Open Source, DIY 512KB RAM Expansion

[eto]

I'm working on a video about a similar RAM upgrade for the CPC and I was wondering what are some of the best demos/games/apps that showcase having more than 128KB of RAM. I already have FutureOS and SymbOS in the list. Anything else that you would say is really cool? Any dev environments (on the CPC itself) that can use that much RAM for something useful?

I asked a similar question a year ago, there wasn't a lot of examples that really benefit from more than 128K: https://www.cpcwiki.eu/forum/amstrad-cpc-hardware/what-memory-expansion-size-to-choose/msg220291/#msg220291

Afaik @zhulien is working on some projects that will take advantage of a lot of RAM. 

[zhulien]

yes,

MCP (master control program); currently allows different background tasks in AMSDOS 1 per 16kb bank - this is a POC which is reasonable code that doesn't need throwing away.  The idea is to make hardware drivers available to AMSDOS in a standard manner - in a way that get adopted.  This set of drivers likely will also be compatible with PrimalOS - which isn't specifically AMSDOS, but can run on top of AMSDOS too.

I have already coded POCs of memory allocations and such for support up to 4mb RAM - as in a heap.  This uses 24 bit addressing.  I have designed the virtual memory logic to cater for up to 16mb RAM (4mb physical) - using packed far addresses too, the benefit is not to have 16mb RAM, but to allow 128kb systems run software that requires more RAM but allowing systems with 1mb, 2mb, 4mb to run optimally.  If a compiler or assembler catered for what I need here now, it would be sooner than later, but I need to put support in here for my compiler so that it's easy to write large software that also works on 128kb systems (pretty fast) or 64kb systems (pretty slow - but runs).  I am actually almost settled on 4mb RAM ceiling with 64 byte block size instead of 16mb RAM ceiling with 256 byte block size.  But... I guess it would be relatively easy to make 2 separate builds if we ever got a 16mb RAM expansion.  I can elaborate more later, but you cna read the RAM tab here: https://docs.google.com/spreadsheets/d/1XgRVlh27K_C0-gMtroMhN8lK9mAQxVQg1x-3M42kBYo/edit?usp=sharing  Of all the allocation / deallocation tests I have created and coded, the RAT (RAM Allocation Table) method seems to be the best balance for performance and accessibility for a Z80 system with lots of RAM rather than worrying about the loss of every single byte and catering for 24 bit far addresses and tralling long linked lists to find free blocks.

I have been playing with modified locomotive BASIC to improve the ways it uses RAM too. 

RAM usage: I am looking at a solution that to me is the "right way of doing things" on a CPC.  Goal: plug in memory, run some software (MCP? Primal? which initialises RAM and drivers), run applications or games that use the RAM and drivers in a nice way without trashing everything.

Should every CPC owner have at least 576kb RAM? ABSOLUTLY!!!  YES YES YES x 576 times.

[zhulien]

I'm working on a video about a similar RAM upgrade for the CPC and I was wondering what are some of the best demos/games/apps that showcase having more than 128KB of RAM. I already have FutureOS and SymbOS in the list. Anything else that you would say is really cool? Any dev environments (on the CPC itself) that can use that much RAM for something useful?

Try Alyssa Database as reviewed in CPC Attack!

[Anthony Flack]

My Bomb Jack remake requires 128k and a disk drive but the eventual intention is to have it detect if 256k is available and load the entire game (title screen, all backgrounds) into memory at once. I don't have 256k of memory to test with but I guess I'll figure it out.

I do have an M4 board and running the game from that is very fast and I like that; using an extra 128k as a ram disk seems like a worthwhile thing to add for people who have it.

Also it should make for a truly epic disk-grinding session when loading the whole thing from the floppy drive.

[eto]

but I guess I'll figure it out.

You can use Winape to simulate it. 
Or replace the second RAM bank with 256Kbit ICs: https://www.cpcwiki.eu/index.php/CPC_6320_/_CPC_6512_-_internal_320K_/_512K_for_CPC_6128

[Brocky]

I have made a 3D printed box.
You can find the stl-files at Thingiverse: https://www.thingiverse.com/thing:3305898
You will need two smaal screws to assemble it.


I have also 9 bare boards, if anyone needs one, just PM me.

this is slightly offtopic..sorry....

does anyone have a different model for the case for the 512kb ram expansion?

i tried printing the one above 3 times and every time its putting thick strands across the internals (on a diagonal).. which are IMPOSSIBLE to remove....these strands are not showin in the slicer...so i dont know how they are getting there...

my slicer is also bitching that the model is corrupt and needs fixing ...this is what i think is causing the the internal strands..

ive also noticed that the card wont even fit into the slot... the capacitor is too high!..and the IDC slot is too small! (and no its not my printer...everything else ive printed has been perfect...its only this model giving me greif!)

heres a few pics of what i mean...

