Good description of Apple ][ disk controller

[Steven N. Hirsch]

On Mon, 21 Mar 2005, Eric Smith wrote:

> Sellam wrote:
> > I am pretty surprised that I can't find any good technical descriptions of
> > the Apple ][ disk controller.  It's not in the DOS manual and, come to
> > think of it, I can't think of any publication Apple came out with that
> > describes it.  I wonder why this is?
> 
> Because Apple considered it somewhat proprietary.  Though there's
> a patent on it:
>     http://www.brouhaha.com/~eric/patent/us/4210959.pdf
> 
> There's also a patent on the later IWM chip, which was basically
> a single chip version with a few improvements:
>     http://www.brouhaha.com/~eric/patent/us/4742448.pdf
> 

IMHO, this is a good example of proper application of patent law.  Unlike 
some of the complete garbage getting accepted currently, the GCR technique 
was a non-obvious, unique method for dealing with a system of hardware, 
software and mechanical devices that is not 100% predictable (speed 
variations, bit dropouts, etc.)

Just my 0.02..

Steve