WEBVTT - Rerun: Data Preservation and Destruction 0:00:04.480 --> 0:00:12.559 Welcome to tech Stuff, a production from iHeartRadio. Hey there, 0:00:12.600 --> 0:00:15.760 and welcome to tech Stuff. I'm your host Jonathan Strickland 0:00:15.760 --> 0:00:19.440 di'mond executive producer with iHeartRadio. And how the tech are yet. 0:00:20.320 --> 0:00:22.439 You know, I thought it might be interesting to talk 0:00:22.480 --> 0:00:26.600 about how data can both be easy to lose and 0:00:27.120 --> 0:00:30.720 hard to lose. It's a paradise, but really this is 0:00:30.720 --> 0:00:35.840 all about the media upon which we store data and 0:00:36.200 --> 0:00:40.720 how that media can pose various challenges. Now, first up, 0:00:41.159 --> 0:00:46.240 let's just talk about the concept of obsolescence. So as 0:00:46.520 --> 0:00:50.080 our technology, our language, our culture, as all these things 0:00:50.120 --> 0:00:54.360 evolve and we discover new ways to commit information to 0:00:55.000 --> 0:00:59.360 different types of media, we often leave the older methods behind. 0:01:00.400 --> 0:01:03.280 And for example, very few people are recording audio to 0:01:03.400 --> 0:01:07.360 wax cylinders today. For example, you know Thomas Edison did it, 0:01:07.880 --> 0:01:09.800 but you don't see people doing it now, at least 0:01:09.800 --> 0:01:12.920 not outside of you know, historical demonstrations and that sort 0:01:12.959 --> 0:01:17.479 of thing. The days of storing info magnetically onto strips 0:01:17.520 --> 0:01:20.240 of metal, like we saw at the end of the 0:01:20.319 --> 0:01:23.680 nineteenth century, that's pretty far behind us too, although magnetic 0:01:23.720 --> 0:01:26.440 tape is built on the same principle. But before we 0:01:26.560 --> 0:01:31.440 use tape, we used wire, not that frequently, but it 0:01:31.480 --> 0:01:33.080 was one of those things that kind of paved the 0:01:33.120 --> 0:01:38.319 way toward magnetic tape. Now, over time, all media will 0:01:38.400 --> 0:01:42.240 ultimately go obsolete, either because the stuff we recorded upon 0:01:42.840 --> 0:01:47.400 has worn out, the actual physical stuff has broken, or 0:01:47.480 --> 0:01:51.320 because we've lost the ability to retrieve information from that 0:01:51.440 --> 0:01:55.320 type of media. And that inability to retrieve can range 0:01:55.400 --> 0:01:59.000 from the technical to just our knowledge of how to 0:01:59.040 --> 0:02:02.120 do it. So let's take a moment to consider something 0:02:02.200 --> 0:02:05.800 that is pretty far removed from modern technology unless you 0:02:05.840 --> 0:02:12.320 watch stargate, and that is hieroglyphs. So thousands of years ago, 0:02:12.720 --> 0:02:16.080 the people of ancient Egypt developed a writing system that 0:02:16.320 --> 0:02:20.560 was complicated, to say the least. So our Latin alphabet, 0:02:21.000 --> 0:02:23.520 the one that we use in English, for example, has 0:02:23.560 --> 0:02:27.000 twenty six characters write twenty six letters in the alphabet, 0:02:27.880 --> 0:02:35.480 and hieroglyphs had hundreds of characters, like a thousand or more. Now, 0:02:35.520 --> 0:02:40.480 some of the characters in ancient Egypt represented basic phonemes. 0:02:41.400 --> 0:02:45.440 Phonemes are sounds within a language, right, like would be 0:02:45.560 --> 0:02:50.680 a phoneeme or like these are basic sounds. But other 0:02:51.080 --> 0:02:55.280 characters in ancient Egyptian hieroglyphs, they represented entire words, or 0:02:55.320 --> 0:03:01.880 at least parts of words. Some represented stills, so not 0:03:02.280 --> 0:03:06.200 necessarily parts of words like you would think, but a 0:03:06.240 --> 0:03:10.360 syllable that was common in ancient Egypt. But over the millennia, 0:03:10.919 --> 0:03:15.440 the knowledge of how to read hieroglyphs faded from Egyptian culture. 