Page 1 of 1

Which memory expansions with more than +37K are you using?

Posted: Tue Feb 13, 2018 6:23 am
by pixel
I've got the Ultimem/VicMIDI – but I'm wondering which other expansions would be worth supporting.

Re: Which memory expansions with more than +37K are you using?

Posted: Tue Feb 13, 2018 6:42 am
by Mike
Yet another memory expansion poll? :lol:

Main issue: an application program is not supposed to do any accesses into I/O 2/3, for whatever reason. You have no way to ensure, whether there is RAM, ROM, or read/write sensitive I/O which can do anything else than store data. It could perform a reset, change the banking scheme, erase the flash memory, etc. IMO, the only legit user of I/O 2/3 is the cartridge firmware in question. Nothing else.

That being said: the only other widespread cartridge I know which supports more than +32K +3K RAM is FE3. There, you could use the FE3 RAM Disk to have an abstracted interface for data storage. It could be worthwhile to port this RAM Disk driver over to Ultimem.

Megacart, while not officially giving extra RAM in I/O 2/3, has NVRAM there to store cartridge settings, and also holds registers in that range. A small address range in I/O 3 is unused by the cartridge firmware and has been "converted" for stripped down versions of SJLOAD, etc. The considerations about unwanted side effects noted above apply nonetheless.

So there...


Edit: Ich weiß, ich bin da eine Spaßbremse. Aber hier steht das gleiche auch schon. ;)

Edit 2: hast PM.

Re: Which memory expansions with more than +37K are you using?

Posted: Tue Feb 13, 2018 6:56 am
by pixel
Mike wrote:Yet another memory expansion poll? :lol:
Am really losing track of a lot of things at the moment. :)
Main issue: an application program is not supposed to do any accesses into I/O 2/3, for whatever reason. You have no way to ensure, whether there is RAM, ROM, or read/write sensitive I/O which can do anything else than store data. It could perform a reset, change the banking scheme, erase the flash memory, etc. IMO, the only legit user of I/O 2/3 is the cartridge firmware in question. Nothing else.
Am not a fan of that area. In fact banked BLK5 is what I'd prefer at the moment.
That being said: the only other widespread cartridge I know which supports more than +32K +3K RAM is FE3. There, you could use the FE3 RAM Disk to have an abstracted interface for data storage. It could be worthwhile to port this RAM Disk driver over to Ultimem.
Näääh! I want to play digis via NMI with no extra interface in between.

btw: I came up with a simple journaling Flash FS for the Ultimem. g boots from it.
Edit: Ich weiß, ich bin da eine Spaßbremse. Aber hier steht das gleiche auch schon. ;)
Passt scho. Kenne hier nur eine Spaßbremse, die wahrscheinlich bald das Kamener Kreuz am Bande bekommt, fürs Aufmischen des Forums. :/

Re: Which memory expansions with more than +37K are you using?

Posted: Tue Feb 13, 2018 6:57 am
by beamrider
so that's why my MegaCart settings keep getting corrupted :x

Re: Which memory expansions with more than +37K are you using?

Posted: Tue Feb 13, 2018 8:01 am
by Mike
pixel wrote:das Kamener Kreuz am Bande
Muaharhar! Den kannte ich noch nicht. :lol:
beamrider wrote:so that's why my MegaCart settings keep getting corrupted :x
Should be easy to find out the culprit. For now, there are not too many candidates out there. While we're at this ... http://sleepingelephant.com/ipw-web/bul ... 90&start=7, and to quote from there:
tokra wrote:Possibly the MegaCart would need to be restored through the Service Menu to its factory settings or stored preferences afterwards.
Mike wrote:Any program or game which requires me to do this, because it wrote all over the Mega-Cart NVRAM won't get a second chance to run on my VIC-20.

Re: Which memory expansions with more than +37K are you using?

Posted: Tue Feb 13, 2018 8:05 am
by pixel
Mike wrote:
pixel wrote:das Kamener Kreuz am Bande
Muaharhar! Den kannte ich noch nicht. :lol:
Erlebe mich angesoffen auf der Revision, wenn ich Deutsch rede. ;)

Re: Which memory expansions with more than +37K are you using?

Posted: Tue Feb 13, 2018 8:59 am
by tokra
Topic-drift: Are you coming to Revision?

http://sleepingelephant.com/ipw-web/bul ... f=1&t=8814

Be ready to have nuclear fusion explained in detail by Mike :mrgreen:

Back-to-topic: Personally, I don't mind using RAM in IO2/3, but such a program will not have the luxury of being used in the real world by a lot of people. 35K expansion is already pushing it and most people only got those to be able to play "Doom". I take full responsibility for talking Kweepa into using 35K back then.

Re: Which memory expansions with more than +37K are you using?

Posted: Tue Feb 13, 2018 9:10 am
by pixel
tokra wrote:Topic-drift: Are you coming to Revision?
Can't tell. Dad's in palliative chemo...
Be ready to have nuclear fusion explained in detail by Mike :mrgreen:
As long as I can make him hate me, too. ;)
Back-to-topic: Personally, I don't mind using RAM in IO2/3, but such a program will not have the luxury of being used in the real world by a lot of people. 35K expansion is already pushing it and most people only got those to be able to play "Doom". I take full responsibility for talking Kweepa into using 35K back then.
I thought it was +37K? :shock:

Re: Which memory expansions with more than +37K are you using?

Posted: Tue Feb 13, 2018 9:36 am
by Mike
tokra wrote:Be ready to have nuclear fusion explained in detail by Mike :mrgreen:
Awww! Don't spoil the fun for me! ;)

In any case, I pointed pixel to the home page of my employer already some time ago. :)
pixel wrote:As long as I can make him hate me, too. ;)
Unlikely. Someone needs to be obliged as aide for developing planets. :twisted:
I thought it was +37K? :shock:
No it isn't. Just +35K flat.

Even that is uncommon enough to be overlooked and/or taken as "doesn't just +32K suffice?" by many people.


Edit:
tokra wrote:I take full responsibility for talking Kweepa into using 35K back then.
I don't see any problem in this. First, both Mega-Cart and FE3 (<- there, fingers crossed though) provide this RAM expansion and are widespread enough to make use of this RAM expansion option a viable choice. Second, even with 'of-that-time' equipment, +35K are possible with a cartridge extender hosting one VIC-1111, two VIC-1110 switched for BLK3 and BLK5 and one VIC-1210. Or any other 3rd party cartridge.

If you're talking about sensible RAM limits, then +16K was that figure, when one insists on using only original CBM equipment and rules out a cartridge extender. That's actually a limit I honoured for some of my programs. :)

Re: Which memory expansions with more than +37K are you using?

Posted: Tue Feb 13, 2018 9:37 am
by tokra
Nope, Doom uses +35K:

RAM1,2,3 = 3K
BLK1,2,3,5 = 32K

It does NOT use IO2/3.

Re: Which memory expansions with more than +37K are you using?

Posted: Tue Feb 13, 2018 10:54 am
by MCes
BLK5 banked?

I'm remembering something....

http://sleepingelephant.com/ipw-web/bul ... hilit=123k

Re: Which memory expansions with more than +37K are you using?

Posted: Tue Feb 13, 2018 11:15 am
by pixel
MCes wrote:BLK5 banked?

I'm remembering something....

http://sleepingelephant.com/ipw-web/bul ... hilit=123k
Perfect match! :D