TechStuff Classic: TechStuff Looks at Solid State Drives

thousand twelve, just days after technology had been invented. This particular episode covers solid state drives, something that is far more common these days, was already, you know, fairly common back in two thousand twelve, but now it's becoming a standard feature and it's rare when you come across other types of hard drives in a lot of different technologies. So let's join past Jonathan Strickland and his co host

Chris Palette and learn about solid state drives. Hey there, So today we wanted to talk a little bit about solid state drives and what makes them work and how they are different from the traditional forms of storage media that we are used to in the world of computers. Now, some of you out there may be used to solid state drives, and so you're thinking how our solid state drives different from other solid state drives. That's not what

I mean. I mean those of us who have used hard disks that use magnetic storage in some form and uh there are a lot of differences, mainly mechanical physical differences, because when you're talking about a hard disk I gus a traditional hard hard disk drive, you're talking about a device that has moving parts and UM, it has platters that are that have information stored on the magnetically use magnetic fields to change uh informations into zeros and ones,

those bits that we use to create the data that computers can understand. And you have a physical device that reads that information off of the platters. The players have to spin for this to happen. Uh. Turns out those devices they take up they take a lot of time to pull that information up relatively speaking. Right When I

say a lot of time, we're talking milliseconds. But still, yeah, there are When you think about getting information into and out of uh your computers basically what you're doing right now, there there's several different ways it does that. There's uh, some information that is available for you know, ready retrieval. UM. You know in the cash that's built in you have level one, level two cash. You may not have necessarily

known what that was. I didn't, uh, you know, and it's sort of uh, it's sort of intuitive when you think about it. It keeps it this information in this cash on hand. So stuff that you're doing right now is is kept right there close by in a very fast um uh, in a very fast retrieval system, so I can pull it back at at at a nanoseconds.

Notice right, in fact, if we if we go, it's easy to imagine this if we think of the CPU first, just look at the central processing of your computer and think of that as this is the place where operations are executed upon data. Right. It pulls data in, it executes an operation on it, it gets a result. That's the purpose of the CPU. Now, a CPU has something called registers. Registers are where the CPU can hold data. But registers hold a very small amount of data comparatively speaking,

usually just a few hundred bytes. You can build larger registers, and you can build more registers for your CPU, but that tends to be pretty expensive. Now, the benefit of having information and registers on the CPU is that you have next to no time at all between when you pull the information and when you can execute an operation upon that information. So that means that we say that the latency for the information within a CPUs registers is zero.

Latency is that time between when you retrieve information and when you can or when you send a request for information and when you actually retrieve it. So there's no latency when you're talking about a the CPUs registers. However, only a few hundred bytes are exist within those registers. It's not a lot of data. Now you were talking about the cash is the level one cash is kind

of the information that the CPU uses frequently. It's going to in whatever application you have to be in at that time, right, So this is information that the CPU is having to go to again and again, and it needs it to be as close as possible so that it keeps that latency down because of course, if you have to go further out for your information, it's going to take longer for it to get back. So at level one cash, you're talking about around bytes of data

per CPU core. If you're running an ivy Bridge processor and I seven core ivy Bridge processor from Mentel, so that's three per UH core and as far as that level one cash goes, and that takes a nanosecond to pull that data up. So that's one billionth of a second. Yep. And uh, you know, just on the just to comment on the ivy bridge notation that the cash is themselves, Um, you know they exist on all these different processors. That's just that figure was just specific to the ivy bridge,

But other processors do have this as well. Yes, yes, just in case there was any confusion. And then you could have a level to cash just slightly further out. You know, think of think of it like concentric circles, right, So the level two cash is a concentric circle further out from the CPU. It can hold a little more data. It's a little slower to pull that information up, it's a few nanoseconds. Then it may even have a level

three cash. Not all CPUs do, but many do, and then that is even larger and holds even more data and takes even longer again in relative terms, to get that data to the CPU. And beyond that, that's when you go to your computer's actual memory, because all the stuff we've been talking about right now is all located on the CPU die itself, so it's all part of that that chip. Yeah, it's not you know, it's not separate. It's not another element that's on the motherboard. This is

