WEBVTT - Data Preservation and Destruction 0:00:04.400 --> 0:00:07.800 Welcome to tech Stuff, a production from I Heart Radio. 0:00:12.039 --> 0:00:14.680 Hey there, and welcome to tech Stuff. I'm your host, 0:00:14.760 --> 0:00:18.159 Jonathan Strickland, Diamond executive producer with I Heart Radio and 0:00:18.200 --> 0:00:20.960 how the tech are yet. You know, I thought it 0:00:21.040 --> 0:00:24.320 might be interesting to talk about how data can both 0:00:24.400 --> 0:00:29.560 be easy to lose and hard to lose. It's a paradox, 0:00:29.920 --> 0:00:33.240 but really this is all about the media upon which 0:00:33.720 --> 0:00:40.000 we store data and how that media can pose various challenges. Now, 0:00:40.080 --> 0:00:44.760 first up, let's just talk about the concept of obsolescence. 0:00:45.400 --> 0:00:49.519 So as our technology, our language, our culture, as all 0:00:49.560 --> 0:00:53.080 these things evolve and we discover new ways to commit 0:00:53.400 --> 0:00:58.000 information to different types of media, we often leave the 0:00:58.080 --> 0:01:02.640 older methods behind. For example, very few people are recording 0:01:02.640 --> 0:01:06.600 audio to wax cylinders today. For example, you know, Thomas 0:01:06.720 --> 0:01:09.240 Edison did it, but you don't see people doing it now, 0:01:09.319 --> 0:01:12.319 at least not outside of you know, historical demonstrations and 0:01:12.360 --> 0:01:16.440 that sort of thing. The days of storing info magnetically 0:01:16.520 --> 0:01:20.039 onto strips of metal, like we saw at the end 0:01:20.080 --> 0:01:22.640 of the nineteenth century, that's pretty far behind us too, 0:01:22.640 --> 0:01:25.840 although magnetic tape is built on the same principle. But 0:01:25.959 --> 0:01:31.120 before we use tape, we used wire um, not that frequently, 0:01:31.160 --> 0:01:32.480 but it was one of those things that kind of 0:01:32.520 --> 0:01:37.360 paved the way toward magnetic tape. Now, over time, all 0:01:37.440 --> 0:01:41.280 media will ultimately go obsolete, either because the stuff we 0:01:41.360 --> 0:01:46.560 recorded upon has worn out, the actual physical stuff has broken, 0:01:47.240 --> 0:01:51.120 or because we've lost the ability to retrieve information from 0:01:51.160 --> 0:01:54.880 that type of media. And that inability to retrieve can 0:01:55.000 --> 0:01:58.840 range from the technical to just our knowledge of how 0:01:58.840 --> 0:02:00.800 to do it. So let's take a moment to consider 0:02:01.600 --> 0:02:05.639 something that is pretty far removed from modern technology unless 0:02:05.680 --> 0:02:11.280 you watch stargate, and that is hieroglyphs. So thousands of 0:02:11.400 --> 0:02:15.320 years ago, the people of ancient Egypt developed a writing 0:02:15.360 --> 0:02:19.520 system that was complicated, to say the least. So our 0:02:19.639 --> 0:02:22.760 Latin alphabet, the one that we use in in English, 0:02:22.800 --> 0:02:26.079 for example, has twenty six characters, right, twenty six letters 0:02:26.120 --> 0:02:32.720 in the alphabet, and hieroglyphs had hundreds of characters, like 0:02:33.040 --> 0:02:37.040 a thousand or more. Now, some of the characters in 0:02:37.200 --> 0:02:44.200 ancient Egypt represented basic phonemes. Phonemes are sounds within a language, right, 0:02:44.280 --> 0:02:49.360 like would be a phoneme or like these are basic sounds. 0:02:50.160 --> 0:02:55.080 But other characters in ancient Egyptian hieroglyphs they represented entire words, 0:02:55.200 --> 0:03:00.440 or at least parts of words. Uh. Some represented still bles, 0:03:01.000 --> 0:03:05.399 so not necessarily parts of words like you would think, 0:03:05.400 --> 0:03:09.040 but a syllable that was common in ancient Egypt. But 0:03:09.120 --> 0:03:13.519 over the millennia, the knowledge of how to read hieroglyphs 0:03:13.600 --> 0:03:17.200 faded from Egyptian culture. There were a lot of reasons 0:03:17.240 --> 0:03:21.320 for this, I mean, the the style of writing down 0:03:21.360 --> 0:03:26.840 information changed from hieroglyphs to like demonic writing, and beyond also, 0:03:26.880 --> 0:03:30.600 you had folks like you know, Europeans, like Greeks and 0:03:30.720 --> 0:03:34.480 