cartridge questions

[Overdoc]

Hi VIC Lovers,

I recently had a look at VIC (game)cartridges, and noticed that most of them are 8K, which use Memory Location BLK5 $A000-$C000, and don't require any other additional ram.
Some also seem be 16K ones, which seem to occupy BLK5 $A000-$C000, as well as BLK3 $6000-$8000, wich no additional ram needed.

However, I have not seen any 24K or 32K cartridges?
Also, I think there are none which need an additional 8K or 16K ram expansion, or have 8/16K ram integrated besides their 8/16K Rom?

Is there any technical reason for this ?
Or would such a cartridge simply have been to expensive? (rams were probably more expensive than eproms?)

What do you think?
I think the VIC would have seen some even greater games with combined rom/ram cartridges.

[beamrider]

I think it would have been far too expensive back in the day especially as the RAM is effectively wasted unless you have the option to disable AutoStart.

No reason it couldn't be done today. The only advantage is that it allows a larger "working storage" area for the code.

[Mike]

For most of the cartridges of the time, the 5K internal RAM of the VIC-20 probably was more than sufficient to do their job.

After all, their machine code surely didn't need anything of the BASIC interpreter (with a few exceptions), neither didn't they (need to) call most of the KERNAL routines. Especially, none of the file system calls were necessary, as the code was already 'there', in BLK5 (and possibly somewhere else in BLK1..3). So the code was free to use most of zero page and stack and all other RAM built into the VIC-20 for their own.

Some utility cartridges didn't come with extra RAM, but surely could make use of it. Most notably, language extensions like Waterloo BASIC, those few FORTH cartridges and so on. That use case then required a cartridge extender, of course.

As a notable exception, Super Expander came with an extra +3K RAM. Otherwise, its primary use as BASIC extension for hires graphics wouldn't have worked at all - the graphics screen nearly takes up all internal RAM, so any user (BASIC) program has to go somewhere else.


That being said, newer cartridge developments do tend to combine RAM and ROM into one cartridge. Notable examples include Mega-Cart, FE3, Ultimem, Penultimate. Also, game cartridges like Cheese & Onion feature extra, non-volatile RAM to save game states.