"Error en el bus" from python

greg greg at cosc.canterbury.ac.nz
Tue Oct 13 01:46:24 CEST 2009

Jorgen Grahn wrote:

> "Bus Error" is an old BSD-ism which I guess you don't see much in
> Linux or Solaris these days (or maybe I never run buggy code ;-).  It
> translates roughly to "segmentation fault", but IIRC it is more about
> accessing memory words on nonaligned adresses than about accessing
> addresses your process doesn't own.

I think the term goes back to the PDP-11 or thereabouts. The
Unibus used a handshaking protocol, and if you tried to access
an address that didn't have any memory or I/O device assigned
to it, the bus hardware would time out and you got an interrupt.

The 68K family also used the term in a similar way.

I think the distinction between a bus error and a seg fault is
that bus errors are to do with physical addresses, and seg
faults are to do with virtual addresses.


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