0:03:16.280 --> 0:03:17.919 There were a lot of reasons for this. I mean, 0:03:17.960 --> 0:03:23.760 the style of writing down information changed from hieroglyphs to 0:03:23.800 --> 0:03:27.920 like demonic writing, and beyond Also, you had folks like 0:03:28.680 --> 0:03:32.120 you know, Europeans, like Greeks and Romans, who were invading 0:03:32.160 --> 0:03:37.280 Egypt and changing things and disrupting Egyptian culture significantly. By 0:03:37.320 --> 0:03:40.360 the time we got a few centuries into the common era, 0:03:40.720 --> 0:03:44.200 pretty much no one knew how to read the hieroglyphs 0:03:44.280 --> 0:03:48.000 of ancient Egypt anymore. So we had all this knowledge 0:03:48.080 --> 0:03:52.840 stored in various places and no way to retrieve that knowledge. 0:03:53.040 --> 0:03:55.240 It appeared as though we had lost all of it, 0:03:55.440 --> 0:04:00.160 or that we had, due to some misconceptions, completely miss 0:04:00.200 --> 0:04:03.560 interpreted that knowledge. So by the time we got into 0:04:03.560 --> 0:04:08.120 the medieval era, there was this prevailing hypothesis that the 0:04:08.160 --> 0:04:13.280 Egyptian hieroglyphs were symbolic in meaning, And by that I 0:04:13.320 --> 0:04:15.840 mean that the images that the Egyptians used were thought 0:04:15.880 --> 0:04:18.680 of to be direct symbols of whatever the message was. 0:04:19.360 --> 0:04:22.800 So let's say you had images of a boat and 0:04:22.880 --> 0:04:25.359 a snake, then you might be led to think that 0:04:25.400 --> 0:04:29.320 what you're looking at must be an allegorical story about 0:04:29.360 --> 0:04:34.240 snakes on a boat, possibly starring Samuel L. Jackson. But no, 0:04:35.400 --> 0:04:39.600 the symbols used weren't meant to represent exactly what they 0:04:39.640 --> 0:04:44.000 looked like. They represented elements of a language. So, for example, 0:04:44.000 --> 0:04:46.880 if you want to understand what I'm saying, our letter 0:04:47.120 --> 0:04:50.080 S looks kind of like a snake, right, but it 0:04:50.120 --> 0:04:52.880 doesn't mean snake. When you see the letter S, that 0:04:52.960 --> 0:04:57.120 doesn't mean snake. It could be the beginning of the 0:04:57.120 --> 0:04:59.719 word snake. Obviously that begins with S, but it could 0:04:59.720 --> 0:05:03.640 mean anything. It represents the S sound, which is found 0:05:03.680 --> 0:05:06.919 in lots of words, not just snake. And the hieroglyphs 0:05:06.920 --> 0:05:09.560 were similar, but no one had a document that matched 0:05:09.640 --> 0:05:14.360 hieroglyphs to some other known language so that someone could 0:05:14.360 --> 0:05:17.240 actually decipher the symbols. So it just seemed to be, 0:05:18.000 --> 0:05:21.640 you know, all these icons that the meaning had been 0:05:21.680 --> 0:05:27.200 completely lost. But then came Napoleon Ponaparte and his armies 0:05:27.320 --> 0:05:30.680 invaded Egypt toward the end of the eighteenth century, and 0:05:30.760 --> 0:05:35.599 in the process the armies happened across something incredibly important, 0:05:36.120 --> 0:05:39.440 and it would later be called the Rosetta Stone. Now, 0:05:39.480 --> 0:05:43.880 the Rosetta Stone itself is a type of monument, and 0:05:43.960 --> 0:05:47.760 there are carvings on the monument that represent an official 0:05:48.000 --> 0:05:53.040 dynastic decree. The carvings are in three different written languages. 0:05:53.440 --> 0:05:56.279 So at the base of the monument you have the 0:05:56.360 --> 0:06:00.719 carving in ancient Greek, above that is Demotic that is 0:06:00.760 --> 0:06:04.480 an Egyptian language that followed the High language, and at 0:06:04.480 --> 0:06:07.880 the top are hieroglyphs. And since all three carvings represented 0:06:07.920 --> 0:06:11.919 the same decree, this gave experts the opportunity to finally 0:06:11.960 --> 0:06:17.400 begin deciphering Egyptian hieroglyphs, and so began the long process 0:06:17.440 --> 0:06:22.120 of uncovering lost knowledge. And this was helped by subsequent 0:06:22.160 --> 0:06:27.800 discoveries of similar decrees, so that we, over time were 0:06:27.839 --> 0:06:32.560 able to understand what these hieroglyphs actually stood for. We 0:06:32.640 --> 0:06:36.080 understood that it was a written language that wasn't just 0:06:36.160 --> 0:06:40.520 purely symbolic. Now, my point in telling the story is 0:06:40.520 --> 0:06:42.880 that we have to remind ourselves that while we have 0:06:43.080 --> 0:06:46.520 ways to record knowledge. It would be foolish for us 0:06:46.600 --> 0:06:49.600 to assume that any way that we use