Why 4KB RAM computers used to send humans to the Moon, but now 4GB RAM is not enough to play games?

It turns out that space exploration doesn’t consume as much computer resources as playing high-graphics games.

In 1969, NASA astronauts became the first people to set foot on the Moon on a Saturn V rocket researched and developed by the agency. For many people, it is strange that such a great step forward for mankind was made on a computer with only 4KB of RAM, whereas at present, with a capacity of about 4GB of RAM – 1 million times more. last time – users couldn’t even play some medium graphics games.

But in fact, the fact that humans set foot on the Moon with 4KB of RAM is only part of the truth. In total, there are four computers on the Saturn V rocket to conquer the Moon, not just one.

AGC computer guided Apollo to the Moon

It is true that only one of these computers is used to control this rocket into orbit and to the Moon, but there are other computers such as the Apollo Guidance Computer (AGC) along with other computers. two computers on the Moon landing module (Apollo Lunar Module – ALM). One ALM computer is similar to a navigation computer but with different software, and the other ALM computer is used in emergency situations.

Even so, these are not all the computers used to send humans to the Moon. At the underground center, there are mainframe computers that do complex tasks like calculating the distance to the moon and back. The computers accompanying the astronauts only followed the route outlined by the central computers in advance.

The mainframe computers did most of the calculations for the Apollo ship

ROM memory on Apollo’s AGC computer to the Moon

These mainframe computers have 1MB of RAM each. The AGC navigation computer has 38K 16-bit words. So yes, this computer has 4KB of RAM but it also has 72KB of read-only memory (ROM memory) to store programs. Moreover, the user interface of the machine is also extremely minimalist and has no graphical elements. The lines of code are also written in Assembler machine language, so there is no need for an operating system, in order to reduce the amount of RAM used.

This means that to put the first people on the Moon, computers need a lot more memory than 4KB of RAM, possibly up to many MB of RAM, but compared to the GB of RAM for current computers. At present, this number is still too small. Why is that?

Why do today’s computers need so much RAM?

Graphics, not to mention games with high quality graphics, are the main reason modern computers need so much RAM. It is not an exaggeration to say that the complexity of rendering 3D images on Full HD resolution is much greater than sending a man to the Moon.

AGC navigation computer and astronaut control panel

Astronauts only had to deal with the simple text that appeared on the screen, like the old MS-DOS. With these lines of text, there is no need for too much RAM to store and process. With 4KB of RAM, it can hold up to 4,096 characters of text – while a small resolution image can now also take up 2MB of memory.

What’s more, the rocket’s computer calculations are performed only once and displayed on a low-resolution screen. Meanwhile, with current screens, which usually have Full HD resolution (1920 x 1080 pixels) and 60 Hz refresh rate, in-game calculations have to perform up to 124 million times per second to display the image on the screen. screen.

You want to see this image…

… or this image when playing the game

Not to mention the graphical effects in modern games, which constantly change every time you move the mouse or press a button on the keyboard. Even if you do nothing, the state of the program changes, the world in the game always has objects that move or interact with each other.

For example, to get the hairs of a game character to move like a real person, AMD had to write a whole new code library called TressFX, which even when started up took up 2GB of graphics memory. In order to process the movement of a hair in the wind, in the water or in the mountains and running, the computer must continuously perform trigonometric as well as 3D calculations to accurately display the pixels on the screen. That’s not to mention the other movements in the game.

Either way, rocket technology has come a long way since man first set foot on the Moon nearly 50 years ago. Components such as RAM, memory or sensors and processors are no longer as expensive as they used to be. Even so, the processing power of the computer on each human journey into the universe is still far behind the minimum configuration for graphics games.

For example, SpaceX’s Falcon 9 rocket, which holds the world record for reuse, is also equipped with only 3 x86 dual-core processors and runs Linux on each core. Meanwhile, to run smoothly today’s high-graphics games, computer CPUs often need 4 cores, 8 threads or more. That’s not to mention GPU or RAM, all of which must have large parameters to meet the needs of these games.

Refer to Quora