Here's one for the lawyers!

[JimS]

Hmmm.... Isn't the 6502 itself a knock-off of the Motorola 6800? (not a typo! there was such a chip)

Speaking of that book... I was recently copying my scanned Amiga magazines onto the new HD big enough to hold them all... I came across the Byte 'obituary' for Commodore in 1994. The author says "It would take a book to explain the death od Commodore"... took a while, but guess so. :-)
 

 

[JimS]

From the Wikipedia....

The 6502 was designed primarily by the same team that had designed the Motorola 6800. After quitting Motorola en-masse, they quickly designed the 6501, a completely new design that was nevertheless pin-compatible with the 6800. Motorola sued immediately, and although today the case would have been dismissed out of hand, the damage to MOS was enough for them to agree to stop producing the 6501.

The result was the "lawsuit-compatible" 6502, differing only by a pinout re-arrangement unusable in a 6800 motherboard; now Motorola was apparently no longer interested.

[JimS]

InTheSand wrote:
Any chance you might be able to make the Byte obituary available online somewhere?

 - Ali

Sure. Try here...

[img=http://img484.imageshack.us/img484/5606/byteripcommodore940ta.th.jpg]

[JimS]

Oliver wrote:
Wow, that's lame.  Pin compatible chips with different implementations are so common now.

Hmm... maybe so for trivial stuff like a quad input Nand package, but I think you could make a tougher argument when talking about a CPU. There's a lot of thought behind the design of the register layout & instruction set.  These days, that sort of thing is copyrightable (or maybe patentable). Just consider the 'cores' the FPGA fans talk about.