is permanent, 0:06:50.600 --> 0:06:53.920 because we've got plenty of examples of knowledge being lost 0:06:53.960 --> 0:06:57.039 in the past, whether it's because people forgot how to 0:06:57.279 --> 0:07:01.800 access that knowledge, or maybe the knowledge was based in 0:07:01.920 --> 0:07:05.680 folklore and the people that were the stewards of that 0:07:05.800 --> 0:07:09.800 knowledge were wiped out or assimilated and the knowledge was lost, 0:07:10.280 --> 0:07:13.720 or maybe the physical copies, if it was like a 0:07:13.760 --> 0:07:16.840 written language, maybe the physical copies were lost. And a 0:07:16.880 --> 0:07:20.760 shout out to the late great Library of Alexandria, which 0:07:20.760 --> 0:07:23.360 I should add kind of faded away, not just because 0:07:23.400 --> 0:07:26.480 the famous fire set by Julius Caesar's forces, though that 0:07:26.640 --> 0:07:31.480 clearly was a catastrophic event, but also there was a 0:07:31.560 --> 0:07:34.880 long period in which leaders were cracking down on scholars 0:07:34.920 --> 0:07:38.480 because well, a little knowledge is a dangerous thing, so 0:07:38.520 --> 0:07:41.040 a lot of knowledge has got to be absolutely deadly, right. 0:07:41.480 --> 0:07:45.280 But anyway, let's skip ahead to the modern era. So 0:07:45.520 --> 0:07:48.760 even today we run the risk of losing access to 0:07:48.800 --> 0:07:53.080 information because we no longer make the stuff, what plays 0:07:53.200 --> 0:07:55.920 the media that we used in the old days, or 0:07:55.920 --> 0:07:58.480 at least in many cases, it is getting really tricky 0:07:58.520 --> 0:08:02.320 to track down the components that can retrieve data from 0:08:02.440 --> 0:08:05.040 those types of media. Right, you might be able to 0:08:05.080 --> 0:08:10.040 find old working equipment that can access certain types of 0:08:10.160 --> 0:08:14.280 stuff that otherwise we no longer can access. But it's 0:08:14.400 --> 0:08:17.120 rare that you're gonna find someone make a new version 0:08:17.160 --> 0:08:19.880 of that. It's not impossible. It's not like we've lost 0:08:20.280 --> 0:08:23.840 all ability to It's just that unless there is a 0:08:24.560 --> 0:08:29.720 pressing financial benefit to creating that kind of stuff, no 0:08:29.760 --> 0:08:32.040 one's going to bother to do it. Because you know, 0:08:32.240 --> 0:08:39.360 it's expensive to produce older types of technologies, and unless 0:08:39.360 --> 0:08:42.920 there's a financial incentive, no one's going to do it. 0:08:42.920 --> 0:08:45.840 It's had to say so. There's also the danger that 0:08:45.880 --> 0:08:49.559 the media we rely upon could wear out and deteriorate 0:08:49.679 --> 0:08:54.320 over time. So, for example, let's consider celluloid or film. 0:08:55.080 --> 0:08:59.560 Cinematic film degrades over time, particularly if it's in a 0:08:59.720 --> 0:09:03.600 hot and moist environment. And you might have heard about 0:09:03.880 --> 0:09:07.880 some filmmakers storing prints of their movies or masters of 0:09:07.920 --> 0:09:11.360 their movies in old salt mines such as the one 0:09:11.360 --> 0:09:16.000 that's below Hutchinson, Kansas in the United States. These subterranean 0:09:16.080 --> 0:09:20.640 spaces maintain a constant temperature of around sixty eight fahrenheit 0:09:20.840 --> 0:09:24.880 or twenty celsius, and they have a low humidity somewhere 0:09:24.960 --> 0:09:28.319 between like forty to forty five percent humidity. Of course, 0:09:28.320 --> 0:09:30.440 movies are not the only things stored in those minds. 0:09:30.840 --> 0:09:33.760 That in fact, we got the idea because of the 0:09:34.200 --> 0:09:38.360 story of the monument men who ended up finding lots 0:09:38.360 --> 0:09:43.120 of stolen art from various parts of Europe that the 0:09:43.200 --> 0:09:46.280 Nazis had collected and stored in salt mines. We ended 0:09:46.320 --> 0:09:49.800 up kind of using the same idea because it's a 0:09:49.840 --> 0:09:53.880 great way to preserve stuff. If you otherwise, it's in 0:09:53.960 --> 0:09:57.880 danger of deterioration. Also, we have to acknowledge that while 0:09:57.920 --> 0:09:59.960 it's a great way to preserve stuff, there's a tragedy 0:10:00.080 --> 0:10:04.480 here because we're also removing it right from us. You know, 0:10:04.520 --> 0:10:07.080 we're storing it and we're preserving it, But to what 0:10:07.280 --> 0:10:12.400 end if you can't access it, then it doesn't really 0:10:12.800 --> 0:10:15.560 like there's a lot of questions. There are philosophical questions. 