[00WReX]

Firstly, I've gotta say how crazy it is that this 3d print was released in December 2018, and 6 years later we a both printing this on the same day. Second, sorry for the long post, this is part of my therapy after spending way longer than I should have on this 3d print.

Anyway, long story short, I manage to coax the 512k RAM board into that 3d case...but wow, what a f%#@^&* pain in the @r$* it was. I have a cheap Creality printer and just used the Creality splicer (I did not get any errors).

I chose to print the case vertical, exactly how it would sit normally.

The trouble with this print is that it is basically one thin case, not split into a front and back half like other cartridge type cases, so any internal clean up is very awkward.
Even removing the case vent supports was painful.

I did not get thick strands like you mention, but did get a lot of little supports running down the PCB channel.
I very slowly managed to clear most of the PCB channel, and then made the mistake of trying to fit the RAM board.
It was an extremely tight fit all round and luckily I had previously mounted the capacitor on it's side.
About quarter of the way in, the board got so tight I had to coax it in with a rubber mallet...
It was then that I realised the opening for the connector was a fraction too small...
So about 80% into the case and the PCB was stuck solid.
It took a very long time (was at the point of cutting up the 3d print to retrieve the board), eventually the rubber mallet with a block of wood managed to get it out.
So then I filed the opening for the connector, and tried again (still had to used the rubber mallet to insert the PCB.
The tolerances are very exact, so everything is extremely tight, with absolutely no wiggle room.
So this is my one and only 512k RAM cartridge case...

Here are some pictures, the bare board is to show the capacitor mounted flat.

Cheers,
Shane

[Brocky]

Firstly, I've gotta say how crazy it is that this 3d print was released in December 2018, and 6 years later we a both printing this on the same day. Second, sorry for the long post, this is part of my therapy after spending way longer than I should have on this 3d print.

Anyway, long story short, I manage to coax the 512k RAM board into that 3d case...but wow, what a f%#@^&* pain in the @r$* it was. I have a cheap Creality printer and just used the Creality splicer (I did not get any errors).

I chose to print the case vertical, exactly how it would sit normally.

The trouble with this print is that it is basically one thin case, not split into a front and back half like other cartridge type cases, so any internal clean up is very awkward.
Even removing the case vent supports was painful.

I did not get thick strands like you mention, but did get a lot of little supports running down the PCB channel.
I very slowly managed to clear most of the PCB channel, and then made the mistake of trying to fit the RAM board.
It was an extremely tight fit all round and luckily I had previously mounted the capacitor on it's side.
About quarter of the way in, the board got so tight I had to coax it in with a rubber mallet...
It was then that I realised the opening for the connector was a fraction too small...
So about 80% into the case and the PCB was stuck solid.
It took a very long time (was at the point of cutting up the 3d print to retrieve the board), eventually the rubber mallet with a block of wood managed to get it out.
So then I filed the opening for the connector, and tried again (still had to used the rubber mallet to insert the PCB.
The tolerances are very exact, so everything is extremely tight, with absolutely no wiggle room.
So this is my one and only 512k RAM cartridge case...

Here are some pictures, the bare board is to show the capacitor mounted flat.

Cheers,
Shane

interesting!....glad you got it sorted!

i too flipped the case around to print it as it would stand (the slicer would bitch about a floating cantilever if it wasnt printed the right way up!).... i also didnt need to print with supports it printed the slots perfect every time...

one glaring thing im noticing now thanks to your pics..... youre using the board with discrete logic... im using the v1.1 board which has the capacitor in a different place..and the board is actually smaller...
my board doesnt actually fit into the PCB channel.... the channels are 90mm apart... where my board is only 76mm wide...and the PCB itself is slightly too thick to even slot into the channel...
so it seems this case is not the right one for me anyways!

guess im gonna have to model my own...
ive only had my Creality printer a few weeks ($100 off at jaycar!) so havent needed to model my own ..yet.. i might look at resizing the M4 case, to keep things looking the same...

[00WReX]

It seems we are both Australians.
I also purchased my printer from Jaycar at the start of the year when they had the same special. 
Creality Ender-3 V3 SE.  Used it a bit at first...this was the first thing I printed in around 5 months.

Cheers,
Shane

[Brocky]

It seems we are both Australians.
I also purchased my printer from Jaycar at the start of the year when they had the same special.
Creality Ender-3 V3 SE.  Used it a bit at first...this was the first thing I printed in around 5 months.

Cheers,
Shane

thats the printer i got too...
as i said..everything else ive thrown at it has printed pretty good, except when i tuned the speed to 200%.. and got all sorts of buring and stringing..i know not to do that anymore! 
ive already gone through about 800g of 1kg roll of filament, doing test prints and printing a few cases for the M4 board and GBS8200