Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!wuarchive!usc!henry.jpl.nasa.gov!elroy.jpl.nasa.gov!gryphon!pnet02!lampi From: lampi@pnet02.gryphon.com (Michael Lampi) Newsgroups: comp.sys.apollo Subject: Re: Adding Centronics Port to DN3000 Message-ID: <22839@gryphon.COM> Date: 28 Nov 89 19:40:18 GMT Sender: root@gryphon.COM Organization: People-Net [pnet02], Redondo Beach, CA. Lines: 20 The Apollo SPE (Serial Parallel Expansion) board was, originally, a bottom of the line serial/parallel board to provide just such functionality. However, it had insufficient buffering and/or intelligence so that the DN-xx00 would, typically, spend most of its time servicing interrupts from the SPE when simply printing a file. The 'new' SPE has fairly deep FIFO buffers so as to reduce the number of interrupts per character processed without loss of data on input. Anyway, yes you can add such a board to a DN-3000. The driver would be pretty simple, and you would have all the overhead problems that the Apollo SPE had. One 'gotcha' is that you would probably have to write an extensible streams type manager so that the Context printer server would know how to talk to your board. Examples of such things are available with the Apollo Open Systems Toolkit software package. Michael Lampi MDL Corporation 213/782-7888 fax 213/782-7927 UUCP: {ames!elroy, }!gryphon!pnet02!lampi INET: lampi@pnet02.gryphon.com "My opinions are that of my corporation!"