0:10:15.880 --> 0:10:18.760 If you have a priceless work of art stored in 0:10:18.800 --> 0:10:21.280 assault mind and no one can go there, is it 0:10:21.360 --> 0:10:24.360 the same as not having it at all. Now, in 0:10:24.400 --> 0:10:26.880 the case of film, a lot of studios will actually 0:10:27.000 --> 0:10:30.120 use those master recordings. When they want to do a 0:10:30.200 --> 0:10:33.080 remastered version of the film they want to release it 0:10:33.120 --> 0:10:36.240 on say like Blu ray or something, they'll go to 0:10:36.440 --> 0:10:39.800 the original print that's stored in as salt mine and 0:10:39.840 --> 0:10:42.480 they'll pull from that. But yeah, there's lots of other 0:10:42.480 --> 0:10:45.480 stuff besides just film down there, anything that needs a 0:10:45.480 --> 0:10:50.319 controlled environment in order to stop or at least slow deterioration. Now, 0:10:50.360 --> 0:10:54.760 magnetic tape is another important storage method, and we've been 0:10:54.840 --> 0:10:58.200 using magnetic tape as storage since the mid twentieth century, 0:10:58.240 --> 0:11:01.240 around nineteen fifty one or so, and again the basic 0:11:01.360 --> 0:11:04.559 principle behind it dates back to the late nineteenth century. 0:11:04.559 --> 0:11:09.880 That was when we were using magnetic wire. But whether 0:11:10.000 --> 0:11:14.280 it's real to real tape, or cassettes or VHS tapes, 0:11:14.679 --> 0:11:18.079 we've relied on this methodology to store all sorts of information, 0:11:18.320 --> 0:11:23.200 from computer information to music in the case of like 0:11:23.280 --> 0:11:28.520 the cassette tapes of the eighties nineties or the VHS videotapes, 0:11:29.520 --> 0:11:32.960 all sorts of info we have committed to magnetic tape, 0:11:33.760 --> 0:11:35.959 and a lot of companies still rely on magnetic tape 0:11:36.000 --> 0:11:39.640 for long term storage and backups. When I use long 0:11:39.720 --> 0:11:43.720 term storage, i'm speaking relatively as we will see now 0:11:43.840 --> 0:11:48.000 some older forms of magnetic tape are largely obsolete because 0:11:48.040 --> 0:11:50.640 the devices we'd use to read the data from them 0:11:51.200 --> 0:11:55.120 are out of production. You might find a working device 0:11:55.160 --> 0:11:57.640 here or there, but they can be pretty rare, and 0:11:58.000 --> 0:12:01.839 being mechanical in nature, they will eventually require maintenance or 0:12:01.960 --> 0:12:05.120 they'll stop working. And when you're talking about this kind 0:12:05.160 --> 0:12:08.720 of stuff, often you're talking about things that have parts 0:12:08.760 --> 0:12:11.840 that no one's making anymore, so it becomes very challenging 0:12:11.840 --> 0:12:14.480 to keep them in good working order because there's a 0:12:14.559 --> 0:12:18.120 limited supply of components you can use to make replacements 0:12:18.120 --> 0:12:21.160 when something breaks down. On top of all that, magnetic 0:12:21.240 --> 0:12:25.720 information itself can degrade over time, actually can degrade really 0:12:25.800 --> 0:12:28.560 quickly if it's in the presence of a strong magnetic field, 0:12:28.640 --> 0:12:30.679 which is why as a kid I was told never 0:12:30.720 --> 0:12:33.120 to bring a magnet close to a computer or computer 0:12:33.240 --> 0:12:39.360 discs because you could actually corrupt information that's stored on 0:12:39.400 --> 0:12:44.320 those devices because the magnet would realign the magnetic components 0:12:44.320 --> 0:12:47.560 that were on this plastic film, or in the case 0:12:47.559 --> 0:12:52.200 of a computer, a raid on a platter inside the 0:12:52.200 --> 0:12:57.439 hard disk drive. Now, on average, if stored in decent conditions, 0:12:57.920 --> 0:13:02.120 magnetic tape typically will retain data from anywhere between ten 0:13:02.160 --> 0:13:06.400 to twenty years. When stored in prime conditions like in 0:13:06.440 --> 