I think the reason for this is pretty obvious. At the time -- for many of the paper terminals, line feed simply rotated the platen, and the print head stayed at the same column position. Carriage return returned the print head to the first column without advancing the paper (remember overstriking?). But there were also some terminals that both advanced the paper and returned the print head (I'm hazy about this, but I think the IBM Selectric was one...).

The Honeywell system in Murray Hill had a teletype driver that attempted to paper over these differences. If it saw a linefeed on some tty's they would issue the line feed and then space out to the previous column location. If it saw a carriage return it would backspace to the first column. It did recognize CR/LF and did something more reasonable.

I do remember one guy who wrote his program to output LF/CR instead of CR/LF. The teletype driver would do a LF and then space out to the previous column and then do a carriage return. Pretty painful at 300 baud!

Doug might remember better than I but I suspect some terminal did the combined CR/LF only, so that's why Unix adopted it. Certainly by the time glass teletypes came along, making overstriking (and often underlining) impossible, I don't think anybody objected.

Steve

----- Original Message -----
From:
"Dave Horsfall" <dave@horsfall.org>

To:
"The Eunuchs Hysterical Society" <tuhs@tuhs.org>
Cc:

Sent:
Sun, 3 Sep 2017 12:54:02 +1000 (EST)
Subject:
Re: [TUHS] Line Terminators in Text Files [Was: Re: Why Pascal is Not My Favorite Programming Language - Unearthed!]

On Sat, 2 Sep 2017, Nemo wrote:

> Hhhmmm... This begs the historical question: When did LF replace CR/LF
> in UNIX?

Unix has always used NL as the terminator :-)

--
Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."