Speaker 1: Get in text with technology with tech Stuff from works
Speaker 1: dot com. Hey there, and welcome to tex Stuff. I'm
Speaker 1: your host, Jonathan Strickland. I'm also an executive producer at
Speaker 1: how Stuff Works, and I love all things tech and
Speaker 1: recently I had a request from a listener. The listener
Speaker 1: asked me about doing an episode about data retrieval. Now, specifically,
Speaker 1: this listener was curious about how you go about retrieving
Speaker 1: data that was marked for deletion, and this curiosity was
Speaker 1: sparked by news stories of various agencies following investigations and
Speaker 1: trying to look for evidence of deleted materials. So the
Speaker 1: listener asked if I might be able to go into
Speaker 1: that without it becoming a political discussion. Right, Uh, And
Speaker 1: I completely respect that. I definitely have a very particular
Speaker 1: political philosophy, but I also acknowledge that these sort of
Speaker 1: investigations can happen to any political side of the spectrum. Right,
Speaker 1: It's not a specific problem that involves one side or
Speaker 1: the other. Everyone, at some point or another has been
Speaker 1: involved in this kind of stuff. Everyone by that, I
Speaker 1: mean all the major political parties, and that there's always
Speaker 1: some sort of question about an investigation. And then well,
Speaker 1: did they have possession of information and then they willingly
Speaker 1: got rid of that information or they worked to delete it,
Speaker 1: and if so, how do you go about retrieving that?
Speaker 1: So this goes well beyond politics. By the way, politics
Speaker 1: is an obvious example of how this happens. But you
Speaker 1: also hear about these investigations into big corporations that involve
Speaker 1: trying to retrieve data from the void. I mean, this
Speaker 1: goes back ancient times, really, but if in modern era
Speaker 1: it goes back to before you're talking about hard drives
Speaker 1: and things like shredded documents and stuff. I remember in
Speaker 1: the late nineties early two thousand's when there were a
Speaker 1: lot of stories about this, like if you really want
Speaker 1: a good one, you can read up on en Ron.
Speaker 1: But in that era, when you have an investigation and
Speaker 1: they're looking for evidence, what steps do you have to take?
Speaker 1: Or if you're looking at the other way, if you
Speaker 1: have a device that's got data on it and you
Speaker 1: want to get rid of that device for whatever reason,
Speaker 1: how can you be sure, absolutely certain that your information
Speaker 1: is no longer on that device. That's what we're gonna
Speaker 1: talk about today. So what happens when you mark a
Speaker 1: file for deletion? How does that file actually go through
Speaker 1: the deletion process, and to what extent can that file
Speaker 1: then be recovered. Long time listeners of tech stuff may
Speaker 1: remember that I've done an episode similar to this particular
Speaker 1: one in the past, But things have changed a bit
Speaker 1: since that last episode. In fact, the big one would
Speaker 1: be that cloud computing and cloud storage has become a
Speaker 1: major industry and it's really changed the conversation as well,
Speaker 1: because now we have other stuff to worry about, not
Speaker 1: just the the devices that are in your possession, but
Speaker 1: the places where data could exist outside of your control.
Speaker 1: So how does that change things? The answer to that
Speaker 1: is a lot. Well, first, let's talk about what happens
Speaker 1: when you actually delete a file on a device you own.
Speaker 1: So you've decided to free up some space on a
Speaker 1: hard drive on a computer, and I'm talking about a
Speaker 1: physical hard drive here. You're going to delete a folder
Speaker 1: that contains old term papers because you're never going to
Speaker 1: need those again, let's be honest, there's no reason to
Speaker 1: keep them. And what is happening behind the scenes when
Speaker 1: you mark those documents for deletion, Well, the particulars depend
Speaker 1: upon the device you're using. So, for example, if you're
Speaker 1: on a Windows PC, you're following the rules dictated by
Speaker 1: the nt f S file system. Now in t f
Speaker 1: S stands for New Technology File System, I guess that
Speaker 1: means I just said new Technology file system files is
Speaker 1: them kind of like pen number or a t M machine.
Speaker 1: So whoop see daisy on that one, guys. Anyway, when
Speaker 1: you delete a file, the file pops on over to
Speaker 1: the recycle bin or the trash bin, depending upon what
Speaker 1: operating system you're using. But the principle remains the same.
Speaker 1: And when I say pops on over, the file doesn't
Speaker 1: actually change locations on the hard drive. It's designation changes.
Speaker 1: So instead of the file being listed as being inside
Speaker 1: the docks folder, it's being listed in the recycle bin.
Speaker 1: So the physical location of data on your computer is
Speaker 1: not tied directly to its file location. Within a file directory,
Speaker 1: those two things are separate. The file directory gives us
Speaker 1: a very convenient way for human beings to look at
Speaker 1: all the information that's stored on a device, or at
Speaker 1: least all the information that is viewable. Sometimes you have
Speaker 1: hidden files that won't show up in a file directory.
Speaker 1: But let's just for argument's sake, say all the files.
Speaker 1: It's an easy way to organize that so that we
Speaker 1: as human beings can find what we're looking for. If
Speaker 1: it were just a giant storage bend that had data
Speaker 1: kind of haphazardly connected inside of it, it would be
Speaker 1: very difficult to find anything specific you wanted. So the
Speaker 1: file system is mainly meant as something to let us
Speaker 1: humans access our information more easily. It's not so much
Speaker 1: for the computer. It's for us on the physical side.
Speaker 1: That data could be located next to data that's in
Speaker 1: a totally different file folder, in a totally different section,
Speaker 1: even in a different drive on your computer. So that's
Speaker 1: something to keep in mind. The physical location of your
Speaker 1: data and the files location are not necessarily connected. That's
Speaker 1: important to remember. But the file designation has changed, so
Speaker 1: the associated programs with that file will no longer connect
Speaker 1: to it. By that, I mean, let's say it's a
Speaker 1: word document. I had mentioned term papers earlier, so you've
Speaker 1: got a term paper. It's a word document. Let's say
Speaker 1: you used a Microsoft word and you save the document there,
Speaker 1: and when you delete it, it means that the file
Speaker 1: designation changes so that that file is now appearing in
Speaker 1: the recycled bin as opposed to the documents folder and
Speaker 1: you pull up Word and you want to pull up
Speaker 1: that particular document, you can't because it's trying to connect
Speaker 1: to a file that was last in the documents folder.
Speaker 1: That's not where it is anymore. So Word is not
Speaker 1: going to find that anymore. It's it's kind of the
Speaker 1: first step to saying this file is gone, but the
Speaker 1: file is not really gone. It's over in that recycle bin.
Speaker 1: Like you could actually open up the recycle bin and
Speaker 1: see the files that are inside of it, assuming you
Speaker 1: don't have your recycle bin set to auto delete as
Speaker 1: soon as something goes into it. Uh. It means that
Speaker 1: you actually have a bit of a safety net, which
Speaker 1: is a good thing, right, because sometimes you might select
Speaker 1: a file to delete and it turns out, whoop, see Daisy,
Speaker 1: I did not mean to actually delete that. That was
Speaker 1: a pick you're of my niece, and I want to
Speaker 1: keep it forever and ever. So you could go into
Speaker 1: a recycle bin or a trash bin and restore a file.
Speaker 1: And that's kind of a nice little way to rescue
Speaker 1: something when you you make just a human mistake. Uh.
Speaker 1: And thankfully it does exist, because I have certainly use
Speaker 1: that more than once where I've realized that I accidentally
Speaker 1: sent the wrong file to delete, and so I go
Speaker 1: into the recycled bin and restore it. But what happens
Speaker 1: if you choose to empty your recycle bin, because that's
Speaker 1: typically something that you are allowed to do. You might
Speaker 1: have it set to automatically empty every certain incremental amount
Speaker 1: of time, or it may just be totally manual, uh,
Speaker 1: And which case, it's whenever you go in there, or
Speaker 1: if you hit a certain threshold of data, like if
Speaker 1: there's a certain amount of data in the recycle bin,
Speaker 1: it may auto empty once it hits that threshold. But
Speaker 1: however you choose to do it, what happens when that
Speaker 1: recycle bin is emptied. Is the file totally gone? Then no,
Speaker 1: it's not at that point. What happens behind the scenes again,
Speaker 1: is the operating system removes the file name entry from
Speaker 1: the file system. So now you can't even find it
Speaker 1: within the recycle ben. There's no account of it in
Speaker 1: the file system itself. But the physical space on your
Speaker 1: hard drive, because remember we're talking about a physical hard
Speaker 1: drive example here, the physical space that that file occupies
Speaker 1: still has the file in it. It's just that that
Speaker 1: space is marked as being free or freely available, but
Speaker 1: there's actually still the file, the information, the zeros and ones,
Speaker 1: they're all still right there. They haven't disappeared. So this
Speaker 1: means that the computer is free to write over that
Speaker 1: section of the hard drive space. It doesn't mean it
Speaker 1: will right away, but it could. It might happen immediately,
Speaker 1: or it might happen months later, or it might not
Speaker 1: happen at all. So if you lead a file and
Speaker 1: a few months later you decide to get rid of
Speaker 1: your computer, the traces of that file may still be
Speaker 1: on that hard drive. All the deletion means is saying, hey, computer,
Speaker 1: if you need this space to store something, it's totally available,
Speaker 1: so just go ahead and move on in. But in
Speaker 1: the meantime, I'm just gonna hold this old information that's
Speaker 1: sitting here because it's not really relevant to anything anymore.
