A megabyte of RAM in your Apple II - in 1983

Nice story here about acquiring and fixing a very rare memory upgrade card, from Legend:


Nice though that is, I cannot imagine what you’d use 1MB for! I wrote and published games back in the day on these machines; Henri on Atari 800 was 6k if 6502 assembler, Bellum was 9-10k of assembler, Elektraglide was sub 16k of code also.

Sure, the limit on bitmap graphics usage was partly memory, but mostly the speed of the 6502 to move bytes fast enough.

I can not think what would use more than 64k on 6502. Time sharing did use more
ram but the 6502 is just under powered for more users as it is a 8 bit cpu.

A very common usage of large memory cards on these old systems was as RAM disks. ProDOS on the Apple II has support for this.

Some late-life program for the Apple II used a very large amount of RAM, and ordinarily operated via overlays; the Apple II DeskTop was one such package, which provided a very Mac-like interface with mouse and hot-swappable disks (IIgs-style) on the 8-bit IIs. I don’t know if any of those packages could use RAM extensions, but I know that competing products on other platforms, such as GEOS for The C64/128, could. (There was also GEOS for Apple II, I don’t know how much it shared with GEOS for C64.)

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This made me wonder. There were quite a few 8-bit minis in the 1980s and S100 machines were commonly used for multi-user applications, as well. Given the rather small amount of registers of the 6502, it should be quite efficient for switching users, if we switched banks including the stack and zero-page on a simple hardware interrupt (NMI), and use serial communications with dedicated controllers. (Without any RAM sharing for video, we should be able to drive it in the up-to-2MHz range.)
Still, I don’t know any 6502 based small time sharing system. – Were there any of note?

ProDOS - Ramdisk, AppleWorks, VisiCalc…

I’m fairly sure they could all use, or be patched to use as much extra RAM as you could afford.

Lets not forget the business apps. were still selling Apple IIs (or IIe, Platinums, &c. ) well into the 90s…


We’ve mentioned this one before - from Austria, like yourself!
The es65 multi-user 6502 system from Austria
(It’s not typical for multi-user, in that it does contain one CPU for each user.)

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Well, that’s pretty niche… :slight_smile:

Any like that for the 6809?