What is a Screen in a Computer?
A screen is a flat electronic surface where a computer displays its images for you to see and interact with. It's through the screen that we see what is happening "inside" the computer, in the virtual world: it's the hardware part that makes the software visible.
On PCs, the screen is attached to the monitor, which is connected to graphics card inside the tower (the "CPU") of the computer through a cable. Multiple screens may be connected to a single GPU. On laptops, tablets, and smartphones, the screen is built into the computer as a single device.
Measurements
There are various ways to measure a screen:
Its physical size: in inches, according to the length of a diagonal line from one corner to the opposite corner of the screen (i.e. the hypotenuse). For example, a 20 inches screen could have 16 inches of width and 12 inches of height, or 16 of height by 12 of width, because 202=162+122.
Its resolution: how many pixels can fit in it. For example, the most common screen resolution according to Steam's hardware surveys is 1920x10801 (1920 pixels in width, 1080 pixels in height).
There are various terms for these screen resolutions. For example, a 4K screen is a screen with more or less 4000 pixels in either axis, e.g. 3840x2160.
Its refresh rate: measured in Hertz (or Hz), the amount of times the screen refresh in one second. For example, 60Hz would be 60 times per second. If you're playing a game that your GPU can render at 120 FPS (frames per second), but your screen only refreshes 60 times per second, 50% of those frames would be wasted because the screen literally can't refresh that fast.
Fun fact: Hertz is the same unit used to measure the CPU speed, but that is normally in gigahertz (billions of times per second).
Common Problems
A computer screen is a window to what is happening inside the computer, but there are several parts between your eyes and the software: the actual screen, the table, the graphics card, and whatever software sends data to the graphics card (e.g. the graphics card driver).
If you turn your computer on the screen remains black, that doesn't necessarily mean the computer isn't working, you simply aren't being shown what is going on anymore. The computer may be functioning normally and will start up normally, you just won't see anything. Normally, an operating system makes sounds when it starts up, so if your computer makes typical start up sounds through the speakers, but the screen remains black, the problem is in the graphics card, cable, monitor, or screen, while the computer itself is working normally. This means you just have to replace the broken part. On the other hand, if no sound is being made, then the problem isn't in any of these parts, but in another part of the hardware or software.
Similarly, if your screen freezes or turns black, that doesn't mean the computer isn't working normally. Most importantly, if your cursor doesn't seem to move on the screen, it could be still moving in the virtual world, that simply isn't getting shown to you. So avoid clicking randomly when the cursor appears frozen, as it could still be moving around and activating things without you seeing it. Similarly, avoid pressing keys on the keyboard when this happens.
It's also possible for the image on the screen to appear distorted or corrupted, but still refresh. These problems could be in the screen itself (e.g. "dead pixels" which happen when a pixel gets stuck a given color when doesn't change anymore), or they could be in the graphics card and its driver (e.g. graphics getting stretched because the GPU got a texture's dimensions wrong).
References
- https://store.steampowered.com/hwsurvey/Steam-Hardware-Software-Survey-Welcome-to-Steam (accessed 2024-03-28) ↩︎
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