System memory (RAM) is the primary area where the system temporarily stores program instructions and data.
The larger the memory capacity, the more data and programs can be stored, and the faster the computer will naturally run.
Mobile phones and computers usually have 2GB and 16GB memory, but even so, we will occasionally freeze when using, but surprisingly, the computer that landed on the moon in the United States only ran 4KB, which is not as big as the current one.
In addition, computers in the 60s of the 20th century often occupied an entire room, but the computers carried by the United States to the moon were only about the size of a suitcase, which inevitably made people doubt the authenticity of the American moon landing.
In order to refute the rumors, the United States could only take out this computer with only 4 kb of memory and tell what happened back then.
In the course of the Cold War between the United States and the Soviet Union, aerospace has always been the top priority, and with the launch of the first artificial satellite by the Soviet Union and the first man into space, the United States is about to fall into the disadvantage.
So the United States hurriedly launched the Apollo moon landing program, and soon selected three astronauts, namely Armstrong, Aldrin and Collins.
Landing the capsule on the moon is the most important part of the entire lunar landing program, and the space environment is extremely complex and there is little previous experience, so each link of the lunar landing needs to be carefully calculated.
What data is needed?
A series of data such as the flight speed of the spacecraft, the speed of the ambient airflow, the deviation angle of the spacecraft, the ignition time of the engine, the direction of duration, the terrain characteristics, and the pre-selected landing site are impossible for astronauts to calculate with a pen and paper, nor can they be operated with subjective feelings, and these data need to be classified into the system to get accurate answers.
Therefore, astronauts need a computer, in addition to planning the optimal route of the spacecraft from the earth to the moon, but also to calculate the timing and power required to get rid of the gravitational pull of the earth's orbit and enter the lunar orbit, and also need to monitor the status of various sensors and switches of the spacecraft in real time.
In order to avoid the knowledge loopholes of astronauts, the computer also needs to maintain contact with the ground at all times, the computer at that time was the size of a whole room at every turn, and every gram of weight of the spacecraft needed to be carefully calculated, and it also involved the thrust of the rocket.
The United States urgently needs to build a computer that can do many of these things, but is small and small.
We are now using 32-bit or 64-bit computers, simply put, the more bits, the better the processing performance of the computer, but the "Apollo Guidance Computer" (AGC) only runs 15 bits, and if you count the extra 1 bit of the test, it is only 16 bits.
Surprisingly, the AGC is indeed only 4KB, but it can store 2048 words, it can store data by changing the direction of magnetization of the core, and astronauts can interact with the computer by entering two-digit verbs and nouns, such as "0633", where "06" stands for "display", "33" for "spacecraft position", and two strings of numbers entered together, it means "show spacecraft position", and the information will appear on the screen.
In 1966, the United States built the Apollo Guidance Computer (AGC) non-stop.
On July 10, 1969, American astronauts took the AGC to 110 kilometers above the moon.
At this time, the lunar mission had reached the descent stage, and when astronaut Aldrin entered ** to the AGC, wanting to know the landing site and distance of the spacecraft's descent, the accident happened.
The computer did not show the results, but sounded a series of sharp alarms, because the Apollo program is the first attempt to make a manned landing in human history, so the United States is not at ease, for fear that the computer will have a system error, so it added an emergency restart function, and can retain the original data.
After the astronauts asked for help from the ground control center, they were instructed to "continue", and the AGC's first crash passed without danger.
Just when the astronauts breathed a sigh of relief and were about to get the exact route from the AGC again, the computer crashed and crashed again, and there was no choice but to restart and continue working.
When the lunar module descended to a distance of 6 kilometers from the lunar surface, the AGC actually crashed again, repeating the above operation, restarting and continuing, this is the third crash.
The lunar module descended to 610 meters from the lunar surface, just when the moon landing was almost a kick, the computer crashed again, this crash caused a huge psychological blow to the astronauts, because the fourth crash is different from the previous three, this time there is no error data, if the AGC can not complete the restart or can not work normally after the restart, the United States in addition to the failure of the moon landing, three astronauts are likely to die in space.
Fortunately, the computer was bizarrely back to normal after three minutes, and just when the astronauts were relieved and the lunar module was only 244 meters from the lunar surface, the calculator crashed for the fifth time, but fortunately it returned to normal after this restart.
In this way, the United States relied on a computer with only 4KB of memory to complete the feat of landing on the moon, which is indeed shocking, why can a 4KB computer complete the moon landing, in layman's terms, AGC only processes fixed data, and our mobile phones and computers need to deal with a lot of things.
For example, 24 hours a day, Zhang San only needs to read a book for 30 minutes to complete the task, while Li Si needs to do 500 things to complete, so it is also "to complete the task", and the latter needs more powerful "ability".