Seeing the Terminator-Movies again I questioned myself: Why does the Terminator (T-800) have a HUD?

When we see the world through the "eyes" of the Terminator, often times crucial informations are displayed on the HUD. For instance when looking for appropriate clothes in the beginning of the movie, we see him scanning for a match and displaying "missmatch".

Why would the terminator need to show the information, that he scans, on a HUD? Obviously this is done so the viewer notices what the Terminator is doing at that times, but is there an in-universe answer to this? Was the Terminator maybe meant to be remote controlled and so some Terminator-Operator can see what the Terminator sees?

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    A Terminator is a pretty complicated piece of hardware and software. Many times while it was being developed the developer probably pounded her fists on her keyboard and shouted "WTF is this thing doing, and why?!" So the developer added code to display an overview of system status and control logic. Judgment Day happened and Skynet picked up where the human left off. Skynet left the debug code in because there was no point in removing it.
    – Kyle Jones
    Commented Sep 27, 2014 at 17:53
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    @KyleJones I guess that's how humans have managed to hack the Terminators - Skynet has been shipping a debug build the entire time!
    – Tom W
    Commented Sep 27, 2014 at 19:41
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    @Xantec - Assuming skynet is building code on top of code, rewriting completely from scratch could lead to all sorts of difficulties; stackoverflow.com/questions/1064403/…
    – Valorum
    Commented Sep 27, 2014 at 19:58
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    @Tasos - Yes she did, along with quite a lot of human-readable text
    – Valorum
    Commented Sep 27, 2014 at 22:11
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    @Tasos - In T3, when the Terminator's Operating system is under attack it turns blue when benign and red when back to normal "kill John COnnor" mode.
    – Valorum
    Commented Sep 27, 2014 at 22:15

6 Answers 6


The only answers I can think of which make sense to me are:

1) Terminators are a product of humanity. While they are designed and built by machines, those machines were designed and built by humans. As a result, computer programs and analytic algorithms might still be generating an in system GUI summarizing what the terminator is "thinking," simply because that is how earlier programs were written. It might not serve a real purpose anymore, but that aspect of the programming has yet to be further altered.

2) Terminator systems are designed to run in paralell. The processor that makes all final decisions on what to do is just one processor of many, each running their own programs. The data from those slaved programs is interpreted in the primary CPU in a manner consistent with the HUD we see. So, what you see is the primary computer telling a secondary system to analyse a series of targets to see if they adequately match the terminator's size. That primary system can then focus on other details, while that secondary system sends a series of 'no's until it finds a 'yes'.

3) There is no HUD. It is only present to symbolically represent the T-800's thought processes, and has no literal analogue in universe.

Edit added in response to some of the comments, as I was having difficulty adequately explaining within the character limits for comments.

Whether the information would believably be converted into visual form depends largely on the design of the processor. In computing today, we have computers build complex three dimensional models in order to work out how a group of actions interact. These models take a tremendous amount of time and processor power to build, but can then process movement within that field with a vastly smaller processor investment.

So, one group of processors collects sensory information, and translates it into a usable form. A second group is given a series of directions by the primary system do things with that data. In this specific case, that primary system would tell a sub-processor to analyze each human it encountered to find an adequate size match for clothing. The highlight effect you see is a message from that subsystem that it is currently using the eyes to create a model of a particular individual. That model is then compared to the existing model of the t-800 in order to determine match/no match. There would then be a signal back to the primary system of the results of each scan.

Would the end result be something we could come even remotely close to recognizing? While Skynet's machines in general would likely use a simpler and more direct language created for their use, the terminators already needed to have English hard coded so they could interact believably with humans, so they might "think" in English. The way that final processor worked*, the one that was used to design the computers that lead to Skynet's creation, is, I believe, modeled off of the human brain, increasing the odds that the machine might create a visual hud.

While it seems to us that it would be a waste for the terminators to bother with a visual interface, working with a three dimensional model including input from various subsystems would offer a small but valuable improvement to reaction time, and would allow most of the work of collating and comparing data to be carried out by subsystems while the main processor only has to deal with the final levels.

*My apologies. I can't seem to find the quote I'm thinking of. It's from the second movie, when the computer engineer from the second movie is explaining the chip his work has been based off of. If I'm misremembering what was said, I apologize doubly.

