[Coco] CoCo and Rasberry Pi ( and Software Rant )

[Allen Huffman]

On Apr 10, 2013, at 9:01 AM, Brett Gordon <beretta42 at gmail.com> wrote:
> Oh yeah the PI is amazingly cheap.

You had me at that part. :-)

> have.  Even after you boot from ROM you get a static enviroment:  both
> RS-DOS and RBF systems have NO SUPPORT FOR PARTITIONING.  This is
> stupid. Disk Partition Tables have been agreed upon and in use in the

Actually... I wrote some articles "back in the day" about how I was effectively partitioning a SCSI hard drive with RGB-DOS so I could use it all. RGB-DOS (HDB-DOS, etc.) starts at a sector offset in ROM, and then goes from there. You could make it skip past the first part of the drive for OS-9 to live there (sorta a partition), but I had routines that would bank the drives in and out to see other sections. It could not see more than 255 drives at a time, but I could get to way more than 255 disk images. It was really neat.

> Why an interrupted 8 bit becker/boisy port?  8 bits is our inherent
> data bus on the 6809.  16 bits would be a touch faster on the 6809,
> but 8 bits is more doable on the Pi than 16 bits.  Yes, DMA would be
> awesomely faster, but has two drawbacks: (1) unless the DMA controller
> could put drive data exactly where our OS's want it, then its no
> faster than a plain becker/boisy port. and (2) this is complicated.

That sounds great. Where do we start?

		-- Allen