Speaker 1: Um So, that free designation only means that the file
Speaker 1: space is available, not that it is actually empty. So
Speaker 1: if you delete a file from your computer and you
Speaker 1: empty the recycled bin, the information will still be on
Speaker 1: the storage device, and as you save more information to
Speaker 1: the computer, the operating system has the option of storing
Speaker 1: that new information by writing over the old info represented
Speaker 1: by the deleted file. At that point, when you have
Speaker 1: a new file in place, you've effectively erased at least
Speaker 1: part of the old information. So let's say we're using
Speaker 1: that term paper example again, and you end up getting
Speaker 1: a game because of course you wanted to free up
Speaker 1: computer space on your computer to install a new game
Speaker 1: on it, right, And when you install it, it starts
Speaker 1: to write the data to the hard drive, and part
Speaker 1: of the the section of the hard drive it writes
Speaker 1: over happens to be part that held that term paper.
Speaker 1: Now your term paper is a race because the hard
Speaker 1: drive has been altered so that new data is on
Speaker 1: top of what used to be old data, not really
Speaker 1: on top replaces. It replaces the old data, which means
Speaker 1: the old data is gone, or at least part of
Speaker 1: it's gone. You know. It all depends on where in
Speaker 1: the physical space that reallocation happens. So you could have
Speaker 1: a tiny bit of the term paper left. It would
Speaker 1: probably be meaningless bits at that point because you wouldn't
Speaker 1: necessarily have any of the information related to what type
Speaker 1: of file it used to be, but there might still
Speaker 1: be some zeros and ones that used to belong to
Speaker 1: that term paper on that hard drive, but for the
Speaker 1: most part it would be erased gone because you have
Speaker 1: new information takeing up that same physical space. Now, once
Speaker 1: you've done all this, you won't be able to retrieve
Speaker 1: a deleted file easily. Right once you set that recycle
Speaker 1: bin too empty, the operating system will no longer be
Speaker 1: able to identify that marked file in your system. So
Speaker 1: even though it may physically still exist on the hard drive,
Speaker 1: there's no record of its existence in the software side,
Speaker 1: right like there's no there's no map to that destination anymore.
Speaker 1: So the destination may still exist, but you don't know
Speaker 1: how to get there. This is when you would have
Speaker 1: to bring a device to perhaps a service or use
Speaker 1: special software to search for that information and potentially retrieve it. Now,
Speaker 1: there's no guarantee that you're going to be able to
Speaker 1: retrieve a deleted file, particularly if you've continued to use
Speaker 1: that same device for a good amount of time afterward,
Speaker 1: because that increases the chances that you've overwritten that old information.
Speaker 1: But assuming that you haven't, you could potentially retrieve all
Speaker 1: sorts of old data. And uh, again, it all really
Speaker 1: depends on how much use you've got to that machine
Speaker 1: and how frequently you're writing data to it. If it's
Speaker 1: not frequent, then there's a better chance that you'll be
Speaker 1: able to retrieve at least some of that information. Now,
Speaker 1: in some ways that's great news, but say you've got
Speaker 1: a computer that had files marked for deletion and later
Speaker 1: on you find out that you actually need those files. Uh,
Speaker 1: if you are quick enough, and if you're lucky enough,
Speaker 1: you may be able to retrieve some or potentially even
Speaker 1: all of that data using data retrieval tools. And it
Speaker 1: could also mean that if your computer had suffered some damage.
Speaker 1: Let's say that you weren't trying to delete files at all,
Speaker 1: but your computer has suffered damage that has made it
Speaker 1: impossible to access the hard drive. This also means that
Speaker 1: you could potentially take a hard drive to one of
Speaker 1: these data retrieval services and get information that otherwise would
Speaker 1: be inaccessible to you. I'll talk more about that a
Speaker 1: little bit later in the podcast, because there are some
Speaker 1: really phenomenal stories about data retrieval in extreme circumstances that
Speaker 1: blew my mind when I heard about them. But in
Speaker 1: other ways, this is not such a good thing. It's
Speaker 1: actually a bad thing, because if you've brought let's say
Speaker 1: let's let's say you go out and you get a
Speaker 1: brand new computer. You've got an old one that you've
Speaker 1: been using for a while and it's time to upgrade.
Speaker 1: So you go out and you buy a new computer,
Speaker 1: and then you think, well, what do I do with
Speaker 1: this old computer? I don't need it, I'm not going
Speaker 1: to use it, so maybe I want to sell it,
Speaker 1: or maybe I want to donate it. Well, if you're
Speaker 1: going to do that, you're really gonna want to get
Speaker 1: rid of any personal information, any data that's sensitive on
Speaker 1: that machine. You want to get rid of that as
Speaker 1: best you can before you hand it over to someone
Speaker 1: else who could potentially exploit that information. So you may
Speaker 1: want to figure out a way of wiping it off
Speaker 1: for good. And one thing you could do is run
Speaker 1: a third party program or application that will guarantee that
Speaker 1: it will delete all of the info on your machine.
Speaker 1: It does this, by the way, by not just marking
Speaker 1: it for deletion, but then writing random data to the drive,
Speaker 1: so just meaningless gibberish. In other words, over all that
Speaker 1: space that was marked for deletion, typically it maybe the
Speaker 1: entire drive. Like there are a lot of of options
Speaker 1: where you know, there's no subtlety here. It's wipe everything others.
Speaker 1: It may be designated parts of a drive, like specific folders.
Speaker 1: Sometimes it may be partitions. If you create different partitions
Speaker 1: of your hard drive, you might be able to target
Speaker 1: a specific partition over others. But my advice is if
Speaker 1: you're using one of these, just use it with the
Speaker 1: assumption that it's going to hit everything, which means, before
Speaker 1: you do this, if you have anything on that machine
Speaker 1: that you want to keep, back up your hard drive.
Speaker 1: I know that seems weird if you're going to get
Speaker 1: rid of everything anyway but back it up. You should
Speaker 1: be backing up your hard drives anyway because stuff goes
Speaker 1: wrong and occasionally you just need to get access to
Speaker 1: old stuff, and if you don't back it up, it
Speaker 1: can make that much more difficult and expensive. These services
Speaker 1: that do data retrieval can sometimes be pretty costly, depending
Speaker 1: upon how extensive the problem is. So if you do
Speaker 1: use one of these services to rewrite data over a
Speaker 1: physical hard drive, it takes time. You know, this is
Speaker 1: a hard drive that uses platters, and that means also
Speaker 1: that this particular approach creates wear and tear on your device.
