WEBVTT - TechStuff Classic: TechStuff Looks at Solid State Drives 0:00:04.240 --> 0:00:07.240 Welcome to tech Stuff, a production of I Heart Radios 0:00:07.320 --> 0:00:13.920 How Stuff Works. Hey there, and welcome to tech Stuff. 0:00:13.960 --> 0:00:17.040 I'm your host, Jonathan Strickland. I'm an executive producer with 0:00:17.079 --> 0:00:18.920 How Stuff Works and I Heart Radio and a love 0:00:18.920 --> 0:00:22.280 of all things tech and his time for another classic 0:00:22.440 --> 0:00:27.800 tech Stuff episode. This episode originally published on July two 0:00:27.920 --> 0:00:32.839 thousand twelve, just days after technology had been invented. This 0:00:32.920 --> 0:00:37.479 particular episode covers solid state drives, something that is far 0:00:37.560 --> 0:00:40.640 more common these days, was already, you know, fairly common 0:00:40.680 --> 0:00:43.479 back in two thousand twelve, but now it's becoming a 0:00:43.560 --> 0:00:46.680 standard feature and it's rare when you come across other 0:00:46.680 --> 0:00:49.560 types of hard drives in a lot of different technologies. 0:00:49.840 --> 0:00:54.360 So let's join past Jonathan Strickland and his co host 0:00:54.440 --> 0:00:58.560 Chris Palette and learn about solid state drives. Hey there, 0:00:59.800 --> 0:01:02.640 So today we wanted to talk a little bit about 0:01:03.000 --> 0:01:08.040 solid state drives and what makes them work and how 0:01:08.080 --> 0:01:12.199 they are different from the traditional forms of storage media 0:01:12.319 --> 0:01:15.520 that we are used to in the world of computers. Now, 0:01:15.760 --> 0:01:17.520 some of you out there may be used to solid 0:01:17.520 --> 0:01:19.520 state drives, and so you're thinking how our solid state 0:01:19.600 --> 0:01:21.679 drives different from other solid state drives. That's not what 0:01:21.720 --> 0:01:23.959 I mean. I mean those of us who have used 0:01:24.800 --> 0:01:28.400 hard disks that use magnetic storage in some form and 0:01:28.640 --> 0:01:33.319 uh there are a lot of differences, mainly mechanical physical differences, 0:01:33.400 --> 0:01:36.119 because when you're talking about a hard disk I gus 0:01:36.520 --> 0:01:40.120 a traditional hard hard disk drive, you're talking about a 0:01:40.160 --> 0:01:44.960 device that has moving parts and UM, it has platters 0:01:44.959 --> 0:01:49.080 that are that have information stored on the magnetically use 0:01:49.160 --> 0:01:53.160 magnetic fields to change uh informations into zeros and ones, 0:01:53.600 --> 0:01:56.560 those bits that we use to create the data that 0:01:56.600 --> 0:02:01.560 computers can understand. And you have a physical device that 0:02:01.680 --> 0:02:04.320 reads that information off of the platters. The players have 0:02:04.360 --> 0:02:08.000 to spin for this to happen. Uh. Turns out those 0:02:08.040 --> 0:02:11.480 devices they take up they take a lot of time 0:02:11.880 --> 0:02:15.680 to pull that information up relatively speaking. Right When I 0:02:15.680 --> 0:02:19.880 say a lot of time, we're talking milliseconds. But still, yeah, 0:02:19.880 --> 0:02:24.320 there are When you think about getting information into and 0:02:24.360 --> 0:02:28.840 out of uh your computers basically what you're doing right now, 0:02:28.880 --> 0:02:32.840 there there's several different ways it does that. There's uh, 0:02:32.919 --> 0:02:38.640 some information that is available for you know, ready retrieval. UM. 0:02:38.680 --> 0:02:41.040 You know in the cash that's built in you have 0:02:41.160 --> 0:02:44.160 level one, level two cash. You may not have necessarily 0:02:44.200 --> 0:02:47.400 known what that was. I didn't, uh, you know, and 0:02:48.320 --> 0:02:50.800 it's sort of uh, it's sort of intuitive when you 0:02:50.800 --> 0:02:53.200 think about it. It keeps it this information in this 0:02:53.320 --> 0:02:58.120 cash on hand. So stuff that you're doing right now 0:02:58.800 --> 0:03:01.320 is is kept right there close by in a very 0:03:01.400 --> 0:03:05.960 fast um uh, in a very fast retrieval system, so 0:03:06.120 --> 0:03:08.960 I can pull it back at at at a nanoseconds. 0:03:09.000 --> 0:03:11.720 Notice right, in fact, if we if we go, it's 0:03:11.720 --> 0:03:15.080 easy to imagine this if we think of the CPU first, 0:03:15.400 --> 0:03:17.840 just look at the central processing of your computer and 0:03:17.880 --> 0:03:21.280 think of that as this is the place where operations 0:03:21.320 --> 0:03:25.160 are executed upon data. Right. It pulls data in, it 0:03:25.240 --> 0:03:27.799 executes an operation on it, it gets a result. That's 0:03:27.840 --> 0:03:31.560 the purpose of the CPU. Now, a CPU has something 0:03:31.600 --> 0:03:35.960 called registers. Registers are where the CPU can hold data. 0:03:36.080 --> 0:03:40.440 But registers hold a very small amount of data comparatively speaking, 0:03:41.160 --> 0:03:44.760 usually just a few hundred bytes. You can build larger registers, 0:03:44.760 --> 0:03:47.440 and you can build more registers for your CPU, but 0:03:47.520 --> 0:03:50.280 that tends to be pretty expensive. Now, the benefit of 0:03:50.320 --> 0:03:53.800 having information and registers on the CPU is that you 0:03:53.880 --> 0:03:57.640 have next to no time at all between when you 0:03:57.680 --> 0:04:00.520 pull the information and when you can execute an operation 0:04:00.640 --> 0:04:04.480 upon that information. So that means that we say that 0:04:04.520 --> 0:04:09.920 the latency for the information within a CPUs registers is zero. 0:04:10.360 --> 0:04:13.440 Latency is that time between when you retrieve information and 0:04:13.480 --> 0:04:15.600 when you can or when you send a request for 0:04:15.720 --> 0:04:18.560 information and when you actually retrieve it. So there's no 0:04:18.720 --> 0:04:23.040 latency when you're talking about a the CPUs registers. However, 0:04:23.480 --> 0:04:26.880 only a few hundred bytes are exist within those registers. 0:04:26.880 --> 0:04:29.280 It's not a lot of data. Now you were talking 0:04:29.279 --> 0:04:31.680 about the cash is the level one cash is kind 0:04:31.680 --> 0:04:35.360 of the information that the CPU uses frequently. It's going 0:04:35.400 --> 0:04:37.600 to in whatever application you have to be in at 0:04:37.640 --> 0:04:40.160 that time, right, So this is information that the CPU 0:04:40.240 --> 0:04:42.680 is having to go to again and again, and it 0:04:42.720 --> 0:04:45.400 needs it to be as close as possible so that 0:04:45.839 --> 0:04:49.080 it keeps that latency down because of course, if you 0:04:49.120 --> 0:04:51.479 have to go further out for your information, it's going 0:04:51.520 --> 0:04:53.720 to take longer for it to get back. So at 0:04:53.800 --> 0:04:58.279 level one cash, you're talking about around bytes of data 0:04:58.480 --> 0:05:04.880 per CPU core. If you're running an ivy Bridge processor 0:05:04.920 --> 0:05:08.600 and I seven core ivy Bridge processor from Mentel, so 0:05:08.680 --> 0:05:14.640 that's three per UH core and as far as that 0:05:14.720 --> 0:05:18.440 level one cash goes, and that takes a nanosecond to 0:05:18.520 --> 0:05:23.080 pull that data up. So that's one billionth of a second. Yep. 0:05:23.440 --> 0:05:26.279 And uh, you know, just on the just to comment 0:05:26.360 --> 0:05:30.880 on the ivy bridge notation that the cash is themselves, Um, 0:05:30.920 --> 0:05:34.400 you know they exist on all these different processors. That's 0:05:34.480 --> 0:05:38.559 just that figure was just specific to the ivy bridge, 0:05:38.560 --> 0:05:41.080 But other processors do have this as well. Yes, yes, 0:05:41.240 --> 0:05:43.680 just in case there was any confusion. And then you 0:05:43.720 --> 0:05:46.400 could have a level to cash just slightly further out. 0:05:46.680 --> 0:05:49.320 You know, think of think of it like concentric circles, right, 0:05:49.680 --> 0:05:52.599 So the level two cash is a concentric circle further 0:05:52.680 --> 0:05:55.560 out from the CPU. It can hold a little more data. 0:05:55.640 --> 0:05:57.880 It's a little slower to pull that information up, it's 0:05:57.880 --> 0:06:00.840 a few nanoseconds. Then it may even have a level 0:06:00.880 --> 0:06:04.840 three cash. Not all CPUs do, but many do, and 0:06:04.920 --> 0:06:07.520 then that is even larger and holds even more data 0:06:07.839 --> 0:06:11.640 and takes even longer again in relative terms, to get 0:06:11.640 --> 0:06:14.719 that data to the CPU. And beyond that, that's when 0:06:14.720 --> 0:06:18.919 you go to your computer's actual memory, because all the 0:06:18.920 --> 0:06:21.760 stuff we've been talking about right now is all located 0:06:22.360 --> 0:06:25.680 on the CPU die itself, so it's all part of 0:06:25.720 --> 0:06:29.320 that that chip. Yeah, it's not you know, it's not separate. 