Expanded memory

[ivop]

Hi,

 

Did anyone ever consider expanding the memory in such a way that one can switch 32kB banks, starting from $0000. Having a different stack and zero page would be very nice for a multitasking OS. Another possibility might be a small circuit that remaps $00xx and/or $01xx to any other page, selected by two 8-bit latches somewhere in the hardware area.

 

Regards,

Edited November 4, 2012 by ivop

[candle]

you can do that using vbxe memory mapping

[Rybags]

VBXE can do that. Problem is, we've got enough compatability problems with what's out there already re creating yet more memory mapping schemes.

 

Multitasking is something not much touched upon - I made a start on something for 128K and over some time back that was to allow task switching on warmstart but put it aside.

 

Pre-emptive MT is pretty much out of the question, even cooperative is pushing it, and the 6502 doesn't do any favours for us either. The Display List feature of Antic would make doing some sort of Amiga-like UI possible, but IMO a useful multitasking system for Atari would need to support existing software and not impose too many rules.

Edited November 4, 2012 by Rybags

[ClausB]

Did anyone ever consider expanding the memory in such a way that one can switch 32kB banks, starting from $0000?

 

Yes.

http://www.atariage.com/forums/topic/122470-ram-upgrade-applications/page__st__75?do=findComment&comment=1656892

[ivop]

@Claus, thanks! I remember reading that article a while ago but totally forgot about it.

 

@Rybags, I agree that more memory mapping schemes might be inconvenient, but I suppose having two expansions side by side would not be such a problem, i.e. traditional portb $4000-7fff and another expansion for the lower 16kB