WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 00:00:00.000 --> 00:00:02.430 [MUSIC PLAYING] 00:00:09.261 --> 00:00:11.760 DAVID J. MALAN: Odds are, you use a computer most every day. 00:00:11.760 --> 00:00:15.010 But what's going on inside of that laptop or that desktop. 00:00:15.010 --> 00:00:17.676 Well, inside of a computer are all these 0s and 1s. 00:00:17.676 --> 00:00:19.800 And you may have heard, indeed, that computers only 00:00:19.800 --> 00:00:23.280 understand 0s and 1s, or the, so-called, binary system. 00:00:23.280 --> 00:00:25.620 But if computers today can do so much, how can 00:00:25.620 --> 00:00:28.920 they do so much if they can only speak 0s and 1s and not 00:00:28.920 --> 00:00:31.230 even the entire alphabet that we humans have. 00:00:31.230 --> 00:00:33.000 Well, consider this. 00:00:33.000 --> 00:00:37.130 Back in our human world, you might recognize a pattern of symbols 00:00:37.130 --> 00:00:40.590 like this as the number 123. 00:00:40.590 --> 00:00:41.460 But why is that? 00:00:41.460 --> 00:00:44.670 After all, all I did was draw three shapes, really, three glyphs, 00:00:44.670 --> 00:00:47.160 or three symbols or digits on the screen. 00:00:47.160 --> 00:00:50.130 But each of these digits has some predefined meaning. 00:00:50.130 --> 00:00:53.850 If, in fact, if you went to grade school like I did and you learned numbers 00:00:53.850 --> 00:00:56.610 in this way, odds are, you might recall, that this rightmost 00:00:56.610 --> 00:00:59.940 column is the so-called one's column or one's place. 00:00:59.940 --> 00:01:01.590 Then this is the ten's place. 00:01:01.590 --> 00:01:03.510 And then this is the hundred's place. 00:01:03.510 --> 00:01:05.349 Now why is that significant? 00:01:05.349 --> 00:01:09.060 Well, the reason that 1, 2, 3-- that pattern represents 00:01:09.060 --> 00:01:11.970 the number we humans know is 123 is that there's 00:01:11.970 --> 00:01:13.830 a bit of arithmetic going on here. 00:01:13.830 --> 00:01:19.770 This, after all, means that you should do 100 times 1 plus 10 times 00:01:19.770 --> 00:01:23.280 2 plus 1 times 3. 00:01:23.280 --> 00:01:30.930 That, of course, gives us 100 plus 20 plus 3 or 123. 00:01:30.930 --> 00:01:33.540 In other words, there's a pattern to these digits, 00:01:33.540 --> 00:01:36.000 and there's a meaning behind each of their places. 00:01:36.000 --> 00:01:39.930 Well, it turns out that computers only, indeed, understand 0s and 1s. 00:01:39.930 --> 00:01:43.920 They can't count as high as 2 and 3 and 4 in the same way we humans can. 00:01:43.920 --> 00:01:47.080 But they use those 0s and 1s in exactly the same way. 00:01:47.080 --> 00:01:48.640 In fact, consider this. 00:01:48.640 --> 00:01:54.292 If we consider this pattern 0, 0, 0, to be inside of a computer, 00:01:54.292 --> 00:01:56.250 and that's what the computer is thinking, well, 00:01:56.250 --> 00:01:57.610 what number might this be. 00:01:57.610 --> 00:01:59.360 Well, the spoiler is that this is actually 00:01:59.360 --> 00:02:02.760 going to represent just 0, thankfully, just like in our human world. 00:02:02.760 --> 00:02:03.910 But why is that the case? 00:02:03.910 --> 00:02:06.030 And how can we count higher than 0? 00:02:06.030 --> 00:02:09.030 Well, in the computer world, realize that these places are just 00:02:09.030 --> 00:02:09.870 a little different. 00:02:09.870 --> 00:02:11.869 This is still the one's place, but this next one 00:02:11.869 --> 00:02:13.440 is not the ten's place anymore. 00:02:13.440 --> 00:02:15.239 It's, instead, the two's place. 00:02:15.239 --> 00:02:17.530 And this next place is not the hundred's place anymore. 00:02:17.530 --> 00:02:20.412 It's, instead, the four's place. 00:02:20.412 --> 00:02:22.620 And if you think about this, there's still a pattern. 00:02:22.620 --> 00:02:26.370 Previously, it was 1, 10, 100, and then if we kept going, 00:02:26.370 --> 00:02:29.855 1,000, 10,000 100,000, and so forth. 00:02:29.855 --> 00:02:31.230 And here, too, there's a pattern. 00:02:31.230 --> 00:02:34.210 1, 2, 4-- and if I kept going-- 00:02:34.210 --> 00:02:36.540 8, 16, and 32. 00:02:36.540 --> 00:02:39.930 And so, in our human world, we tend to use powers of 10. 00:02:39.930 --> 00:02:45.810 10 to 0 is 1, 10 to the 1 is 10, 10 to the 2 is 100. 00:02:45.810 --> 00:02:51.510 And in the computer world, this is 2 to the 0, which is 1, 2 to 1, 00:02:51.510 --> 00:02:54.780 which is 2, 2 to the 2, or 2 squared, which is 4. 00:02:54.780 --> 00:02:57.820 2 to 3 would be 8 and so forth. 00:02:57.820 --> 00:03:01.050 So all we're doing is changing the base that we're using, so to speak. 