all part of the CPU. Yeah. If you if you pull your hard drive out of the computer toss it on the floor, don't don't do that. Um. And uh. And you you pull the the RAM chips out of your computer and toss them on the floor, don't do that either. Um. Then I'm glad you did that, because I was thinking it. It was just funny that you said it. Um. Then the the registry and the cashes will still be there on the computer and I won't be able to do a whole lot with them. But still, um,

so you know that, just to illustrate that. So, yes, the next part will pick this stuff gently back up off the floor and put it inside. The RAM is essentially the next ring out if you will, from the cash is however many that you happen to have on your CPU, right, And these these memory chips have been optimized so that the latency is really really low. However, they are not located on the CPU. They are connected

by circuits by by pathways to the CPU. Well, because they are not located on the CPU, and because that information does have to actually travel a physical distance, that increases the latency time. So when your CPU has to pull information out and that information is not in the cash for the CPU, it has to but it resides within the memory of your computer. Then it has to travel this pathway and for the request and retrieval that can take between forty an eighty nanoseconds. So we're still

talking a fraction of a second. Yeah, I mean this is these are are times that you or I will not even be able to notice. Yeah, we can't. We we have no ability to to register that using our senses. We would have to use incredibly sensitive measurement devices in order to be able to tell the difference between forty and eighty nano seconds. To us, there's no meaningful difference at all. But the but the thing about RAM is when you shut off the computer, all that information that's

in RAM. Yeah, it's it's held there by the electrical charge UM, which is relative to the computer. Now you're hard drive with the information stored we're talking traditional when the information stored man magnetically on those platters. Um, it's able to save that stuff so that when you turn the computer back on, you can read the hard drive

and get it back. Um. The thing is that hard drives have different rotating speeds UM typical to see a laptop with a rpm uh drive or or even revolutions per minute just in case you aren't familiar with the term UM, and you're more likely to see fat those and faster in desktop computers UM and the faster these rotate. In general, that means the faster the information can be pulled from the hard drive and sent to memory and then onto your CPU. UM. So if you if you

took your hard drive. The thing is that these systems are are delicate their their machine to very precise tolerances. That the head UM that reads the disc, it looks like it looks like a record player for those of us who remember that, But the the head doesn't actually touch the disc. If it does, that's what they call a bad thing. Yeah, it looks like it's in contact because it's so close to the platter, but in actuality there is like a millimeter's difference between where it is

or even less. It's amazing, And that's the thing. If you did take your if you did take your hard drive and throw it on the floor, it is very possible that the head crashed into the platters, which is very bad right. If you ever hear a clicking noise from your hard drive, that usually means that the platters are out of alignment or that the head is actually coming into contact, something is hitting against something else within that physical mechanical device, and that means that it is

breaking down. That that also means you should take that hard drive as soon as you can to a professional who can pull the data off of the hard drive, because the the hard drive itself may or may not be uh you may or may not be able to repair it. So you definitely want to be able to retrieve the information. And the reason why we're even talking about this physical device is because you may have guessed, because you've got this mechanical element, it's going to take

a lot longer to retrieve that information. Comparatively speaking, we're talking about milliseconds now as opposed to nanoseconds, and in the world of computers, that's a long time. You know, a you're talking about these other fractions of a second, billions of a second, and then several or you know, you go to a couple orders of magnitude up you realize this is this is a lot longer, and it's going to mean that in general, the operations that you start to use on your computer are going to take

more and more time. Well, there are only so many ways we can limit how much time it takes to retrieve information from a hard drive. Some of that includes creating better interfaces, which is when we went from the two SATA interfaces s A T A interfaces. Uh, that was actually a big improvement. It meant that we could move data much more quickly from the hard drive into RAM. But there's only so so much faster you can go without really turning up that RPM speed to ludicrous amounts.

And of course the faster it goes, the more likely you have mechanical problems down the line. I mean we're in tear and things of that nature. So, Um, you have the incredibly reliable hard drive. I mean we've been using these things for years and years now. Um, they've gone up to very large sizes. Uh. And and they're they're fairly cheap compared to the way they were just a few years ago. But they have they have their own problems. I mean, they're they're delicate. You can't necessarily

take them everywhere, um, you know, and expect them to operate. Uh. Flawlessly. Um and uh you know, as you pointed out, they're they're only so fast. So uh, flash memory in general is you know, an alternative, a very pleasant alternative. It works in our in our smartphones and our music players. UM, it works in in memory sticks, I mean d some drives.

