Path: utzoo!attcan!uunet!lll-winken!lll-lcc!lll-tis!helios.ee.lbl.gov!pasteur!agate!bionet!apple!claris!ames!amdahl!pacbell!pbhyf!kjk
From: kjk@pbhyf.PacBell.COM (Ken Keirnan)
Newsgroups: comp.unix.microport
Subject: Re: Mail to uport doesn't work
Keywords: mail, microport
Message-ID: <4167@pbhyf.PacBell.COM>
Date: 4 Nov 88 20:19:35 GMT
References: <4893@b-tech.ann-arbor.mi.us> <134@twwells.uucp> <378@mccc.UUCP> <4154@pbhyf.PacBell.COM> <165@jetson.UPMA.MD.US>
Reply-To: kjk@pbhyf.PacBell.COM (Ken Keirnan)
Organization: Pacific * Bell, San Ramon, CA
Lines: 37

In article <165@jetson.UPMA.MD.US> john@jetson.UPMA.MD.US (John Owens) writes:

[ stuff deleted ]

>Parallel ports on PCompatibles typically use one of three I/O port
>base addresses:  03BC, 0378, and 0278 (hex).  The ROM BIOS searches
>for parallel ports at these three addresses, and places the ones it
>finds, in order, in a table in RAM.  The first one it finds becomes
>LPT1 (as referred to by DOS), the second one LPT2, and the third LPT3.
>So if you only have one printer port, it will always be LPT1 under
>DOS.
>
>The microport drivers (apparently) and the SCO Xenix drivers have lp0,
>lp1, and lp2 always associated with the three fixed port addresses.  I
>like the microport/Xenix way myself, but I tend to keep track of which
>ports my cards are on.  I suppose the way the BIOS (and therefore DOS)
>does it is better for people who don't.
>


This would certainly explain why some people with 386 DOS Merge 1.1 have
a tough time trying to use "direct attachment" of the parallel printer
port.  Microport has 3 entries in /etc/dosdev for direct attachment of
a parallel port: lpt1, lpt2 and lpt3 which correspond to the three
*common* address for DOS LPT1/2/3.  It appears that direct attachment
may have to be achieved using "+alpt2" or "+alpt3" depending on the
address used by the specific hardware.  Actually, it may be more
convenient, and certainly less confusing, to change the /etc/dosdev
entry(ies) to correspond to the way DOS sees the printer port(s) for a
particular system.  Has anyone done this?  If so, does it function
correctly?


Ken Keirnan
-- 

Ken Keirnan - Pacific Bell - {att,bellcore,sun,ames,pyramid}!pacbell!pbhyf!kjk
  San Ramon, California	                    kjk@pbhyf.PacBell.COM