Speaker 1: So let me elaborate on that, like how how can
Speaker 1: this actually create wear and tear on a hard drive? Well,
Speaker 1: the hard drive is the data storage space on a computer, right,
Speaker 1: This is your data repository. This is the thing that
Speaker 1: can hold information indefinitely, even after power is cut off
Speaker 1: to the computer, that it remains there. It is stable
Speaker 1: from between power cycles. So it's not like RAM random
Speaker 1: axis memory, which only exists for as long as the
Speaker 1: computer receives power. This is semi permanent right until you
Speaker 1: markt for deletion. The old physical addresses are stored information
Speaker 1: using magnetism. In other words, you're using magnets to create
Speaker 1: the zeros and ones on these platters. It can hold
Speaker 1: this information indefinitely. These hard drives have a circular plate
Speaker 1: in them. That's what is the platter. So the platter
Speaker 1: is a circular plate. They're shiny, and they're at least
Speaker 1: coded in magnetic material. Most hard drive platters tend to
Speaker 1: be made out of either glass or aluminum, and then
Speaker 1: they're coated with a layer of metal that can be
Speaker 1: magnetized and demagnetized. The platter surface contains billions of tiny
Speaker 1: little areas individually distinct from another, and every single one
Speaker 1: of those billions of areas can be magnetized, which would
Speaker 1: represent the number one in binary, or demagnetized, which would
Speaker 1: represent the number zero. Now, using ones and zeros, you
Speaker 1: can represent all sorts of data, but it takes a
Speaker 1: lot of zeros and ones to represent a relatively small
Speaker 1: amount of information. So, for example, if you wanted to
Speaker 1: create the binary for an upper case A, you would
Speaker 1: use the eight digits of zero one zero, zero, zero
Speaker 1: zero zero one. But if you want to do a
Speaker 1: lower case A, that would be a zero one one
Speaker 1: zero zero zero zero one. Minor distinction, but it makes
Speaker 1: a big difference in binary. And when you figure this
Speaker 1: out that every single one of those areas can be
Speaker 1: either a zero or a one, and it takes eight
Speaker 1: of them just to make one character, you realize, I'm
Speaker 1: gonna need a whole lot of those areas to store
Speaker 1: any meaningful amount of information. So it really is billions
Speaker 1: of them, and uh, that's why you gotta that's why
Speaker 1: you gotta pack all that into the hard drive, otherwise
Speaker 1: you wouldn't be able to save any meaningful amount of
Speaker 1: information to it. Now, the way a computer writes data
Speaker 1: to a hard drive involves using a very tiny magnet
Speaker 1: on the end of a mechanical arm, and it looks
Speaker 1: kind of like a record player, which I know you
Speaker 1: guys know about now. Like for the longest time, I
Speaker 1: always had to say, hey, ask your parents, But hey,
Speaker 1: vinyls coming back. People own record players again. There are
Speaker 1: bands putting out Vinyl albums. I'm so excited about this,
Speaker 1: largely because I no longer have to explain what it
Speaker 1: is anymore, because you guys already know. So it looks
Speaker 1: kind of like a record player. You've got a mechanical
Speaker 1: arm on the end of it. Instead of a needle,
Speaker 1: you have a magnet, and the mechanical arm can swing
Speaker 1: back and forth over a spinning platter. It can also
Speaker 1: hit all different spots of that. So you've got this
Speaker 1: basic mechanism here. It's pretty simple at least in theory,
Speaker 1: and that magnet can be used to magnetize demagnetize each
Speaker 1: of the areas on the hard disk. So with this
Speaker 1: type of hard drive, the computer tends to store data
Speaker 1: for files and physically adjacent or nearby areas. So in
Speaker 1: other words, the data that makes up the files on
Speaker 1: your physical hard drive tends to be located within the
Speaker 1: same general area of a platter, kind of like a
Speaker 1: track on a vinyl record album. So each song obviously
Speaker 1: is one section of a track that's in a concentric
Speaker 1: circle around this vinyl disc, right, Because if you just
Speaker 1: randomly assigned bits and pieces of songs throughout an album,
Speaker 1: it would be a mess. You wouldn't have anything really
Speaker 1: that you could easily listen to and make it meaningful.
Speaker 1: Same thing with hard drive platters. They tend to collect
Speaker 1: all the data for a file within adjacent spots on
Speaker 1: the platter, if possible. It also makes it easier and
Speaker 1: faster when a hard drive is reading data back that
Speaker 1: it can just focus on a specific section of the
Speaker 1: our drive platter and pull that information out. If it
Speaker 1: had to skip all over the platter, that would take
Speaker 1: up more time and create more wear and tear on
Speaker 1: the system. Those areas of data are called tracks, by
Speaker 1: the way, and they, like I said, are concentric circles
Speaker 1: their pathways that are on the platters themselves. Each track
Speaker 1: inside of it has smaller areas called sectors, and the
Speaker 1: computer keeps a record of all the sectors, and it
Speaker 1: knows which ones have files stored on them and which
Speaker 1: ones are free to write over. Now, the free ones
Speaker 1: may also have data on them, but it just means
Speaker 1: this is data that's not important, so you can write
Speaker 1: over it whenever you want. In a Windows machine, we
Speaker 1: call this record the file Allocation table or f a
Speaker 1: T or FAT. Now, notice all of that is for
Speaker 1: physical hard drives. If you have a machine that uses
Speaker 1: a solid state drive, it works a lot differently. Solid
Speaker 1: state drives will store data on lots of different available
Speaker 1: areas within the drive, so you don't necessarily end up
Speaker 1: with a sector or track of related data. The data
Speaker 1: is all on the drive, but it could be broken
Speaker 1: up into smaller pieces, kind of like Mike TV and
Speaker 1: Willy Wonka and the chocolate factory, you know, when he's
Speaker 1: being broadcast over the year. But they still store data
Speaker 1: in the forms of zeros and ones. All of that
Speaker 1: is still the same. It's still based on this binary code.
Speaker 1: And I'll get into how so these solid state drives
Speaker 1: organized data in just a minute, because it's important and
Speaker 1: it's a little weird. So if you wanted to wipe
Speaker 1: out a file on a physical hard drive, you'd want
Speaker 1: to use a program that would identify all the free
Speaker 1: areas on a hard disk platter. And then override that
Speaker 1: gibberish on top of those areas. And some of the programs,
Speaker 1: such as the ones used by military and intelligence agencies,
Speaker 1: will do this more than once to ensure that all
Speaker 1: records have been completely eradicated, So they'll override a hard
Speaker 1: drive two or three times, which is frankly overkill if
Speaker 1: you're doing it correctly, but it really does make sure
Speaker 1: that that data is irretrievable at least uh there's no
Speaker 1: there's nothing meaningful on there because it's been just completely
Speaker 1: replaced by gibberish multiple times. This process does take time,
Speaker 1: and since you are just writing meaningless information onto a
Speaker 1: physical hard drive, you know, think about saving a really
Speaker 1: big file to your hard drive and how long that
Speaker 1: can take. Well, if you're formatting an entired hard drive,
Speaker 1: this is gonna take as long as you know that
Speaker 1: hard drive can you know whatever that capacity is and
Speaker 1: whatever it's spinning rate is as well, so that ReadWrite
Speaker 1: rate is gonna matter a lot, and also just the
Speaker 1: capacity of the hard drive if it's really big, it's
Speaker 1: gonna take a really long time to write meaningless data
Speaker 1: to every single free sector on there. And like I
Speaker 1: said earlier, it can contribute to wear and tear on
Speaker 1: the hard drive, because you gotta remember, these are mechanical
Speaker 1: elements in that system, right, There's that mechanical arm, there's
Speaker 1: the the plate that spins along the for the for
Speaker 1: the platter to rotate properly. Those pieces all wear out
Speaker 1: over time, and by overriding a hard drive, you're really
Speaker 1: putting them to work more than they normally would be.
Speaker 1: Now that's not to say that by running a program
Speaker 1: like this you would completely wear out your machine, but
Speaker 1: it will hasten the eventual need to replace the hard drive,
Speaker 1: because eventually all physical hard drives will fail. That's just
Speaker 1: a truth. Um, if you use it long enough, it
Speaker 1: will fail. Now, if you get rid of the computer
Speaker 1: before you get to that point, sure, technically you got
Speaker 1: around it. But if you're just constantly using a hard drive,
Speaker 1: sooner or later it's gonna it's gonna fail because those
Speaker 1: mechanical parts are just gonna wear out. Also, most of
Speaker 1: these programs that I know of do this indiscriminately as
Speaker 1: to which parts of the hard drive get over written.
Speaker 1: So that's a nice way of saying they'll nuke it
Speaker 1: from orbit just to be sure, which includes the deleted
Speaker 1: data you definitely didn't want anyone to have any access to,
Speaker 1: plus everything else as well. So if you plan on
Speaker 1: using this method to clean a hard disk that's still
Speaker 1: has stuff on it that you want to keep, like
Speaker 1: I said, pump those breaks just a little bit. Make
Speaker 1: sure you have a backup copy of your hard drive
Speaker 1: that you're going to keep, that you know in case
Speaker 1: there's any relevant data on there that you need to
Speaker 1: have access to later on, and then do it. Because
Speaker 1: if it's doing its job correctly and it allows you
Speaker 1: to designate specific specific parts of your hard drive for
Speaker 1: this process, you might be fine and everything you wanted
Speaker 1: to keep might still be there. But if things go
Speaker 1: wrong or you don't use the software properly, or it's
Speaker 1: software that's meant to tackle an entire hard drive and
Speaker 1: not just the bits that you want to get rid of,
Speaker 1: you'll be thankful to have that backup copy. Solid state
Speaker 1: drives don't have any moving parts, so the element of
Speaker 1: wear and tear that I was just talking about isn't
Speaker 1: as big an issue. There is wear and tear on
Speaker 1: solid state drive, but not through mechanical stress. I did
Speaker 1: mention that things get a little weird with them. So
Speaker 1: here's my attempt to explain how a computer stores data
Speaker 1: in a solid state drive. Now, imagine that the solid
Speaker 1: state drive has a collection of datas storage units called blocks.
