Recent comments in /f/explainlikeimfive
[deleted] t1_iy401wd wrote
Reply to comment by Frogman400 in ELI5:How did people start calling police officer using a ''nickname''? by PokeBattle_Fan
[deleted]
KevinNeedsToTalk t1_iy400d7 wrote
Reply to comment by Frogman400 in ELI5:How did people start calling police officer using a ''nickname''? by PokeBattle_Fan
Definitely a backronym and not the actual origin.
Professor_Dr_Dr t1_iy3zyzt wrote
Reply to comment by LlamadeusGame in eli5 How is computer memory deleted? by unlikemike123
https://www.crucial.com/articles/about-ssd/what-is-trim
Here is a short explanation by Crucial, so yeah. You can't restore files once they have been deleted in modern SSDs it seems. TIL
OvernightSiren OP t1_iy3zd8j wrote
Reply to comment by Wallaby99 in ELI5: Health insurance basics. What are copay and deductibles and can you use them in some basic examples? by OvernightSiren
This was a huge help. I'm starting a job as office manager of an endodontist office and I'm mostly worried about all the insurance stuff, knowing how kuch to charge people, etc
YessikZiiiq t1_iy3yr9i wrote
Reply to comment by Laerson123 in ELI5: how are chinese protesters able to post videos with the great chinese firewall controlling internet? by TImetalker
>3- For things like the lockdown "protests" (that are basically color revolutions funded by imperialist countries)
This kids is how you identify a Tankie. Tankie is a slur used for Authoritarians who pretend to be leftist. They will more often than not deny any crime that the states that they support commit, and if you can prove a crime, they'll say that it was justified.
Tankies are not leftists.
unlikemike123 OP t1_iy3ympg wrote
Reply to comment by snozzberrypatch in eli5 How is computer memory deleted? by unlikemike123
I am very concerned about Putin seeing my endless lists of goals that are never achieved tbh, he's a harsh critic
YessikZiiiq t1_iy3y8nm wrote
Reply to ELI5: how are chinese protesters able to post videos with the great chinese firewall controlling internet? by TImetalker
Unless the country runs an Intranet (which would cripple the country in many ways), outside access must be possible. If outside access is possible, there's several ways of accessing the internet in ways that are untraceable. These ways aren't secret, the government knows about them, there's just little that can be done if you want the benefits of the internet in your country.
2workigo t1_iy3y2z5 wrote
Reply to comment by indy_cision in Eli5 why do traffic lights have red, yellow and green color? Why not use other colors so that even colourblind people can drive. by [deleted]
I obviously haven’t had enough coffee yet because I don’t understand this. The placement of the lights is standardized. The three different colors are illuminated. Green is on bottom. So at night (or really anytime), if the bottom light is glowing, you know it’s green.
[deleted] t1_iy3x5vo wrote
PSUAth t1_iy3x5rn wrote
Reply to eli5 How is computer memory deleted? by unlikemike123
Think of your hard drive as having a bunch of small cubbies in it, not one massive storage hole. These cubbies are much smaller than most typical files these days. So when you have a file to save, the computer breaks up that file into the correct number of pieces to fit into those cubbies. It could start out as it just goes from cubbie 1 to 30 for one file, 31 to 40 for the next, and so on.
Now in order to be useful, the computer has a log of all these files with the locations of all of the cubbies to make up the full file. It also has a list of "available" cubbies to put new files in. So when you first start out it's possible to go from cubby 1 to the end. But as you use the computer and make and delete files, these cubbies are "out of order" but the computer keeps track of what cubby is "used" and what is "open". Now when you delete a file, the computer just deletes the entry of the file and the associated cubby locations, moving them to the available list. It doesn't clean out the contents, because well it doesn't need to. So now a new files needs to be saved, it is given a list of cubbies to use and as it moves through them just tosses what was previously left in them and places the new file info in there.
FellowConspirator t1_iy3wxpl wrote
Reply to eli5 How is computer memory deleted? by unlikemike123
Files can be anywhere, so there’s a big table in a predetermined spot that lists all the files and the place(s) where the file is stored. You can also look there to see what space is in use by files.
When you write a file, the computer looks for a spot that isn’t in use, reserves it, puts stuff there, and updates the table so it shows where the file is.
When you delete a file, the computer simply removes the entry in the table that says where it is and what area was reserved for it. There’s no need to delete the actual data because once the name disappears from the table, it might as well not exist as far as programs are concerned.
Since the space isn’t reserved anymore, the space is free to be used to store other files in the future and will eventually get written over.
therealpigman t1_iy3wumy wrote
Reply to comment by unlikemike123 in eli5 How is computer memory deleted? by unlikemike123
Some memory cards have the ability to write the deleted data with all 0s in the places, but that isn’t guaranteed behavior and usually takes more time and energy than allowing the old stuff to be overwritten
PBmeup t1_iy3wr4z wrote
Are we also wondering where the nickname “pig” came from?
Hyperspacehost t1_iy3wgqy wrote
Reply to comment by unlikemike123 in eli5 How is computer memory deleted? by unlikemike123
It’s worth thinking of computer memory less like a resource that’s used up, like water being scooped out of a bucket and drank, and more like sand in a sandbox.
Sometimes it’s being used for something meaningful, like being a castle or making the walls of a big hole or having letters written in it, and sometimes it just lying around doing nothing, but there’s not any more or less of it.
You might draw a line around a bit and say, “my castle is here, don’t use anything inside the line”, and at the end of the day you rub the line out and go, “I’m all done now, so do whatever”. Maybe you come back and the castle is still there or maybe someone has knocked it down and built something else with it.
lohborn t1_iy3w6t6 wrote
Reply to comment by smart_guy007 in Eli5 why we feel sleepy after eating food by T0xicalGr33k
That's not the only reason we feel sleepy though.
