Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!ucbvax!mtxinu!sybase!ohday!tim
From: tim@ohday.sybase.com (Tim Wood)
Newsgroups: comp.unix.questions
Subject: Re: Help-Bus Errors
Keywords: what causes them
Message-ID: <8403@sybase.sybase.com>
Date: 14 Feb 90 18:41:12 GMT
References: <1810@lzga.ATT.COM> <1990Feb10.192028.16025@eddie.mit.edu>
Sender: news@Sybase.COM
Reply-To: tim@ohday.sybase.com (Tim Wood)
Organization: Sybase, Inc.
Lines: 18

In article <1990Feb10.192028.16025@eddie.mit.edu> aryeh@eddie.MIT.EDU (Aryeh M. Weiss) writes:
>SIGBUS errors are
>quite machine dependent, but in my experience can be caused by ...
>[referencing] an odd address with a word oriented instruction
>(this is a no-no on Vaxes and 68000's, but 80x86 systems don't mind).
		     ^^^^^
The VAX does not have alignment restrictions, that is,
one may read or write a multi-byte operands at a byte-boundary address.
Doing this incurs some performance penalties on the VAX, as well as
making your program less portable.  The trend these days, especially with
RISC, seems to be toward alignment restriction.  Nice explanation of coredump 
signals, BTW.
-TW
---
Sybase, Inc. / 6475 Christie Ave. / Emeryville, CA / 94608	  415-596-3500
tim@sybase.com          {pacbell,pyramid,sun,{uunet,ucbvax}!mtxinu}!sybase!tim
		This message is solely my personal opinion.
		It is not a representation of Sybase, Inc.  OK.