[Coco] hardware scrolling

[Steve Bjork]

On 12/1/2013 2:35 AM, Simon Jonassen wrote:
> Hey Steve !
>
> I hear what your saying...
>
> If i see a "glitch" on the screen when i play with the vdg/sam, i'm at it
> like a dog with a bone until i get it to work ! - in the 80's i programmed
> demos etc for the c64....
>
> But at the same time, alot of people might not have seen all these tricks
> that you are saying have been lost to the eons of time....
>
> So my re-inventing the wheel and making the sourcecode for it freely
> available might help these tricks survive !
>
> Another thing, why was the "DMA" mode such a big no no ???????? - it's in
> there and it can be exploited.....
It was simple that the undocumented modes may not always be there in 
future versions CoCo.

The future was key word for CoCo programmers.  The games that I would 
start work on Today may not hit the stores for almost a year.

To get a game in to the next Catalog that hit the stores in August, the 
final version would need to be in Tandy's hands no later than April.  
Most games where contracted by December for next year's Holiday season.

With these types of lead times, you always had to be watchful of the 
changes in the future.

Add in the fact that there was always a new model of the CoCo on the 
drawing boards.  So, undocumented modes could be gone by the time your 
software hit the stores.  That's not good for sells!

Steve