Romans who were invading Egypt and changing things and disrupting 0:03:34.720 --> 0:03:38.400 Egyptian culture significantly. By the time we got a few 0:03:38.440 --> 0:03:42.160 centuries into the common era, pretty much no one knew 0:03:42.160 --> 0:03:46.360 how to read the hieroglyphs of ancient Egypt anymore. So 0:03:46.400 --> 0:03:50.480 we had all this knowledge stored in various places and 0:03:50.720 --> 0:03:54.000 no way to retrieve that knowledge. It appeared as though 0:03:54.040 --> 0:03:56.240 we had lost all of it, or that we had, 0:03:56.840 --> 0:04:02.240 due to some misconceptions, completely miss interpreted that knowledge. So 0:04:02.320 --> 0:04:05.119 by the time we got into the medieval era, there 0:04:05.160 --> 0:04:11.000 was this prevailing hypothesis that the Egyptian hieroglyphs were symbolic 0:04:11.560 --> 0:04:14.200 in meaning and by that I mean that the images 0:04:14.240 --> 0:04:16.800 that the Egyptians used were thought of to be direct 0:04:16.880 --> 0:04:20.400 symbols of whatever the message was. So let's say you 0:04:20.520 --> 0:04:24.279 had images of a boat and a snake, then you 0:04:24.360 --> 0:04:26.120 might be led to think that what you're looking at 0:04:26.480 --> 0:04:30.200 must be an allegorical story about snakes on a boat, 0:04:30.440 --> 0:04:36.559 possibly starring Samuel L. Jackson. But no, the symbols used 0:04:36.560 --> 0:04:40.400 weren't meant to represent exactly what they looked like. They 0:04:40.480 --> 0:04:44.159 represented elements of a language. So for example, if you 0:04:44.200 --> 0:04:48.320 want to understand what I'm saying, our letter S looks 0:04:48.440 --> 0:04:51.400 kind of like a snake, right, but it doesn't mean snake. 0:04:51.480 --> 0:04:55.240 When you see the letter S, that doesn't mean snake. Uh. 0:04:55.320 --> 0:04:58.200 It could be the beginning of the word snake. Obviously 0:04:58.240 --> 0:05:00.640 that begins with S, but it could mean anything. It 0:05:00.680 --> 0:05:04.560 represents the S sound, which is found in lots of words, 0:05:04.560 --> 0:05:07.880 not just snake. And the hieroglyphs were similar, but no 0:05:07.920 --> 0:05:11.200 one had a document that matched hieroglyphs to some other 0:05:11.480 --> 0:05:15.920 known language so that someone could actually decipher the symbols. 0:05:16.000 --> 0:05:19.560 So it just seemed to be, you know, all these 0:05:19.839 --> 0:05:23.800 icons that the meaning had been completely lost. But then 0:05:23.920 --> 0:05:28.880 came Napoleon Bonaparte and his armies invaded Egypt toward the 0:05:29.000 --> 0:05:32.200 end of the eighteenth century, and in the process the 0:05:32.400 --> 0:05:36.880 armies happened across something incredibly important, and it would later 0:05:36.920 --> 0:05:40.760 be called the Rosetta Stone. Now, the Rosetta Stone itself 0:05:41.320 --> 0:05:45.120 is a type of monument, and there are carvings on 0:05:45.200 --> 0:05:50.480 the monument that represent an official dynastic decree. The carvings 0:05:50.520 --> 0:05:54.360 are in three different written languages. So at the base 0:05:54.560 --> 0:05:57.599 of the monument you have the carving in ancient Greek, 0:05:58.320 --> 0:06:01.800 above that is Demotic, that is an Egyptian language that 0:06:01.880 --> 0:06:05.800 followed the hieroglyphic language, and at the top are hieroglyphs. 0:06:05.839 --> 0:06:09.640 And since all three carvings represented the same decree, this 0:06:09.720 --> 0:06:14.960 gave experts the opportunity to finally begin deciphering Egyptian hieroglyphs, 0:06:15.000 --> 0:06:20.320 and so began the long process of uncovering lost knowledge. 