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    Since it would be difficult to explain why a machine self-narrates for the audience, the simplest concession would be a "HUD" for the viewers to read and interpret the actions of the machine. Imagine the movie without the HUD and you can see its actions would be difficult to interpret and confirm which is what the viewer wants to be able to do. Commented Sep 27, 2014 at 17:59
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    @Xantec - You do still see a HUD though; terminator.wikia.com/wiki/File:Decibel_overload.jpg
    – Valorum
    Commented Sep 27, 2014 at 19:13
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    @Xantec Possible response: Yes/no. Or what? Go away. Please come back later.
    – Mazura
    Commented Sep 27, 2014 at 21:39
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    @nras, no you didn't ask "for" an in-universe answer. You asked "if" there was an in-universe answer. Thaddeus was simply trying to explain the most likely answer to your question, which is: no, the HUD is just a visual cue for the audience, as there are only very poorly contrived reasons why a computer would need to display information to itself.
    – Lakey
    Commented Sep 28, 2014 at 0:43
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    While #3 is most likely, #2 does raise an interesting point. Helper processors could very well be analyzing raw images and extracting useful information to feed to the primary processor. However, the means by which they relay this information would probably not be graphically. It would make no sense for the helper processors to analyze an image and extract useful information, only to put that information back into graphical form and send it to the primary processor, which then must analyze the graphics in order to re-extract said useful information.
    – Lakey
    Commented Sep 28, 2014 at 0:53

I was actually putting together my own question about this exact subject when I found this question.

From what I have gathered, there seem to be a couple of possibilities, which are probably both accurate to different degrees.


The HUD is a narrative device, intended to let the audience in on the Terminators' thought processes. Let's take a look at a screenshot of one example of the HUD:

enter image description here

By showing us this image, the director can convey information about how the Terminator is assessing its surroundings and making decisions. The only other way this could be achieved is to have the Terminator actually talk to itself, or act as a narrator, and explain what it is seeing, thinking, and how it is making its decisions; to have the Terminator do this would make no sense, and would pull the audience out of the moment, breaking the willful suspension of disbelief, and destroying the illusion of being present in the situation.

Another example (with some NSFW text):

enter image description here

This is from a scene in the first Terminator movie, in which the Terminator is in his flophouse apartment repairing some damage to his face. The landlord comes to the door, having smelled the rotting flesh of the Terminator, and asks if there is a dead cat in the room. The Terminator's HUD displays a list of possible responses to the landlord's question, and (hilariously), the Terminator chooses the most offensive option.

In this case, the narrative device of the HUD is even more useful than it is in the second movie, because the first Terminator is an enigma to us as the audience. We get very little insight into the "mind" of the character, and we never know what he is thinking. He is entirely remote, alien, and emotionless, and there is no way to relate to him. He is a completely unsympathetic character. By giving us a glimpse of his mindset and thought process, we get a better feel for the character. It is a brilliant device, because it simultaneously allows us to see the world through the Terminator's eyes, and spy in its inner thoughts, but it also reinforces the idea that this thing is cold, calculating, and completely devoid of any human feelings.


The HUD doesn't make sense if you assume that Terminators were never anything more than the tools Skynet uses to destroy humanity. If the Terminators were designed and built by Skynet without any input from humans, an HUD would be totally unnecessary, and in fact, actively detrimental to the Terminators' mission. By using a visual, graphic display system, the Terminator is wasting CPU space and slowing down its decision making process.

But the first Terminators were originally designed by humans, and these humans didn't expect that their creations would eventually turn against them. The designers and programmers expected to control the Terminators in much the same way people control military drones. Once the Terminators were operational, they would be operated by humans, and these humans would need to see a visual, graphic display. This display would have to be easy to understand, and it would have to provide information about the status of the Terminator's systems, as well as a video feed of what the Terminator was seeing. The operators would also need to see a display of options to choose from, related to what instructions the Terminator would be given, how it should react to its situation, targeting priorities, mission parameters, and so on.

Therefore, at the time the Terminators were being designed and assembled, the HUD was absolutely vital to their operation. This changed, however, when Skynet took over and set the Terminators to its own purposes. From that point on, we might argue that the HUD was no longer necessary, and was actively detrimental to the Terminators' operations. Again, it wastes memory, consumes an inordinate amount of processing speed and CPU functionality, and slows down the decision making process.

