[Unix-jun72] Fwd: Trying to restore 1972 UNIX

James A. Markevitch jam at magic.com
Thu May 1 17:52:25 AEST 2008

> I have dug up another listing of the PDP-11 assembly languge
> version, which seems to about contemporary with the
> one you have.  The files mostly bear a copyright date
> of 1972, but like other printouts from the time,
> the datestamps only give month and day, not year.
> They are generally from May.  It is post 11/45,
> and has segmentation and floating-point support.

Very cool!  (fpsym, presumably)

> I replied and asked if we could get either a scan copy of the "other listing",
> or if he could send a photocopy to Tim.

As usual, the key is a high resolution, high quality scan.  There is a huge
difference between 300dpi and 400dpi/600dpi for this old stuff, since the
signal to noise ratio is much better with the better scans.

This sounds like a broken record, but there was a 1200 page listing were
the first 400 pages were at 300dpi and the remaining 800 pages were at
400dpi.  When you zoomed in, the differences were astounding and the
OCR results reflected that (the person needed to do a lot of editing on
the first third of the document to get it to compile).

If someone can get me a hardcopy, I'll scan it at 600dpi, as I am sure
Al would, if Tim isn't set up to scan stuff like this.

James Markevitch

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