The document looks to be nicely rendered, likely from Postscript. Maybe generated by roff, since it doesn't look like TeX. Screen cap bitmaps could be converted to EPS and inserted into the Postscript.
If it was a PS document, you would have to spool it to a printer or screen renderer to read it anyway. The X Window System debuted in 1984, so on-screen renders would have been not too hard to find in a CS department in 1989.
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The document looks to be nicely rendered, likely from Postscript. Maybe generated by roff, since it doesn't look like TeX. Screen cap bitmaps could be converted to EPS and inserted into the Postscript.
If it was a PS document, you would have to spool it to a printer or screen renderer to read it anyway. The X Window System debuted in 1984, so on-screen renders would have been not too hard to find in a CS department in 1989.