0:06:29.320 --> 0:06:31.760 It's not another element that's on the motherboard. This is 0:06:31.800 --> 0:06:34.039 all part of the CPU. Yeah. If you if you 0:06:34.040 --> 0:06:36.359 pull your hard drive out of the computer toss it 0:06:36.360 --> 0:06:39.520 on the floor, don't don't do that. Um. And uh. 0:06:39.560 --> 0:06:42.080 And you you pull the the RAM chips out of 0:06:42.120 --> 0:06:43.960 your computer and toss them on the floor, don't do 0:06:44.000 --> 0:06:47.279 that either. Um. Then I'm glad you did that, because 0:06:47.320 --> 0:06:49.760 I was thinking it. It was just funny that you 0:06:49.760 --> 0:06:54.520 said it. Um. Then the the registry and the cashes 0:06:54.960 --> 0:06:57.720 will still be there on the computer and I won't 0:06:57.720 --> 0:07:01.400 be able to do a whole lot with them. But still, um, 0:07:01.520 --> 0:07:04.479 so you know that, just to illustrate that. So, yes, 0:07:04.560 --> 0:07:07.840 the next part will pick this stuff gently back up 0:07:07.880 --> 0:07:10.280 off the floor and put it inside. The RAM is 0:07:11.200 --> 0:07:13.720 essentially the next ring out if you will, from the 0:07:13.760 --> 0:07:16.080 cash is however many that you happen to have on 0:07:16.120 --> 0:07:20.040 your CPU, right, And these these memory chips have been 0:07:20.080 --> 0:07:23.880 optimized so that the latency is really really low. However, 0:07:24.640 --> 0:07:29.520 they are not located on the CPU. They are connected 0:07:29.560 --> 0:07:34.600 by circuits by by pathways to the CPU. Well, because 0:07:34.640 --> 0:07:36.840 they are not located on the CPU, and because that 0:07:36.920 --> 0:07:40.360 information does have to actually travel a physical distance, that 0:07:40.480 --> 0:07:44.600 increases the latency time. So when your CPU has to 0:07:44.640 --> 0:07:47.960 pull information out and that information is not in the 0:07:48.080 --> 0:07:50.880 cash for the CPU, it has to but it resides 0:07:50.920 --> 0:07:54.520 within the memory of your computer. Then it has to 0:07:54.560 --> 0:07:58.800 travel this pathway and for the request and retrieval that 0:07:58.840 --> 0:08:01.800 can take between forty an eighty nanoseconds. So we're still 0:08:01.840 --> 0:08:05.040 talking a fraction of a second. Yeah, I mean this 0:08:05.120 --> 0:08:07.840 is these are are times that you or I will 0:08:07.880 --> 0:08:10.400 not even be able to notice. Yeah, we can't. We 0:08:10.520 --> 0:08:16.000 we have no ability to to register that using our senses. 0:08:16.040 --> 0:08:21.520 We would have to use incredibly sensitive measurement devices in 0:08:21.600 --> 0:08:24.520 order to be able to tell the difference between forty 0:08:24.600 --> 0:08:27.880 and eighty nano seconds. To us, there's no meaningful difference 0:08:27.880 --> 0:08:31.560 at all. But the but the thing about RAM is 0:08:32.080 --> 0:08:35.480 when you shut off the computer, all that information that's 0:08:35.520 --> 0:08:41.040 in RAM. Yeah, it's it's held there by the electrical 0:08:41.120 --> 0:08:44.920 charge UM, which is relative to the computer. Now you're 0:08:44.960 --> 0:08:48.199 hard drive with the information stored we're talking traditional when 0:08:48.200 --> 0:08:52.040 the information stored man magnetically on those platters. Um, it's 0:08:52.080 --> 0:08:53.880 able to save that stuff so that when you turn 0:08:53.920 --> 0:08:56.440 the computer back on, you can read the hard drive 0:08:56.480 --> 0:09:00.839 and get it back. Um. The thing is that hard 0:09:00.920 --> 0:09:04.880 drives have different rotating speeds UM typical to see a 0:09:04.960 --> 0:09:12.400 laptop with a rpm uh drive or or even revolutions 0:09:12.440 --> 0:09:14.440 per minute just in case you aren't familiar with the 0:09:14.559 --> 0:09:17.160 term UM, and you're more likely to see fat those 0:09:17.200 --> 0:09:22.079 and faster in desktop computers UM and the faster these rotate. 0:09:22.360 --> 0:09:25.320 In general, that means the faster the information can be 0:09:25.400 --> 0:09:29.360 pulled from the hard drive and sent to memory and 0:09:29.760 --> 0:09:33.200 then onto your CPU. UM. So if you if you 0:09:33.240 --> 0:09:36.280 took your hard drive. The thing is that these systems 0:09:36.320 --> 0:09:41.040 are are delicate their their machine to very precise tolerances. 0:09:41.080 --> 0:09:44.559 That the head UM that reads the disc, it looks 0:09:44.600 --> 0:09:46.720 like it looks like a record player for those of 0:09:46.760 --> 0:09:49.880 us who remember that, But the the head doesn't actually 0:09:50.040 --> 0:09:52.440 touch the disc. If it does, that's what they call 0:09:52.760 --> 0:09:55.680 a bad thing. Yeah, it looks like it's in contact 0:09:55.679 --> 0:09:58.480 because it's so close to the platter, but in actuality 0:09:58.520 --> 0:10:02.560 there is like a millimeter's difference between where it is 0:10:02.840 --> 0:10:05.920 or even less. It's amazing, And that's the thing. If 0:10:06.000 --> 0:10:08.480 you did take your if you did take your hard 0:10:08.559 --> 0:10:10.360 drive and throw it on the floor, it is very 0:10:10.360 --> 0:10:15.400 possible that the head crashed into the platters, which is 0:10:16.559 --> 0:10:19.720 very bad right. If you ever hear a clicking noise 0:10:19.760 --> 0:10:22.200 from your hard drive, that usually means that the platters 0:10:22.240 --> 0:10:24.480 are out of alignment or that the head is actually 0:10:24.520 --> 0:10:28.160 coming into contact, something is hitting against something else within 0:10:28.200 --> 0:10:31.680 that physical mechanical device, and that means that it is 0:10:31.720 --> 0:10:35.400 breaking down. That that also means you should take that 0:10:35.640 --> 0:10:38.640 hard drive as soon as you can to a professional 0:10:38.679 --> 0:10:42.280 who can pull the data off of the hard drive, 0:10:42.600 --> 0:10:44.679 because the the hard drive itself may or may not 0:10:44.760 --> 0:10:47.440 be uh you may or may not be able to 0:10:47.440 --> 0:10:49.760 repair it. So you definitely want to be able to 0:10:49.760 --> 0:10:53.000 retrieve the information. And the reason why we're even talking 0:10:53.040 --> 0:10:56.240 about this physical device is because you may have guessed, 0:10:56.280 --> 0:10:59.480 because you've got this mechanical element, it's going to take 0:10:59.559 --> 0:11:03.160 a lot longer to retrieve that information. Comparatively speaking, we're 0:11:03.160 --> 0:11:06.920 talking about milliseconds now as opposed to nanoseconds, and in 0:11:06.960 --> 0:11:10.199 the world of computers, that's a long time. You know, 0:11:10.240 --> 0:11:12.800 a you're talking about these other fractions of a second, 0:11:12.800 --> 0:11:15.520 billions of a second, and then several or you know, 0:11:15.559 --> 0:11:18.640 you go to a couple orders of magnitude up you 0:11:18.679 --> 0:11:20.679 realize this is this is a lot longer, and it's 0:11:20.720 --> 0:11:24.040 going to mean that in general, the operations that you 0:11:24.080 --> 0:11:26.600 start to use on your computer are going to take 0:11:26.640 --> 0:11:28.920 more and more time. Well, there are only so many 0:11:28.960 --> 0:11:32.840 ways we can limit how much time it takes to 0:11:32.880 --> 0:11:36.479 retrieve information from a hard drive. Some of that includes 0:11:37.080 --> 0:11:41.720 creating better interfaces, which is when we went from the 0:11:42.000 --> 0:11:45.959 two SATA interfaces s A T A interfaces. Uh, that 0:11:46.040 --> 0:11:48.040 was actually a big improvement. It meant that we could 0:11:48.040 --> 0:11:52.920 move data much more quickly from the hard drive into RAM. 0:11:53.040 --> 0:11:57.360 But there's only so so much faster you can go 0:11:57.800 --> 0:12:02.400 without really turning up that RPM speed to ludicrous amounts. 0:12:02.440 --> 0:12:04.160 And of course the faster it goes, the more likely 0:12:04.240 --> 0:12:07.520 you have mechanical problems down the line. I mean we're 0:12:07.520 --> 0:12:10.800 in tear and things of that nature. So, Um, you 0:12:10.880 --> 0:12:14.480 have the incredibly reliable hard drive. I mean we've been 0:12:14.559 --> 0:12:17.440 using these things for years and years now. Um, they've 0:12:17.480 --> 0:12:20.840 gone up to very large sizes. Uh. And and they're 0:12:20.880 --> 0:12:24.200 they're fairly cheap compared to the way they were just 0:12:24.440 --> 0:12:28.000 a few years ago. But they have they have their 0:12:28.000 --> 0:12:30.559 own problems. I mean, they're they're delicate. You can't necessarily 0:12:30.559 --> 0:12:36.320 take them everywhere, um, you know, and expect them to operate. Uh. Flawlessly. 