On 26 April 2011 10:08, Chris Pile <[email protected]> wrote:
> Hi Si, > > Yep - clear as mud! :-) > > Seriously, many thanks for the explanation - even my hardware-limited brain > managed > to understand all that! I take my hat off to hardware designers, it's > certainly a black art! > > Mmm. I often used to wonder why VRAM wasn't used... I guess Sam just missed the price drop? Can't find any readily available data on prices of VRAM in 1988 although the suggestion is that by 1990 or so it was only a 20% premium over DRAM. There's a page which suggests that up to then it was about 100%, which explains it I suppose. Would it have been better to have 48kB of more expensive display memory, giving only the live display and a secondary (for double-buffering) but losing the ability to use any page in RAM as the screen? I guess that means no more infinite-ball demos ... but I'm sure we could live with that :-) For me the real mistake, though, was the lack of capability to set the display address counter for instant free hardware scrolling (and for not much electronics, unless I'm missing something) - even the BBC Micro had that in 1982. Apologies, I'm hijacking the thread again. Erm, Hula-hoops: beef or salt-n-vinegar? G
