More than 128 mB on a CSPPC?

Since 1997, I'm 'proud owner' of a towered Amiga 4000 with CyberstormPPC card, which is still in use.

For a while, I also had a CyberVisionPPC graphics card, but the onboard video ram size of just 8 mB quickly turned out to be insufficient and so I exchanged it for a Voodoo4 PCI graca in the Mediator PCI busboard.

But meanwhile, also the 128 mB 64 Bit wide FastRAM on the CSPPC are too little.

But there exists - at least for WIntel-PCs - the possibility to 'alienate' the GPU and also the graphics memory on the graca and use it for calculations and as working memory, if I got that right.

The CyberVisionPPC is connected to the CyberStormPPC via a "25 mHz local PCI bus" and has "8 mB of 64 Bit wide SGRAM" onboard.

Now I was wondering if it could theoretically be possible to make a small harware add-on with - lets say - 128 mB (or more?) of 64 Bit wide SGRAM onboard and to connect this to the „25 mHz local PCI bus“ on the CSPPC with the apropriate plug and provide this additional Ram `somehow to the AmigaOS?

Ram expansion boards like the ZorRAM can only be used for "swapping" - perhaps could more RAM be provided as working memory this way - like on WIntel PCs? It has often been raved about the fast linking of the CVPPC to the CSPPC via this "local PCI bus" - it should somehow be possible to capitalise on it, shouldn't it?

In theory it should be possible, but I think there might be DMA issues from the Zorro-III bus not being able to access the RAM on the local PCI connector. Such a limitation wouldn't have mattered for a CyberVision card as nothing other than the CPU would want to write to it and it didn't need access to anything other than the accelerator, but if system-wide fast RAM is available there, it could be allocated for DMA by any other device.

@Dandy

http://www.osdever.net/FreeVGA/vga/vgamem.htm

Well its possible, but the PCI memory, is normally paged memory of 64K per page, so memory has to be virtual memory, you can't access all memory directly. The PCI bus maybe bit faster then Zorro bus, it's not ideal. It's also 66Mhz, so it will be bottleneck.

I see there is also 128kb window, I guess it has nothing to do with paged memory.

@ LiveForIt - #3:

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Thanks for this link - very interesting read, indeed.
But how dated is this article?
I mean - it says "The standard VGA hardware contains up to 256K of onboard display memory.".
"VGA hardware"?
"up to 256K of onboard display memory"?
That seems to have been a while ago...

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Great!

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Bummer!

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Even worse - it's just a "25 mHz local PCI bus"!
As I read, also the Zorro III bus is just 25 mHz and "can be overclocked to 33 mHz too but real amiga video and sound will probably suffer" (http://www.amiga.org/forums/archive/index.php/t-51791.html).

I'm wondering at what clock speed the PCI bus on an Mediator in a 25 mHz Zorro-III slot runs...

@Dandy

https://www.mankier.com/3/vga_setpage

Well svga lib has some called linear addressing, but this just memory mapped address space, what we call today virtual memory.

Basically the paging is just hidden.

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Yes it was an old article, because the Wikipedia one does have any technical details, and because the standard PCI has not changed, PCI was replaced by AGP in 1997, sense then the PCI standard has been a legacy bus, then AGP was replaced by PCI Express, PCIe is a lot different from PCI.

First of all PCI express is full Duplex, and it's serial, while old PCI standard is Parallel, and only half duplex.

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I'm sure that's not right, I think way they say 25 MHz there is because they are talking about zorro to PCI adapters.

It illogical that be anything else then 33Mhz or 66Mhz slot on CyberStorm.

As Zorro slots uses absolute (memory) addresses, most of memory is revered, there is really is not any free address space to map the PCI memory to.

Paged memory might actually not be bad idea, as it does not take up so big address space footprint.

@Dandy

Flog the CSPPC to a collector, buy an X5000 and use the change to get an 030 or 040 CPU card for the A4000.