0:13:09.160 that salt mine, for example, you might stretch it to 0:13:09.240 --> 0:13:12.439 around thirty years. So magnetic tape can hold on to 0:13:12.559 --> 0:13:17.240 data for a while, but certainly not indefinitely. It will 0:13:17.960 --> 0:13:22.360 sooner or later degrade to a point where the information 0:13:22.400 --> 0:13:26.760 will be corrupted or irretrievable. Now, on a similar note, 0:13:27.200 --> 0:13:29.720 let's talk floppy disks. So when I was a kid, 0:13:29.760 --> 0:13:32.040 our Apple two E computer had a five and a 0:13:32.120 --> 0:13:36.000 quarter inch floppy disk drive. These were not the first 0:13:36.040 --> 0:13:38.520 floppy disks. There were older ones. There were larger ones. 0:13:38.559 --> 0:13:43.000 IBM created eight inch floppy disks for example. And the 0:13:43.320 --> 0:13:45.839 discs that I was familiar with back when I was 0:13:45.920 --> 0:13:49.439 using the Apple to E were these plastic envelopes, and 0:13:49.520 --> 0:13:53.320 the envelopes were covering a disc of magnetic film on 0:13:53.400 --> 0:13:58.520 the inside, and it was on this magnetic disc that 0:13:58.600 --> 0:14:02.000 you could save and retreat data. And I actually had 0:14:02.040 --> 0:14:04.320 to look this up because I could not remember it myself. 0:14:04.320 --> 0:14:07.000 But the original five and a quarter inch floppy disks 0:14:07.520 --> 0:14:10.120 could hold up to ninety kilobytes of data. That's when 0:14:10.120 --> 0:14:15.200 they were first created. So that's just ninety kilobytes. But 0:14:15.520 --> 0:14:20.720 over time, you know, engineers improved the technology. They increased 0:14:20.760 --> 0:14:24.160 the capacity of floppy discs. Typically, they did this by 0:14:24.200 --> 0:14:27.280 creating more precise read write heads so they could store 0:14:27.920 --> 0:14:33.120 data in smaller physical sizes, which meant you could cram 0:14:33.200 --> 0:14:35.640 more of it onto the same sized disc. They also 0:14:35.840 --> 0:14:39.800 figured out how to multilayer discs, so that increased storage 0:14:39.840 --> 0:14:44.480 as well. I think, you know, some discs maxed out 0:14:44.480 --> 0:14:47.720 at around seven hundred and twenty kilobytes, so significantly more 0:14:47.760 --> 0:14:50.360 than ninety, but still way less than what we use today. 0:14:51.800 --> 0:14:54.600 Now I'm going to talk more about floppy disks and 0:14:54.680 --> 0:14:59.920 other forms of storage and why all these different types 0:15:00.080 --> 0:15:02.760 have kind of a limited shelf life of one span 0:15:03.000 --> 0:15:05.240 or another. But before we get to that, let's take 0:15:05.480 --> 0:15:16.200 a quick break. Okay, we're back, and we were talking 0:15:16.200 --> 0:15:20.080 about floppy discs. Well, my parents write novels, and so 0:15:20.240 --> 0:15:23.400 my dad's first books, which were written in the early eighties, 0:15:23.400 --> 0:15:25.880 they were written on that old Apple two E computer, 0:15:26.440 --> 0:15:29.960 and he would save chapters of his books to floppy discs. 0:15:30.440 --> 0:15:33.520 Each novel would take up several discs, like I don't know, 0:15:33.600 --> 0:15:36.680 around a dozen or so, I can't quite remember. I 0:15:36.720 --> 0:15:41.240 remember we had disk holders that would hold like maybe 0:15:41.280 --> 0:15:44.600 three of his novels, because that's how many discs would 0:15:44.600 --> 0:15:49.440 be taken up just by storing chapters onto them. I'm 0:15:49.440 --> 0:15:52.680 not sure if he actually still owns those floppy discs, 0:15:53.000 --> 0:15:54.880 but I imagine that even if he does, he doesn't 0:15:54.920 --> 0:15:56.720 have any way to check and see if the data 0:15:56.840 --> 0:15:59.560 is still there or not. He would need an Apple 0:15:59.600 --> 0:16:03.720 to E or an emulator to simulate an Apple to 0:16:03.840 --> 0:16:06.200 E on another machine. Plus he would have to have 0:16:06.240 --> 0:16:09.680 a floppy disk drive connected to whatever computer he was 0:16:09.760 --> 0:16:13.040 using in order to try and read those disks. And 0:16:13.240 --> 0:16:17.120 floppy disk drives are not completely gone. You can still 0:16:17.200 --> 0:16:22.280 find them. They are increasingly