You know, kids of all ages now take them to school with them because you know that you can keep um I remember one gigabyte hard drives that were huge, and now you can keep sixteen gigs on a tiny thumb drive that cost you know, a very tiny fraction of the price. Spies, Spies use them to uh to put malware onto secure systems. Because both both stucks net and Flame appear to have been injected into target computers using UH and an offsite sort of storage device, So

some sort of well offsite from the computer system. UH so something like a thumb drive. So you can imagine there's a guy who might have paid a little visit to an Iranian UH uranium enrichment plant and happened to have this thumb drive, plug it into a computer system and infected it that way. That's just one potential way

that scenario could have unfolded. But yeah, I mean, these things have have become ubiquitous in all areas of computing, So why not a hard drive out of the same sort of approach, Because it means that you're using instead of a mechanical system, you're using an integrated circuit in order to store information. You no longer have to worry about spinning platters or reading heads or anything like that.

You can really decrease the amount of time that that latency time, so that when you are pulling information from the hard drive, it's much closer to the speeds that you would see on the CPU die itself, or at least in the computer's memory, as opposed to on a traditional hard drive. And before we get too far into this, I do want to say something about what some of

the sources of information we pulled from. We do have a great article on how stuff works about how flash drives work, and a lot of the information applies to solid state drives. Yeah they're not exactly the same, but yeah, they're they're kind of principles, are there. Yeah, they're close cousins because a lot of the thing that go into what makes flash drives work apply to solid state drives.

But an excellent resource on the Web is an Ours Technica series, one of which one of the articles in that series is called Solid State Revolution in Depth on how s s d s Really work by Lee Hutchinson. And I can't say enough good things about this article. It really is a comprehensive approach to how solid state drives work. And there's a little, uh, little latitude in the article, so it makes it it's not it's not

dry reading. No, well, our our Technica is like that. Um. It's also just just as a note, it's also very technical in spots too, so if you know, it's it's a they there site. It takes a little bit different approach to technology than than we do in a good way. It's at a different level. So it's it's definitely more serious if you if you're already familiar, Yeah, if you're already familiar with UM with computer art, texture and data

and that sort of thing. Uh, it's an excellent resource. Otherwise, it may it may feel a little advanced for someone who is just curious about this but doesn't have any real background. However, acts well worthy. Chris and I will return in just a moment to talk more about solid state drives, but first let's take a quick break. So getting back to solid state drives. So the idea of creating a solid state drive is was really really attractive

because of that decreased latency. Um, there were some challenges of course, because solid state drives they do not store information magnetically the way traditional hard drives do. Now, actually it sort of reminds me of electronic ink in a way. Interesting. Well, if you know something about electronic ink, you know that the capsules white or black generally are stored in between a sandwich of h material that holds a positive or negative charge, and that's how it reads a page. But

once the page is there, it stays there. I see. So you're thinking of that as for it. Let's just say, for example, that the black parts of the screen are ones and the white parts are zeros, and they retain that even when the power is off, so they're non volatile. Right. That means that when you remove the power source from this system, it keeps that information. Of that of course is extremely important when it comes to computers because, like Chris was saying, RAM is volatile memory. If you lose

that power, then that information goes away. There's no longer a charge to maintain the information that's stored in your computer's memory. You don't want that to happen to your hard drive because that means that every time you would turn off your computer or lose power, you would lose all the data stored there. You have to have non

volatile memory to keep storage a possibility. Well, nice, yeah, because I mean the old, the old, old, old computers that that Chris and I worked on didn't have hard drives. You had to store things on magnetic discs. If you turned your computer on, it just went to its initial state. The only thing that was stored on there was the operating system because it was written in read only memory, which was non volatile, but it was also unchangeable. You

couldn't write to it. So that meant that, you know, if you wanted to write a program, you had to store it on a disk, because if you tried to write it just on your computer, you didn't have a disk in there, and you turned the computer off, all your work has gone. This is also why if you've ever worked on a computer, and you've ever heard anyone say save your work, often that's why when you save your work, it's being saved to your hard drive not

to your computer's memory. So if you're working on something and you haven't saved it in a while, it may only exist in your computer's memory. If power goes out, you may lose all that work, as I have done on multiple asians. I was actually in my college's computer lab during a storm and the screams power went out.

