Timesharing/multiuser BASIC for MC68K

Kirk Davis kirkbdavis at me.com
Mon Mar 20 17:10:44 CDT 2017


> On Mar 20, 2017, at 2:20 PM, Joseph Zatarski via cctalk <cctalk at classiccmp.org> wrote:
> I just wanted to share a little project I've been working on, it's an
> adaptation of Lee Davison's EhBASIC to become a timeshared multiuser BASIC.
> There's still a bit more to do, but here's a video of it in operation:
> https://youtu.be/SAJpHiBPMcQ
> In that video, it's only running 3 sessions (I had no convenient 4th
> terminal) but it's capable of running 4. It is a very very simple
> preemptive multitasking 'kernel' providing I/O services and performing
> periodic context switches for the instances of the interpreter. It only
> runs a fixed number of processes, and all the process memory is statically
> allocated. EhBASIC lends itself well to this, the code is position
> independent by design, and the memory range is passed in. Everything is
> dereferenced relative to the 'start of memory' pointer. This means no need
> for an MMU or relocation.
> I'm hoping to set this up at VCF MW in September, running 4 terminals.
> More info on the hardware I'm using is available here:
> https://hackaday.io/project/6150-beckman-du600-reverse-engineering
> Pictures:
> https://www.dropbox.com/sh/uw6cjqigk2sdwdy/AAAwP55aelyzrYeP1HVUDdMqa?dl=0
> And another software project I'm working on as well (a ROM monitor program):
> https://github.com/jzatarski/Joe-Mon

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