[pdp7-unix] use of tabs

Warner Losh imp at bsdimp.com
Fri Oct 25 00:21:02 AEST 2019

On Wed, Oct 23, 2019 at 11:59 PM Angelo Papenhoff via pdp7-unix <
pdp7-unix at minnie.tuhs.org> wrote:

> On 24/10/19, Sebastian Rasmussen via pdp7-unix wrote:
> > > My personal preference is to replicate the files visually, and I've
> > > used spaces to achieve this, including entering unindented code
> > > without any identation.
> >
> > This is my approach too. Hence I keep the indentation as is, whether
> > it is none, 1 space, 2 space or 3 spaces. If the owners of the git repo
> > asks me to differently I'll adapt of course. And I trust that most people
> > here are able to reindent text files to their own liking. :)
> I think i solved the mystery: the code has been indented by ind.b.
> Now whether that was just meant for printing or if the source was truly
> kept on disk with 3 spaces i don't know.
> So i guess one could say nobody used spaces OR tabs, it was all a
> program.

We know, from the 5th Edition sources, that the majority (all?) of the
assembler used hard tabs. These are the first sources we have, afaik, that
have come down to us in machine readable form.

Well, that's not entirely true. the "s2" tape from 1971-ish in the unix-72
area of the archive does have a maki.s in it, in addition to the binaries.
It uses a single space to indent and separate.

Dennis also posted one pdp-7 .s file to usenet a million years ago (dsw).
the link works). This shows the same single-space indentation that maki.s
shows in the pdp-11 maki.s file. It does come from an old notebook, not
from machine readable media, though. Again, it's suggestive but not

I suspect that it was kept on disk as single space since that would allow
for easier 'ed'ing of the file if everything is uniformly done that way.
However, that's at best speculation based on years-old memory of stuff that
tripped me up when using TECO to edit files on a PDP-11 in the early 80s on
a DECwriter II running at 300 baud... Well that, and a comment from Brian
Kernaghan at Unix50 about the bevity of Unix commands wasn't due to the
printing, which was faster than researchers could type, it was for the
typing because the TTYs of the time were a physical workout to type on...

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