Speaker 1: All right, so you've got blocks. Within those blocks, you
Speaker 1: have multiple pages. So you can kind of think of
Speaker 1: a block like a book. Right, So solid state drive
Speaker 1: has a whole library shelf filled with blank books inside
Speaker 1: of it. Each book has an equal number of blank pages.
Speaker 1: We're just gonna use examples, like saying sixteen, So each
Speaker 1: book has sixteen pages in it blank pages. You can
Speaker 1: write data to any blank page, or really, the computer
Speaker 1: can write data to any blank page. A single file
Speaker 1: might require more than one page within a block or
Speaker 1: a book. So let's say a file takes up three pages.
Speaker 1: That's fine. You still have thirteen more pages left in
Speaker 1: that book where you can write data to it. So
Speaker 1: let's say that we've got a block that can hold
Speaker 1: sixteen pages. You write data to that, or you send
Speaker 1: a command to the computer that writes data to the
Speaker 1: first five of those. You still have eleven page is left. Now,
Speaker 1: let's say you eventually fill up those other eleven pages
Speaker 1: saving other stuff to your computer's hard drive. And now
Speaker 1: the block is full. All sixteen pages have stuff on it.
Speaker 1: It cannot fit more pages. You have other blocks in
Speaker 1: the drive. It's not a drive that only has one block,
Speaker 1: but that specific block completely full. You can't add anything
Speaker 1: to it. Then, let's say you realize that one file,
Speaker 1: let's say that's stored on page number two. One file
Speaker 1: is superfluous. It offends your sensibilities, and you wish to
Speaker 1: delete it post haste. But hang on their sport. Because
Speaker 1: ssd s don't behave the way hard disk drives do.
Speaker 1: You can't just delete a single page within a block.
Speaker 1: You actually have to delete an entire block with all
Speaker 1: of its pages. In other words, you can't just rip
Speaker 1: out one page of a book. You have to erase
Speaker 1: the entire book to get rid of that one page.
Speaker 1: So how do you do that? How do you delete
Speaker 1: one page out of a block while keeping everything else?
Speaker 1: If you have to delete an entire block at a time, Well,
Speaker 1: this turns into a super simple version of the old
Speaker 1: puzzle that states you got a rowboat, a wolf, a goat,
Speaker 1: and a cabbage. Now the boat is big enough to
Speaker 1: hold you plus one of the other three companions at
Speaker 1: a time, And yes, I'm promoting cabbage to companion status
Speaker 1: because I've seen Doctor Who, and some of those companions
Speaker 1: were thick. Anyway, you need to transport all three across
Speaker 1: a river. But if you leave the goat with the cabbage,
Speaker 1: the goat's gonna eat the cabbage. If you leave the
Speaker 1: wolf with the goat, the wolf will eat the goat.
Speaker 1: The cabbage doesn't eat anybody. It's a vegetarian. So how
Speaker 1: do you get all three across the river? Except, of course,
Speaker 1: with the SSD puzzle it is way easier. And I
Speaker 1: bet you've already figured out how it works. But if
Speaker 1: you haven't and you want to hear the answer, you're
Speaker 1: gonna have to wait just a second while we take
Speaker 1: a quick break to thank our sponsor. Her. Okay, I
Speaker 1: promised you an answer, and I guess I'm gonna answer
Speaker 1: both riddles. So the first riddle, you know, the one
Speaker 1: about the goat and the cabbage and the wolf, Well,
Speaker 1: you would take the goat across the river first, because
Speaker 1: the wolf is not gonna eat the cabbage, and the
Speaker 1: cabbage will not eat the wolf. So you leave the
Speaker 1: goat on the other side of the river. Then you
Speaker 1: row back across. You pick up the cabbage, and you
Speaker 1: roll back to the other side of the river. Then
Speaker 1: you leave the cabbage on that side, but you take
Speaker 1: the goat, because if you leave the goat and the
Speaker 1: cabbage together, the goats gonna eat the cabbage. So you
Speaker 1: bring the goat back across to the side where you started.
Speaker 1: Then you take the wolf, but of course you have
Speaker 1: to leave the goat. You can't take both the wolf
Speaker 1: and the goat. Boat boats not big enough, so you
Speaker 1: put the goat back on the shore, You put the
Speaker 1: wolf in the rowboat, you row back across. You put
Speaker 1: the wolf on the side with the cabbage, go back
Speaker 1: across one more time to grab the goat, and final
Speaker 1: time you row back across, and then you the goat,
Speaker 1: the wolf, and the cabbage can carry on your merry way,
Speaker 1: happy knowing that you solved a basic riddle and that
Speaker 1: you totally blasted your packs. Bra that's a lot of rowing.
Speaker 1: You really got some cardio done. Well done. But for
Speaker 1: the solid state drives, the answer is actually much more simple.
Speaker 1: So if you need to delete a file, what actually
Speaker 1: happens is you have to copy all the pages inside
Speaker 1: a block containing the files you want to keep, and
Speaker 1: only those and you have to put them over into
Speaker 1: a new block. So you've got block number one and
Speaker 1: it's got, you know, all sixteen pages filled out, and
Speaker 1: you want to get rid of page number two. What
Speaker 1: you would do is you would copy pages one and
Speaker 1: then three through sixteen and poured them over to block
Speaker 1: number two, which has empty pages in it. Then you
Speaker 1: come back to block number one, which still has all
Speaker 1: sixteen pages. Right, we haven't done anything yet to those,
Speaker 1: so you actually have copies of information in two different
Speaker 1: blocks at this point. Then you delete all the pages
Speaker 1: inside block number one, including page number two. This is
Speaker 1: just to get rid of page number two. Right, You
Speaker 1: have to go through and copy fifteen pages, paste them
Speaker 1: into another block, and then delete sixteen pages just to
Speaker 1: get rid of one page. That seems kind of ridiculous, right,
Speaker 1: seems like a lot of work. Well, it also creates
Speaker 1: wear and tear on the flash drive. Now there's no
Speaker 1: or solid state drive, I should say, there's no moving
Speaker 1: parts here, right, you don't have any mechanical things to
Speaker 1: worry about. But there is a limited number of times
Speaker 1: that you can write to a block, and eventually you're
Speaker 1: going to run out of that many times, and that's
Speaker 1: when the capacity for your drive starts to diminish, so
Speaker 1: you can actually see It's kind of like seeing how
Speaker 1: rechargeable batteries get less effective over multiple recharges, same kind
Speaker 1: of thing, and that you'll see the storage capacity of
Speaker 1: a solid state I decrease over a long amount of time. Uh,
Speaker 1: the amount of time is largely dependent upon how big
Speaker 1: the solid state drive is because it can sometimes distribute
Speaker 1: this across a lot of different blocks. And how frequently
Speaker 1: you do this process. By the way, this process is
Speaker 1: called garbage collection, and I am not making that up.
Speaker 1: That is what is referred to when you're trying to
Speaker 1: do this deletion process through solid state drives. So you
Speaker 1: wanna be careful with how often you do this, how
Speaker 1: frequently this happens. A lot of sites suggest that this
Speaker 1: is done regularly but not frequently, so maybe check into that,
Speaker 1: because you want to make sure that you're not decreasing
Speaker 1: the useful lifespan of your storage media, otherwise you're gonna
Speaker 1: have to replace it. And while story storage has gotten
Speaker 1: cheaper over time, it's still you know, you don't want
Speaker 1: to have to replace it unless you absolutely need to. Now,
Speaker 1: to get a little bit further into the weeds on this.
Speaker 1: The storage media itself does not know about files marked
Speaker 1: for deletion, and the operating system doesn't know which blocks
Speaker 1: have data in them. The operating system is essentially saying,
Speaker 1: right files to this, or delete files to this. The
Speaker 1: solid state drive is just thinking, all right, well, I
Speaker 1: need this is where something is, this is where something
Speaker 1: can go. So let's use another example to explain sort
Speaker 1: of how this works, because it's a little tricky to
Speaker 1: think about. So you've got a block with sixteen free pages.
Speaker 1: Then you write stuff to twelve of those pages. So
Speaker 1: the last two of those pages, pages eleven and twelve,
Speaker 1: represent a file that you decide you want to delete.
Speaker 1: So pages one through ten you don't want to touch.