0:06:20.640 --> 0:06:24.400 And this was helped by subsequent discoveries of similar decrees, 0:06:25.120 --> 0:06:29.960 so that we over time we're able to understand what 0:06:30.240 --> 0:06:33.360 these these hieroglyphs actually stood for. We understood that it 0:06:33.480 --> 0:06:38.360 was a written language that wasn't just purely symbolic. Now, 0:06:38.480 --> 0:06:40.920 my point in telling the story is that we have 0:06:40.960 --> 0:06:44.440 to remind ourselves that while we have ways to record knowledge, 0:06:45.200 --> 0:06:47.719 it would be foolish for us to assume that any 0:06:47.760 --> 0:06:51.960 way that we use is permanent, because we've got plenty 0:06:51.960 --> 0:06:55.080 of examples of knowledge being lost in the past, whether 0:06:55.120 --> 0:06:59.240 it's because people forgot how to access that knowledge, or 0:06:59.800 --> 0:07:03.159 maybe the knowledge was based in folklore and the people 0:07:03.720 --> 0:07:07.159 that were the stewards of that knowledge were wiped out 0:07:07.240 --> 0:07:11.600 or assimilated and the knowledge was lost, or maybe the 0:07:11.640 --> 0:07:14.600 physical copies, if it was like a written language, maybe 0:07:14.600 --> 0:07:17.560 the physical copies were lost. And shout out to the 0:07:17.680 --> 0:07:21.640 late Great Library of Alexandria, which I should add kind 0:07:21.640 --> 0:07:24.080 of faded away, not just because of the famous fire 0:07:24.080 --> 0:07:28.600 set by Julius Caesar's forces, though that clearly was a 0:07:28.680 --> 0:07:32.240 catastrophic event, but also there was a long period in 0:07:32.280 --> 0:07:36.640 which leaders were cracking down on scholars because well, a 0:07:36.640 --> 0:07:38.800 little knowledge is a dangerous thing, so a lot of 0:07:38.800 --> 0:07:42.280 knowledge has got to be absolutely deadly right. But anyway, 0:07:42.760 --> 0:07:46.120 let's skip ahead to the modern era. So even today 0:07:46.400 --> 0:07:50.280 we run the risk of losing access to information because 0:07:50.320 --> 0:07:53.800 we no longer make the stuff, what plays the media 0:07:54.000 --> 0:07:56.160 that we used in the old days, or at least 0:07:56.200 --> 0:07:58.800 in many cases, it is getting really tricky to track 0:07:58.880 --> 0:08:02.920 down the components that can retrieve data from those types 0:08:02.960 --> 0:08:05.680 of media. Right, you might be able to find old 0:08:05.760 --> 0:08:10.600 working equipment that can access certain types of stuff that 0:08:10.640 --> 0:08:14.560 otherwise we no longer can access, but it's it's rare 0:08:14.600 --> 0:08:17.440 that you're gonna find someone make a new version of that. 0:08:17.800 --> 0:08:20.920 It's not impossible. It's not like we've lost all ability 0:08:21.000 --> 0:08:25.880 to It's just that unless there is a pressing financial 0:08:26.760 --> 0:08:30.160 benefit to creating that kind of stuff, no one's gonna 0:08:30.160 --> 0:08:33.280 bother to do it. Because you know, it's expensive to 0:08:33.400 --> 0:08:39.559 produce older types of of technologies, and unless there's a 0:08:39.600 --> 0:08:43.200 financial incentive, no one's gonna do it. Um, it's sad 0:08:43.280 --> 0:08:46.240 to say so. There's also the danger that the media 0:08:46.320 --> 0:08:51.000 we rely upon could wear out and deteriorate over time. So, 0:08:51.120 --> 0:08:56.719 for example, let's consider celluloid or film. Cinematic film degrades 0:08:56.960 --> 0:09:01.720 over time, particularly if it's in a hot and moist environment. 0:09:02.160 --> 0:09:06.080 And you might have heard about some filmmakers storing prints 0:09:06.120 --> 0:09:09.360 of their movies or masters of their movies in old 0:09:09.400 --> 0:09:13.120 salt mines such as the one that's below Hutchinson, Kansas 0:09:13.160 --> 0:09:18.000 in the United States. These subterranean spaces maintain a constant 0:09:18.040 --> 0:09:22.600 temperature of around sixty eight fahrenheit or twenty celsius, and 0:09:22.679 --> 0:09:27.800 they have a low humidity somewhere between like forty humidity. 0:09:27.840 --> 0:09:29.760 Of course, movies are not the only thing stored in 0:09:29.800 --> 0:09:33.520 those minds that in fact, we got the idea because 0:09:33.520 --> 0:09:36.600 of the story of the monument men who ended up 0:09:36.640 --> 0:09:42.840 finding lots of stolen art from various parts of Europe 0:09:42.840 --> 0:09:45.679 that the Nazis had collected and stored in salt mines. 