From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Olson Subject: Re: hardware questions Date: Sat, 30 Nov 2002 19:09:00 -0800 (PST) Sender: linux-8086-owner@vger.kernel.org Message-ID: <20021130190533.B93589-100000@agora.rdrop.com> References: Mime-Version: 1.0 Return-path: In-Reply-To: List-Id: Content-Type: TEXT/PLAIN; charset="us-ascii" Content-Transfer-Encoding: 7bit To: jb1@btstream.com Cc: elks > Watch out for address line A20. The IBM and clones use it, but it actually > comes from an I/O pin on the keyboard controller rather than the CPU. > Sorry, I don't remember any details. > > The Intel databook for the 8088 is titled "iAPX 88 Book". Mine is dated > July 1981, and has stickers on it indicating that it was actually > published by Reston Publishing Company, Inc., a Prentice-Hall company. No! > I won't part with it! Thanks, maybe this kind-of leads into what has been confusing me a little, that being how the 8086 and the newer 16 bit data bus CPUs talk to other devices on the bus. I only see a need for 19 of the 20 address lines because only even addresses would be needed, the odd and even bytes would both be transfered at the same time. I'll keep hunting for more information. Dan