TI-99/4A Floppies

[Tony Duell]

> I never used a 99/4 of any flavor, but I recall hearing a very different 
> explanation why the stock BASIC was so slow.  The graphics chip had 
> nothing to do with it; as far as I know there is no way to run code on 
> the graphics chip (it is a simple raster+sprite engine).

I've never used a TI99/4A either, I do have one somewhere, but I've never 
done anything with it.

I assume the grahpics chip is a TMS9918 or similar. In which case you can 
hang RAM off that, it doesn't appear in the main CPU memory map, but is 
accessed thorugh some registes in said chip. I'd heard that on an 
unexpanded 99/4A _all_ the RAM was on the video chip, your BASIC program 
was stored in said RAM, and the interpretter (in ROM, in the CPU address 
space) had to read your program via the video chip registers.

This (a) made the machine very slow and (b) made it impossble to program 
in machine code.


-tony