How did the early industrial computers, such as UNIVAC, ENIAC, MARK I, etc display output before monitors existed?

Did the first personal computers, like the Altair 8800 or the Simon use monitors, or did they use some alternate output as well?

  • 12
    Punch cards, punch tape, teletypes, .... the list goes on. The PC didn't take off until there were cheap monitors.
    – ChrisF
    Dec 1 '11 at 11:52
  • 4
    – WernerCD
    Dec 1 '11 at 15:40
  • 3
    "We've all got our switches, lights, and knobs to deal with, Striker. I mean, down here there are literally hundreds and thousands of blinking, beeping, and flashing lights, blinking, beeping and flashing - they're flashing and they're beeping." -Airplane II
    – LarsTech
    Dec 1 '11 at 16:00
  • 2
    The answers are all over the place as to what constitutes the meaning of the first computer, ill-defined in the question, and half of them say to just look up Wikipedia, this is either not a real question or not constructive @nea
    – random
    Dec 1 '11 at 19:21
  • 2
    Where's the research behind this question?
    – Kris
    Dec 2 '11 at 9:47

The first computers used punch cards or lights. Wikipedia says for ENIAC:

an IBM card punch was used for output

The German Wikipedia-article about Zuse's Z3 (the first apparatus that can be called computer) says:

einer Tastatur mit Lampenfeld für Ein- und Ausgabe von Zahlen und manuelle Steuerung von Berechnungen

That means: it had a keyboard with lights for input and output (programs were read from punch cards, as NobbZ said).

As computers got more common, they used often the already existent teletypes, that means output was made through printing text on paper. Until today, Unix-Terminal emulate to some degree teletypes.

EDIT: You asked specifically about PCs. First PCs came up in the 50s and had different methods for output. The IBM 610 used a keyboard for input and an electric typewriter for output. Also, some other early PCs used printers, i.e. Olivetti Programma 101. The Simon or the Kenbak-1 used lamps for output.

Monitors seem to come up 20 years later, in the 70s. One early model with monitor is the Datapoint 2200 from 1970. And naturally, the milestone Xerox Alto.

More infos about history of PCs at Wikipedia (as usual).

  • The Altair used front panel toggle switches (although you could hook up a teletype to its RS-232 interface), so I'm not sure how far you want to go back. Maybe the Altair is considered a "hobbyist" computer, rather than a "personal" computer? Dec 1 '11 at 17:29
  • Simon is older than the IBM 610 and is arguably the first personal computer
    – rlemon
    Dec 2 '11 at 15:11
  • Many of the early PCs, such as the Apple I, hooked up to a standard television for output.
    – vocaro
    Dec 3 '11 at 7:07
  • Relevant Willy Wonka video: youtube.com/watch?v=9sFYSW6QHCQ Dec 4 '11 at 16:15
  • @rlemon: Wikipedia states the IBM would be first, but the dates itself are strange. I reword that. Dec 6 '11 at 19:27

You may want to check out the Computer History museum's timeline or http://www.thocp.net/index.html

It's been a while since I spent much time there but it is very interesting and may be helpful. It will probably give you some computer names that you could then research to find out how people interacted with them.

  • Really nice resource. Nice answer.
    – Moshe
    Dec 1 '11 at 11:34
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    Yeah, if you go to the second link, under the hardware section and look at the "teletype" you realise how far back the keyboard goes. This even makes me appreciate the mono video terminals I started on in '80.
    – Dennis
    Dec 1 '11 at 11:39

Before monitors, computers used Punch Cards, Paper Tape, Banks of Lights, Fan Fold Paper, and Bells for output.

When I was going to school, we submitted our programs to the sysadmin (input) on punch cards and the output was printed on fanfold paper.

To answer your specific questions:

To illustrate an alternate input / output method in use near the dawn of the PC:

  • Pong (1975): Used two knobs for input and a TV for output.

Some other early computers:

And even before all that:

And even before that, as @WernerCD and @artistoex pointed out, calculation assistance has been going on for quite a while:

  • Teletype. Why /dev is populated with all those tty devices... Dec 16 '11 at 8:01
  • Yes indeed, I remember the ASR-33 Teletype with its smooth rolls of paper. The first game I played was Adventure on a Teletype. Dec 20 '11 at 15:37
  • 35,000 BC: Tally Sticks
    – wnrph
    Jan 12 '12 at 10:18
  • @artistoex Well done! I'll add that in, thank you. Jan 12 '12 at 17:49
  • @Sean I quoted the wiki article incorrectly--it reads 35,000 yrs ago rather than 35,000 BC. I'm sorry.
    – wnrph
    Jan 12 '12 at 19:12

There have been many I/O devices in the history of computing, from simple light emitting devices such as incandescent light bulbs (and later LEDs) to punch cards to mechanically operated alpha-numerical displays. Pretty much any way you can think of interacting with anything has probably been used to interact with computers, such as bells, whistles and other such things.