Speaker 1: Pages eleven and twelve you no longer need them. You
Speaker 1: want to delete them. In your operating system, you select
Speaker 1: that file, you delete it. Everything from your side looks
Speaker 1: like it's gone. There's no way for you to access
Speaker 1: that file anymore. You can't even see that it exists. Uh.
Speaker 1: The operating system essentially says, no problem, that file is
Speaker 1: totes history, but the solid state drive doesn't do anything yet.
Speaker 1: You then decide later on to save a new file
Speaker 1: to the solid state drive, and it would go into
Speaker 1: the first two empty pages, and that would be eleven
Speaker 1: and twelve because you had set those to delete. But
Speaker 1: the solid state drive didn't understand that until it gets
Speaker 1: the command to write two pages eleven and twelve. It
Speaker 1: goes to right to eleven and twelve, sees that eleven
Speaker 1: and twelve have data in them, the data from the
Speaker 1: deleted file, and then adds it to thirteen and fourteen
Speaker 1: pages thirteen and fourteen, But it designates at that point
Speaker 1: pages eleven and twelve for a garbage collection. Essentially says,
Speaker 1: the next time you do garbage collection, these two pages
Speaker 1: are not needed anymore and can be wiped. So we
Speaker 1: when we do that process I talked about earlier about
Speaker 1: copying all the pages to another block, don't copy pages
Speaker 1: eleven and twelve. We don't need them. But this is
Speaker 1: not terribly efficient because it could mean that you've got
Speaker 1: an entire block copied over before any of this gets
Speaker 1: marked for deletion. It could mean that you're essentially increasing
Speaker 1: wear and tear. It's called right amplification because you're amplifying
Speaker 1: the number of files that need to be written to
Speaker 1: a new block. Because it hasn't picked up the fact
Speaker 1: that those files are actually supposed to be gone. There
Speaker 1: is an exception to this, obviously. There there's a application
Speaker 1: called trim t r I M. This is a command
Speaker 1: that helps reduce the number of times data gets copied
Speaker 1: during that garbage collection process. Trim tells the solid state
Speaker 1: drive which files and therefore which pages you have marked
Speaker 1: for deletion. So the logical layer on the solid state
Speaker 1: drive knows that pages eleven and twelve can be ignored
Speaker 1: during garbage collection, so they won't be copied to a
Speaker 1: new block. It takes one step out of the process
Speaker 1: I just described a minute ago. Now, one thing you
Speaker 1: can and should do with solid state drives is encrypt
Speaker 1: the draw. If you can encrypt the data that's stored there,
Speaker 1: which means you create a strong password that you use
Speaker 1: to access that information. And if you don't have the
Speaker 1: strong password, then everything appears to be meaningless data. It's
Speaker 1: all encrypted and you can't read it easily without decrypting
Speaker 1: it first. Even if someone gets access to your drive
Speaker 1: at that point, the information will be difficult, if not impossible,
Speaker 1: to access. Assuming that you don't have a ridiculous farm
Speaker 1: of GPUs working to decrypt through brute force it it
Speaker 1: would be pretty hard to get access to that information.
Speaker 1: As for a racing solid state drives permanently, there are
Speaker 1: a lot of utility programs you can use that are
Speaker 1: meant to do that reliably. They say that they are
Speaker 1: able to delete data off of s s d s
Speaker 1: with a certain degree of of guarantee. The complexity of
Speaker 1: solid state drives, however, can lead to mistakes, either in
Speaker 1: deleting something you didn't want to get rid of or
Speaker 1: overlooking data that you meant to hasted into the ABYSS.
Speaker 1: And according to one study by a group of engineers
Speaker 1: at the University of California, it's not exactly a guarantee.
Speaker 1: They use different methods of trying to delete data from
Speaker 1: an SSD, and they found that the process could leave
Speaker 1: behind anything from four percent to seventy of the original data, which,
Speaker 1: depending on what that data is, could be really damaging
Speaker 1: to you. So that's kind of scary to think about,
Speaker 1: where the process of deleting is not necessarily a guarantee
Speaker 1: that the information is actually gone if you're really really
Speaker 1: determined to try and retrieve the data. Alright, but let's
Speaker 1: say you've deleted the information, and you absolutely want to
Speaker 1: make sure that no one ever gets access to that data,
Speaker 1: just in case, even if it's just a smidgen of
Speaker 1: that data, how do you guarantee this well, Once you're
Speaker 1: finished using software to wipe the disk, you can move
Speaker 1: on to more physical solutions. So with hard disk drives,
Speaker 1: one thing you could do is pull the drive out
Speaker 1: of the computer case and use a good old hammer
Speaker 1: and nail so that you can drive a nail through
Speaker 1: the case of the hard drive to puncture the disk,
Speaker 1: potentially doing this in multiple places on the disk to
Speaker 1: make sure it's impossible to read later on. Now, if
Speaker 1: you want to do this, you have to promise me
Speaker 1: to do the following things. First, wear eye protection because
Speaker 1: you never know when something's gonna fly off there. Wear
Speaker 1: some heavy gloves because thumbs and hammers love to get together,
Speaker 1: so it's good for you to protect yourself because you're
Speaker 1: gonna be holding a nail on a metal case and
Speaker 1: then striking it with a heavy hammer, and put the
Speaker 1: hard drive on top of a block of wood like
Speaker 1: a two by four or something, because there's a good
Speaker 1: chance you're gonna drive that nail straight through the case.
Speaker 1: And if you do You don't want to damage whatever
Speaker 1: is on the underside of that hard drive, So follow
Speaker 1: those rules if you're gonna do this, and be very careful. Now,
Speaker 1: depending upon what the platter is made out of, you
Speaker 1: might even shatter it. Right. It may not just have
Speaker 1: a nail driven through it. It might shatter the drive,
Speaker 1: which is good news for you, since it would be
Speaker 1: exceedingly difficult to put together a shattered drive in any
Speaker 1: meaningful way. Chances are that data is just irretrievable. You've
Speaker 1: gone beyond the capabilities of the data retrieval industry. But
Speaker 1: with solid state drives, you really need to smash the
Speaker 1: chips that hold the data. So that typically means you
Speaker 1: have to pull apart the drive, find the relevant chips
Speaker 1: inside of it, then swing a hammer and start smashing
Speaker 1: like crazy. Now, sometimes it could be a little tricky
Speaker 1: figuring out which chips are the ones that actually hold
Speaker 1: the data, So in those cases, just go nuts and
Speaker 1: smash all of them. You know, why leave anything out
Speaker 1: be safe. Alternatively, you could make use of a service
Speaker 1: that will physically destroy your hardware for you, and typically
Speaker 1: they use a shredder, which is kind of like an
Speaker 1: industrial version of a wood chipper, something that uses very
Speaker 1: high power, very uh strong hydraulics typically that will grind
Speaker 1: the stuff into tiny pieces. These shredding services will reduce
Speaker 1: your media to unusable pieces of junk. I even found
Speaker 1: a few that claimed they follow environmental best practices so
Speaker 1: that they reduced the impact those materials might have on
Speaker 1: the surrounding environment. Because a lot of computer equipment contains
Speaker 1: stuff in it that we would rather not release out
Speaker 1: into the wild, like lead or mercury or other potentially
Speaker 1: harmful materials. So it is something that you want to
Speaker 1: be careful about and responsible with because it's one of
Speaker 1: the big problems with e waste. You may have heard
Speaker 1: previous episodes where I talked about e waste and how
Speaker 1: that can contribute to environmental problems. You want to find
Speaker 1: a company that has a good reputation for dealing with
Speaker 1: this in a responsible way. For hard disk drives, the
Speaker 1: physical types, some services might first make use of a
Speaker 1: really powerful magnet before going on to physically destroy the media.
Speaker 1: That's because the magnet can change the sectors of a
Speaker 1: hard drive so that they all align with the magnetic
Speaker 1: field of the magnet itself. At least for older hard drives,
Speaker 1: that's a possibility. It certainly works for older forms of
Speaker 1: magnetic storage in general, like VHS tapes or a credit
Speaker 1: card stripes. If you've ever had a credit card and
Speaker 1: you've stored it next to like, back to back with
Speaker 1: another credit card, you may find that suddenly it's not
Speaker 1: working anymore unless people physically put the number into a machine,
Speaker 1: the stripe no longer seems to work. Well, that's a
Speaker 1: magnetic stripe, and if it's exposed to a strong enough magnet,
Speaker 1: it can demagnetize that magnetic stripe, and then you have
Speaker 1: meaningless data on there. It's no longer associated with your account.
