Found RAM card for GVP CPU

[Heiroglyph]

I came up with a cool find today:
http://www.amiga-hardware.com/showhardware.cgi?HARDID=228

It's the RAM expansion module for GVP T-Rex cards that has 6 additional slots to expand the total memory to 256MB!

I had no idea any existing CPU card could even hold that much.

If I don't find a compatible CPU card in the warehouse, I'll probably sell this little gem.

Edit: As was pointed out, the link is incorrect, there are no 32MB GVP SIMMs.

[Matt_H]

Nice find, but I don't think it can actually reach 256MB - I'm pretty sure 16MB was the largest SIMM size GVP made.

Hope it finds a good home

[Heiroglyph]

Nice find, but I don't think it can actually reach 256MB - I'm pretty sure 16MB was the largest SIMM size GVP made.

Hope it finds a good home

Good point...I was just going by the Big Book comments.

Anyway, something I'd never seen before and I'd still like to find the CPU to go with it.

[Matt_H]

Big Book is good, but not infallible
Then again, I also wouldn't be surprised if GVP's wizards found a way around the 128MB limit with some prototype 32MB SIMMs and non-autoconfig space

As to the TRex itself, didn't Softhut produce a batch of these last year? Or was that a different model? (I seem to recall an integrated SCSI controller)

[Heiroglyph]

Those are the 4060's, this is for the T-Rex which was an 040 as far as I know and had a connector for a SCSI module that never saw the light of day.

I've been looking at making some hardware lately and I don't see why everyone stopped at 128MB other than RAM prices and density.

Looks like there's plenty of room for a couple GB up there with the densities we have today.

[Colmiga]

The memory address space for the CPU slot on the A3000(T)/A4000(T) is limited to 128MB max anyway. This means 256MB is impossible unless GVP devised some way to get around this limitation (which I doubt). I'm guessing that's why the RAM board has 6 slots (plus 2 on the T-Rex) to accomodate 8x16MB GVP SIMMs for 128MB.

I wish I had one of these when I owned a T-Rex board. Reason I sold mine was because it could not take any more RAM than the 32MB it had on it.

[Heiroglyph]

Is there a documented limit other than 32bits and addresses used by other devices?

Local bus slaves (at least on A3000, the only reference I have) are within $08000000 to $0fffffff, so there is a limit there.

I don't see why you couldn't map some of the the RAM into another unused area  like $80000000 to $FEFFFFFF, decode it yourself instead of using Gary, then link it in at runtime.

That's about 2GB of additional space without even getting touching the Z3 address space.

[Zac67]

The memory address space for the CPU slot on the A3000(T)/A4000(T) is limited to 128MB max anyway.

True. But this should be relatively easy to overcome if you provide your own address decoder and abandon DMA from mobo to accelerator RAM.

[Jakodemus]

Nice find, but sadly little useless. Those 16mb GVP-simms cost so much that it's cheaper to buy another accelerator. Thats why my T-Rex only has 8mb of ram.