0:12:36.880 --> 0:12:39.720 Um and uh you know, as you pointed out, they're 0:12:39.880 --> 0:12:45.040 they're only so fast. So uh, flash memory in general 0:12:45.440 --> 0:12:48.920 is you know, an alternative, a very pleasant alternative. It 0:12:49.000 --> 0:12:53.240 works in our in our smartphones and our music players. UM, 0:12:53.400 --> 0:12:56.640 it works in in memory sticks, I mean d some drives. 0:12:56.800 --> 0:12:58.720 You know, kids of all ages now take them to 0:12:58.760 --> 0:13:00.800 school with them because you know that you can keep 0:13:01.280 --> 0:13:05.000 um I remember one gigabyte hard drives that were huge, 0:13:05.120 --> 0:13:08.160 and now you can keep sixteen gigs on a tiny 0:13:08.200 --> 0:13:11.240 thumb drive that cost you know, a very tiny fraction 0:13:11.280 --> 0:13:14.320 of the price. Spies, Spies use them to uh to 0:13:14.640 --> 0:13:20.240 put malware onto secure systems. Because both both stucks net 0:13:20.360 --> 0:13:25.000 and Flame appear to have been injected into target computers 0:13:25.120 --> 0:13:29.520 using UH and an offsite sort of storage device, So 0:13:29.559 --> 0:13:33.040 some sort of well offsite from the computer system. UH 0:13:33.080 --> 0:13:35.720 so something like a thumb drive. So you can imagine 0:13:35.760 --> 0:13:38.240 there's a guy who might have paid a little visit 0:13:38.280 --> 0:13:43.400 to an Iranian UH uranium enrichment plant and happened to 0:13:43.440 --> 0:13:45.640 have this thumb drive, plug it into a computer system 0:13:45.640 --> 0:13:48.679 and infected it that way. That's just one potential way 0:13:48.720 --> 0:13:51.960 that scenario could have unfolded. But yeah, I mean, these 0:13:52.000 --> 0:13:57.120 things have have become ubiquitous in all areas of computing, 0:13:57.440 --> 0:14:01.960 So why not a hard drive out of the same 0:14:02.120 --> 0:14:06.320 sort of approach, Because it means that you're using instead 0:14:06.360 --> 0:14:09.840 of a mechanical system, you're using an integrated circuit in 0:14:09.960 --> 0:14:13.480 order to store information. You no longer have to worry 0:14:13.559 --> 0:14:17.800 about spinning platters or reading heads or anything like that. 0:14:17.880 --> 0:14:21.640 You can really decrease the amount of time that that 0:14:21.720 --> 0:14:25.560 latency time, so that when you are pulling information from 0:14:25.640 --> 0:14:29.240 the hard drive, it's much closer to the speeds that 0:14:29.280 --> 0:14:32.160 you would see on the CPU die itself, or at 0:14:32.200 --> 0:14:35.280 least in the computer's memory, as opposed to on a 0:14:35.320 --> 0:14:38.320 traditional hard drive. And before we get too far into this, 0:14:38.440 --> 0:14:41.400 I do want to say something about what some of 0:14:41.440 --> 0:14:44.280 the sources of information we pulled from. We do have 0:14:44.320 --> 0:14:47.880 a great article on how stuff works about how flash 0:14:47.960 --> 0:14:50.480 drives work, and a lot of the information applies to 0:14:51.040 --> 0:14:55.080 solid state drives. Yeah they're not exactly the same, but yeah, 0:14:55.120 --> 0:14:57.880 they're they're kind of principles, are there. Yeah, they're close 0:14:57.920 --> 0:15:01.080 cousins because a lot of the thing that go into 0:15:01.280 --> 0:15:04.560 what makes flash drives work apply to solid state drives. 0:15:04.560 --> 0:15:08.840 But an excellent resource on the Web is an Ours 0:15:08.960 --> 0:15:12.200 Technica series, one of which one of the articles in 0:15:12.200 --> 0:15:15.640 that series is called Solid State Revolution in Depth on 0:15:15.720 --> 0:15:19.160 how s s d s Really work by Lee Hutchinson. 0:15:19.800 --> 0:15:22.880 And I can't say enough good things about this article. 0:15:23.000 --> 0:15:27.080 It really is a comprehensive approach to how solid state 0:15:27.160 --> 0:15:31.600 drives work. And there's a little, uh, little latitude in 0:15:31.640 --> 0:15:33.560 the article, so it makes it it's not it's not 0:15:33.680 --> 0:15:37.200 dry reading. No, well, our our Technica is like that. Um. 0:15:37.200 --> 0:15:40.280 It's also just just as a note, it's also very 0:15:40.360 --> 0:15:43.560 technical in spots too, so if you know, it's it's 0:15:43.560 --> 0:15:46.360 a they there site. It takes a little bit different 0:15:46.360 --> 0:15:50.360 approach to technology than than we do in a good way. 0:15:50.840 --> 0:15:53.000 It's at a different level. So it's it's definitely more 0:15:53.000 --> 0:15:56.880 serious if you if you're already familiar, Yeah, if you're 0:15:56.880 --> 0:16:01.120 already familiar with UM with computer art, texture and data 0:16:01.160 --> 0:16:04.480 and that sort of thing. Uh, it's an excellent resource. Otherwise, 0:16:04.480 --> 0:16:08.560 it may it may feel a little advanced for someone 0:16:08.600 --> 0:16:11.520 who is just curious about this but doesn't have any 0:16:11.520 --> 0:16:16.880 real background. However, acts well worthy. Chris and I will 0:16:16.920 --> 0:16:19.400 return in just a moment to talk more about solid 0:16:19.400 --> 0:16:29.640 state drives, but first let's take a quick break. So 0:16:29.720 --> 0:16:33.600 getting back to solid state drives. So the idea of 0:16:33.640 --> 0:16:37.880 creating a solid state drive is was really really attractive 0:16:38.280 --> 0:16:42.280 because of that decreased latency. Um, there were some challenges 0:16:42.360 --> 0:16:45.640 of course, because solid state drives they do not store 0:16:45.760 --> 0:16:51.280 information magnetically the way traditional hard drives do. Now, actually 0:16:51.320 --> 0:16:56.240 it sort of reminds me of electronic ink in a way. Interesting. Well, 0:16:56.640 --> 0:16:58.760 if you know something about electronic ink, you know that 0:16:59.240 --> 0:17:03.600 the capsules white or black generally are stored in between 0:17:03.640 --> 0:17:08.639 a sandwich of h material that holds a positive or 0:17:08.720 --> 0:17:11.280 negative charge, and that's how it reads a page. But 0:17:11.320 --> 0:17:14.359 once the page is there, it stays there. I see. 0:17:14.400 --> 0:17:17.600 So you're thinking of that as for it. Let's just say, 0:17:17.640 --> 0:17:20.720 for example, that the black parts of the screen are 0:17:20.800 --> 0:17:24.480 ones and the white parts are zeros, and they retain 0:17:24.640 --> 0:17:28.680 that even when the power is off, so they're non volatile. Right. 0:17:28.800 --> 0:17:31.720 That means that when you remove the power source from 0:17:31.760 --> 0:17:34.920 this system, it keeps that information. Of that of course 0:17:35.000 --> 0:17:37.439 is extremely important when it comes to computers because, like 0:17:37.520 --> 0:17:42.200 Chris was saying, RAM is volatile memory. If you lose 0:17:42.280 --> 0:17:46.400 that power, then that information goes away. There's no longer 0:17:46.440 --> 0:17:49.360 a charge to maintain the information that's stored in your 0:17:49.359 --> 0:17:51.959 computer's memory. You don't want that to happen to your 0:17:52.000 --> 0:17:53.879 hard drive because that means that every time you would 0:17:53.880 --> 0:17:56.680 turn off your computer or lose power, you would lose 0:17:56.800 --> 0:17:59.080 all the data stored there. You have to have non 0:17:59.200 --> 0:18:04.800 volatile memory to keep storage a possibility. Well, nice, yeah, 0:18:04.880 --> 0:18:07.720 because I mean the old, the old, old, old computers 0:18:07.760 --> 0:18:10.679 that that Chris and I worked on didn't have hard drives. 0:18:11.200 --> 0:18:14.560 You had to store things on magnetic discs. If you 0:18:14.640 --> 0:18:17.800 turned your computer on, it just went to its initial state. 