rare, however, so it's easy 0:16:22.320 --> 0:16:25.320 to imagine that a day will come when anything stored 0:16:25.360 --> 0:16:28.400 on discs like that, like my dad's books, will just 0:16:28.440 --> 0:16:31.600 become lost simply because no one makes the stuff capable 0:16:31.640 --> 0:16:34.800 of reading it anymore. And the stuff that already exists 0:16:34.840 --> 0:16:43.880 will eventually break down, and you know, the actual magnetic 0:16:43.880 --> 0:16:46.640 information on the discs will degrade over time too, just 0:16:46.680 --> 0:16:51.520 like with magnetic tape. Eventually you'll have some of those 0:16:51.600 --> 0:16:55.160 magnetic particles move out of alignment. That's going to corrupt 0:16:55.200 --> 0:16:57.880 your data. I know I keep saying data and data. 0:16:57.920 --> 0:17:00.160 I know I do that. I don't know why I 0:17:00.200 --> 0:17:02.160 do that, and I can't predict when it happens. It 0:17:02.320 --> 0:17:04.320 just does. I apologize for it, though, because I know 0:17:04.359 --> 0:17:08.119 it drives some of you crazy, and my apologies. It 0:17:08.240 --> 0:17:12.000 just happens anyway. Those particles will move out of alignment, 0:17:12.280 --> 0:17:15.720 the information gets corrupted, So yeah, switch to information there, 0:17:16.240 --> 0:17:18.359 and then you can't retrieve it anymore. So that can 0:17:18.400 --> 0:17:21.560 happen too. Even if you have a working computer system 0:17:21.960 --> 0:17:25.200 that could theoretically pull that information off the disc, sometimes 0:17:25.200 --> 0:17:28.520 the information on the disc itself will become corrupt. Now, 0:17:28.560 --> 0:17:31.199 we also have to keep in mind that media that 0:17:31.240 --> 0:17:34.000 we still use today because hardly. I mean, people do 0:17:34.040 --> 0:17:36.959 still use floppy disks depending on the situation, but it's 0:17:37.000 --> 0:17:39.560 pretty rare. But even the stuff that we do use today, 0:17:39.640 --> 0:17:43.440 eventually that's going to become obsolete too. Just a few 0:17:43.520 --> 0:17:46.959 years ago, compact discs were the go to for data storage, 0:17:47.119 --> 0:17:49.800 at least for personal computers, though a lot of enterprises 0:17:49.840 --> 0:17:52.879 would continue to rely on magnetic tape for more long 0:17:53.000 --> 0:17:57.920 term backups, and compact discs are a type of optical storage, 0:17:57.920 --> 0:18:01.879 meaning that Rather than using magnetism to align tiny particles 0:18:01.960 --> 0:18:07.639 on a physical surface, we're using lasers to write and 0:18:07.720 --> 0:18:12.159 to read from these discs. The information is stored in 0:18:12.240 --> 0:18:17.120 water called pits and lands, pits being a designated pit 0:18:17.400 --> 0:18:20.280 in the surface, and lands being the spaces between pits. 0:18:21.040 --> 0:18:24.359 Though rewriteable CDs actually kind of use foggy and clear 0:18:25.680 --> 0:18:28.439 sections that are very very tiny, you wouldn't be able 0:18:28.480 --> 0:18:31.400 to see them with the naked eye. Now, compact discs 0:18:32.000 --> 0:18:34.520 allow us to create a more dense storage system, so 0:18:34.560 --> 0:18:37.800 we could put way more information on a single CD 0:18:38.840 --> 0:18:42.159 than we could with stuff like floppy discs. Now, Unlike 0:18:42.200 --> 0:18:46.400 cassettes and floppy disks, optical discs are not affected by magnetism. 0:18:46.600 --> 0:18:49.520 So if you did bring a powerful magnet close to 0:18:49.560 --> 0:18:51.760 a bunch of floppy disks or cassette tapes or anything 0:18:51.760 --> 0:18:55.840 that uses magnetic storage, you would scramble the information on 0:18:55.960 --> 0:18:59.600 there because the powerful magnet would realign the magnetic particles 0:18:59.680 --> 0:19:03.000 that are on the tape. But optical discs don't have 0:19:03.119 --> 0:19:06.440 magnetic particles, so they would be immune to that kind 0:19:06.480 --> 0:19:11.080 of interference. However, this does not mean that optical discs 0:19:11.160 --> 0:19:17.399 last forever, so there are many layers on a compact disc. 0:19:17.720 --> 0:19:19.760 Same thing with DVDs and blue rays. By the way, 0:19:20.280 --> 0:19:24.560 there are several layers involved, and