0:09:45.760 --> 0:09:48.839 We ended up kind of using the same idea. So, 0:09:49.000 --> 0:09:52.079 because it's a great way to preserve stuff, if you 0:09:53.080 --> 0:09:56.800 otherwise it's in danger of deterioration. Also, we have to 0:09:57.000 --> 0:09:59.079 acknowledge that while it's a great way to preserve stuff, 0:09:59.120 --> 0:10:02.120 there's a tragedy year because we're also removing it right 0:10:02.280 --> 0:10:06.600 from us. You know, we're storing it and we're preserving it, 0:10:06.640 --> 0:10:11.160 but to what end if you can't access it, then 0:10:11.280 --> 0:10:14.160 it doesn't really like there's a lot of questions. There 0:10:14.160 --> 0:10:17.640 are philosophical questions. If you have a priceless work of 0:10:17.760 --> 0:10:20.400 art stored an assault mine and no one can go there, 0:10:21.000 --> 0:10:23.280 is it the same as not having it at all? 0:10:24.080 --> 0:10:26.280 Now in the case of film. A lot of studios 0:10:26.280 --> 0:10:29.680 will actually use those master recordings when they want to 0:10:29.720 --> 0:10:32.560 do a remastered version of the film they want to 0:10:32.559 --> 0:10:35.800 release it on, say like Blu ray or something, they'll 0:10:35.800 --> 0:10:38.959 go to the the original print that's stored in a 0:10:39.080 --> 0:10:41.960 salt mine and they'll pull from that. But yeah, there's 0:10:42.000 --> 0:10:44.959 lots of other stuff besides just film down there, anything 0:10:45.000 --> 0:10:47.319 that needs a controlled environment in order to stop or 0:10:47.360 --> 0:10:52.719 at least slow deterioration. Now, magnetic tape is another important 0:10:52.840 --> 0:10:56.520 storage method, and we've been using magnetic tape as storage 0:10:56.600 --> 0:11:00.400 since the mid twenty century, around nine or so, and 0:11:00.440 --> 0:11:03.240 again the basic principle behind it dates back to the 0:11:03.320 --> 0:11:08.360 late nineteenth century. That was when we were using magnetic wire. 0:11:09.360 --> 0:11:13.040 But whether it's real to real tape, or cassettes or 0:11:13.280 --> 0:11:17.040 VHS tapes, we've relied on this methodology to store all 0:11:17.080 --> 0:11:22.160 sorts of information, from you know, computer information to music 0:11:22.200 --> 0:11:24.439 in the case of like the cassette tapes of the 0:11:24.520 --> 0:11:30.040 eighties nineties or the VHS video tapes, all sorts of 0:11:30.040 --> 0:11:34.040 info we have committed to magnetic tape, and a lot 0:11:34.080 --> 0:11:36.680 of companies still rely on magnetic tape for long term 0:11:36.720 --> 0:11:40.720 storage and backups. When I use long term storage. I'm 0:11:40.760 --> 0:11:44.800 speaking relatively, as we will see now, some older forms 0:11:44.800 --> 0:11:48.760 of magnetic tape are largely obsolete because the devices we'd 0:11:48.840 --> 0:11:52.719 use to read the data from them are out of production. 0:11:53.200 --> 0:11:56.000 You might find a working device here or there, but 0:11:56.200 --> 0:11:59.160 they can be pretty rare, and being mechanical in nature, 0:11:59.679 --> 0:12:03.800 they will eventually require maintenance or they'll stop working. And 0:12:03.880 --> 0:12:06.199 when you're talking about this kind of stuff, often you're 0:12:06.240 --> 0:12:09.960 talking about things that have parts that no one's making anymore. 0:12:10.120 --> 0:12:12.640 So it becomes very challenging to keep them in good 0:12:12.679 --> 0:12:16.200 working order because there's a limited supply of components you 0:12:16.200 --> 0:12:19.760 can use to make replacements when something breaks down. On 0:12:19.840 --> 0:12:23.520 top of all that, magnetic information itself can degrade over time, 0:12:24.360 --> 0:12:27.040 actually can degrade really quickly if it's in the presence 0:12:27.040 --> 0:12:29.640 of a strong magnetic field, which is why as a 0:12:29.720 --> 0:12:31.720 kid I was told never to bring a magnet close 0:12:31.720 --> 0:12:35.400 to a computer or computer disks because you could actually 0:12:35.920 --> 0:12:41.280 uh corrupt information that's stored on those those devices, because 0:12:41.400 --> 0:12:45.240 the magnet would realign the magnetic components that were on 0:12:45.360 --> 0:12:48.160 this plastic film or in the case of a computer, 0:12:48.840 --> 0:12:53.559 uh arraid on a platter inside the hard disk drive. Now, 0:12:53.600 --> 0:12:59.720 on average if stored in decent conditions, magnetic tape typically 0:12:59.720 --> 0:13:02.960 will retained data from anywhere between ten to twenty years. 