0:18:17.960 --> 0:18:20.080 The only thing that was stored on there was the 0:18:20.119 --> 0:18:22.879 operating system because it was written in read only memory, 0:18:22.920 --> 0:18:26.359 which was non volatile, but it was also unchangeable. You 0:18:26.400 --> 0:18:29.919 couldn't write to it. So that meant that, you know, 0:18:30.040 --> 0:18:31.760 if you wanted to write a program, you had to 0:18:31.760 --> 0:18:33.600 store it on a disk, because if you tried to 0:18:33.640 --> 0:18:35.359 write it just on your computer, you didn't have a 0:18:35.400 --> 0:18:37.040 disk in there, and you turned the computer off, all 0:18:37.080 --> 0:18:39.520 your work has gone. This is also why if you've 0:18:39.560 --> 0:18:41.679 ever worked on a computer, and you've ever heard anyone 0:18:41.720 --> 0:18:45.800 say save your work, often that's why when you save 0:18:45.840 --> 0:18:48.600 your work, it's being saved to your hard drive not 0:18:48.680 --> 0:18:50.920 to your computer's memory. So if you're working on something 0:18:50.920 --> 0:18:53.040 and you haven't saved it in a while, it may 0:18:53.200 --> 0:18:55.920 only exist in your computer's memory. If power goes out, 0:18:56.000 --> 0:18:58.520 you may lose all that work, as I have done 0:18:58.960 --> 0:19:02.280 on multiple asians. I was actually in my college's computer 0:19:02.359 --> 0:19:07.040 lab during a storm and the screams power went out. 0:19:07.200 --> 0:19:10.920 There's nothing like working in any sort of computer environment 0:19:11.000 --> 0:19:13.280 when the power goes out and then you hear there's 0:19:13.320 --> 0:19:17.040 there's usually about a second and a half delay between 0:19:17.040 --> 0:19:21.120 the power going out and every single person making essentially 0:19:21.119 --> 0:19:26.800 the same noise which sounds like this. Ah. I leaned 0:19:26.800 --> 0:19:28.640 back as I did that, so there was a little 0:19:28.680 --> 0:19:32.760 Doppler effect. But anyway, so yeah, this this sort of 0:19:32.760 --> 0:19:36.879 of non volatile memory means that that information is going 0:19:36.920 --> 0:19:39.240 to stay there even when you turn the power off. 0:19:39.280 --> 0:19:41.720 This is the exact same sort of stuff we find 0:19:41.720 --> 0:19:46.320 in our MP three players and other mobile devices that 0:19:46.600 --> 0:19:49.240 because again, if we didn't have that, then every time 0:19:49.240 --> 0:19:51.800 you turned off your MP three player, you would lose 0:19:51.800 --> 0:19:54.000 your entire library of songs. You have to reload it 0:19:54.040 --> 0:19:56.280 the next time you turn it on. Right, right, Well, 0:19:56.320 --> 0:20:01.159 there is um to to complete my analogy along with 0:20:01.200 --> 0:20:07.040 the electronic ink thing. The flash memory also uses cells. 0:20:07.760 --> 0:20:11.679 Um it stores information in in cells, and that cell 0:20:12.040 --> 0:20:14.640 is either a one or a zero. Right to think 0:20:14.680 --> 0:20:17.359 of the cells like a sheet of grid paper. Yes, 0:20:17.640 --> 0:20:22.040 and you've got rows, and you've got columns. Right, So 0:20:22.119 --> 0:20:25.640 the rows of cells. If you took one row of cells, 0:20:25.760 --> 0:20:28.919 we would call that in in solid state drive terminology, 0:20:29.000 --> 0:20:32.200 that would be a page. So one row of the 0:20:32.600 --> 0:20:34.560 cells would be a page, and then you would have 0:20:34.920 --> 0:20:37.840 several rows of cells and several columns of cells that 0:20:37.920 --> 0:20:41.560 would form what is called a block. And this is 0:20:41.560 --> 0:20:44.560 really important because it comes down to the way information 0:20:44.960 --> 0:20:48.760 is written and erased in solid state drives. It turns 0:20:48.760 --> 0:20:54.440 out that you cannot individually change the cells within that 0:20:54.960 --> 0:20:56.680 grid paper. For example, if you if you had a 0:20:56.680 --> 0:20:58.480 sheet of grid paper in front of you, you could 0:20:58.480 --> 0:21:01.159 write a one or a zero and every single grid 0:21:01.520 --> 0:21:03.320 and if you wanted to, if you were writing in pencil, 0:21:03.359 --> 0:21:07.520 you could erase a single cell and change that one 0:21:07.600 --> 0:21:10.400 to a zero or zero to a one. You cannot 0:21:10.440 --> 0:21:13.359 do that with a solid state drive. We'll get into 0:21:13.359 --> 0:21:15.040 that in a little bit, but that's an important thing 0:21:15.080 --> 0:21:18.600 to think about from the start. Well, if you know 0:21:18.720 --> 0:21:22.760 something about hard drives. The the magnetic platter hard drives. 0:21:23.280 --> 0:21:26.200 UM when you when your computer, and that pretty much 0:21:26.240 --> 0:21:29.960 goes for all modern operating systems. Let's say you have 0:21:30.640 --> 0:21:34.119 a document and you realize that well, you worked on 0:21:34.119 --> 0:21:37.199 it three years ago, You've turned it in. You know, 0:21:37.240 --> 0:21:38.840 I don't need to save it for anything, So I'm 0:21:38.840 --> 0:21:41.560 going to delete it, and I'm gonna tell my computer delete. 0:21:41.640 --> 0:21:45.000 Well that first of all, the computer doesn't delete it 0:21:45.040 --> 0:21:47.400 deleted if you just tell it to you know, throw 0:21:47.400 --> 0:21:49.040 it in the trash can, empty the trash can or 0:21:49.080 --> 0:21:51.639 recycle bin or whatever. It's actually still there on your 0:21:51.680 --> 0:21:55.040 hard drive, but it's been marked for deletion. So basically, 0:21:55.080 --> 0:21:58.360 when uh, something else, Hey I've created a new document, 0:21:58.520 --> 0:22:01.640 and the computer goes or can I say, ah, this 0:22:01.720 --> 0:22:06.560 is marked for deletion, I'll right over that old one. Um. 0:22:06.640 --> 0:22:09.359 That's one thing to note is that it can do that. 0:22:09.359 --> 0:22:13.040 That's the way that that computers work with magnetic platter 0:22:13.080 --> 0:22:16.320 hard drives. Now it also can do something else. Let's 0:22:16.320 --> 0:22:19.200 say you have five different documents and you've deleted these 0:22:19.280 --> 0:22:24.160 five documents. Well, those gaps are different sizes, but you're 0:22:24.320 --> 0:22:26.640 storing a brand new file and it's larger than all 0:22:26.680 --> 0:22:29.800 five of those. It can fill in sections sort of 0:22:29.840 --> 0:22:32.600 like packets when you send, when you break up an 0:22:32.600 --> 0:22:34.359 email file into a bunch of packets and they go 0:22:34.440 --> 0:22:37.560 and they reassemble themselves on the other side on somebody 0:22:37.560 --> 0:22:41.800 else's computer. These different gaps can be used to store 0:22:41.960 --> 0:22:45.639 parts of this file, which the computer will then reassemble 0:22:45.720 --> 0:22:48.199 as you need it. Um. That's when you need to 0:22:48.320 --> 0:22:51.879 fragment your hard drive. You know, they have sections and 0:22:51.920 --> 0:22:54.600 they're all scattered out. You've got applications, and then they're 0:22:54.640 --> 0:22:58.639 all in different places, in different sectors, on different platters, um, 0:22:58.680 --> 0:23:02.080 And they say, okay, I going to reorganize everything. And 0:23:02.160 --> 0:23:07.240 so the computer basically uses storage empty storage to reshuffle 0:23:07.320 --> 0:23:09.679 everything and put it back into sectors where all the 0:23:09.760 --> 0:23:12.800 parts of the filer together. And that makes a computer 0:23:12.920 --> 0:23:15.159 run a little bit faster when it's accessing those files 0:23:15.160 --> 0:23:16.720 because they're on one place and they don't have to 0:23:16.760 --> 0:23:21.199 reassemble them. Now, you can't do that with uh, solid 0:23:21.200 --> 0:23:23.600 state drives. Yeah. In fact, when it gets down to 0:23:23.760 --> 0:23:29.400 erasing data off a solid state drive, it's pretty pretty complex. 0:23:29.400 --> 0:23:31.400 But before we get into that, let's talk a little 0:23:31.400 --> 0:23:33.399 bit a little a little bit more about the way 0:23:33.600 --> 0:23:36.399 information is stored within these cells. So these grids on 0:23:36.440 --> 0:23:37.960 your grid paper, Yeah, I just thought it would be 0:23:38.000 --> 0:23:41.560 interesting to compare that to a platter drive entirely. Yeah, 0:23:41.600 --> 0:23:44.240 And it is important to make the comparisons between the 0:23:44.280 --> 0:23:47.119 two because there are advantages and disadvantages to both. That 0:23:47.200 --> 0:23:51.639 whole erasing thing or overwriting. You can't overwrite in an SSD. 0:23:52.080 --> 0:23:55.439 You can't erase stuff. But it takes a lot of 0:23:55.480 --> 0:24:01.640 effort actually, um. But anyway, so in order to make 0:24:01.840 --> 0:24:06.119 the the cell have a value in it, you have 0:24:06.200 --> 0:24:10.440 to apply a voltage to that cell. Yes, I couldn't. 0:24:10.480 --> 0:24:14.720 I couldn't read that article without thinking of a C 0:24:14.880 --> 0:24:18.400 d C, the band with the Dirty deeds. That they're 0:24:18.480 --> 0:24:23.360 cheap voltage. It uses high voltage. Actually that's important, yes, yeah, 0:24:23.440 --> 0:24:26.960 in fact they're well uses both high and low voltage. 0:24:28.760 --> 0:24:31.800 There are two different ways of wiring these transistors together. 