Re: Create Text & High Resolution into Screen

[Eric Smith <eric-no-spam-for-me@brouhaha.com>]

"Bill Garber" <willy46pa@comcast.net> writes:
> I must differ with you here in that more than one character can
> be fetched from RAM.

You can differ all you like, but that's how the hardware works.

I said that in one video cycle (which is half of a complete 1.023 MHz clock
cycle), one character is fetched from RAM.  It is unclear to me why you
would think that the memory can provide more then one byte per memory cycle,
since the memory is only one byte wide.

On the IIe and later machines, the memory is arranged to be wider (main
and alternate banks accessed in parallel), so two bytes can be fetched per
memory cycle, used for 80-column text and for double hires graphics.

> Entire lines can be fetched and displayed.

Not in a single cycle.

> Also, I can not buy anything being an "input" to a ROM ( Read
> Only Memory ).

If you don't "input" an address to a ROM, you're not going to get
very useful output from it.  Read a data sheet on a ROM chip sometime.