Today I Learned
What did you learn today? Share it with us!
We learn something new every day. This is a community dedicated to informing each other and helping to spread knowledge.
The rules for posting and commenting, besides the rules defined here for lemmy.world, are as follows:
Rules (interactive)
Rule 1- All posts must begin with TIL. Linking to a source of info is optional, but highly recommended as it helps to spark discussion.
** Posts must be about an actual fact that you have learned, but it doesn't matter if you learned it today. See Rule 6 for all exceptions.**
Rule 2- Your post subject cannot be illegal or NSFW material.
Your post subject cannot be illegal or NSFW material. You will be warned first, banned second.
Rule 3- Do not seek mental, medical and professional help here.
Do not seek mental, medical and professional help here. Breaking this rule will not get you or your post removed, but it will put you at risk, and possibly in danger.
Rule 4- No self promotion or upvote-farming of any kind.
That's it.
Rule 5- No baiting or sealioning or promoting an agenda.
Posts and comments which, instead of being of an innocuous nature, are specifically intended (based on reports and in the opinion of our crack moderation team) to bait users into ideological wars on charged political topics will be removed and the authors warned - or banned - depending on severity.
Rule 6- Regarding non-TIL posts.
Provided it is about the community itself, you may post non-TIL posts using the [META] tag on your post title.
Rule 7- You can't harass or disturb other members.
If you vocally harass or discriminate against any individual member, you will be removed.
Likewise, if you are a member, sympathiser or a resemblant of a movement that is known to largely hate, mock, discriminate against, and/or want to take lives of a group of people, and you were provably vocal about your hate, then you will be banned on sight.
For further explanation, clarification and feedback about this rule, you may follow this link.
Rule 8- All comments should try to stay relevant to their parent content.
Rule 9- Reposts from other platforms are not allowed.
Let everyone have their own content.
Rule 10- Majority of bots aren't allowed to participate here.
Unless included in our Whitelist for Bots, your bot will not be allowed to participate in this community. To have your bot whitelisted, please contact the moderators for a short review.
Partnered Communities
You can view our partnered communities list by following this link. To partner with our community and be included, you are free to message the moderators or comment on a pinned post.
Community Moderation
For inquiry on becoming a moderator of this community, you may comment on the pinned post of the time, or simply shoot a message to the current moderators.
view the rest of the comments
Wait until you learn about SelectaVision, the vinyl record that played videos and still used a stylus.
Oh so it's a helicopter
LaserDisc ran at up to 1800 RPM also in a 30cm form factor
In the Tech Connections video on them, they sound like they're taking off when they spool up.
A very good friend of mine had one of these when I was a kid. We called it laserdisc. I couldn’t tell you how that started.
So, when I got to high school and they were using actual laserdiscs I said, “Where’s the cool outer shell? Is this just like, a school laserdisc setup?” Some kids argued with me that I didn’t know what I was talking about.
I clearly remembered watching Star Wars on them and being mesmerized by that case.
Years later I got to thinking about it and googled “laserdisc with hard casing, mechanism removes disc when played”. Nothing. I chalked it up to it being some kind of false memory. Maybe I was just remembering the sleeve and my buddy was putting the movies in the player in a way that made me think it worked like that.
It wasn’t until years later that I seen a techmoan video in my feed and I was like, “THAT!! That’s what I’ve been talking about all these years!! It’s fucking vinyl! NO WAY!”
I was always tech obsessed so it nearly drove me crazy anytime I thought about it. He’d been dead for years so I couldn’t ask him. His dad and sister had no idea what I was talking about. “He traded a lot stuff around so there’s no telling what he had. There was mismatched technology all over this place.”
Woah! Crazy that something like that existed.
A brilliant idea ruined by some dingus at RCA insisting on an hour per side. Y'know. Like how records aren't.
Also, they whiffed on the cotton-gin problem. They spent ages formulating metallic vinyl. But... the signal is just pits. Same as Laserdisc. All they had to do was press normal vinyl with a shitload of tiny holes and then put metal in 'em. Nontrivial! Probably a hideous cancer risk. But metal powders and some kind of glue are easier to work with when they don't have to withstand a ten-ton press and still act structural.
And genuinely - the consumer hardware was so cheap. It's just a flake of metal in a stylus, which changes capacitance when it's over a pit, and if you amplify that wiggly line, it's a standard TV signal. That's all! Even with 1960s technology, that could've been pocket-sized, if not for the stupidly tiny grooves that skipped over any micrometer of dust. Lasedisc does the same analog-binary video signal, but it needs a laser and laser tracking and electrical conversion and yadda yadda yadda. RCA's solution was like a phonograph, but simpler. They could've sold Star Trek TOS episodes as soon as they aired - if only they'd told people to flip them in the middle.