I recently saw The Terminator (1984) again and I still think it is a great movie.

However, during the movie I was always thinking "Why does the terminator have debug information in its vision?" The Terminator is built by machines, nobody would see that text or those lines of code. Machines themselves probably have much more efficient way to pass debug information.

I am aware that the out-of-universe (or Doylist) explanation is simply: "The debug information is for the viewer, makes the action easier to understand and often funnier."

But I was wondering if there an in-universe (or Watsonian) explanation? Perhaps it is a legacy of the humans that created the first terminator's prototypes?

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    Suppose his vision is constantly recorded for whatever reason back when they were designed. Like a timestamp on a surveillance tape. Maybe adding the debug info to the recording is a lot more efficient and was found useful when all other components were destroyed. As a programmer, I could see how that might be useful as a last resort low res resource although it would seem unlikely this is necessary in such advanced technology. Still though, some people will stick to what works no matter how advanced things get.
    – Kai Qing
    May 22, 2018 at 21:23
  • Without that info, we would not have realized that the T-800 considered "F*** You!" instead of "F*** You, A******!" in one of his human interactions
    – m1gp0z
    Feb 11, 2019 at 20:27
  • It appears to be 6502 based assembler mnemonics, or a CPU using a very similar instructions
    – AndyF
    Feb 2, 2020 at 19:11

3 Answers 3


As said before, no in-universe explanation is given and, a machine wouldn't need to information dumped onto a screen. Furthermore, why would a machine need the headup-display in the first place ? Answer : "it wouldn't", information could simply be fed into it's processer.

Therefore, why does the terminator have a display ?

Simple because, we, as the audience and lowly humans can't 'see' what the terminator is 'thinking' in it's processor.

So, the display is a plot device to communicate information to the audience...


No in-universe explanation, but...

1) Assuming the first models of Terminators (like the drones from T3: Rise of the Machines) were built/designed - not to mention repaired - by humans (rather than by robots and computers), it would make sense to put some sensor- and debug-information on the video/data-stream. When so the robots started building themselves, it's not unreasonable that some core-programming were left unchanged even if it wasn't needed - it would be just the way robot-kind had "always done it".

2) The video we see is not the input from the camera or what the terminator "see", but rather the representation in it's "brain" - multiple data streams (eg. from "eyes" and "ears", gyros, &c), data from sensors, status of various systems, errors, damage, &c...

It wouldn't be too far away from how we perceive the world ourselves. We build-up an image in our minds of our surroundings with ourselves in the middle - based on our external senses, but also of internal senses - like position of limbs, pain, hunger. We supplement with experience and memories - like how things are outside our immediate sensory range. And we add feelings like love or hate.

Because vision is our primary sense, much of how we build-up the mind-image will be visual. But we can imagine that other animals would build-up their mind-image primarily using other senses - like smell for a dog, and "radar" for a bat. Still, I would think the resulting mind-image would be very similar to our own - but with for example sources of smell moving around, instead of shapes of light and color.

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    I think #1 is a good explanation. The first generation terminators were already built and designed by humans. Skynet would just have to replicate them. There's no need to go back to redesign them to remove unnecessary equipment. Especially if the primary goal is to just build as many as possible as fast as possible.
    – DeeV
    Nov 21, 2018 at 17:42

No in-universe explanation is ever given, all you'll ever find is speculation.

However, remember that machines, while sentient, are still machines. They need code to tell their legs to move. They need code to determine if their actions are correct. So, it still seems logical that they need code to diagnose problems when things go wrong.

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    I agree with you, but that kind of debug information makes no sense for a machine.Let us assume all the numbers you see on the screen are for the Terminator body position. If you need to debug something, as human you can read them easily, for a machine it means to use OCR that is fairly difficult. A binary dump of those numbers would be MUCH easier.
    – user64258
    May 21, 2018 at 13:42
  • 6 of 1, half dozen of the other. It's still binary, just shown onscreen. Think of the "Blue Screen of Death". That info isn't useful to a user, yet it's shown onscreen. You may be right, I may be right, but back to my answer; no one will ever know since no explanation was ever given. May 21, 2018 at 14:16
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    BSOD is indeed intended for end users who are qualified enough
    – user9109
    May 21, 2018 at 20:01
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    Autonomous machines do constant self-evaluation. It is the equivalent of learning. Adapt and improve. May 21, 2018 at 23:21
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    A computer doesnt need to print statements to compute though. I think that's what OP is talking about. Screens are for people.
    – Dpeif
    May 22, 2018 at 2:32

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