There's nothing like working in any sort of computer environment when the power goes out and then you hear there's there's usually about a second and a half delay between the power going out and every single person making essentially the same noise which sounds like this. Ah. I leaned back as I did that, so there was a little Doppler effect. But anyway, so yeah, this this sort of of non volatile memory means that that information is going to stay there even when you turn the power off.

This is the exact same sort of stuff we find in our MP three players and other mobile devices that because again, if we didn't have that, then every time you turned off your MP three player, you would lose your entire library of songs. You have to reload it the next time you turn it on. Right, right, Well, there is um to to complete my analogy along with the electronic ink thing. The flash memory also uses cells. Um it stores information in in cells, and that cell

is either a one or a zero. Right to think of the cells like a sheet of grid paper. Yes, and you've got rows, and you've got columns. Right, So the rows of cells. If you took one row of cells, we would call that in in solid state drive terminology, that would be a page. So one row of the cells would be a page, and then you would have several rows of cells and several columns of cells that would form what is called a block. And this is really important because it comes down to the way information

is written and erased in solid state drives. It turns out that you cannot individually change the cells within that grid paper. For example, if you if you had a sheet of grid paper in front of you, you could write a one or a zero and every single grid and if you wanted to, if you were writing in pencil, you could erase a single cell and change that one to a zero or zero to a one. You cannot do that with a solid state drive. We'll get into that in a little bit, but that's an important thing

to think about from the start. Well, if you know something about hard drives. The the magnetic platter hard drives. UM when you when your computer, and that pretty much goes for all modern operating systems. Let's say you have a document and you realize that well, you worked on it three years ago, You've turned it in. You know, I don't need to save it for anything, So I'm going to delete it, and I'm gonna tell my computer delete.

Well that first of all, the computer doesn't delete it deleted if you just tell it to you know, throw it in the trash can, empty the trash can or recycle bin or whatever. It's actually still there on your hard drive, but it's been marked for deletion. So basically, when uh, something else, Hey I've created a new document, and the computer goes or can I say, ah, this is marked for deletion, I'll right over that old one. Um. That's one thing to note is that it can do that.

That's the way that that computers work with magnetic platter hard drives. Now it also can do something else. Let's say you have five different documents and you've deleted these five documents. Well, those gaps are different sizes, but you're storing a brand new file and it's larger than all five of those. It can fill in sections sort of like packets when you send, when you break up an email file into a bunch of packets and they go and they reassemble themselves on the other side on somebody

else's computer. These different gaps can be used to store parts of this file, which the computer will then reassemble as you need it. Um. That's when you need to fragment your hard drive. You know, they have sections and they're all scattered out. You've got applications, and then they're all in different places, in different sectors, on different platters, um,

And they say, okay, I going to reorganize everything. And so the computer basically uses storage empty storage to reshuffle everything and put it back into sectors where all the parts of the filer together. And that makes a computer run a little bit faster when it's accessing those files because they're on one place and they don't have to reassemble them. Now, you can't do that with uh, solid

state drives. Yeah. In fact, when it gets down to erasing data off a solid state drive, it's pretty pretty complex. But before we get into that, let's talk a little bit a little a little bit more about the way information is stored within these cells. So these grids on your grid paper, Yeah, I just thought it would be interesting to compare that to a platter drive entirely. Yeah, And it is important to make the comparisons between the

two because there are advantages and disadvantages to both. That whole erasing thing or overwriting. You can't overwrite in an SSD. You can't erase stuff. But it takes a lot of effort actually, um. But anyway, so in order to make the the cell have a value in it, you have to apply a voltage to that cell. Yes, I couldn't. I couldn't read that article without thinking of a C d C, the band with the Dirty deeds. That they're

cheap voltage. It uses high voltage. Actually that's important, yes, yeah, in fact they're well uses both high and low voltage. There are two different ways of wiring these transistors together. That's what each of the cells actually represents. Um. There is the nor approach, which is a little simpler but less useful. Really, it's typical of flash drives, however, these smaller drives. So think of think of those those rows there and the uh, the columns as having a a

