I blow hot air.

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Joined 1 year ago
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Cake day: July 6th, 2023

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  • Vent@lemm.eetoMemes@lemmy.mlHey girl
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    2 months ago

    The people in the meme are at about Seattle and NYC, which is a little over 3k miles apart (by car). You’d need to be going 250mph for the entire 12 hours to make that distance. A quick google search says that the maximum operating speed of a bullet train is 200mph, but tests have been conducted at 275mph.

    So, you’d need to go non-stop at 125% max speed to make the trip in 12 hours. Even if you went at 275mph, realistically you’d make a lot of stops along the way, which is going to make the average speed a lot lower. Trains are great, but the US is really big.

    Bonus fact: a non-stop flight from Seattle to NYC takes about 5.5 hours.














  • All these answers read like they’re written for comp sci students rather than a general audience. Let me give an ELI5 (more like ELI12) a shot.

    Ports are just numbers. They aren’t physical pathways or doors or windows or anything like that. A better analogy is a street address, like an apartment number. Your IP address identifies your computer (apartment building), and the port identifies the program on the computer (the apartment). When a program needs to talk to the internet, which is very similar to sending a letter, it hands a packet/letter to your computer and your computer assigns the program a port number. It then puts that number on the return address of the letter so that the recipient knows where to send the response. The computer remembers that port number is associated with that program, so when it gets an incoming letter with that number, it gives it to the program. After the program is done talking to the internet, the computer frees the port up to be used by another program.

    Ports are “closed” when there is no program associated with them. Any incoming letters are ignored because they have nowhere to go.

    Ports are “open” when they’re associated with a program. This happens automatically when programs send outgoing letters, or you can manually open (or “forward”) ports by telling your computer/router what the port should be associated with and that it shouldn’t use the port for something else.

    ELI5 over.

    The internet is networks on top of networks on top of networks, so your computer will have an IP and assign a port number, then your router will remember that and change the address on the letter to its own IP with a different port number, then that process repeats a few more times until eventually it reaches its destination. You don’t have to deal much with your computer’s internal network, but occasionally you have to deal with your router’s by opening/forwarding a port because it has a NAT that has to deal with all of the devices on your network. Forwarding the port just tells your router to always send incoming letters with that port number to a specific device.