Uograding VIC-20/C64 BASIC

[robert_sissco]

I know in the C128 into U36 you can put in a BASIC 8 ROM chip to upgrade the BASIC there, and in the PET's there is a version 4 of BASIC, but that the VIC-20 and C64 are both stuck on version 2 of BASIC without an expander cartridge for the systems.

Is is possible to maybe put an upgrade BASIC ROM into either of the middle children of the Commodore 8-bit line so when you boot up it loads that upgraded BASIC version? Or is there something in the KERNALs for the systems that would break this?

I was just curious and not finding a lot on the topic.

 

[Timo W.]

I don't know for sure, but it is very unlikely. On the C64, the region of the BASIC ROM can be switched in and out in order to use the full 64k of memory. That means it can not be any larger. So an upgraded BASIC with more functions and features won't fit into the fixed memory region dedicated to it. Apart from that, you would certainly break compatibility even with games.

 

[Ruud]

There are kind of upgrade ROMs like Simon's BASIC and RadarSoft 50K BASIC. But I'm quite sure that these two are not compatible with othee Commodore BASICs like 3.5 from the Plus/4, 4.0 from the CBMs and 7.0 from the C128.

 

[robert_sissco]

There are kind of upgrade ROMs like Simon's BASIC and RadarSoft 50K BASIC. But I'm quite sure that these two are not compatible with othee Commodore BASICs like 3.5 from the Plus/4, 4.0 from the CBMs and 7.0 from the C128.

And I have several of them for both the C64 and VIC20, I was just wondering if there were updated BASIC ROM's that you could replace on the board like there are KERNAL ROM's

 

[Ruud]

Quite some of those KERNAL ROMs are realized by discarding some other things like the cassette and/or RS232 part and replace with their goodies, for example, handle IEEE drives. I have changed KERNALs for my own reasons but I never thought about doing that to upgrade the original BASIC. And I don't think that it is possible to upgrade to a known higher version because they support the cassette recorder and RS232 as well and that means there is hardly any room left for an upgrade. The only possibility I see is adding extra hardware that enables one to switch ROMs on the fly.