart1.2 on his Amiga1000 had a problem giving the coders the right type of Ram anyway.

Early game developers did a lot of "Don't" without think it might influence comaptibillity:

1. Don't care about Fast Ram (old Kickstart V1.2 couldn't do anyway)
2. Don't wait until the Blitter was ready, games with faster CPUs will crash
3. Used self modifying codes that will even crash with an 68010 because it had a longer prefetch que (some kind of instruction cache)
4. Switch of OS and do all floppy access by themselfes, so it will never run from HD.

Last edited by Arko on 24-Jun-2012 at 10:12 AM.
Last edited by Arko on 24-Jun-2012 at 10:06 AM.
Last edited by Arko on 24-Jun-2012 at 10:03 AM.
Last edited by Arko on 24-Jun-2012 at 10:02 AM.
Last edited by Arko on 24-Jun-2012 at 10:01 AM.

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Edit: I originally said here that bogomem should be 1, but then realised it's a multiple of 256KB, not 512KB. chipmem_size is a multiple of 512KB.

Bart Simpson vs The Space Mutants, Jimmy White's Whirlwind Snooker and It Came From The Desert (intro scene) have been the most problematic games (in terms of uae settings) for me, then again I've probably not tried as many games on uae as other people have.

Last edited by MickJT on 24-Jun-2012 at 02:06 PM.
Last edited by MickJT on 24-Jun-2012 at 02:03 PM.
Last edited by MickJT on 24-Jun-2012 at 02:02 PM.
Last edited by MickJT on 24-Jun-2012 at 01:50 PM.

@ChrisH

In answer to:
Point 1 – the extra 0.5mb would improve compatibility overall.
Point 2 – yes & I don't see why you would want 3 extra floppy drives anyway. The extra ram may help with some games that don't like extra drives but not all.

I would go with the following two configurations along with kickstart 1.3 (or 1.2):
Games 1985-1990
512k chip 512k fast, with no extra floppy drive (& OCS)
Games 1991+
1mb chip ram & at least 1mb fast ram (& ECS) would be most compatible. A 2nd drive should be fine generally if you have 1mb chip. I don’t remember any post 1991 games having a problem with the extra ram in my 2mb A500 (apart from a few that needed 1mb chip; I only had 0.5mb).

You don’t have to worry about all the configuration nonsense if you use WHLoad, which is excellent.

Last edited by Tpod on 30-Jun-2012 at 08:26 PM.

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