Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!zaphod.mps.ohio-state.edu!wuarchive!uunet!viusys!uxui!unislc!harem!wes
From: wes@harem.clydeunix.com (Barnacle Wes)
Newsgroups: comp.unix.sysv386
Subject: Re: cu/ecu through TCP/IP (plus ecu porting status)
Summary: The C code doesn't dictate the memory image!
Message-ID: <313@harem.clydeunix.com>
Date: 31 May 91 22:13:19 GMT
References: <7525@spdcc.SPDCC.COM> <409@n4hgf.Mt-Park.GA.US> <1060@aega84.UUCP> <1061@aega84.UUCP>
Organization: Clyde's Harem; Eunuchs Guard
Lines: 32

In article <1061@aega84.UUCP>, lh@aega84.UUCP (L. Hirschbiegel) writes:
> [Discussion of ioctl's not working across RFS on heterogeneous
> machines...]
> Our RFS server is of course the same type of machine (all Compaqs)
> running the identical os version.
> But anyway: the structs used by the ioctl's should never be dependend
> on the type of cpu - as long as it is all SysV.3 or SysV.4 (and this
> IS in fact the limiting factor for RFS:-). I didn't find any differences
> in struct termio (which is obviously used here) depending on the
> version of SysV.

The C code for the structure is not the problem; the problem comes with
such things as byte order and data element alignment.  One machine may
stick "gaps" of unused memory in the middle of a struct - such as the
MIPS where nearly everything gets aligned on a 4-byte (32-bit word)
boundary.  And, of course, if you try to go from a little-endian to a
big-endian (say, Intel to Motorola) cpu without byte-swapping, you're
really screwed.

> To conclude, we have used shared serial devices via RFS very extensively
> with almost zero problems, but the question still remains: can it be
> done with an RS6000? (Think this was the original posters equipment).
> If there is no RFS for the beast the problem is void.

I Dunno, but I doubt it.  What's the byte order on the RS?

	Wes Peters
-- 
#include <std/disclaimer.h>                               The worst day sailing
My opinions, your screen.                                   is much better than
Raxco had nothing to do with this!                        the best day at work.
     Wes Peters:  wes@harem.clydeunix.com   ...!sun!unislc!harem!wes