a circuit line going through each one. All right, so there are rows of circuit and columns of circuits, uh, connections, really electronic connections, I should say, not just circuits, but electronic connections. So the rows would be word lines, the columns would be bitlines. So you would have this grid of word lines and bitlines. Sort of it would look kind of like a city block, like if you were looking for a city landscape if you were looking at

it from the air. So you have these these streets that are criss crossing um and you would kind of tell each cell what its contents were based upon applying voltages across these lines. I'm not going to get too far into this because it really gets kind of complex and also involves a concept called quantum tunneling, which we have talked about here on tech stuff before. But it makes my brain hurt because it's Quantum Tunneling is one

of those things that is crazy to me. Tunneling is this concept that and it's it's a real thing, otherwise our electronics wouldn't work. Tunneling is this concept where you have a barrier, let's say, and you've got an electron. That part of me an electron that's on one side of that barrier. With the right kind of energy, that electron can pass from one side of the barrier to the other side of the barrier as if it has

tunneled through without actually physically tunneling through. And this all has to do with the potential for the electron to be in one position versus another. UH. There's sort of you can think of it as a there's a radius around an electron that represents all the different locations that electron could be in. UH. If that electrons at the proper energy state, and there is a barrier next to the electron, that radius might extend beyond the other side

of that barrier. That means that there's the potential for that electron to be on the other side of that barrier, which means if there is a potential for it, sometimes the electron is on the other side of that barrier, as if the area weren't there. This drives me insane. It's like saying, if I'm if I'm running fast enough, there's a chance I'm going to be on the other side of the wall, not on this side of the wall. But every time I try that, I end up with

the bloody knows I'm not quantum enough, is what it. Yeah, we'll return to this classic episode of tech stuff in just a moment after we take this break to thank our sponsor. In the nand one, the bitlines are actually kind of um daisy chained in a way from one cell down to the next, and this becomes important when you were actually reading from the memory in order to

determine what bit is in each cell uh. And the way that works is that you apply a weak voltage across these lines to try and determine if a full circuit is being made, and if there, you get two different outcomes depending on if there's a one or a zero. Right. So if you get one outcome, for example, if the circuit is made, you know that the value is uh, you know what the value is inside that cell because

it can only be that value. And if the circuit is not made, then you know it's the opposite value, right. And so you're you're thinking, well, if the charge goes through, it means this. If the charge doesn't go through, it means that you collect that with all of these cells,

and that's what builds up data. Remember, each of these cells represents one bit, so a zero or a one, unless that's a well, I guess I should say that that would be an s l C, a single level cell which can represent either a zero or a one. You could also have a multi level cell, and in fact, most ssd s are multi level cells. Now, these can contain UH two or more bits. Usually it's two bits or three bits, which means that if it's a two bit system, there are four show values that you could

find within that cell. It would either be zero, zero, zero, one, one zero, or one one. But with a multi level cell, UH, it's a little more complicated as well, because you know, like I said, you could use the weak voltage to determine whether or not the content of a single layer

cell is a zero or a one. With multi level level cell, because there are four potential UH outcomes, you have to use different voltages and essentially you work from the weakest and you work your way up and as soon as that circuit is complete, then you know what the value of that cell is. Did I just Chris's brains are actually leaking out of his ears right now. I just find the whole thing revolting. Yeah, I thought

you would get a charge out of it, So anyway. Yeah, it all has to do with these voltages and uh and that that's all the reading information to write to a to it is um even more complex actually. Well. One of the things to note though is that making these changes, uh the voltage changes can be dangerous um using the high voltage to to do these changes, which is one of the reasons why it is so difficult to uh to erase and rewrite on this flash memory

that that's used in SMCS. That's one of the reasons. The other reason is that when you are writing information to a an SSD, you have to write it in in pages so rows. So think of think of this grid paper again. You can only write to a single row at a time, all right, when you're erasing, you have to erase these in blocks of pages. You can't

erase one row, you can't erase one page. You have to erase a block of pages, which tends to be about eight rows total, which equals about five and twelve kilobytes. There's actually some extra information there too, because there are a few, uh few cells that are dedicated to things like error correction and other information. So there's technically a little more than that. But the data that you're actually writing to the s s D or erasing from the