At this point, we might say that the HUD had become a spandrel: something that is still used and replicated in successive generations of Terminators, but which serves no purpose whatsoever. Since humans aren't controlling the Terminators anymore, a user friendly interface is worse than useless. Even the language of the HUD - a mix of English and processing languages - makes no sense.


So, in short, the HUD was a logical feature for as long as humans were in charge of the design process, but once Skynet took over, it became unnecessary. Skynet may have continued to use the HUD for reasons which are unclear to us, but the most practical reason for its use in the movies is the opportunity it provides the audience to see the world through the eyes of the Terminators, and to convey information that would otherwise have to be spoken aloud by the Terminators, which would not make sense.

Think of the scene in which the Terminator scans the big biker dude to see if his clothes are the right size. Now imagine what the scene would be like if the Terminator was saying the things that appear in the HUD the whole time:

"Your inseam is the correct size. Your waist is the correct size. Your chest is the correct size. Your sleeves are the correct size. Your shoes are the correct size. Your shoulders are the correct size. Your neckline is the correct size. Your clothes are the correct size. I need your clothes, your boots,and your motorcycle. Give them to me. Now."

See why that wouldn't work?

The point is this: In-universe, during the initial stages of development, it made sense to use an HUD. Out-of-universe, it always made sense to use an HUD. You can attribute however much significance to each of these factors as you like.

I think the best way to interpret the HUD is on a case by case basis. For example, this screenshot of an HUD display from Terminator 2: Judgement Day only makes sense for out-of-universe reasons:

enter image description here

Whereas this image, from a deleted scene from the same movie, in which the Terminator is rebooting after having been shut down temporarily so John and Sarah could switch its CPU from a "read only" setting to a sort of "learning mode" setting, makes sense in both the out-of-universe and the in-universe contexts:

enter image description here Note: If you are wondering why the Terminator sees himself in this picture, it's because he is looking into a mirror.


This answer addresses why they might want to employ a HUD as apposed to needing one.


Bear in mind that the brain has better algorithms for compressing certain types of information than computers do. The amount of data supplied by animalistic observation is difficult for a machine to store and retrieve efficiently. If we assume that they store data compressed into fractals, slipping in HUD data along the sides where no vital information lays would save metadata space.

Fractal compression is a lossy compression method for digital images, based on fractals. The method is best suited for textures and natural images, relying on the fact that parts of an image often resemble other parts of the same image.[citation needed] Fractal algorithms convert these parts into mathematical data called "fractal codes" which are used to recreate the encoded image.

Individual frame per second data might be stored as fractals and would need to be visual in order to be compressed. This would store relevant on-screen, overlayed (meta)data for an image in it. Interestingly, fractals become more efficient at compression the larger the discrepancy for the data is, excellent for the tremendous amount that would be streaming in. Although I'm speculative about a computer choosing to use lossy compression, this is succinct enough to acquire a target and execute them. Anything better would be high resolution noise. Not stopping to smell the roses makes them more efficient killers. However, they could if they wanted to and with infinitely more (lossy) definition:

The original digital image (Arthur Clarke, Fractals, The Colors of Infinity 40m0s): Original images

Now passed through a fractal compression analyzer using predictions based on an algorithm created from the original image, up-scaling it to an infinite resolution: Passed through fractal compression analyzer

This may actually be observed in-movie. Teaching the T2 how to smile, lips are zoomed-in on becoming a foreground image at the same resolution. Assuming they don't independently use binocular vision, fractal algorithms can accomplish this type of "magnification".

Being a learning computer, the terminator is Stack Exchanging its own questions. As when it looks up how to use a clutch for the semi-truck in the first movie. The saved picture would contain the truck in question in the background; the applicable answer in the foreground. No more subsequent delays, asked and answered. Intelligence stems from the ability to associate data not just store it.

enter image description here enter image description here

Intrapersonal communication

Writing (by hand, or with a word processor, etc.) one's thoughts or observations: the additional activities, on top of thinking, of writing and reading back may again increase self-understanding ("How do I know what I mean until I see what I say?") and concentration. It aids ordering one's thoughts; in addition it produces a record that can be used later again.

