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Date:      Mon, 17 Dec 2001 21:36:17 -0500 (EST)
From:      Garrett Wollman <wollman@khavrinen.lcs.mit.edu>
To:        imp@harmony.village.org
Cc:        arch@FreeBSD.org
Subject:   Re: Please review: changes to MI bus code for sparc64 
Message-ID:  <200112180236.fBI2aHM39997@khavrinen.lcs.mit.edu>
In-Reply-To: <200112180212.fBI2CUM81074@harmony.village.org>
References:  <20011213211544.A4747@crow.dom2ip.de> <20011213192033.A871@crow.dom2ip.de> <200112131901.fBDJ1hl02003@mass.dis.org> <20011213211544.A4747@crow.dom2ip.de>

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In article <200112180212.fBI2CUM81074@harmony.village.org> you write:
>I don't understand the difference between boundary and alignment.

A boundary is a locus which an allocation must not cross.  Consider,
for example, the crufty old ISA DMA hardware: 16-bit transfers need
only 16-bit alignment, but must not cross a 64-kbyte ``page''
boundary, because the address-generation logic was kluged out of a
16-bit DMA controller and an 8-bit latch.

-GAWollman

-- 
Garrett A. Wollman   | O Siem / We are all family / O Siem / We're all the same
wollman@lcs.mit.edu  | O Siem / The fires of freedom 
Opinions not those of| Dance in the burning flame
MIT, LCS, CRS, or NSA|                     - Susan Aglukark and Chad Irschick

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