SSD is either in four or eight kilobyte pages. Again, that depends upon the format of the solid state drive. And uh, when you're racing's twenty eight pages, so five and twelve kilobites so or for the four kilobyte pages anyway, so you've got you can write in a page, you erase in a block. This is why it's really hard to You can't. This is why you cannot overwrite information because your file that you know that this has nothing to do with file size, is just the individual bits

that are found within those cells. Right, So a block might contain the end of one file in the beginning of another file. So you can't erase an entire block, uh, just because you erased one particular file, because you if you did that, then you would lose the beginning of a of an unrelated file that you did not delete, right, And and it treats old files that have been marked

for deletion as information that should be saved. It doesn't make there's on every drive there is a controller that provides instruction for the drive, and it doesn't know the difference between the file that I just uh quote unquote on my computer deleted and the computer marks for delete. No, it's okay to overwrite this sector of the drive versus a file that I want to keep, So it treats anything that's written in there as well. I better save this and just so that you guys can kind of

envision what is going on here. So let's go back to that grid paper example. Let's say you've got a sheet of grid paper. If this were like a solid state drive, every single one of those cells, if this was a brand new sheet, nothing had been saved to the sheet. Yet, actually every single one of those cells would have a one in them. And when you were writing information, what you do is you apply a certain voltage and you would switch that one to a zero. Switch.

Switching the one to a zero is not such a big deal. Switching the zero back to one is a huge deal. And here's here's why you cannot overwrite specific parts of this this page. You have to use enough voltage to switch that back to a one that if you were to try and target a single cell, that energy could overflow into neighboring cells, which would make those flip.

And if you're making all of those flip. That means you've just corrupted the data, right because not all those not all of those rows need to be turned back into one's sound effective. Students going yeah, so that's so, that's why you can't target a specific cell. You have to do it in these blocks. And uh. The way, the way a solid state drive actually does this handles this because eventually you will have to have that information erased or else you'll run out of space. You'll run

out of space. Just even every time you save a new version of that document, if it's a document that you're working on as opposed to like we'll use that as an example, um as a type of file you're creating. Let's say that you've created a document. Every time you save a new version of it, it's writing that information to more pages on your solid state drive. Well, if you never erased, if if it never had the opportunity to erase the information on that drive, you would run

out of space eventually. Yes, So the way it tries to handle this is that eventually there's a there's got to be a connection between the operating system and the solid state drive that lets the solid state drive no this particular information that is stored within your pages is stale. This information does not really um this, this isn't pertinent anymore. You can get rid of this. What will happen is rubbish. Yeah,

and there's this is called garbage collection. Actually, what happens is the solid state drive will take a block that contains the pages that have stale information, and we'll copy that entire block and save it again within the drive. So now you're saying, wait a minute, now you just uh, well, technically it only copy the stuff that is um that does not stale. So you've got a block of of pages. Some of those pages are stale, some of the pages

aren't stale. The solid state drive will copy the stuff that's not stale and paste into a new block and a new series of pages. So you've just doubled all the non stale content that is on your solid state drive. And I hear you screaming, but you said this is to conserve space. How can you conserve space by copying and pasting? Here's how. After that information has been copied and pasted into the new section of the solid state drive, the old block that has both the stale and not

stale information in it can be erased. You can apply that high voltage flip those zeros back to one's, and you can do it safely because you've already duplicated the non stale data into new pages. The stale data does not get duplicated, so it gets erased, which means that that block is now available to write to again. There's another downside here, which is that every single time you're writing to those cells, you're actually breaking down the system

a little bit. There's only so many times you can do this and the cells will remain viable. Eventually, the cells will no longer be able to hold a charge because they've been broken down too many times with this voltage being applied to them. Um SSD vendors have gone to some effort to prevent that from being an issue, at least for a while. Um In a lot of cases, there will be uhm extra space on the drive of

which you are unaware. Right. You might have a say, let's say that you get I don't know, a sixty gigabit gigabyte rather hard drive space, and there's actually sixty

eight gigabytes in there. You just don't know about this other eight because they've been included to take into account this issue so that one uh, this whole garbage collection process has some space to work in and you won't end up filling up your hard drive before it can take advantage of that and to as cells die and are unusable, it can open up new pages of cells that have not been written to an x number of times.

