Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!gatech!udel!rochester!pt.cs.cmu.edu!b.gp.cs.cmu.edu!Ralf.Brown@B.GP.CS.CMU.EDU
From: Ralf.Brown@B.GP.CS.CMU.EDU
Newsgroups: comp.sys.ibm.pc
Subject: Re: Usable I/O Address range on the PC bus ...
Message-ID: <23841a7a@ralf>
Date: 18 Nov 88 12:41:30 GMT
Sender: ralf@b.gp.cs.cmu.edu
Lines: 13
In-Reply-To: <5065@whuts.ATT.COM>

In article <5065@whuts.ATT.COM>, jmbj@whuts.ATT.COM (BITTMAN) writes:
}Assuming a "byte" here is an I/O address, there are at least 1024
}addresses available for each I/O address claimed, the 8-bit PC XT bus has
}10 "extra" address lines (1024) and the AT has 14 "extra" for a

I/O addresses only have 16 bits, on both PC and AT, thus there are 64 I/O
addresses for each value of the lower ten bits.

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