0:13:03.600 --> 0:13:07.080 When stored in prime conditions like in that salt mine, 0:13:07.120 --> 0:13:10.520 for example, you might stretch it to around thirty years. 0:13:10.840 --> 0:13:13.360 So magnetic tape can hold onto data for a while, 0:13:14.000 --> 0:13:19.760 but certainly not indefinitely. It will sooner or later degrade 0:13:19.800 --> 0:13:23.040 to a point where the the information will be corrupted 0:13:23.480 --> 0:13:28.480 or irretrievable. Now, on a similar note, let's talk floppy disks. 0:13:28.760 --> 0:13:30.559 So when I was a kid, our Apple to E 0:13:30.800 --> 0:13:34.360 computer had a five and a quarter inch floppy disk drive. 0:13:35.200 --> 0:13:37.520 These were not the first floppy discs. There were older ones. 0:13:37.559 --> 0:13:40.640 There were larger ones. IBM created eight inch floppy disks 0:13:40.679 --> 0:13:45.080 for example, And the disks that I was familiar with 0:13:45.240 --> 0:13:47.520 back when I was using the Apple to E were 0:13:47.559 --> 0:13:51.760 these plastic envelopes, and the envelopes were covering a disc 0:13:51.880 --> 0:13:56.559 of magnetic film on the inside, and it was on 0:13:56.640 --> 0:14:00.839 this magnetic disc that you could save and retreat data. 0:14:01.240 --> 0:14:02.839 And I actually had to look this up because I 0:14:02.880 --> 0:14:05.400 could not remember it myself, but the original five and 0:14:05.480 --> 0:14:08.439 a quarter inch floppy disks could hold up to nine 0:14:09.040 --> 0:14:12.040 bytes of data. That's when they were first created, so 0:14:12.120 --> 0:14:18.160 that's just ninety kilobytes. But over time, you know, engineers 0:14:18.240 --> 0:14:23.280 improved the technology. They increased the capacity of floppy disks. Typically, 0:14:23.360 --> 0:14:26.240 they did this by creating more precise read write heads 0:14:26.360 --> 0:14:31.600 so they could store data in smaller physical sizes, which 0:14:31.680 --> 0:14:34.120 meant you could cram more of it onto the same 0:14:34.200 --> 0:14:37.640 sized disc. They also figured out how to multilayer discs, 0:14:37.760 --> 0:14:42.440 so that increased storage as well. I think, you know, 0:14:42.840 --> 0:14:47.760 some disks maxed out at around so significantly more than 0:14:47.880 --> 0:14:50.240 ninety but still weigh less than what we use today. 0:14:51.720 --> 0:14:54.760 Now I'm gonna talk more about floppy disks and other 0:14:54.840 --> 0:15:00.280 forms of storage and why all these different types kind 0:15:00.280 --> 0:15:03.320 of a limited shelf life of one span or another. 0:15:03.480 --> 0:15:14.160 But before we get to that, let's take a quick break. Okay, 0:15:14.560 --> 0:15:17.320 we're back, and we were talking about floppy discs. Well, 0:15:17.560 --> 0:15:21.320 my parents write novels, and so my dad's first books, 0:15:21.840 --> 0:15:23.880 which were written in the early eighties, they were written 0:15:23.960 --> 0:15:26.920 on that old Apple to E computer, and he would 0:15:27.000 --> 0:15:30.960 save chapters of his books too floppy disks. Each novel 0:15:31.040 --> 0:15:33.840 would take up several discs, like I don't know, around 0:15:34.200 --> 0:15:36.920 a dozen or so. I can't quite remember I remember 0:15:36.960 --> 0:15:41.400 we had disc holders that would hold like maybe three 0:15:41.520 --> 0:15:44.560 of his novels, because that's how many discs would be 0:15:45.400 --> 0:15:48.320 taken up just by you know, storing chapters onto them. 0:15:49.160 --> 0:15:52.560 I'm not sure if he actually still owns those floppy discs, 0:15:52.920 --> 0:15:54.800 but I imagine that even if he does, he doesn't 0:15:54.840 --> 0:15:56.640 have any way to check and see if the data 0:15:56.760 --> 0:15:59.520 is still there or not. He would need an Apple 0:15:59.560 --> 0:16:03.640 to E or an emulator to simulate an Apple to 0:16:03.760 --> 0:16:06.040 E on another machine. Plus he would have to have 0:16:06.160 --> 0:16:09.560 a floppy disk drive connected to whatever computer he was 0:16:09.680 --> 0:16:12.880 using in order to try and read those disks. And 0:16:13.120 --> 0:16:16.680 floppy disk drives are not completely gone. They you can 0:16:16.760 --> 0:16:21.880 still