0:24:31.840 --> 0:24:35.679 That's what each of the cells actually represents. Um. There 0:24:35.920 --> 0:24:39.840 is the nor approach, which is a little simpler but 0:24:40.160 --> 0:24:44.640 less useful. Really, it's typical of flash drives, however, these 0:24:44.680 --> 0:24:48.520 smaller drives. So think of think of those those rows 0:24:48.640 --> 0:24:55.000 there and the uh, the columns as having a a 0:24:55.000 --> 0:24:57.920 a circuit line going through each one. All right, so 0:24:58.000 --> 0:25:03.000 there are rows of circuit and columns of circuits, uh, connections, 0:25:03.000 --> 0:25:05.639 really electronic connections, I should say, not just circuits, but 0:25:05.720 --> 0:25:10.720 electronic connections. So the rows would be word lines, the 0:25:10.840 --> 0:25:13.600 columns would be bitlines. So you would have this grid 0:25:13.800 --> 0:25:17.280 of word lines and bitlines. Sort of it would look 0:25:17.359 --> 0:25:19.600 kind of like a city block, like if you were 0:25:19.640 --> 0:25:21.959 looking for a city landscape if you were looking at 0:25:21.960 --> 0:25:24.880 it from the air. So you have these these streets 0:25:24.880 --> 0:25:29.560 that are criss crossing um and you would kind of 0:25:30.680 --> 0:25:35.400 tell each cell what its contents were based upon applying 0:25:35.920 --> 0:25:38.920 voltages across these lines. I'm not going to get too 0:25:38.920 --> 0:25:42.399 far into this because it really gets kind of complex 0:25:42.400 --> 0:25:46.119 and also involves a concept called quantum tunneling, which we 0:25:46.160 --> 0:25:49.000 have talked about here on tech stuff before. But it 0:25:49.040 --> 0:25:53.280 makes my brain hurt because it's Quantum Tunneling is one 0:25:53.320 --> 0:25:57.040 of those things that is crazy to me. Tunneling is 0:25:57.080 --> 0:26:00.399 this concept that and it's it's a real thing, otherwise 0:26:00.400 --> 0:26:03.879 our electronics wouldn't work. Tunneling is this concept where you 0:26:03.960 --> 0:26:07.560 have a barrier, let's say, and you've got an electron. 0:26:07.680 --> 0:26:10.320 That part of me an electron that's on one side 0:26:10.359 --> 0:26:14.760 of that barrier. With the right kind of energy, that 0:26:14.880 --> 0:26:17.520 electron can pass from one side of the barrier to 0:26:17.560 --> 0:26:19.119 the other side of the barrier as if it has 0:26:19.160 --> 0:26:23.320 tunneled through without actually physically tunneling through. And this all 0:26:23.359 --> 0:26:25.679 has to do with the potential for the electron to 0:26:25.800 --> 0:26:29.399 be in one position versus another. UH. There's sort of 0:26:29.480 --> 0:26:31.080 you can think of it as a there's a radius 0:26:31.119 --> 0:26:35.159 around an electron that represents all the different locations that 0:26:35.240 --> 0:26:39.399 electron could be in. UH. If that electrons at the 0:26:39.480 --> 0:26:42.439 proper energy state, and there is a barrier next to 0:26:42.440 --> 0:26:46.399 the electron, that radius might extend beyond the other side 0:26:46.600 --> 0:26:49.760 of that barrier. That means that there's the potential for 0:26:49.840 --> 0:26:52.520 that electron to be on the other side of that barrier, 0:26:53.040 --> 0:26:55.960 which means if there is a potential for it, sometimes 0:26:56.040 --> 0:26:58.439 the electron is on the other side of that barrier, 0:26:59.520 --> 0:27:03.919 as if the area weren't there. This drives me insane. 0:27:04.320 --> 0:27:06.240 It's like saying, if I'm if I'm running fast enough, 0:27:06.240 --> 0:27:07.640 there's a chance I'm going to be on the other 0:27:07.680 --> 0:27:09.160 side of the wall, not on this side of the wall. 0:27:09.200 --> 0:27:10.720 But every time I try that, I end up with 0:27:10.720 --> 0:27:17.120 the bloody knows I'm not quantum enough, is what it. Yeah, 0:27:17.440 --> 0:27:20.320 we'll return to this classic episode of tech stuff in 0:27:20.400 --> 0:27:22.560 just a moment after we take this break to thank 0:27:22.560 --> 0:27:33.439 our sponsor. In the nand one, the bitlines are actually 0:27:33.520 --> 0:27:36.880 kind of um daisy chained in a way from one 0:27:36.920 --> 0:27:41.399 cell down to the next, and this becomes important when 0:27:41.400 --> 0:27:44.000 you were actually reading from the memory in order to 0:27:44.040 --> 0:27:48.679 determine what bit is in each cell uh. And the 0:27:48.720 --> 0:27:52.800 way that works is that you apply a weak voltage 0:27:53.640 --> 0:27:57.240 across these lines to try and determine if a full 0:27:57.320 --> 0:28:01.120 circuit is being made, and if there, you get two 0:28:01.160 --> 0:28:05.920 different outcomes depending on if there's a one or a zero. Right. 0:28:07.119 --> 0:28:10.639 So if you get one outcome, for example, if the 0:28:10.640 --> 0:28:14.120 circuit is made, you know that the value is uh, 0:28:14.520 --> 0:28:16.560 you know what the value is inside that cell because 0:28:16.560 --> 0:28:18.840 it can only be that value. And if the circuit 0:28:18.920 --> 0:28:21.720 is not made, then you know it's the opposite value, right. 0:28:22.480 --> 0:28:25.400 And so you're you're thinking, well, if the charge goes through, 0:28:25.440 --> 0:28:27.399 it means this. If the charge doesn't go through, it 0:28:27.400 --> 0:28:31.040 means that you collect that with all of these cells, 0:28:31.160 --> 0:28:33.439 and that's what builds up data. Remember, each of these 0:28:33.440 --> 0:28:36.880 cells represents one bit, so a zero or a one, 0:28:37.000 --> 0:28:40.640 unless that's a well, I guess I should say that 0:28:40.640 --> 0:28:43.800 that would be an s l C, a single level 0:28:43.840 --> 0:28:47.040 cell which can represent either a zero or a one. 0:28:47.320 --> 0:28:49.520 You could also have a multi level cell, and in fact, 0:28:49.560 --> 0:28:52.200 most ssd s are multi level cells. Now, these can 0:28:52.240 --> 0:28:55.560 contain UH two or more bits. Usually it's two bits 0:28:55.640 --> 0:28:57.800 or three bits, which means that if it's a two 0:28:57.800 --> 0:29:01.360 bit system, there are four show values that you could 0:29:01.360 --> 0:29:05.120 find within that cell. It would either be zero, zero, zero, one, 0:29:05.280 --> 0:29:10.280 one zero, or one one. But with a multi level cell, UH, 0:29:10.400 --> 0:29:12.520 it's a little more complicated as well, because you know, 0:29:12.600 --> 0:29:14.440 like I said, you could use the weak voltage to 0:29:14.520 --> 0:29:18.160 determine whether or not the content of a single layer 0:29:18.200 --> 0:29:20.840 cell is a zero or a one. With multi level 0:29:20.960 --> 0:29:25.480 level cell, because there are four potential UH outcomes, you 0:29:25.520 --> 0:29:28.440 have to use different voltages and essentially you work from 0:29:28.440 --> 0:29:30.280 the weakest and you work your way up and as 0:29:30.280 --> 0:29:32.680 soon as that circuit is complete, then you know what 0:29:32.800 --> 0:29:38.320 the value of that cell is. Did I just Chris's 0:29:38.360 --> 0:29:40.760 brains are actually leaking out of his ears right now. 0:29:42.080 --> 0:29:44.560 I just find the whole thing revolting. Yeah, I thought 0:29:44.600 --> 0:29:47.960 you would get a charge out of it, So anyway. Yeah, 0:29:47.960 --> 0:29:50.600 it all has to do with these voltages and uh 0:29:50.760 --> 0:29:55.840 and that that's all the reading information to write to 0:29:56.000 --> 0:30:01.320 a to it is um even more complex actually. Well. 0:30:01.880 --> 0:30:04.880 One of the things to note though is that making 0:30:04.920 --> 0:30:11.320 these changes, uh the voltage changes can be dangerous um 0:30:11.400 --> 0:30:14.400 using the high voltage to to do these changes, which 0:30:14.440 --> 0:30:17.200 is one of the reasons why it is so difficult 0:30:17.240 --> 0:30:23.280 to uh to erase and rewrite on this flash memory 0:30:23.320 --> 0:30:25.600 that that's used in SMCS. That's one of the reasons. 0:30:25.640 --> 0:30:29.080 The other reason is that when you are writing information 0:30:29.320 --> 0:30:33.000 to a an SSD, you have to write it in 0:30:33.000 --> 0:30:36.360 in pages so rows. So think of think of this 0:30:36.440 --> 0:30:39.720 grid paper again. You can only write to a single 0:30:39.800 --> 0:30:43.640 row at a time, all right, when you're erasing, you 0:30:43.720 --> 0:30:46.800 have to erase these in blocks of pages. You can't 0:30:46.840 --> 0:30:50.200 erase one row, you can't erase one page. You have 0:30:50.240 --> 0:30:52.520 to erase a block of pages, which tends to be 0:30:52.520 --> 0:30:58.040 about eight rows total, which equals about five and twelve kilobytes. 0:30:59.120 --> 0:31:03.240 There's actually some extra information there too, because there are 0:31:03.280 --> 0:31:06.840 a few, uh few cells that are dedicated to things 0:31:06.880 --> 0:31:10.840 like error correction and other information. So there's technically a 0:31:10.880 --> 0:31:13.600 little more than that. But the data that you're actually 0:31:13.640 --> 0:31:17.040 writing to the s s D or erasing from the 0:31:17.120 --> 0:31:21.560 SSD is either in four or eight kilobyte pages. Again, 0:31:21.560 --> 0:31:25.080 that depends upon the format of the solid state drive. 