Speaker 1: This is why you shouldn't have a credit card stored
Speaker 1: in a clutch or a wallet that has a magnetic clasp,
Speaker 1: because it can in fact affect that stripe. Now, hard
Speaker 1: drives are a little more dy with that they may
Speaker 1: not even be affected by neodymium magnet At least the
Speaker 1: data might not be. It may not even affect a
Speaker 1: single bit stored on that hard drive, depending upon when
Speaker 1: the hard drive was manufactured. So what is actually happening here? While,
Speaker 1: as it turns out, materials have what is called coercivity,
Speaker 1: that's coercivity Like coercion, in a way, coercivity refers to
Speaker 1: materials resistance to being demagnetized. So if you magnetize something
Speaker 1: and it has high coercivity, it means that it is
Speaker 1: resistant to having that magnetization altered in any way. Um
Speaker 1: if it's if that coercivity is lower than it means
Speaker 1: the magnetization can easily or more easily be altered. The
Speaker 1: unit we associate with this trait is called the Ersted
Speaker 1: O E R S T E d uh. And like
Speaker 1: I said, the higher the coercivity, the less likely the
Speaker 1: magnetic field will dem agnetize a material. Now, VHS tapes
Speaker 1: and credit card stripes typically falls somewhere in the five
Speaker 1: hundred to one thousand Ersted range. Hard Drives have higher coercivity,
Speaker 1: especially more recent physical hard drives, and some of them
Speaker 1: are enough to protect it from any sort of accidental demagnetization,
Speaker 1: which is a good thing. I mean. You may have
Speaker 1: heard about ancient computers, and by that I mean the
Speaker 1: ones that we had in the eighties and nineties where
Speaker 1: you didn't want to have a magnet anywhere close to
Speaker 1: a floppy disk because you could demagnetize the floppy disk
Speaker 1: and destroy all the data on it. Well, there was
Speaker 1: a lot of fear that the same thing could happen
Speaker 1: to hard drives, But as it turns out, you need
Speaker 1: a really, really powerful magnet to do that, which is
Speaker 1: why these data destruction services use extremely powerful electro magnets
Speaker 1: to do this. But more and more of them have
Speaker 1: been leaning heavily on physically destroying the media itself because
Speaker 1: it's less expensive and it's more efficient when it turns
Speaker 1: when all of a sudden and done. So you don't
Speaker 1: see it as frequently now as you used to, but
Speaker 1: it used to be a kind of standard part of
Speaker 1: the procedure. And I need to stress this. Do not
Speaker 1: bring a magnet near a hard drive in order to
Speaker 1: demonstrate how robust that hard drive is, how it can
Speaker 1: keep data intact even in the presence of a strong
Speaker 1: manetic field. Now why do I say that, I mean
Speaker 1: I just finished saying that. Chances are you're not going
Speaker 1: to alter one bit of information stored on a hard
Speaker 1: drive using a magnet. Why keep it away? Well, because
Speaker 1: there are things inside these physical hard drives that are
Speaker 1: reactive to magnets, like they will be attracted to a
Speaker 1: magnet parts of the mechanical systems, like the electric motors
Speaker 1: and the mechanical arm and various elements that make everything work.
Speaker 1: You could do physical damage to the hard drive itself.
Speaker 1: So while the bits would all be still perfectly intact
Speaker 1: on the platter, you know, you hadn't change the magnetization
Speaker 1: of the platter. You could wreck the workings of the
Speaker 1: hard of itself. You could tear it apart from the inside,
Speaker 1: which sounds cool, but then you're not going to be
Speaker 1: able to get to your data without taking your hard
Speaker 1: drive to some sort of repair shop or data retrieval system,
Speaker 1: and then you've really made it expensive. So keep those
Speaker 1: magnets away from the hard drives, all right. Now, let's
Speaker 1: talk about trying to get data back. What if our
Speaker 1: computers have been through some sort of trauma and we
Speaker 1: need to retrieve data on it. So we haven't tried
Speaker 1: to delete the information In this case, it's not like
Speaker 1: we've deleted something and then oh no, I need to
Speaker 1: get that file back. This is whoops, I accidentally drove
Speaker 1: over my laptop or a computer was caught in some
Speaker 1: other terrible accident. How do we get something back when
Speaker 1: we can no longer actually run the computer, or it
Speaker 1: can no longer access information off the hard drive. Well,
Speaker 1: there are businesses that are dedicated to doing this, and
Speaker 1: some of them have had remarkable success, even in extreme cases.
Speaker 1: So remember how I said. Physical drives can experience wear
Speaker 1: and tear to a point where they're not really operable anymore.
Speaker 1: A few things can make the mechanical operation of a
Speaker 1: hard drive impossible. You could have a broken motor. You
Speaker 1: can have a platter that gets warped and so it
Speaker 1: can no longer spend freely inside the hard drive, which
Speaker 1: makes it and it makes the data inaccessible. In those cases,
Speaker 1: bringing the hard drive to a data retrieval services a
Speaker 1: company that could be your best bet. Now, those services
Speaker 1: typically operate a space that's similar to a clean room
Speaker 1: in a microprocessor manufacturing facility. These are rooms where you
Speaker 1: have really powerful machines that are circulating all the air,
Speaker 1: which filters the air to remove any dust particles that
Speaker 1: could potentially get in the way. Because remember, the elements
Speaker 1: on a hard disk drive platter are microscopic in nature
Speaker 1: beyond microscopic, and a single dust moat is enormous in comparison.
Speaker 1: So in these environments, engineers wearing clean suits or bunny
Speaker 1: suits sometimes they're called. These are the white suits that
Speaker 1: zip up over a person's normal clothing and keep things
Speaker 1: like like human dust, essentially skin flakes, that kind of
Speaker 1: stuff from polluting the environment. They will take apart these
Speaker 1: old disk drives and attempt to put them together with
Speaker 1: other working elements. So you might remove a platter from
Speaker 1: an old disk drive and put it into a new
Speaker 1: system to try and retrieve data off of it. And
Speaker 1: like I said, there are a lot of remarkable success
Speaker 1: stories out there, so I'm gonna share just one because
Speaker 1: I think it's pretty cool and it's it's indicative of
Speaker 1: some of the more extreme cases of data retrieval. There
Speaker 1: was a uh AN incident at Southampton University a few
Speaker 1: years ago. There was a severe fire that damaged computers
Speaker 1: in a research and development wing. So you had these
Speaker 1: doctoral students PhD students who had been using these computers
Speaker 1: to store their data and to crunch numbers and you know,
Speaker 1: just to work on these projects. So the information on
Speaker 1: those computers represented years of work and potentially millions of
Speaker 1: dollars worth of R and D information. The university had
Speaker 1: this terrible fire and the fire damaged seventy computers in
Speaker 1: this R and D wing, so they contracted a company
Speaker 1: called Kroll on Track to try and get as much
Speaker 1: of the data back as possible from these machines. These
Speaker 1: are computers that some of them had been melted from
Speaker 1: the fire and had suffered fire damage heat damage. Uh
Speaker 1: the ones that didn't suffer direct fire heat damage had
Speaker 1: suffered smoke damage and water damage, So they're talking about
Speaker 1: an extensive amount of trauma that these computers experienced. A
Speaker 1: an engineer named Robert Winter with carl on Track, led
Speaker 1: this effort to salvage as much data as he could
Speaker 1: off of the seventy hard drives that the university had
Speaker 1: given over to him. So the engineers made copies of
Speaker 1: every single hard drive that they were able to, although
Speaker 1: some of them were so damaged by heat it was
Speaker 1: just irrecoverable. These computers ended up giving up about of
Speaker 1: the data they had stored on them, so, in other words,
Speaker 1: they were able to get back the vast majority of
Speaker 1: information stored on these computers even after they had been
Speaker 1: through fire and water and smoke damage. They were subjected
Speaker 1: to some of the worst conditions that a computer can
Speaker 1: endure and still hold information and yet a firm was
Speaker 1: able to get that data off of those computers, which
Speaker 1: is both inspiring and if you're concerned with data security,
Speaker 1: a little scary, because if if data retrieval specialists can
Speaker 1: get information off a computer that's been in a fire
Speaker 1: and subjected to water damage, you got to go to
Speaker 1: some pretty big extremes in order to take care of
Speaker 1: the information and make sure no one gets access to it.
