Why 80 Columns? Very interesting article.

[cwpab]

I've personally never used the term "80 columns" as I've only used 8 bit computers for gaming.

So I was very interested in discovering why on Earth would someone define a screen resolution like that. I even counted "columns" in text displays, but there were only a few of them, never 80. What was going on?

Coincidentally, a couple of days ago I came across an earlyexplanation of this in the "Home Computers" article of an 1983 issue of the American magazine "Consumer Reports":



And only today, I found a very cool article explaining the origins of the "80 columns" measurement: Corecursive: Why still 80 columns? This Day In History.

Enjoy the reading of those 2!  They have a lot of cool stuff.

[cwpab]

Update: Apparently both articles are getting some things wrong:

1) The Consumer Reports one lists the C64 as a minor player in late 83, when they were already destroying the competition

2) The Why 80 Columns one seems to ignore that printers were a major reason why 80 columns were used: apparently, even the VIC-20 could print on 80 columns wihout having that display

[andycadley]

@cwpab 
1) Was it though? I'm sure sales were picking up by then but I think I'd take a contemporary article over assumptions about how it was viewed in the market at the time.

2) Most printers could do more than 80 columns and where they were limited to 80, it's because that was the "standard" screen resolution and thus and obvious number to pick rather than the other way around.

[cwpab]

Interesting! You're probably right about point 2 (printers).

About point 1, however, please note the article I mention as being wrong is the one written in late 83 ("Consumer Reports" magazine, not specialized in computers). So it's not a "contemporary" take. 

[eto]

I can't believe that punch cards have anything to do with the 80 column display. The holes in punchcards are basically bits. Why should it have any relevance to map those bits to characters on screen?



But... I don't know - just based on observations I could imagine that 80 was the "sweet spot", at least based on restrictions from the early/mid 70s.

• CRTs needed to have borders, so you can't use the full width of a monitor
• the screens were probably quite small. At least that's what I assume from pictures of vintage computer systems. Much more columns and lines might have been hard to read
• 80x25 almost perfectly fits into 2K of screen RAM - anything even slightly above requires twice as much screen RAM.
• 80 characters fit fine on a normal letter page with typical borders and well readable (monospaced) font size (10 points). 

[Prodatron]

I think here you get all answers:

https://en.wikipedia.org/wiki/Characters_per_line

72CPL was the standard for US typewriters. Some punchcards extended it to 80CPL for storing additional information per line.

In general 80 CPL provides a very good ratio between readability and utilization of the space when using A4 paper and monospaced characters.

That's probably the reason why 80 CPL became the standard for printers at least in the 80ies.

So it was a very professional feature, if the computer system supported a 80char screen as well, as then you already had a kind of WYSIWYG when editing texts.

[ZorrO]

A typical typewriter since Second War could place 48 lines of 80 characters on a page. So, professional computers displayed half of paper page, plus a line with options.
Even today, electricity bills, telephone bills or bank statements have 48 lines.