0:31:26.000 --> 0:31:29.040 And uh, when you're racing's twenty eight pages, so five 0:31:29.240 --> 0:31:34.360 and twelve kilobites so or for the four kilobyte pages anyway, 0:31:34.680 --> 0:31:39.160 so you've got you can write in a page, you 0:31:39.240 --> 0:31:42.880 erase in a block. This is why it's really hard 0:31:43.000 --> 0:31:46.400 to You can't. This is why you cannot overwrite information 0:31:46.560 --> 0:31:50.080 because your file that you know that this has nothing 0:31:50.120 --> 0:31:53.440 to do with file size, is just the individual bits 0:31:53.680 --> 0:31:58.640 that are found within those cells. Right, So a block 0:31:58.840 --> 0:32:01.600 might contain the end of one file in the beginning 0:32:01.640 --> 0:32:05.840 of another file. So you can't erase an entire block, uh, 0:32:06.280 --> 0:32:10.000 just because you erased one particular file, because you if 0:32:10.040 --> 0:32:11.840 you did that, then you would lose the beginning of 0:32:11.920 --> 0:32:16.120 a of an unrelated file that you did not delete, right, 0:32:16.400 --> 0:32:20.240 And and it treats old files that have been marked 0:32:20.280 --> 0:32:24.960 for deletion as information that should be saved. It doesn't 0:32:25.080 --> 0:32:29.520 make there's on every drive there is a controller that 0:32:29.640 --> 0:32:32.000 provides instruction for the drive, and it doesn't know the 0:32:32.120 --> 0:32:37.560 difference between the file that I just uh quote unquote 0:32:37.640 --> 0:32:41.720 on my computer deleted and the computer marks for delete. No, 0:32:41.960 --> 0:32:45.800 it's okay to overwrite this sector of the drive versus 0:32:46.480 --> 0:32:49.719 a file that I want to keep, So it treats 0:32:49.800 --> 0:32:52.360 anything that's written in there as well. I better save 0:32:52.480 --> 0:32:56.560 this and just so that you guys can kind of 0:32:56.720 --> 0:32:59.120 envision what is going on here. So let's go back 0:32:59.160 --> 0:33:02.040 to that grid paper example. Let's say you've got a 0:33:02.400 --> 0:33:05.680 sheet of grid paper. If this were like a solid 0:33:05.760 --> 0:33:07.800 state drive, every single one of those cells, if this 0:33:07.920 --> 0:33:11.360 was a brand new sheet, nothing had been saved to 0:33:11.520 --> 0:33:14.680 the sheet. Yet, actually every single one of those cells 0:33:14.760 --> 0:33:17.160 would have a one in them. And when you were 0:33:17.240 --> 0:33:20.200 writing information, what you do is you apply a certain 0:33:20.280 --> 0:33:24.160 voltage and you would switch that one to a zero. Switch. 0:33:24.240 --> 0:33:26.560 Switching the one to a zero is not such a 0:33:26.640 --> 0:33:30.160 big deal. Switching the zero back to one is a 0:33:30.360 --> 0:33:34.920 huge deal. And here's here's why you cannot overwrite specific 0:33:35.040 --> 0:33:39.320 parts of this this page. You have to use enough 0:33:39.440 --> 0:33:43.680 voltage to switch that back to a one that if 0:33:43.720 --> 0:33:46.600 you were to try and target a single cell, that 0:33:46.960 --> 0:33:51.840 energy could overflow into neighboring cells, which would make those flip. 0:33:53.160 --> 0:33:55.240 And if you're making all of those flip. That means 0:33:55.280 --> 0:33:58.440 you've just corrupted the data, right because not all those 0:33:58.760 --> 0:34:01.080 not all of those rows need to be turned back 0:34:01.120 --> 0:34:06.080 into one's sound effective. Students going yeah, so that's so, 0:34:06.240 --> 0:34:08.800 that's why you can't target a specific cell. You have 0:34:08.920 --> 0:34:11.799 to do it in these blocks. And uh. The way, 0:34:12.400 --> 0:34:15.480 the way a solid state drive actually does this handles 0:34:15.520 --> 0:34:18.440 this because eventually you will have to have that information 0:34:19.360 --> 0:34:22.600 erased or else you'll run out of space. You'll run 0:34:22.640 --> 0:34:25.120 out of space. Just even every time you save a 0:34:25.280 --> 0:34:28.120 new version of that document, if it's a document that 0:34:28.160 --> 0:34:29.960 you're working on as opposed to like we'll use that 0:34:30.000 --> 0:34:34.680 as an example, um as a type of file you're creating. 0:34:34.760 --> 0:34:37.239 Let's say that you've created a document. Every time you 0:34:37.280 --> 0:34:39.600 save a new version of it, it's writing that information 0:34:39.800 --> 0:34:43.600 to more pages on your solid state drive. Well, if 0:34:43.760 --> 0:34:46.880 you never erased, if if it never had the opportunity 0:34:46.960 --> 0:34:49.279 to erase the information on that drive, you would run 0:34:49.320 --> 0:34:53.960 out of space eventually. Yes, So the way it tries 0:34:54.040 --> 0:34:57.160 to handle this is that eventually there's a there's got 0:34:57.239 --> 0:35:01.040 to be a connection between the operating system and the 0:35:01.120 --> 0:35:04.640 solid state drive that lets the solid state drive no 0:35:05.520 --> 0:35:10.760 this particular information that is stored within your pages is stale. 0:35:11.480 --> 0:35:15.880 This information does not really um this, this isn't pertinent anymore. 0:35:16.160 --> 0:35:19.919 You can get rid of this. What will happen is rubbish. Yeah, 0:35:20.160 --> 0:35:24.160 and there's this is called garbage collection. Actually, what happens 0:35:24.280 --> 0:35:27.560 is the solid state drive will take a block that 0:35:27.719 --> 0:35:32.680 contains the pages that have stale information, and we'll copy 0:35:32.800 --> 0:35:37.640 that entire block and save it again within the drive. 0:35:38.000 --> 0:35:41.759 So now you're saying, wait a minute, now you just uh, well, 0:35:41.840 --> 0:35:45.440 technically it only copy the stuff that is um that 0:35:45.520 --> 0:35:49.040 does not stale. So you've got a block of of pages. 0:35:49.360 --> 0:35:51.160 Some of those pages are stale, some of the pages 0:35:51.239 --> 0:35:54.760 aren't stale. The solid state drive will copy the stuff 0:35:54.760 --> 0:35:57.400 that's not stale and paste into a new block and 0:35:57.600 --> 0:36:01.319 a new series of pages. So you've just doubled all 0:36:01.440 --> 0:36:04.920 the non stale content that is on your solid state drive. 0:36:04.960 --> 0:36:06.800 And I hear you screaming, but you said this is 0:36:06.840 --> 0:36:09.760 to conserve space. How can you conserve space by copying 0:36:09.840 --> 0:36:13.520 and pasting? Here's how. After that information has been copied 0:36:13.560 --> 0:36:17.359 and pasted into the new section of the solid state drive, 0:36:17.920 --> 0:36:20.840 the old block that has both the stale and not 0:36:21.080 --> 0:36:25.000 stale information in it can be erased. You can apply 0:36:25.160 --> 0:36:28.080 that high voltage flip those zeros back to one's, and 0:36:28.160 --> 0:36:31.160 you can do it safely because you've already duplicated the 0:36:31.320 --> 0:36:35.640 non stale data into new pages. The stale data does 0:36:35.719 --> 0:36:38.120 not get duplicated, so it gets erased, which means that 0:36:38.600 --> 0:36:43.439 that block is now available to write to again. There's 0:36:43.440 --> 0:36:47.040 another downside here, which is that every single time you're 0:36:47.080 --> 0:36:51.560 writing to those cells, you're actually breaking down the system 0:36:51.600 --> 0:36:54.400 a little bit. There's only so many times you can 0:36:54.520 --> 0:36:58.279 do this and the cells will remain viable. Eventually, the 0:36:58.360 --> 0:37:01.200 cells will no longer be able to hold a charge 0:37:01.239 --> 0:37:03.520 because they've been broken down too many times with this 0:37:03.640 --> 0:37:08.680 voltage being applied to them. Um SSD vendors have gone 0:37:08.840 --> 0:37:12.400 to some effort to prevent that from being an issue, 0:37:12.800 --> 0:37:15.520 at least for a while. Um In a lot of cases, 0:37:16.320 --> 0:37:20.480 there will be uhm extra space on the drive of 0:37:20.560 --> 0:37:23.120 which you are unaware. Right. You might have a say, 0:37:24.040 --> 0:37:26.880 let's say that you get I don't know, a sixty 0:37:26.960 --> 0:37:32.200 gigabit gigabyte rather hard drive space, and there's actually sixty 0:37:32.280 --> 0:37:34.200 eight gigabytes in there. You just don't know about this 0:37:34.320 --> 0:37:38.560 other eight because they've been included to take into account 0:37:38.680 --> 0:37:43.320 this issue so that one uh, this whole garbage collection 0:37:43.480 --> 0:37:47.200 process has some space to work in and you won't 0:37:47.440 --> 0:37:49.520 end up filling up your hard drive before it can 0:37:50.040 --> 0:37:55.000 take advantage of that and to as cells die and 0:37:55.080 --> 0:37:58.080 are unusable, it can open up new pages of cells 0:37:58.160 --> 0:38:02.439 that have not been written to an x number of times. 