And we're talking thousands of times here. It's not like, you know, it's not like you're gonna fill up your hard drive and three days later it's gonna be useless. But well, it shouldn't be, No, it shouldn't be. But but but you know, your mileage may vary depending upon manufacturer and model, but the ideally it would take thousands and thousands and thousands of times before it would become obsolete,

before it would not work anymore. And the thing is that most of us use our computers frequently enough where eventually that could happen. I mean, if you upgrade on a regular basis, you may never notice this problem. But if you don't, you might notice that your computer takes longer to pull information from the hard drive that it used to and you may notice that you are running out of hard drive space when you thought that you should really have more. Why has all that gone? And

it's because those cells are no longer viable. Well. UM. To prevent this, the controller on the S s D is designed to route traffic in a way that will try to put a fairly even uh distribution, distribution of usage across the different cells on the drive uh, thus hopefully ensuring that no set of cells is worn down more than the others. They're trying to put put even wear and tear on it. Um. But the more full you get now they're one of the complaints about S s D s is that they seem to grow slower

as time goes on. That's because that information, uh, those those cells are getting full of information. Those pages are filling up. And because of the way they work um and they have to write and rewrite blank pages at a time, UH, it can seem to slow down because there isn't as much space to uh for them to the controller to route the information and regroup things into pages uh fresh pages that can be written and rewritten or not rewritten, but um erased and written to UM.

So UM you know that that's that's sort of a I would say an illusion. It's not really an illusion, but that's why it's not because the drive is uh crapping out generally, I mean, uh yeah, I mean the vendors for these devices generally say that they're good for you know, tens of thousands of read write cycles, so they should be good for for years. Of course, that

doesn't mean you shouldn't back up your hard drive. However, it does mean that defragging like we used to do with the magnetic traditional platter drives is not a good idea because you're adding to writing and rewriting uh those cells right right, You're you're effectively you are decreasing the life span of your hard drive. And the controller really should be doing that anyway, with the garbage collection and um organization of that that work, so it should be

less of an issue than it used to be. And the controller really is kind of like a very small, very specialized computer. So in a way, you have a computer within your computer because the controller is is taking this information and putting it in the most uh the the optimized format and layout. So yeah, it's uh, it's an interesting approach using this voltage difference instead of magnetism in order to store information, and it has become incredibly useful,

especially for things like portable electronics. I mean, it's really decreased the size of what our electronics can be. Plus you can go running with it and not worry about crashing the platters on your hard drive. Yeah, this is why back when I remember when m P three's were MP three players were first coming out, and there was always the argument of do you get the one with the spinning hard drive or do you get the one

with the flash hard drive? And the flash hard drives tended to be more expensive, but they also were the ones you could go and exercise with and not worry about them, you know, something skipping around or or or corrupting a file or crashing. Um, do you would you would you like to wrap up? Or should we mention encryption? We could mention, well, you can mention encryption because frankly,

my my research did not cover that topic. UM okay, well the uh UM This is another in the series of articles UM on our technical about s s d S, also written by Lee Hutchinson UM. And it's kind of fascinating because uh in in the process of UM compression UM, they go through a d D duplication phase. So it's sort of you know, if they find two copies of the same information, it will essentially get rid of one so that it takes up less space in the hard

rid That's essentially how how these things are done. And it's done in UM other types of files to UM image and sound and uh, you know those kinds of things that they find the same information, they can reduce the amount of information in that file. Well, they do that with hard drives too. But one of the interesting things that that Hutchinson mentions is now that modern operating systems are allowing you to encrypt your entire hard drive. That actually makes it tougher for s s d s

because they can't de duplicate that information anymore. Because once you encrypted a file, it has its own individual signature. So even if they were the same exact document um, the computer sees it as two different encrypted documents because the encryption information is slightly different, so will no longer recognize them as the same information. So you will see

them as completely different information. Taking Bulky and safe exactly, so it takes up the same file will take up twice as much space if it's been duplicated, and it will not be deleted because there's just enough difference there, so that it has essentially fooled the controller into thinking it's two files, not one that's been duplicated to two