find them. They are increasingly rare, however, so it's 0:16:21.880 --> 0:16:24.840 easy to imagine that a day will come when anything 0:16:24.920 --> 0:16:28.120 stored on disks like that, like my dad's books, will 0:16:28.200 --> 0:16:31.040 just become lost simply because no one makes the stuff 0:16:31.080 --> 0:16:34.200 capable of reading it anymore. And the stuff that already 0:16:34.240 --> 0:16:39.960 exists will eventually break down. Um and you know, the 0:16:40.920 --> 0:16:45.680 the actual magnetic information on the discs will degrade over 0:16:45.760 --> 0:16:50.400 time to just like with magnetic tape. The eventually you'll 0:16:50.480 --> 0:16:53.720 you'll have some of those magnetic particles move out of alignment. 0:16:54.320 --> 0:16:56.840 That's going to corrupt your data. I know, I keep 0:16:56.840 --> 0:16:58.960 saying data and data. I know I do that. I 0:16:59.160 --> 0:17:01.440 don't know why do that, and I can't predict when 0:17:01.480 --> 0:17:03.760 it happens. It just does. I apologize for it though, 0:17:03.800 --> 0:17:06.280 because I know it drives some of you crazy, and 0:17:06.600 --> 0:17:11.239 my apologies. It just happens anyway, Those particles will move 0:17:11.280 --> 0:17:14.879 out of alignment, the information gets corrupted. So yeah, switch 0:17:14.920 --> 0:17:17.640 to information there, and then you can't retrieve it anymore. 0:17:17.840 --> 0:17:19.680 So that can happen to even if you have a 0:17:19.800 --> 0:17:23.919 working computer system that could theoretically pull that information off 0:17:23.960 --> 0:17:26.640 the disk. Sometimes the information on the disc itself will 0:17:26.680 --> 0:17:29.520 become corrupt. Now, we also have to keep in mind 0:17:30.320 --> 0:17:33.280 that media that we still use today because hardly. I mean, 0:17:33.400 --> 0:17:36.400 people do still use floppy disks depending on the situation, 0:17:36.600 --> 0:17:38.720 but it's pretty rare. But even the stuff that we 0:17:38.800 --> 0:17:42.960 do use today, eventually that's gonna become obsolete too. Just 0:17:43.119 --> 0:17:45.600 a few years ago, compact discs were the go to 0:17:45.800 --> 0:17:48.840 for data storage, at least for personal computers, though a 0:17:48.920 --> 0:17:51.840 lot of enterprises would continue to rely on magnetic tape 0:17:51.880 --> 0:17:56.000 for more long term backups, and compact discs are a 0:17:56.119 --> 0:17:59.880 type of optical storage, meaning that rather than using magnetism 0:18:00.240 --> 0:18:06.040 to align tiny particles on a physical surface, we're using 0:18:06.280 --> 0:18:10.119 lasers to write and to read from these disks. UH, 0:18:10.560 --> 0:18:13.679 the information is stored in water called pits and lands, 0:18:14.080 --> 0:18:18.960 pits being designated pit in the surface, and lands being 0:18:19.000 --> 0:18:22.560 the spaces between PITSU. The rewriteable CD is actually kind 0:18:22.560 --> 0:18:27.199 of use foggy and clear UH sections that are very 0:18:27.320 --> 0:18:28.840 very tiny. You wouldn't be able to see them with 0:18:28.840 --> 0:18:32.680 the naked eye. Now, compact discs allow us to create 0:18:32.720 --> 0:18:35.360 a more dense storage system, so we could put way 0:18:35.520 --> 0:18:39.480 more information on a single CD than we could with 0:18:39.560 --> 0:18:43.560 stuff like floppy disks. Now, unlike cassettes and floppy disks, 0:18:43.640 --> 0:18:47.119 optical discs are not affected by magnetism. So if you 0:18:47.240 --> 0:18:49.800 did bring a powerful magnet close to a bunch of 0:18:49.840 --> 0:18:53.120 floppy disks or cassette tapes or anything that uses magnetic storage, 0:18:53.920 --> 0:18:57.119 you would scramble the information on there because the powerful 0:18:57.160 --> 0:19:00.760 magnet would realign the magnetic particles that are on the tape. 0:19:01.320 --> 0:19:04.879 But optical discs don't have magnetic particles, so they would 0:19:05.000 --> 0:19:09.560 be immune to that kind of interference. However, this does 0:19:09.600 --> 0:19:14.840 not mean that optical discs last forever, so the there 0:19:14.920 --> 0:19:18.119 are many layers on a compact disc. Same thing with 0:19:18.240 --> 0:19:20.960 