Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!wugate!uunet!mmlai!burzio
From: burzio@mmlai.UUCP (Anthony Burzio)
Newsgroups: comp.graphics
Subject: Re: Tektronix 4125
Summary: DMA and TEK4129
Message-ID: <601@mmlai.UUCP>
Date: 10 Oct 89 11:44:47 GMT
References: <335@nessie.dde.dk> <101880013@hpcvlx.cv.hp.com>
Organization: Martin Marietta Labs, Baltimore, MD
Lines: 19

In article <101880013@hpcvlx.cv.hp.com>, tomg@hpcvlx.cv.hp.com (Thomas J. Gilg) writes:
> >     I have this `old' tektronix 4125 terminal.
> >     The normal communication line for this is RS-232 at
> >     maximum speed 38400.
> > 
> If I'm not mistaken, a DMA connection is available for some non-TEK
> computers, including the VAX series.  During my college days at 
> Montana State, we had a TEK-4129 DMA'ed into a VAX 11-750.

The DMA connection does not work in a LAVC (local area VAX cluster).  We
tried out a DMA card in our uVAXII but got extremely poor performance
(worse than RS-232) because of bus contention.  Tektronix could not
fix the problem so we didn't get the DMA card (got a TurboSRX instead :-)

*********************************************************************
Tony Burzio               * Speed!  More speed!
Martin Marietta Labs      *
mmlai!burzio@uunet.uu.net *
*********************************************************************