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    This doesn't make any attempt to answer the question of why the Terminator has a heads-up-display.
    – Valorum
    Commented Sep 27, 2014 at 19:37
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    Storage space is probably not at a premium, but the retrieval speed of pertinent data is. I don't clam to truly understand fractals or data compression, but this seems to me a reasonable file system for machine read data.
    – Mazura
    Commented Sep 27, 2014 at 19:50
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    The question isn't about the way that the Terminator stores data, it's about the reasons why the HUD contains human-readable language.
    – Valorum
    Commented Sep 27, 2014 at 19:59
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    All language is readable, if you know it. If we're wondering why it's in English I think that's a pretty obvious answer as stated in User62707's. I read it as why a T needs visually, descriptive language in its observational data at all. @Richard
    – Mazura
    Commented Sep 27, 2014 at 20:06
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    Digital computers as we know and love 'em have some inherent limitations on the way they perceive and relate to the real-world. It's possible that in order for the Terminators to relate to the real world in a human-like way (in order to infiltrate human resistance groups) they were made with "brains" that are more-or-less analog rather than digital. But it may not be possible for a human-like brain to input data directly - info has to be processed in a way more like ours do, through intermediate senses. Just a blue-sky thought.
    – Joe L.
    Commented Sep 28, 2014 at 21:06

It's more likely that you aren't seeing a video feed from its "eyes." Instead you're seeing multiple things: the video feed and the logs of its internal thought processes. The movie chose to visually display both things on screen for you to see simultaneously.

Your idea that it may be taking orders would make sense for humans to receive and react to input (like in Agents of S.H.I.E.L.D. with the mechanical eyes) but this wouldn't make sense for a machine, because it doesn't need to read from video to get input when it could simply receive and process that input on its own. That would involve receiving data, overlaying that on the video feed, and then reading that again, which is entirely redundant and wasteful.

Since it's not human, there is no such thing as a distinct difference between the data of a visual feed or of a log of its thought processes. It's all just a bunch of 1's and 0's inside the processor, so the movie had to display something visually, and it chose to show the video feed and the thought process logs which were both things that can be shown visually.

  • +1 it's a raw data feed, -1 no plausible excuse for having a HUD.
    – Mazura
    Commented Sep 28, 2014 at 17:57
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    Actually, we know from the Sarah Connor Chronicles (specifically the episode "Vick's Chip") that the HUD is real and can be read directly by humans. They play it onto a monitor.
    – Valorum
    Commented Sep 28, 2014 at 18:32
  • @Richard That seems to be a nice information. This would support the sentence "[...] and so some Terminator-Operator can see what the Terminator sees?". Maybe this gets more attention if you would make an answer, maybe with the correct citation and or a screenshot of that in it.
    – Nras
    Commented Sep 29, 2014 at 7:00

It's telemetry. Terminators were originally built by humans. They would likely have built in some way to remotely monitor their creations, much like modern drones that can fly on autopilot. This is called telemetry.

Modern drones typically transmit a video feed with data such as speed and heading overlaid. What we see in the film is this technology left over from early model terminators, before it became unnecessary.

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    Exactly, as we see in t3, drones are the predecessors of terminators
    – user16696
    Commented Mar 24, 2015 at 16:48

As a programmer i make list of little programs to produce an overall effect.

Coming from humans, there would be no reason to remove this which we placed there. I generally leave my test programming in the final code, just inactive.

This is a great example 😉

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    Firstly the question was about the t-800, secondly there is no reason to think skynet would throw out the software. The logical choice would be "if it works keep it"...
    – smurfted
    Commented Apr 23, 2020 at 22:42
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    But the T-800 wasn't programmed by a human, it was programmed by Skynet
    – Valorum
    Commented Apr 23, 2020 at 22:43
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    My second point. If its not broken, why try & fix it?
    – smurfted
    Commented Apr 23, 2020 at 22:46
  • Sure, but can you provide any level of evidence to back up this bold assertion? Or is it just your own personal fan-theory? And that being the case, why is it any more likely than that the HUD is useful to the humans who're forced to run the Terminator factory (for example), or that the HUD is somehow essential to how the Terminator operates?
    – Valorum
    Commented Apr 23, 2020 at 22:50
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    Chicken or the egg. Miles dyson said in T2 that most of his ai research was based on the broken chip from 1984. Presumption yes, but its leads to that conclusion because of the predestination paradox...
    – smurfted
    Commented Apr 23, 2020 at 22:58

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