these layers can have 0:19:24.640 --> 0:19:28.720 chemical reactions in them, and those chemical reactions can cause 0:19:28.760 --> 0:19:32.879 those layers to degrade over time. So like a CD 0:19:33.000 --> 0:19:35.679 that's stored in a very humid and warm place, like 0:19:36.119 --> 0:19:40.240 if people had stored their CDs, their music CDs inside 0:19:40.280 --> 0:19:43.119 their car and the summer in Georgia, they might find 0:19:43.119 --> 0:19:45.520 that those CDs don't last that long, like they might 0:19:45.640 --> 0:19:50.720 last a few seasons, but eventually they degrade, and they will. 0:19:50.840 --> 0:19:52.920 You know, if you're in a hot and humid environment, 0:19:53.000 --> 0:19:57.840 then a disc is going to degrade faster, not like instantaneously, 0:19:58.119 --> 0:20:01.000 but it will start to degrade faster than it would 0:20:01.040 --> 0:20:05.520 if you stored it in a cooler, dry place. And 0:20:06.240 --> 0:20:09.919 that outer layer on a CD, that's the clear layer, right, 0:20:09.960 --> 0:20:12.920 It's protective and it's clear so that a laser can 0:20:12.960 --> 0:20:16.160 go through it. But sometimes that clear layer can start 0:20:16.160 --> 0:20:18.879 to rot away and it can leave the reflective layer 0:20:18.920 --> 0:20:23.639 that's underneath it exposed. And with some CDs, that reflective 0:20:23.680 --> 0:20:29.280 layer is made up of silver or sometimes a silver compound, 0:20:29.320 --> 0:20:33.960 and silver when exposed to air will tarnish. The tarnished 0:20:34.000 --> 0:20:37.000 silver won't reflect a laser properly, and so you start 0:20:37.040 --> 0:20:39.800 to get errors when you're trying to read information off 0:20:39.840 --> 0:20:43.120 of that kind of CD. Now, not all CDs were 0:20:43.160 --> 0:20:46.600 made that way, right, so only some CDs have this 0:20:46.640 --> 0:20:50.760 particular bronzing issue. In fact, our research group determined that 0:20:50.880 --> 0:20:54.840 the CDs that really have this specific problem we're all 0:20:54.880 --> 0:20:59.000 pressed in Blackburn, Lancashire, England, between the years nineteen eighty 0:20:59.040 --> 0:21:04.800 eight and nineteen nine. That's pretty darn specific. Now. The 0:21:05.440 --> 0:21:08.240 issue here, though, is that there's really no way to 0:21:08.280 --> 0:21:12.040 give an average lifespan for a compact disc because there's 0:21:12.040 --> 0:21:14.960 no such thing as an average compact discs there were 0:21:15.000 --> 0:21:18.639 there were so many different manufacturing and pressing processes and 0:21:18.720 --> 0:21:25.560 recording processes that different ones could last a different you know, 0:21:26.320 --> 0:21:29.639 theoretical maximum amount of time. So we can't really answer 0:21:29.720 --> 0:21:33.040 the question how long on average will as CD last. 0:21:33.680 --> 0:21:36.639 I've seen a lot of people suggest five to ten years, 0:21:36.640 --> 0:21:38.800 some people saying ten to twenty, some people going as 0:21:38.800 --> 0:21:41.679 far as fifty. I think it really depends on the 0:21:41.720 --> 0:21:46.240 way the CD was made and what storage facility it's in, Like, 0:21:46.480 --> 0:21:49.439 is it in a house where it's kept out of 0:21:49.600 --> 0:21:54.520 sunlight because UV radiation can affect CDs. Is it kept 0:21:54.640 --> 0:21:57.200 cool and dry, then it's gonna last longer. Is it 0:21:57.240 --> 0:22:00.760 not handled a lot? Like if it's it's your favorite 0:22:01.200 --> 0:22:04.720 music CD, and you handle it a lot, then it's 0:22:04.760 --> 0:22:08.360 going to degrade faster. Again, not instantaneously, and it may 0:22:08.400 --> 0:22:11.560 not even be noticeable at first, but eventually you might 0:22:11.560 --> 0:22:14.280 get the things where it starts to skip on a 0:22:14.280 --> 0:22:17.960 certain track, or it won't even play certain tracks. That 0:22:18.040 --> 0:22:21.399 will happen over time. And it's a similar story for 0:22:21.440 --> 0:22:24.440 other optical formats, which include you know, DVDs and Blu 0:22:24.560 --> 0:22:28.240 ray discs. These two have a limited lifespan, though that 0:22:28.280 --> 0:22:31.639 lifespan may stretch to as long as a century under 0:22:31.680 --> 