@ Rob - #6:

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Sorry - but this does not make any sense for the A4000.
Why should anyone be so stupid and throw a rare, powerful 060 out in favour for an inferior, under-performing 030 or 040?

I have an 030 @ 40 mHz 'running' in my A1200.
And the A1200 is sitting in the corner collecting dust most of the time, as it is non-usable nowadays in terms of performance - from my POV.

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I would like to get one of those - but I would not give the CSPPC away for it...

@ LiveForIt - #5:

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Hmmm - the original CVPPC manual by Phase5 does not mention the "local PCI bus".
I took this info from the Amiga Resource website:
CyberVision PPC:

...
RTG graphics card
...
- 25 MHz local PCI bus
- 8 MB 64 bit wide SGRAM

Nothing with regard to "zorro to PCI adapters" - sorry.

I have no idea if the figures given there are correct...

@Dandy

I bet if you had an X5000 there you'd soon find the A4000 with CSPPC sat in the corner too. However you don't so I would totally understand your scepticism. Pity you can't have both so you could find out for yourself which you'd prefer.

I only suggested 030 because I didn't know about the A1200 you had and it's always nice to have a system for WHDload if you still enjoy the old games or some of less demanding serious applications that rely on Commodore hardware.

Maybe when the Vampire 1200 appears the A4000 and A1200 will swap places.

@ Rob - #9:

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That might very well be.
I'd really love to get my hands on one and play with the XENA/XORRO thingie.

But - as I already pointed out - I currently have a system that has and runs all the software I need.
With an NG system I would have to test first which of my old classic software runs flawlessly on the new environment and would have to look for NG software to replace those classic software titles that don't run satisfactorily on the NG system.

And this could turn out to be an impossible task, as we all know that the available NG software is still far from being on the same level than what was available for the classic Amiga systems (especially when it comes to productivity software) when they were still supported by mayor software companies.

So I might as well end up using both systems...

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I might be able to find a way to fund an X5000 next year, if no further unexpected expenses come up.

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Yeah - aside from the A4kPPC I also have an towered A1200 with 030@40 and two A500s with Viper520, and bags full of old floppy disks with all kind of games.
So many that I never found the time to try every disk and look what games are on them...
(I got the disks when I bought used Miggies)
I have a nice "CompetitionPro" and even a pair of analogue joysticks.
But to be honest I can't remember how long ago it is when I at last played a game on one of my Miggies...

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The problem is that most of those "less demanding serious applications" don't exactly do what I need/want to do...yeah, I know - me and my weird hobbies...


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Wasn't there also talk about a Vampire 4000?
And then there still are my two A500s in the locker...
So I might end up with four Vampires (just dreaming)...

But still - even if I would buy a Vamp - I would have to rely on hardware (namely the mobos) that is between 20 and 30 years old...

And furthermore (found on the 'Apollo Accelerators' homepage):

"Loads of memory: Ever heard of the sentence "640K Ought to be Enough for Anyone"? Vampire is cranking it up to 128MB."

Yeah - Bill Gates once said that.

But here on the 'Detailed datasheet' they say:

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"At least" normally means that there will also be versions with more FastRAM than just 128 mB.

512 mB or 1 gB might be enough for my demands - I actually HAVE 128 mB of RAM in my A4kPPC, and it is NOT enough...

@Dandy

there is discussion relating to a standalone version that has a faster FPGA and at least 1 GB RAM, it even seems that it becomes available relative soon (this year or early next year). We will see what happens. So if you can wait (and as I understood your money supply is limited anyway) I would at least wait for it and then you can decide what you want and can afford.

digging I found this:
http://www.apollo-core.com/knowledge.php?b=1¬e=2723

@ OlafS3 - #11:

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That sounds promising!
A standalone version would render the need of having to use 20-30 yrs old hardware redundant.

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Thanks for the link! Interesting read...