Speaker 1: And what happens if the computer isn't yours, then what
Speaker 1: you do? Well, I'm going to cover that in a
Speaker 1: little bit, but first let's take another quick break to
Speaker 1: thank our sponsor. All Right, let's say that you have
Speaker 1: practiced really good data security. You've also practiced backing up
Speaker 1: your computer. You want to make sure that you have
Speaker 1: access to information if something should go wrong, so you've
Speaker 1: got to back up for your computer. Uh. If you're
Speaker 1: like most people, I'd say that, at least until fairly recently,
Speaker 1: I'd say that you'd likely use some sort of external
Speaker 1: hard drive, and you're backing up regularly to that, maybe
Speaker 1: once a week or once a month, something like that. Uh,
Speaker 1: maybe you have it set up where it does that
Speaker 1: automatically every given amount of time and so you're external
Speaker 1: hard drive represents a continuing timeline of what used to
Speaker 1: be on your computer or still is on your computer
Speaker 1: and some cases, and that means that if you do
Speaker 1: delete something off of your hard drive, you could go
Speaker 1: to your backup and retrieve it in case you realize
Speaker 1: later that that was a bone headed mistake. Let's say
Speaker 1: you're doing that. Now, Let's say that you're going even further.
Speaker 1: Let's say that you're practicing the next step making sure
Speaker 1: you have your data backed up securely, and you're using
Speaker 1: offsite data backups. Now that means that you are saving
Speaker 1: to a machine that's in a different location than your
Speaker 1: primary machine. And the added benefit here is that if
Speaker 1: anything should happen to your physical device, perhaps the building
Speaker 1: that your physical device is in, you still have access
Speaker 1: to the information. I've worked at companies that did this,
Speaker 1: where we paid a data company to run servers that
Speaker 1: we would end up saving our information to. So it
Speaker 1: wasn't so much I mean a get technically it's cloud computing,
Speaker 1: but really it was just a data farm that had
Speaker 1: certain computer says aside just for us, and we would
Speaker 1: save backups every day at the end of the day
Speaker 1: to that particular service, and they were dated, and so
Speaker 1: you would keep a certain number of days on file,
Speaker 1: and then you would replace them with a rolling replacement,
Speaker 1: which meant that if you deleted something or over wrote something,
Speaker 1: and then two weeks later you need the original, you
Speaker 1: could actually still get it. This is good if you
Speaker 1: want to make sure that you know you have access
Speaker 1: to that data even if something happens to that physical location.
Speaker 1: So in the case of that Southampton University fire, if
Speaker 1: they had been using offsite backups, yeah, it would have
Speaker 1: been awful already because you're gonna lose equipment. No one
Speaker 1: wants to do that. That's expensive. But you would still
Speaker 1: have that data in the off site storage. You wouldn't
Speaker 1: have to worry about going through these data retrieval processes
Speaker 1: because you would already have the information there. However, it
Speaker 1: does raise the other question of if you want to
Speaker 1: delete something, how can you be sure that it's really gone?
Speaker 1: How do you delete data everywhere? This is particularly complicated.
Speaker 1: Now we're in a world where we have more and
Speaker 1: more connected devices that are having shared resources. So let
Speaker 1: me give you an example. I am very firmly in
Speaker 1: the Google uh sphere, right, I mean that ecosystem. This
Speaker 1: is not for me to advocate for Google. Other ecosystems
Speaker 1: are just as good, if not better. My wife uses
Speaker 1: the Apple ecosystem, for example. So you're you're firmly embedded
Speaker 1: in one of these ecosystems, and one of the benefits
Speaker 1: is that you have access to a lot of information
Speaker 1: across a multitude of devices. So you might be using
Speaker 1: a cellular device, you might use a WiFi connected device,
Speaker 1: you might be using multiple devices. You might be using tablets,
Speaker 1: hand set cell phone essentially our smartphone, laptops, set top boxes,
Speaker 1: all sorts of things to access different data, which means
Speaker 1: that data has to be freely available across these different
Speaker 1: device is. Sometimes you have instances of that data saved
Speaker 1: on a device for a convenience sake, because if it's
Speaker 1: saved to the local device, you're going to pull it
Speaker 1: up much more quickly than if you have to pull
Speaker 1: that data down from a cloud server every single time. Right, So,
Speaker 1: if you want fast access to your information, then having
Speaker 1: a a temporary version of it saved to the device
Speaker 1: for at least some given amount of time is handy.
Speaker 1: But it also means if you want to delete that information,
Speaker 1: you might have instances of it existing on multiple devices
Speaker 1: until the general command is given to wipe it off
Speaker 1: of all of them. Moreover, there's some server somewhere that
Speaker 1: contained that data, and how can you be sure that
Speaker 1: that data is actually gone. Let's make it even more complicated.
Speaker 1: If you are talking about using a cloud storage service
Speaker 1: so that you can save your information off site, which
Speaker 1: again keeps the information relatively safe at least from physical damage.
Speaker 1: Assuming that the cloud service is also practicing very good security,
Speaker 1: it may be giving it superior data security protection from
Speaker 1: potential hackers or snoopers. Let's say all those things are true,
Speaker 1: how can you be sure when you delete something that
Speaker 1: actually goes off of those servers. And not only that,
Speaker 1: but if you're running a really good cloud service, you're
Speaker 1: using multiple computers to store the same information for redundancy sake. Now,
Speaker 1: this is for the same purpose that you would save
Speaker 1: something off site as a backup, right, except you're talking
Speaker 1: about a cloud service. If I have a document in
Speaker 1: Google Docs and it's saved through my account somewhere at Google,
Speaker 1: in one of their data centers, or maybe in multiple
Speaker 1: data centers, there are computers that have that document saved
Speaker 1: to them, and it's saved on multiple computers. That way,
Speaker 1: if one computer should break down, because they do break down,
Speaker 1: it just happens. I can still get access to my
Speaker 1: document because it exists on backup computers. This is redundancy.
Speaker 1: It is a very important feature in cloud storage. If
Speaker 1: you don't have redundant systems in cloud storage, then should
Speaker 1: something go wrong with one machine at your service, there's
Speaker 1: gonna be a client out there who can't get access
Speaker 1: to their information, and since that's what they're paying you for,
Speaker 1: that's not good business. However, on the flip side of that,
Speaker 1: when you want to delete something now you not not
Speaker 1: You're not only deleting it from your local devices, you
Speaker 1: wanted deleted from every single instance at the cloud storage service.
Speaker 1: How can you guarantee that happens. And here's the answer
Speaker 1: to that question. You can't. I mean, unless you're able
Speaker 1: to actually physically visit the all the data centers for
Speaker 1: whichever service you're using, and if you're using one of
Speaker 1: the big ones like Amazon or Google, that's a lot
Speaker 1: of data centers across a lot of different locations around
Speaker 1: the world. Unless you can do that yourself, you cannot
Speaker 1: be absolutely certain that the files you've asked to be deleted,
Speaker 1: are really really gone? Now, these companies are going to
Speaker 1: tell you if you send us a request to delete,
Speaker 1: we delete, and you will not have access to that
Speaker 1: file anymore. Don't even bother play in coming to us saying, oh,
Speaker 1: I did not mean to delete that because it is gone. Well,
Speaker 1: of course the companies are going to have to say that,
Speaker 1: because otherwise it would be to suggest that when I
Speaker 1: delete something from their servers, they don't actually delete it,
Speaker 1: and that would be bad business. But we can't be
Speaker 1: sure that when they say they've deleted something that's actually gone.
Speaker 1: What does happen is they essentially sever the connection between
Speaker 1: the customer and that particular information. So if I delete
Speaker 1: a document out of my Google Docs, let's say, then
Speaker 1: what Google is going to do is essentially cut off
Speaker 1: the method that of getting to that document from my account.
Speaker 1: That means that I no longer have a pathway to
Speaker 1: that document, but I can't be certain that it means
Speaker 1: the document itself is gone. It may still exist on
Speaker 1: multiple computers under Google's domain. I just can't get to it,
Speaker 1: but that doesn't mean it's actually deleted. Now a lot
Speaker 1: of these cloud services will also offer encryption services or
Speaker 1: even include that as part of the storage system, meaning
Speaker 1: that your data is encrypted and the only way to
Speaker 1: get to it is to have the decryption key so
Speaker 1: that you can actually read that that information. That's a
Speaker 1: little more useful because if I delete a file and
Speaker 1: they cut off the pathway between me and that file,
Speaker 1: even if it still exists on their computers, it's encrypted,
Speaker 1: so it's not like anyone's reading it or getting access
Speaker 1: to it because they don't have the decryption key. I
Speaker 1: have it, So that's a little bit better. And in fact,
Speaker 1: it's the solution that the I E E E, the
Speaker 1: I triple E, or as Chris Palette and I always
Speaker 1: used to say back in the old days of tech stuff,
Speaker 1: I e. They recommend using encryption for all cloud services.