TheSnarfles t1_iy3w28z wrote
Reply to comment by unlikemike123 in eli5 How is computer memory deleted? by unlikemike123
Think of it like that mural the previous tenet painted on the wall at your apartment. The landlord just paints over it, but you could recover it if you really wanted to.
[deleted] t1_iy3vt0z wrote
Reply to comment by Spadaxim in ELI5:How did people start calling police officer using a ''nickname''? by PokeBattle_Fan
[removed]
PaxNova t1_iy3vssw wrote
Reply to comment by unlikemike123 in eli5 How is computer memory deleted? by unlikemike123
On older hard drives with magnetic memory (not the fancy M.2 and flash stuff we have now), you had to defragment drives.
Data was stored magnetically and you had to move a magnetic reader head over it to recover the data. Because the data took up physical space, it was faster for hard drives to store related data close together. As you deleted some files, the remaining files stayed in the same physical place. To make things faster, you would copy your files every now and then to condense them. Bringing all those fragments together was "defragging."
In modern drives, it takes the same amount of time to access all parts of your hard drive, so defragging is no longer necessary.
ThatGenericName2 t1_iy3vbv5 wrote
Reply to comment by dale_glass in eli5 How is computer memory deleted? by unlikemike123
There's also the lie in the other direction. While I don't think it's practiced anymore, sometimes software would "fake load" in that the program simply just waits for an extra bit of time because people would think that a computer didn't do something properly if it worked too fast.
kucksdorfs t1_iy3uze3 wrote
Reply to comment by unlikemike123 in eli5 How is computer memory deleted? by unlikemike123
Think of it as a table of content in a book. So when you "delete' a file, you just remove the table of content chapter marker, but not the pages. Then, when you need to write more data, you "write" to the pages then update the table of content.
Things can get more complicated when it comes to flash storage (ssd/flash drive) but only when it comes to overwriting the pages.
Defleurville t1_iy3uvx0 wrote
Reply to comment by Kientha in eli5 How is computer memory deleted? by unlikemike123
Another precision for other readers, which I assume Kientha knows, is that when speaking of computers, “randomly” never means randomly, as computers are incapable of doing anything at random (even electronic slot machines aren’t random).
In some cases, in means “not in sequential order”: We don’t continue reading a dictionary from where we stopped last time, but we do go in looking for a specific word, not pop it open and read whatever’s on the page. In computer terms, despite not being at all random, this is called “random access”.
In other cases, it means “made to appear random to a human”. Computers can easily generate values where users can’t tell what it will pick next, but under identical circumstances (the “seed”) it will pick the same values in the same order every time. We generally “cheat” by incorporating the time (down to the millisecond) into generating the numbers, so it’s mostly unpredictable.
Changes in Flash data aren’t random, they’re 100% deterministic and predictable (knowing all the info): they’re just not readily predictable to a user, which is functionally basically the same.
mtheofilos t1_iy3ulgq wrote
Reply to eli5 How is computer memory deleted? by unlikemike123
TL;DR: Files on the disk use space, not memory, the file still exists but it is no longer accessible and the operating system doesn't count it anymore to calculate free/used disk space.
You may be confused with memory and space. Memory refers to what running programs use, e.g. what Chrome uses right now to display stuff, space refers to the capacity of a drive (HDD, SSD, etc). Computers have a file system, which keeps track of where files are located in the disk and gives the programs of your computer some tools to interact with them. When you delete a file, you basically unlink it from the system. The file is no longer accessible, and if the file system supports a trash bin, it moves the link to the file there, so you can link it back to its original position (e.g. to a path like C:\Users\MyUser\Desktop), the links in the path are basically the "\". Once the file is removed from the trash bin, it is no longer accessible from anywhere like Trash Bin, C:\, D:\, e.t.c. and then depending on the hard disk's type (HDD, SSD) does one of the two things, either marks it as free space and then a new file may overwrite the old one (HDD), and for SSDs it gives it a signal that the area the file is no longer used, so the SDD will manage the used space on its own. So if that area is not touched at all, you can use some programs that will scan the disk and they can "recover" the file if it was permanently deleted. What they do is actually locate the file with some tricks and then create a new link so it can be traced again (C:\...\Desktop\MyRecoveredFile.pdf). To permanently delete a file for good, a program will just write a bunch of zeroes on top of the file and then unlink it from the system, like what you would do with a correction tape or fluid on a piece of paper to "remove" the letters and write something new on top. Now that you learned about links, you may understand that when you move files, you actually don't physically move them you just move the link in the file system, that's why cut/paste files is faster than copy/paste.
squigs t1_iy3u6o8 wrote
Reply to comment by unlikemike123 in eli5 How is computer memory deleted? by unlikemike123
Yup. Data recovery firms rely on this.
There are actually some fairly simply tools for most filesystems that will find deleted files.
It's the same with RAM. I think modern systems are more secure, but in the past, hackers were able to break into systems by allocating a large chunk of RAM and seeing if anything that looks like a password was there.
sakzeroone t1_iy3u4dm wrote
Reply to comment by Kalel42 in Eli5 why do traffic lights have red, yellow and green color? Why not use other colors so that even colourblind people can drive. by [deleted]
How do you know?
lazydogjumper t1_iy40q6l wrote
Reply to ELI5- How do people find lost or unknown relatives through DNA if the lost relative has never taken a DNA test? by Future_Train_9723
The most likely explanation is degrees of separation. The daughter never took a test but one of her children probably did, which would also carry evidence of his DNA.
EDIT: also, just because she says she never took a DNA test doesnt mean her DNA has never been tested. DNA tests are not new, easy-access tests are.