files and one now. Um. The other thing, uh, the thing to know is, you know, these the devices are coming down and cost um, they're showing up more often in uh, in laptops, books and and you know, just a few years ago, I remember that it was really unusual to find a solid state drive in a computer, and you were paying a premium for that if you

wanted it. And it was kind of interesting because at the time the solid state drives, while you were paying a premium, tended to have a smaller capacity than the traditional hard drives did when they first started coming out. Well, now we've seen that slowly start to change, and that's to be expected. That's the way technology tends to work in the market. We tend to see when it first comes out, it tends to be pretty expensive and fairly limited.

And as it advances and we get better at the production approach, these prices start to fall and then next thing you know, it's everywhere. Yes, so um, you know it seems like they're they're becoming more common. Um, you know, even even in run of the mill laptops. However, um, you know, the cost is still not as as inexpensive

as traditional hard drives UM. And you know you do have those trade offs to be made versus the traditional So if you were getting, say you really wanted a nice workstation to use at home, you already have a laptop, UM, and you were choosing whether you wanted to spend that extra hundred dollars two hundred dollars for an SSD, you know it does you would get some uh savings in in UH cost if you went with the magnetic drive, UM, but you would trade off speed for that and the

number of read write cycles. Of course, magnetic drives have their own idiosyncrasies and you may or may not lose your your hard drive, right. Yeah. No, it's not not to say that that the older hard drives are any better. They just have a different set of pros and cons. Yeah, exactly. So, yeah, it all depends on what your use case scenario is. And I mean, like, i have machines at home that

of both types. So I've got machines that have a spinning hard drive, I gut machines that have solid state drives. I have an external drive. That's a solid state drive that I used for backups. Uh. You know, there's a lot of different ways of going about this, and I think that both approaches have their own advantages and disadvantages that will apply to you based upon the way you use your machines. So that's always a good thing to think about. Uh. And it may even be that to you.

It doesn't really matter other than maybe the fact that you can get a solid state drive with a small reform factor than you could if it were a physical hard drive, you know, the mechanical hard drive. I should say mechanical, not physical, because they're both physical. It's not it's not a virtual hard drive. Um. So yeah, I mean that's it's all up to the way you use your machines and what you what your personal preferences are, and I guess what your budget is as well. Yeah.

Um yeah, I'll never forget. I knew that solid state memory was going to be a big deal. This flash based memory sticks solid state drives slightly different, but I knew it was gonna be a big deal when we went to I guess is when I went to C E. S. It was the year after the two of us went because the year that Chris and I both went to c S, we picked up lots and lots of press kits that were either paper press kits or c D

comic this space. And then the next year I started seeing companies produce their press kits on USB thumb drives. And that's when I was I thought, Okay, this is a big enough deal, because now it's cheap enough where these companies can produce thousands of these things for an exhibition. Because you've got lots and lots of people at c S, you have to produce tons and tons of these not literally tons and tons, but lots and lots of these thumb drives, uh, in order to give them out to

all the people who stopped by. Of course, nowadays they don't even do that anymore. Now you get a card that has a U R L and you go to a website that has the press release, which is even better really, although it does mean that I don't end up with lots of thumb drives that I can use once I erase the VATA that's on there. You mean you haven't moved everything into the cloud. Now I'm working on it, but you know there, here's the other thing,

about the cloud. I mean, that's a totally different discussions. I'm gonna I'm gonna drop this. I was about to go off on a cloud rant about how all my information is in different pockets in the cloud. That's my problem now, So let's let's that's a totally different podcast, which I'm sure we'll do. And we've talked about cloud storage in the past anyway, so we're gonna wrap this up. Guys. I do recommend you go to ours Technica and look at those articles if you are interested in solid state

drives and what makes them work. And that wraps up another episode, another classic episode of tech Stuff, and hope you guys enjoyed it. I really miss having those conversations with Chris. They were always a lot of fun. If you guys have suggestions for topics that I should cover in future or episodes of tech Stuff, send me an email the addresses tech Stuff at how stuff works dot com, or drop on by our website that's tech Stuff podcast dot com. There you're going to find an archive of

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