Speaker 1: In fact, they're specific recommendation is using what they called
Speaker 1: recursively encrypted red black key tree or RURK r E
Speaker 1: E R E r K, which is a complicated method
Speaker 1: of making sure that off site data is meaningless to
Speaker 1: anyone but the person who actually owns data or has
Speaker 1: the legitimate access to that data. Now, the reason why
Speaker 1: this is a relevant question is because it became clear
Speaker 1: that there are some companies that had purported to have
Speaker 1: only temporary ownership of data or temporary stewardship if you prefer,
Speaker 1: of data, and it turned out that it was less
Speaker 1: temporary than had previously been suspected. So back in for example,
Speaker 1: there was a story of about Snapchat and about how
Speaker 1: the service was keeping photos rather than deleting them after
Speaker 1: a said amount of time. So the general thought was
Speaker 1: that if you took a photo with Snapchat and then
Speaker 1: you shared it with people, it would only exist for
Speaker 1: maybe twenty four hours and then it was gone permanently.
Speaker 1: But then it turned out that the story wasn't entirely true. Now,
Speaker 1: the two thousand thirteen story didn't suggest that Snapchat was
Speaker 1: actually keeping these copies on their servers. Rather, what it
Speaker 1: was saying was that the device you were using to
Speaker 1: access Snapchat and to take photos of yourself would hold
Speaker 1: onto those pictures for a while at least, that they
Speaker 1: were doing it in a way where they were using
Speaker 1: a file extension that made it difficult to see that
Speaker 1: those files still existed on the device. But if you
Speaker 1: knew what you were looking for, and if you used
Speaker 1: a little bit of tech forensics work, you could actually
Speaker 1: find the folder and the photos that you had been
Speaker 1: taking all that time on Snapchat, even though it sounded
Speaker 1: like the app was going to delete the photo from
Speaker 1: your device after a given amount of time, So it
Speaker 1: turned out that it wasn't as gone as you thought
Speaker 1: it was. Now, granted, that's on a local device, right,
Speaker 1: so it only really matters if someone else gets hold
Speaker 1: of your phone, let's say, and has access to it
Speaker 1: and is able to find that folder and find those
Speaker 1: image files which have been renamed, thus making them more
Speaker 1: difficult to find. But if they knew how to do that,
Speaker 1: they could totally see all those images that you were
Speaker 1: being taking on Snapchat and sitting off. So all those
Speaker 1: post workout selfies that I do, but I mean, come on,
Speaker 1: they're working hard. So those still existed on the phones.
Speaker 1: That was the story that broke in two thousand thirteen.
Speaker 1: As for the servers, they do not hold onto user
Speaker 1: data forever, so they don't hold onto those photos and
Speaker 1: other snaps indefinitely, but they might hold on to it
Speaker 1: longer than you expected them to, up to thirty days
Speaker 1: after when you shared the snap. So technically what they'll
Speaker 1: do is they'll delete files once the system detects that
Speaker 1: all the recipients of a snap have viewed it. So
Speaker 1: let's say that you've you're sharing something just to your
Speaker 1: Snapchat followers. That's it. It's not available to anyone else.
Speaker 1: You send this out and the system detects that every
Speaker 1: single one of your Snapchat followers has had a chance
Speaker 1: to look at that snap has opened it at some point.
Speaker 1: It will then mark that snap for deletion, but if
Speaker 1: not everyone has done it, it will keep that snap
Speaker 1: active for up to thirty days after it was taken
Speaker 1: in order to give people who follow you the chance
Speaker 1: to see it, which I don't think is a bad
Speaker 1: thing necessarily. It's just something that might not easily be
Speaker 1: understood by a lot of people who use Snapchat, who
Speaker 1: think this is a very momentary type of media and
Speaker 1: moments after I share it it's gone. That's not the case.
Speaker 1: It can stick around on those servers for up to
Speaker 1: a month later. I don't know that that's necessarily a
Speaker 1: deal breaker, but it is something to keep in mind.
Speaker 1: And it's those kind of stories that got people to
Speaker 1: asking questions about cloud storage. If I decided to delete
Speaker 1: something off of my cloud storage account, how can I
Speaker 1: be sure it's really gone? And again, the answer is
Speaker 1: he can't be certain, so that's kind of buyer beware.
Speaker 1: I suppose that if you're going to use cloud storage,
Speaker 1: which I think is a valuable service, don't get me wrong,
Speaker 1: you do so knowing that there is the potential that
Speaker 1: that information is going to be out there forever, h
Speaker 1: on those servers, or at least on a machine somewhere.
Speaker 1: You have to accept that that is a possibility. It's
Speaker 1: not necessarily something that is definitely gonna happen, but it's
Speaker 1: it's definitely possible. Let's say that you have saved something
Speaker 1: to your account and then they decided to take a
Speaker 1: server offline because they need to replace it in their
Speaker 1: array of servers, and it happens to have a copy
Speaker 1: of that information you saved. Then you choose to delete
Speaker 1: it from your account, but that particular machine has been
Speaker 1: disconnected from the overall service, an instance of your information
Speaker 1: may still be on that machine. Now, granted, if it's
Speaker 1: a legitimate business, what they they should do is wipe
Speaker 1: that machine completely and and overwrite all the information on
Speaker 1: it so that no files on it could possibly ever
Speaker 1: be accessed. But it's still want something to worry about,
Speaker 1: because it's outside of your control. If you're using cloud
Speaker 1: storage responsibly and you are practicing good data security in general,
Speaker 1: I don't see any reason why you should stop relying
Speaker 1: on it, especially if you're using encryption. I think it's
Speaker 1: a valuable thing to use, but it's also good to
Speaker 1: know it's limitations and the potential problems you could encounter
Speaker 1: uh in in a worse case scenario situation. And if
Speaker 1: that worst case scenario isn't that bad for you, there's
Speaker 1: no problem. If you want to save something that is
Speaker 1: more sensitive information, maybe they are trade secrets, something that
Speaker 1: you do not want to get out to the general public.
Speaker 1: Maybe don't save it on cloud storage. Maybe save it
Speaker 1: on local storage. Have an off site but secured data
Speaker 1: server that's just yours. No one else is sharing it.
Speaker 1: Save it to there too for a backup. It's a
Speaker 1: lot of extra work, but it's more of a guarantee
Speaker 1: that your sensitive information will not leave your control, and
Speaker 1: ultimately that's the most important thing in this particular discussion.
Speaker 1: If you've shared it online, if you've posted some information
Speaker 1: on the internet, it's out there forever. Just accept that
Speaker 1: because there's not any easy way to remove something that's
Speaker 1: been posted to the Internet. People on Twitter know this.
Speaker 1: People who have tweeted things that they wish they hadn't
Speaker 1: and had gone back to delete those tweets, they already know.
Speaker 1: There's no such thing as deleting it off the Internet.
Speaker 1: It exists somewhere else already, someone has already saved a
Speaker 1: copy of it, and it is perpetuating out there for
Speaker 1: the rest of all of the Internet's existence. So if
Speaker 1: you think it's sensitive information, don't post it on the Internet.
Speaker 1: That seems like it's incredibly basic information, and yet people
Speaker 1: still do it. So I'm gonna say it here just
Speaker 1: in case any of you were thinking, Hey, I think
Speaker 1: I should post my social Security number on Facebook. Don't
Speaker 1: do that. Don't do it. All Right, that wraps up
Speaker 1: this discussion about data deletion data retrieval. There's a lot
Speaker 1: more of the details I could go into, but it
Speaker 1: gets really technical, and it gets into file systems and
Speaker 1: file trees and all these other concepts that are hoardent,
Speaker 1: but they're also difficult to explain in an audio format,
Speaker 1: and frankly, it gets into greater detail than most of
Speaker 1: you require. I encourage you to practice good habits and
Speaker 1: if you have suggestions for future topics I should cover
Speaker 1: here on tech Stuff, send me a message let me
Speaker 1: know about them. The email address you should use is
Speaker 1: tech Stuff at how stuff works dot com, or you
Speaker 1: can drop me a line on Twitter or Facebook. The
Speaker 1: handle for both of those is tech stuff hs W.
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Speaker 1: follow that and get all the cool updates that Crystal
Speaker 1: keeps posting there. And if you want to watch me
Speaker 1: live on Wednesdays and Fridays, I record the show and
Speaker 1: I stream it on twitch dot tv slash tech Stuff.
Speaker 1: If you go there, you'll see what the schedule is
Speaker 1: Wednesdays at four pm Eastern and Friday's at two third
Speaker 1: p m Eastern. Hope to see you there. We got
Speaker 1: a chat room. You can join in and make jokes
Speaker 1: and point out all the factual errors I I spout out, no,
Speaker 1: please don't do that. Just be really supportive and nice
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Speaker 1: to chat with you guys whenever I'm in a break
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Speaker 1: soon for more on this and bathands of other topics
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