0:22:34.879 ideal conditions. And a century is a long time for 0:22:34.920 --> 0:22:37.960 a single person, right, I mean, that's that's a significant 0:22:37.960 --> 0:22:42.679 amount of time. However, if we step outside of a 0:22:42.760 --> 0:22:46.280 human's lifespan and we look at it from the perspective 0:22:46.520 --> 0:22:51.320 of a historical account, then one hundred years is not 0:22:51.440 --> 0:22:54.600 long at all. I mean, imagine for a moment, if 0:22:54.720 --> 0:22:58.800 you had no access to any information that was recorded 0:22:58.880 --> 0:23:02.719 before nineteen twenty ten, because all the media that we 0:23:02.760 --> 0:23:06.399 had used to record info on had fallen apart or 0:23:06.560 --> 0:23:11.960 was otherwise unusable or inaccessible. That nothing before nineteen twenty 0:23:12.040 --> 0:23:16.159 two would be knowable apart from what people wrote about 0:23:16.200 --> 0:23:21.000 those times post nineteen twenty two. That would be crazy, right, 0:23:21.880 --> 0:23:25.240 But that's the kind of situation we're in when we 0:23:25.280 --> 0:23:29.320 start looking at digital information. All right, Well, what about 0:23:29.480 --> 0:23:31.960 we look at like hard drives, hard disk drives and 0:23:32.040 --> 0:23:34.680 solid state drives, you know, the stuff that's in your 0:23:34.680 --> 0:23:38.080 computer systems, your smartphones, that kind of thing. What do 0:23:38.320 --> 0:23:43.760 they have? You know, how long will information last in those? Well, 0:23:43.920 --> 0:23:47.520 they stored information in different ways. Hard disk drives have 0:23:47.760 --> 0:23:52.160 one or more platters in them, and each platter has 0:23:52.200 --> 0:23:56.199 a magnetic coding on it upon which information can be stored. So, 0:23:56.680 --> 0:24:01.000 just like cassettes and floppy disks and other magnetic storage methods, 0:24:01.160 --> 0:24:04.120 hard disk drives can be affected by powerful magnetic fields 0:24:04.160 --> 0:24:10.719 because they too, store information magnetically. Hardness drives have moving parts, 0:24:11.240 --> 0:24:16.440 so the platters spin quite quickly in fact, and an 0:24:16.480 --> 0:24:20.159 actuator mechanical arm with a read write quote unquote head 0:24:20.280 --> 0:24:23.919 on it. This is the bit that either can read 0:24:24.280 --> 0:24:27.600 the magnetic particles that are stored on a platter, or 0:24:27.840 --> 0:24:33.119 it can actually exert a magnetic field that aligns the particles. 0:24:33.280 --> 0:24:36.959 When you're writing information on the platter, it moves across 0:24:37.000 --> 0:24:40.240 the platter and it starts to retrieve or write information 0:24:40.320 --> 0:24:43.919 to the disc itself. And because we're talking about moving 0:24:44.000 --> 0:24:48.760 parts here, stuff can and does wear down over time 0:24:48.880 --> 0:24:51.480 and use. If it gets a lot of use, it 0:24:51.520 --> 0:24:54.840 wears out more quickly. Also, it means that you should 0:24:54.840 --> 0:24:57.240 be gentle when you're moving anything that happens to have 0:24:57.280 --> 0:24:59.600 a hard disk drive inside of it, because a good 0:24:59.600 --> 0:25:03.040 whack can damage the delicate parts. If you knock that 0:25:03.160 --> 0:25:06.600 actuator arm out of alignment, that's a big problem. It's 0:25:07.040 --> 0:25:12.080 going to be impossible to read or write stuff reliably 0:25:12.280 --> 0:25:16.480 to that hard disk drive. Now, hard drives don't tend 0:25:16.520 --> 0:25:19.720 to last very long because of those mechanical parts. I've 0:25:19.720 --> 0:25:23.000 seen estimates of the life span for hard disk drives 0:25:23.080 --> 0:25:27.359 lasting somewhere between three to maybe six and a half years, 0:25:27.400 --> 0:25:30.840 seven years. Some give it a little bit longer, some 0:25:30.920 --> 0:25:33.280 a little bit shorter. Of course, a hard disk drive 0:25:33.320 --> 0:25:37.760 can last longer than a decade. But that's you know, 0:25:38.560 --> 0:25:41.280 if we're looking at typical use and we're looking at 0:25:41.320 --> 0:25:44.080 the average life span of hard disk drives, we tend 0:25:44.160 --> 0:25:47.359 to fall in that three to seven year range, So 0:25:47.640 --> 0:25:50.639