Arrays of lights were probably the simplest form of monitor as they could be used in a similar way to the pixels you see on monitors these days.

Monitors are only one of the many ways that have been devised to interact with computers and it stuck because it is the most intuitive and technologically realistic method of dealing with information.


Since first Computer is known to be the Zuse Z1 (at least the first binary computer), I looked at it in wikipedia. But all I could find there was that the input was with punched tape. So I would guess, that the output comes on puched tapes too.

Probably you could find it interesting to go through that wikipedia-pages?


Besides all the other output devices mentioned in otehr answers, TV sets were used for output by many computers in the 80s, like Spectrum, Commodore 64, etc.

  • 1
    +1, but a TV is really just a monitor. In ye olden days, a low quality monitor with an RF tuner, but the changes in the technology of monitors have been much more significant than the difference between a monitor and a TV at any particular point in time. These days, the difference between a monitor and a TV is probably even less - odds are already significant and increasing that both will recieve an identical signal via HDMI, for instance.
    – Steve314
    Dec 3 '11 at 22:48

Depending on how early you mean, but printers are also output units. You punched in the program, and when it was done it printed the result.

  • 3
    +1:If you talk to someone who understand printer drivers, they'll tell you old printer drivers literally just redirected the screen output but through a different port.
    – surfasb
    Dec 1 '11 at 14:23
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    @surfasb that's a PC-centric view. UNIX systems, on the other hand, used teletypewriters (a type of printer), and a modern system simulates one (well, more or less - what it actually simulates is a VT100, which is a type of keyboard-and-monitor device that replaced teletypes) on the screen.
    – Random832
    Dec 1 '11 at 14:40
  • @Random832: That is essentially what I was eluding to, but ya.
    – surfasb
    Dec 1 '11 at 15:01
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    My issue was with surfasb's claim that computers naturally had screen output and "printer drivers" are redirecting that output to the printer. (I suspect this is an incorrect oversimplification even for PCs, but that's another issue)
    – Random832
    Dec 1 '11 at 15:19
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    @Random832 - Oh, no. I didn't mean that. I ment to say that printers are output devices, just like screens (of any kind), and that at some time they were used instead of ... Feel free to edit the answer if you think of how it can be better phrased.
    – Rook
    Dec 1 '11 at 15:21

The Difference Engine used brass digits, a bell and a typewriter.


The first "PC" related to what is commonly known as a PC today, the IBM 5150, used a monitor. You could obtain the system with a high-resolution text mode-only MDA card, or a lower-resolution text and/or color graphics CGA card. Around this time (1981) many home computers were designed to be connected to a television, and the CGA card could indeed be connected to a television.

The late 60's/early 70's saw the introduction of video terminals. These combined a keyboard, CRT display, and character generating hardware and were connected to a minicomputer or mainframe by way of some form of an RS-232 port. So for a while the "monitor" or terminal was considered part of separate self-contained peripheral.

The Altair 8800 had LEDs which you could use to show output if you did not connect a serial terminal to it.

Before the introduction of video terminals you had teletypes. Before then you had punch cards.

  • 1
    That's not the first PC: en.wikipedia.org/wiki/… Dec 1 '11 at 12:40
  • PC was an abbreviation for "Personal Computer" before the IBM PC was thought of. PC World magazine (the UK one) even started up before the first IBM PC was released, and covered the personal computers of that time such as the Commodore PET and Apple Lisa. IBM effectively stole a generic term, but since it became generic again (though with a different meaning) afterwards... Anyway, even if the IBM 5150 had been the first PC, it still wasn't the first computer.
    – Steve314
    Dec 1 '11 at 16:37
  • @Steve314: edits made
    – LawrenceC
    Dec 2 '11 at 1:39
  • Yeah, IBM's previous attempt was called the 5100 "Portable Computer" (at 55 pounds). It incorporated into the single case a keyboard, a 5" B&W display (16x6), and a DC300 tape drive (writing a non-standard format). Jan 12 '12 at 19:57
  • But probably the first "PC" should be considered to be the HP 9100, though some would give this honor to the Olivetti Programma 101. Jan 12 '12 at 20:03

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