DVDs and blue race, by the way, there are several 0:19:21.080 --> 0:19:26.400 layers involved, and these layers can have chemical reactions in them, 0:19:26.920 --> 0:19:29.800 and those chemical reactions can cause those layers to degrade 0:19:29.880 --> 0:19:33.680 over time. So like a CD that's stored in a 0:19:33.840 --> 0:19:37.639 very humid and warm place, like if people had stored 0:19:37.760 --> 0:19:40.879 their CDs, their music CDs inside their car in the 0:19:40.960 --> 0:19:43.960 summer and Georgia, they might find that those CDs don't 0:19:44.040 --> 0:19:46.560 last that long, like they might last a few seasons, 0:19:46.640 --> 0:19:51.320 but eventually they degrade and they you know, if you're 0:19:51.359 --> 0:19:54.080 in a hot and humid environment, then disc is going 0:19:54.119 --> 0:19:58.960 to degrade faster, not like instantaneously, but it will start 0:19:59.040 --> 0:20:01.639 to degrade faster than it would if you stored it 0:20:01.760 --> 0:20:07.600 in a cooler, dry place. And that outer layer on 0:20:07.720 --> 0:20:11.159 a CD, that's the clear layer, right, it's protective and 0:20:11.280 --> 0:20:13.399 it's clear so that a laser can go through it. 0:20:14.160 --> 0:20:16.760 But sometimes that clear layer can start to rot away 0:20:17.080 --> 0:20:21.120 and it can leave the reflective layer that's underneath it exposed. 0:20:21.480 --> 0:20:24.600 And with some CDs, that reflective layer is made up 0:20:24.800 --> 0:20:29.680 of a silver or sometimes a silver compound and silver 0:20:29.800 --> 0:20:34.560 when exposed to air will tarnish. The tarnished silver won't 0:20:34.600 --> 0:20:37.280 reflect a laser properly, and so you start to get 0:20:37.560 --> 0:20:39.920 errors when you're trying to read information off of that 0:20:40.359 --> 0:20:43.320 kind of c D. Now, not all CDs were made 0:20:43.680 --> 0:20:47.040 that way, right, so only some CDs have this particular 0:20:47.160 --> 0:20:50.800 bronzing issue. In fact, our research group determined that the 0:20:50.920 --> 0:20:54.679 c ds that really have this specific problem we're all 0:20:54.800 --> 0:20:58.840 pressed in Blackburn, Lancashire, England, between the year's nineteen eight 0:20:59.200 --> 0:21:03.560 and nineteen nine D three. That's pretty darn specific. Now. 0:21:04.680 --> 0:21:07.640 The issue here, though, is that there's really no way 0:21:07.720 --> 0:21:11.720 to give an average lifespan for a compact disc because 0:21:11.760 --> 0:21:14.679 there's no such thing as an average compact discs. There 0:21:14.720 --> 0:21:18.440 were there were so many different manufacturing and pressing processes 0:21:18.480 --> 0:21:24.760 and recording processes that different ones could last a different 0:21:25.240 --> 0:21:28.640 you know, theoretical maximum amount of time. So we can't 0:21:28.840 --> 0:21:31.879 really answer the question how long on average will a 0:21:31.920 --> 0:21:34.520 s c D last. I've seen a lot of people 0:21:34.560 --> 0:21:37.840 suggest five to ten years, some people saying ten to twenty, 0:21:37.960 --> 0:21:40.440 some people going as far as fifty. I think it 0:21:40.520 --> 0:21:43.080 really depends on the way the CD was made and 0:21:43.359 --> 0:21:47.399 what storage facility it's in, Like, is it in a 0:21:47.520 --> 0:21:51.120 house where it's kept out of sunlight because UV radiation 0:21:51.200 --> 0:21:55.240 can affect c D suh. Is it kept cool and dry, 0:21:55.440 --> 0:21:58.280 then it's gonna last longer. Is it not handled a lot? 0:21:58.760 --> 0:22:03.000 Like if it's your favorite music CD and you handle 0:22:03.080 --> 0:22:07.640 it a lot, then it's gonna degrade faster. Again, not instantaneously, 0:22:07.880 --> 0:22:10.520 and it may not even be noticeable at first, but 0:22:10.800 --> 0:22:13.560 eventually you might get the things where it starts to 0:22:13.640 --> 0:22:16.280 skip on a certain track, or it won't even play 0:22:16.440 --> 0:22:20.879 certain tracks. That will happen over time. It's a similar 0:22:20.960 --> 0:22:24.040 story for other optical formats, which include you know, DVDs 0:22:24.080 --> 0:22:27.560 and Blu ray discs. These two have a limited lifespan, 0:22:27.720 --> 