0:38:02.440 --> 0:38:04.440 And we're talking thousands of times here. It's not like, 0:38:05.239 --> 0:38:06.719 you know, it's not like you're gonna fill up your 0:38:06.760 --> 0:38:09.080 hard drive and three days later it's gonna be useless. 0:38:09.480 --> 0:38:12.040 But well, it shouldn't be, No, it shouldn't be. But 0:38:12.320 --> 0:38:14.520 but but you know, your mileage may vary depending upon 0:38:15.200 --> 0:38:20.800 manufacturer and model, but the ideally it would take thousands 0:38:20.840 --> 0:38:24.880 and thousands and thousands of times before it would become obsolete, 0:38:24.960 --> 0:38:28.279 before it would not work anymore. And the thing is 0:38:28.320 --> 0:38:30.959 that most of us use our computers frequently enough where 0:38:31.280 --> 0:38:34.279 eventually that could happen. I mean, if you upgrade on 0:38:34.360 --> 0:38:37.360 a regular basis, you may never notice this problem. But 0:38:37.680 --> 0:38:40.080 if you don't, you might notice that your computer takes 0:38:40.200 --> 0:38:42.800 longer to pull information from the hard drive that it 0:38:42.920 --> 0:38:46.560 used to and you may notice that you are running 0:38:46.560 --> 0:38:48.680 out of hard drive space when you thought that you 0:38:48.960 --> 0:38:52.880 should really have more. Why has all that gone? And 0:38:52.960 --> 0:38:55.920 it's because those cells are no longer viable. Well. UM. 0:38:56.480 --> 0:38:59.440 To prevent this, the controller on the S s D 0:39:00.120 --> 0:39:04.239 is designed to route traffic in a way that will 0:39:04.280 --> 0:39:09.160 try to put a fairly even uh distribution, distribution of 0:39:09.320 --> 0:39:13.200 usage across the different cells on the drive uh, thus 0:39:13.480 --> 0:39:18.399 hopefully ensuring that no set of cells is worn down 0:39:18.520 --> 0:39:20.399 more than the others. They're trying to put put even 0:39:20.480 --> 0:39:23.839 wear and tear on it. Um. But the more full 0:39:23.960 --> 0:39:26.160 you get now they're one of the complaints about S 0:39:26.320 --> 0:39:28.680 s D s is that they seem to grow slower 0:39:28.800 --> 0:39:32.359 as time goes on. That's because that information, uh, those 0:39:32.480 --> 0:39:35.960 those cells are getting full of information. Those pages are 0:39:35.960 --> 0:39:39.879 filling up. And because of the way they work um 0:39:40.480 --> 0:39:43.960 and they have to write and rewrite blank pages at 0:39:43.960 --> 0:39:47.800 a time, UH, it can seem to slow down because 0:39:47.880 --> 0:39:51.239 there isn't as much space to uh for them to 0:39:51.440 --> 0:39:54.960 the controller to route the information and regroup things into 0:39:55.040 --> 0:39:58.000 pages uh fresh pages that can be written and rewritten 0:39:58.360 --> 0:40:02.279 or not rewritten, but um erased and written to UM. 0:40:03.160 --> 0:40:05.680 So UM you know that that's that's sort of a 0:40:07.320 --> 0:40:09.920 I would say an illusion. It's not really an illusion, 0:40:09.960 --> 0:40:12.759 but that's why it's not because the drive is uh 0:40:13.560 --> 0:40:16.520 crapping out generally, I mean, uh yeah, I mean the 0:40:18.239 --> 0:40:21.440 vendors for these devices generally say that they're good for 0:40:21.880 --> 0:40:25.200 you know, tens of thousands of read write cycles, so 0:40:25.360 --> 0:40:28.040 they should be good for for years. Of course, that 0:40:28.080 --> 0:40:31.560 doesn't mean you shouldn't back up your hard drive. However, 0:40:31.760 --> 0:40:34.239 it does mean that defragging like we used to do 0:40:34.400 --> 0:40:38.640 with the magnetic traditional platter drives is not a good 0:40:38.680 --> 0:40:43.680 idea because you're adding to writing and rewriting uh those 0:40:43.760 --> 0:40:47.719 cells right right, You're you're effectively you are decreasing the 0:40:47.960 --> 0:40:51.120 life span of your hard drive. And the controller really 0:40:51.160 --> 0:40:53.440 should be doing that anyway, with the garbage collection and 0:40:53.760 --> 0:40:57.120 um organization of that that work, so it should be 0:40:57.239 --> 0:40:58.640 less of an issue than it used to be. And 0:40:58.680 --> 0:41:01.800 the controller really is kind of like a very small, 0:41:02.000 --> 0:41:05.480 very specialized computer. So in a way, you have a 0:41:05.520 --> 0:41:08.960 computer within your computer because the controller is is taking 0:41:09.080 --> 0:41:12.920 this information and putting it in the most uh the 0:41:13.560 --> 0:41:18.239 the optimized format and layout. So yeah, it's uh, it's 0:41:18.280 --> 0:41:22.680 an interesting approach using this voltage difference instead of magnetism 0:41:22.760 --> 0:41:27.040 in order to store information, and it has become incredibly useful, 0:41:27.200 --> 0:41:30.080 especially for things like portable electronics. I mean, it's really 0:41:30.200 --> 0:41:33.600 decreased the size of what our electronics can be. Plus 0:41:33.680 --> 0:41:35.400 you can go running with it and not worry about 0:41:35.560 --> 0:41:37.759 crashing the platters on your hard drive. Yeah, this is 0:41:37.800 --> 0:41:40.200 why back when I remember when m P three's were 0:41:40.480 --> 0:41:42.440 MP three players were first coming out, and there was 0:41:42.480 --> 0:41:44.680 always the argument of do you get the one with 0:41:44.880 --> 0:41:46.799 the spinning hard drive or do you get the one 0:41:46.840 --> 0:41:48.600 with the flash hard drive? And the flash hard drives 0:41:48.640 --> 0:41:51.160 tended to be more expensive, but they also were the 0:41:51.239 --> 0:41:55.040 ones you could go and exercise with and not worry 0:41:55.120 --> 0:41:58.560 about them, you know, something skipping around or or or 0:41:58.680 --> 0:42:03.719 corrupting a file or crashing. Um, do you would you 0:42:03.719 --> 0:42:06.000 would you like to wrap up? Or should we mention encryption? 0:42:07.239 --> 0:42:10.920 We could mention, well, you can mention encryption because frankly, 0:42:11.000 --> 0:42:14.560 my my research did not cover that topic. UM okay, 0:42:14.680 --> 0:42:17.960 well the uh UM This is another in the series 0:42:18.120 --> 0:42:21.520 of articles UM on our technical about s s d S, 0:42:22.040 --> 0:42:24.640 also written by Lee Hutchinson UM. And it's kind of 0:42:24.680 --> 0:42:30.359 fascinating because uh in in the process of UM compression UM, 0:42:30.800 --> 0:42:34.120 they go through a d D duplication phase. So it's 0:42:34.120 --> 0:42:36.560 sort of you know, if they find two copies of 0:42:36.640 --> 0:42:39.759 the same information, it will essentially get rid of one 0:42:39.960 --> 0:42:41.560 so that it takes up less space in the hard 0:42:41.640 --> 0:42:44.560 rid That's essentially how how these things are done. And 0:42:44.640 --> 0:42:48.759 it's done in UM other types of files to UM 0:42:49.760 --> 0:42:53.400 image and sound and uh, you know those kinds of 0:42:53.480 --> 0:42:55.560 things that they find the same information, they can reduce 0:42:55.640 --> 0:42:58.120 the amount of information in that file. Well, they do 0:42:58.239 --> 0:43:01.000 that with hard drives too. But one of the interesting 0:43:01.080 --> 0:43:04.480 things that that Hutchinson mentions is now that modern operating 0:43:04.520 --> 0:43:07.239 systems are allowing you to encrypt your entire hard drive. 0:43:07.600 --> 0:43:10.360 That actually makes it tougher for s s d s 0:43:10.520 --> 0:43:14.520 because they can't de duplicate that information anymore. Because once 0:43:14.560 --> 0:43:17.440 you encrypted a file, it has its own individual signature. 