Date: Tue, 28 Sep 1999 10:56:18 -0600 From: "Ronald G. Minnich" <rminnich@lanl.gov> To: freebsd-hackers@FreeBSD.ORG Subject: Re: Netscape Bus Error Message-ID: <Pine.SGI.4.10.9909281047290.181652-100000@acl.lanl.gov> In-Reply-To: <37F0DC3D.7F4A969D@calderasystems.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On Tue, 28 Sep 1999, Darren R. Davis wrote: > Nate Williams wrote: > I believe that a Bus Error is specifically referencing miss aligned data vs > segmentation violation > (SIGSEGV) which is accessing data that is either free'd or not yours, etc. > I always thought > it strange on an Intel processor, since this was more a 68K/RISC thing. Original meaning, from the original machine: Bus error: you got a literal bus error when doing a read or write operation on the I/O bus. Usually a bus timeout, i.e. you referenced an address on the bus (well, Unibus back then) and nothing came back in the timeout period. Nowadays it includes the bus timeout type of thing (which has a different name on PCI, but same meaning) as well as other things: for example on SGIs you can get a bus error signal when you use bad pointer alignment. Segv: you referenced memory for which you had no mapping. usually a reference through 0, but also lots of other fun stuff, like trashed return addresses on the stack. Funny but true: in the early days freebsd had the meaning of these reversed, as did most of the bsds descended from 386bsd. This got fixed in openbsd first. I don't know if/when freebsd followed suit. Does anyone out there? I haven't checked lately ... ron To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?Pine.SGI.4.10.9909281047290.181652-100000>