0:22:30.399 though that lifespan may stretch to as long as a 0:22:30.480 --> 0:22:34.440 century under ideal conditions. In a century is a long 0:22:34.520 --> 0:22:36.840 time for a single person, right, I mean, that's that's 0:22:37.040 --> 0:22:41.320 a significant amount of time. However, if we step outside 0:22:41.640 --> 0:22:45.360 of a humans lifespan and we look at it from 0:22:45.440 --> 0:22:50.280 the perspective of, you know, a historical account, then a 0:22:50.359 --> 0:22:53.240 hundred years is not long at all. I mean, imagine 0:22:53.280 --> 0:22:57.240 for a moment, if you had no access to any 0:22:57.359 --> 0:23:01.520 information that was recorded before nineteen twenty because all the 0:23:01.680 --> 0:23:05.400 media that we had used to record info on had 0:23:05.440 --> 0:23:10.840 fallen apart or was otherwise unusable or inaccessible, that nothing 0:23:10.920 --> 0:23:14.280 before nineteen twenty two would be knowable apart from what 0:23:14.440 --> 0:23:19.760 people wrote about those times post nineteen two. That would 0:23:19.800 --> 0:23:24.240 be crazy, right, But that's the kind of situation we're 0:23:24.320 --> 0:23:28.760 in when we start looking at digital information. All right, Well, 0:23:28.800 --> 0:23:31.440 what about we look at like hard drives, hard disk 0:23:31.520 --> 0:23:34.040 drives and solid state drives, you know, the stuff that's 0:23:34.119 --> 0:23:37.080 in your computer systems, your smartphones, that kind of thing. 0:23:37.320 --> 0:23:41.000 What what do they have? You know, how long will 0:23:41.080 --> 0:23:45.920 information last in those? Well, they stored information in different ways. 0:23:46.240 --> 0:23:50.120 Hard disk drives have one or more platters in them, 0:23:50.720 --> 0:23:53.840 and each platter has a magnetic coding on it upon 0:23:53.920 --> 0:23:57.840 which information can be stored. So, just like cassettes and 0:23:57.960 --> 0:24:01.800 floppy disks and other magnetic storage methods, hard disk drives 0:24:01.880 --> 0:24:05.160 can be affected by powerful magnetic fields because they too, 0:24:05.440 --> 0:24:11.200 store information magnetically. Hard disk drives have moving parts, so 0:24:11.400 --> 0:24:16.280 the platters spin quite quite quickly in fact, and an 0:24:16.359 --> 0:24:20.480 actuator mechanical arm with a ReadWrite quote unquote head on it. 0:24:20.640 --> 0:24:24.920 This is the bit that either can read the magnetic 0:24:25.040 --> 0:24:28.120 particles that are stored on a platter, or it can 0:24:28.240 --> 0:24:33.360 actually exert a magnetic field that aligns the particles. When 0:24:33.400 --> 0:24:36.960 you're writing information on the platter, it moves across the 0:24:37.000 --> 0:24:40.280 platter and it starts to retrieve or right information to 0:24:40.359 --> 0:24:44.720 the disc itself. And because we're talking about moving parts here, 0:24:45.160 --> 0:24:49.280 stuff can and does wear down over time and use. 0:24:49.760 --> 0:24:51.960 If it gets a lot of use, it wears out 0:24:52.040 --> 0:24:55.240 more quickly. Also, it means that you should be gentle 0:24:55.359 --> 0:24:57.560 when you're moving anything that happens to have a hard 0:24:57.640 --> 0:25:00.040 disk drive inside of it, because a good whack and 0:25:00.200 --> 0:25:03.920 damage the delicate parts. If you knock that actuator arm 0:25:03.960 --> 0:25:07.120 out of alignment, that's a big problem. It's it's going 0:25:07.200 --> 0:25:12.240 to be impossible to read or write stuff reliably to 0:25:12.400 --> 0:25:16.440 that hard disk drive. Now, hard drives don't tend to 0:25:16.600 --> 0:25:19.840 last very long because of those mechanical parts. I've seen 0:25:20.040 --> 0:25:23.760 estimates of the lifespan for hard disk drives lasting somewhere 0:25:23.800 --> 0:25:27.920 between three two maybe six and a half years, seven years. 0:25:28.560 --> 0:25:31.120 Some give it a little bit longer, some a little 0:25:31.119 --> 0:25:33.720 bit shorter. Of course, a hard disk drive can last 0:25:34.040 --> 0:25:38.800 longer than a decade, but that's you know, if we're 0:25:38.840 --> 0:25:41.960 looking at typical use and we're looking at the average 0:25:42.000 --> 0:25:44.440