0:43:17.880 --> 0:43:21.239 So even if they were the same exact document um, 0:43:21.880 --> 0:43:26.719 the computer sees it as two different encrypted documents because 0:43:26.760 --> 0:43:30.680 the encryption information is slightly different, so will no longer 0:43:30.800 --> 0:43:34.640 recognize them as the same information. So you will see 0:43:34.680 --> 0:43:38.960 them as completely different information. Taking Bulky and safe exactly, 0:43:39.200 --> 0:43:41.719 so it takes up the same file will take up 0:43:41.760 --> 0:43:43.800 twice as much space if it's been duplicated, and it 0:43:43.840 --> 0:43:46.799 will not be deleted because there's just enough difference there, 0:43:47.520 --> 0:43:50.959 so that it has essentially fooled the controller into thinking 0:43:51.440 --> 0:43:54.719 it's two files, not one that's been duplicated to two 0:43:54.760 --> 0:43:57.840 files and one now. Um. The other thing, uh, the 0:43:57.920 --> 0:44:01.080 thing to know is, you know, these the devices are 0:44:01.080 --> 0:44:03.760 coming down and cost um, they're showing up more often 0:44:04.040 --> 0:44:07.600 in uh, in laptops, books and and you know, just 0:44:07.719 --> 0:44:09.600 a few years ago, I remember that it was really 0:44:09.760 --> 0:44:13.480 unusual to find a solid state drive in a computer, 0:44:13.560 --> 0:44:16.120 and you were paying a premium for that if you 0:44:16.200 --> 0:44:18.319 wanted it. And it was kind of interesting because at 0:44:18.360 --> 0:44:21.560 the time the solid state drives, while you were paying 0:44:21.600 --> 0:44:25.279 a premium, tended to have a smaller capacity than the 0:44:25.320 --> 0:44:28.080 traditional hard drives did when they first started coming out. Well, 0:44:28.160 --> 0:44:32.839 now we've seen that slowly start to change, and that's 0:44:32.880 --> 0:44:35.359 to be expected. That's the way technology tends to work 0:44:35.680 --> 0:44:38.319 in the market. We tend to see when it first 0:44:38.360 --> 0:44:41.680 comes out, it tends to be pretty expensive and fairly limited. 0:44:42.040 --> 0:44:44.600 And as it advances and we get better at the 0:44:45.120 --> 0:44:50.560 production approach, these prices start to fall and then next 0:44:50.640 --> 0:44:55.520 thing you know, it's everywhere. Yes, so um, you know 0:44:55.680 --> 0:44:59.120 it seems like they're they're becoming more common. Um, you know, 0:44:59.280 --> 0:45:03.080 even even in run of the mill laptops. However, um, 0:45:03.239 --> 0:45:06.560 you know, the cost is still not as as inexpensive 0:45:06.719 --> 0:45:09.920 as traditional hard drives UM. And you know you do 0:45:10.080 --> 0:45:13.480 have those trade offs to be made versus the traditional 0:45:13.560 --> 0:45:15.600 So if you were getting, say you really wanted a 0:45:15.680 --> 0:45:19.719 nice workstation to use at home, you already have a laptop, UM, 0:45:19.840 --> 0:45:21.600 and you were choosing whether you wanted to spend that 0:45:21.680 --> 0:45:25.560 extra hundred dollars two hundred dollars for an SSD, you 0:45:25.640 --> 0:45:28.440 know it does you would get some uh savings in 0:45:28.760 --> 0:45:32.440 in UH cost if you went with the magnetic drive, UM, 0:45:32.760 --> 0:45:35.840 but you would trade off speed for that and the 0:45:35.920 --> 0:45:38.800 number of read write cycles. Of course, magnetic drives have 0:45:38.920 --> 0:45:42.799 their own idiosyncrasies and you may or may not lose 0:45:42.840 --> 0:45:45.680 your your hard drive, right. Yeah. No, it's not not 0:45:45.840 --> 0:45:49.479 to say that that the older hard drives are any better. 0:45:49.600 --> 0:45:53.839 They just have a different set of pros and cons. Yeah, exactly. So, yeah, 0:45:53.880 --> 0:45:56.719 it all depends on what your use case scenario is. 0:45:56.880 --> 0:45:59.600 And I mean, like, i have machines at home that 0:46:00.440 --> 0:46:02.920 of both types. So I've got machines that have a 0:46:02.960 --> 0:46:05.279 spinning hard drive, I gut machines that have solid state drives. 0:46:05.320 --> 0:46:07.640 I have an external drive. That's a solid state drive 0:46:07.719 --> 0:46:10.360 that I used for backups. Uh. You know, there's a 0:46:10.400 --> 0:46:13.560 lot of different ways of going about this, and I 0:46:14.120 --> 0:46:18.680 think that both approaches have their own advantages and disadvantages 0:46:18.760 --> 0:46:21.279 that will apply to you based upon the way you 0:46:21.400 --> 0:46:24.080 use your machines. So that's always a good thing to 0:46:24.120 --> 0:46:26.800 think about. Uh. And it may even be that to you. 0:46:26.960 --> 0:46:29.400 It doesn't really matter other than maybe the fact that 0:46:29.520 --> 0:46:31.279 you can get a solid state drive with a small 0:46:31.320 --> 0:46:34.040 reform factor than you could if it were a physical 0:46:34.120 --> 0:46:36.200 hard drive, you know, the mechanical hard drive. I should 0:46:36.200 --> 0:46:39.360 say mechanical, not physical, because they're both physical. It's not 0:46:39.680 --> 0:46:43.440 it's not a virtual hard drive. Um. So yeah, I 0:46:43.480 --> 0:46:46.399 mean that's it's all up to the way you use 0:46:46.440 --> 0:46:48.799 your machines and what you what your personal preferences are, 0:46:48.840 --> 0:46:50.799 and I guess what your budget is as well. Yeah. 0:46:51.320 --> 0:46:54.840 Um yeah, I'll never forget. I knew that solid state 0:46:55.120 --> 0:46:58.320 memory was going to be a big deal. This flash 0:46:58.400 --> 0:47:03.719 based memory sticks solid state drives slightly different, but I 0:47:03.800 --> 0:47:06.239 knew it was gonna be a big deal when we 0:47:06.360 --> 0:47:09.040 went to I guess is when I went to C E. S. 0:47:09.080 --> 0:47:10.719 It was the year after the two of us went 0:47:10.800 --> 0:47:12.920 because the year that Chris and I both went to 0:47:13.000 --> 0:47:16.120 c S, we picked up lots and lots of press 0:47:16.239 --> 0:47:19.400 kits that were either paper press kits or c D 0:47:20.120 --> 0:47:24.000 comic this space. And then the next year I started 0:47:24.080 --> 0:47:30.560 seeing companies produce their press kits on USB thumb drives. 0:47:31.200 --> 0:47:33.680 And that's when I was I thought, Okay, this is 0:47:33.719 --> 0:47:35.839 a big enough deal, because now it's cheap enough where 0:47:35.960 --> 0:47:41.160 these companies can produce thousands of these things for an exhibition. 0:47:41.239 --> 0:47:43.960 Because you've got lots and lots of people at c S, 0:47:44.080 --> 0:47:46.400 you have to produce tons and tons of these not 0:47:46.600 --> 0:47:49.120 literally tons and tons, but lots and lots of these 0:47:49.480 --> 0:47:52.279 thumb drives, uh, in order to give them out to 0:47:52.320 --> 0:47:55.120 all the people who stopped by. Of course, nowadays they 0:47:55.160 --> 0:47:57.960 don't even do that anymore. Now you get a card 0:47:58.080 --> 0:47:59.759 that has a U R L and you go to 0:48:00.160 --> 0:48:02.799 a website that has the press release, which is even 0:48:02.920 --> 0:48:05.920 better really, although it does mean that I don't end 0:48:06.040 --> 0:48:10.200 up with lots of thumb drives that I can use 0:48:10.320 --> 0:48:14.040 once I erase the VATA that's on there. You mean 0:48:14.080 --> 0:48:17.200 you haven't moved everything into the cloud. Now I'm working 0:48:17.280 --> 0:48:19.719 on it, but you know there, here's the other thing, 0:48:19.719 --> 0:48:21.600 about the cloud. I mean, that's a totally different discussions. 0:48:21.640 --> 0:48:23.200 I'm gonna I'm gonna drop this. I was about to 0:48:23.239 --> 0:48:24.960 go off on a cloud rant about how all my 0:48:25.080 --> 0:48:27.920 information is in different pockets in the cloud. That's my 0:48:28.080 --> 0:48:32.360 problem now, So let's let's that's a totally different podcast, 0:48:32.440 --> 0:48:34.719 which I'm sure we'll do. And we've talked about cloud 0:48:34.800 --> 0:48:37.960 storage in the past anyway, so we're gonna wrap this up. Guys. 0:48:38.400 --> 0:48:40.600 I do recommend you go to ours Technica and look 0:48:40.640 --> 0:48:43.520 at those articles if you are interested in solid state 0:48:43.600 --> 0:48:46.359 drives and what makes them work. And that wraps up 0:48:46.520 --> 0:48:51.200 another episode, another classic episode of tech Stuff, and hope 0:48:51.200 --> 0:48:54.440 you guys enjoyed it. I really miss having those conversations 0:48:54.480 --> 0:48:56.960 with Chris. They were always a lot of fun. If 0:48:57.000 --> 0:48:59.319 you guys have suggestions for topics that I should cover 0:48:59.440 --> 0:49:02.400 in future or episodes of tech Stuff, send me an 0:49:02.440 --> 0:49:06.080 email the addresses tech Stuff at how stuff works dot com, 0:49:06.600 --> 0:49:10.440 or drop on by our website that's tech Stuff podcast 0:49:10.560 --> 0:49:12.840 dot com. There you're going to find an archive of 0:49:13.040 --> 0:49:15.560 all of our past episodes. It's fully searchable, so you 0:49:15.600 --> 0:49:18.879 can find out if I've covered a specific topic that way, 0:49:19.560 --> 0:49:22.720 and you can also find links to our social media 0:49:23.280 --> 0:49:27.640 presence on places like Facebook and Twitter. You can also 0:49:27.880 --> 0:49:30.400 find a link to our online store, where every purchase 0:49:30.480 --> 0:49:32.480 you make goes to help the show and we greatly 0:49:32.520 --> 0:49:36.040 appreciate it, and I'll talk to you again really soon. 0:49:40.480 --> 0:49:42.680 Text Stuff is a production of I Heart Radio's How 0:49:42.760 --> 0:49:46.120 Stuff Works. For more podcasts from my heart Radio, visit 0:49:46.160 --> 0:49:49.160 the i heart Radio app, Apple Podcasts, or wherever you 0:49:49.320 --> 0:49:50.640 listen to your favorite shows.