00:03:01.050 --> 00:03:03.930 Instead of powers of 10, we're using powers of 2. 00:03:03.930 --> 00:03:09.460 And so why is this number 0, 0, 0 the number we humans know as 0 itself? 00:03:09.460 --> 00:03:15.870 Well, again, if we just do the math, 4 times 0 plus 2 times 0 plus 1 times 0 00:03:15.870 --> 00:03:22.050 is, of course, 0 plus 0 plus 0 or the number we humans know as just 0. 00:03:22.050 --> 00:03:24.420 Well, what if we do another number altogether? 00:03:24.420 --> 00:03:27.817 Suppose we do this pattern 0, 0, 1. 00:03:27.817 --> 00:03:29.400 Well, what number does this represent? 00:03:29.400 --> 00:03:31.120 Well, if you consider the same columns-- 00:03:31.120 --> 00:03:33.030 1, 2, and 4-- 00:03:33.030 --> 00:03:38.490 this means we have four times 0, which is 0, 2 times 0, which is 0, 1 times 00:03:38.490 --> 00:03:40.180 1, which is 1. 00:03:40.180 --> 00:03:42.880 So this is the number we humans know as 1. 00:03:42.880 --> 00:03:43.380 All right. 00:03:43.380 --> 00:03:47.280 So not all that interesting yet, but what about the number 2? 00:03:47.280 --> 00:03:54.190 How, in binary, bi meaning two, and the 2 being a 0 and a 1, how, in binary, 00:03:54.190 --> 00:03:56.480 can I now count as high as 2? 00:03:56.480 --> 00:03:59.260 Well, if this is my one's place, this is my two's place, 00:03:59.260 --> 00:04:04.060 and this is my four's place, what digits do I want to put below those places 00:04:04.060 --> 00:04:07.840 if the only digits I have at my disposal now are not 0 through 9, 00:04:07.840 --> 00:04:09.940 but just 0 through 1? 00:04:09.940 --> 00:04:12.841 Well, I don't need a 4, so I can make that a 0. 00:04:12.841 --> 00:04:15.340 I do need 2 if I want to count to the number we know as two, 00:04:15.340 --> 00:04:16.590 so I'm going to put a 1 there. 00:04:16.590 --> 00:04:19.390 And I don't need an extra 1 because an extra 1 would give me 3. 00:04:19.390 --> 00:04:20.810 So I'm going to do this. 00:04:20.810 --> 00:04:23.650 And so a computer, to store the number we humans 00:04:23.650 --> 00:04:28.540 know as two in decimal which store it in binary as 0, 1, 0. 00:04:28.540 --> 00:04:32.800 Because that's 4 times 0 plus 2 times 1 plus time 1 times 0, 00:04:32.800 --> 00:04:35.380 which, of course, is going to give me the number 2. 00:04:35.380 --> 00:04:36.195 What about 3? 00:04:36.195 --> 00:04:38.050 Well, in the world of computers, if we again 00:04:38.050 --> 00:04:40.210 have our one's place two's place and four's place, 00:04:40.210 --> 00:04:43.966 how do I now arrange my zeros and ones to give me the number we know as 3? 00:04:43.966 --> 00:04:45.340 Well, let's see I don't need a 4. 00:04:45.340 --> 00:04:46.256 That would be too big. 00:04:46.256 --> 00:04:48.340 I do need a 2, and I do need a 1. 00:04:48.340 --> 00:04:49.900 And that is now going to give me 3. 00:04:49.900 --> 00:04:56.110 Because 2 times 1, 1 times 1 is 2, 1 times 1 is 1, 2 plus 1 is 3. 00:04:56.110 --> 00:04:57.399 Now what about 4? 00:04:57.399 --> 00:04:58.690 How do I count as high as four? 00:04:58.690 --> 00:05:02.630 Well, it's even easier, perhaps because we just need a single 1 in this case. 00:05:02.630 --> 00:05:05.016 We just need 1, 0, 0. 00:05:05.016 --> 00:05:06.890 Because now I have one 1 in the four's place. 00:05:06.890 --> 00:05:07.960 And now let's skip ahead. 00:05:07.960 --> 00:05:13.450 Suppose I want to count up as high as, let's say, 7? 00:05:13.450 --> 00:05:14.780 What do I do? 00:05:14.780 --> 00:05:17.280 Well, 7, let me take a byte out of that. 00:05:17.280 --> 00:05:18.490 So this gives me 4. 00:05:18.490 --> 00:05:21.040 Let me take a two, that gives me 4 plus 2, that's 6. 00:05:21.040 --> 00:05:22.930 Let me give myself another 1. 00:05:22.930 --> 00:05:27.160 1, 1, 1, in binary, equals 7. 00:05:27.160 --> 00:05:28.990 Now what about a number like 8? 00:05:28.990 --> 00:05:33.810 I can't seem to count as high as 8 unless I give myself another bit. 00:05:33.810 --> 00:05:36.190 But that's OK because, just as in the human world, 00:05:36.190 --> 00:05:38.773 if you have not a three-digit number, but a four-digit number, 00:05:38.773 --> 00:05:40.000 you simply add another place. 00:05:40.000 --> 00:05:43.456 So it might be the ones column, the tens, the hundreds, the thousands. 00:05:43.456 --> 00:05:46.330 In this case, though, it's going to be the ones, the twos, the fours, 00:05:46.330 --> 00:05:47.020 and the eights. 00:05:47.020 --> 00:05:49.150 And so if we want to count as high as 8 in binary, 00:05:49.150 --> 00:05:54.160 we might do 1, 0, 0, 0, which, of course, gives me 8 times 1. 00:05:54.160 --> 00:05:55.750 And then everything else is 0. 00:05:55.750 --> 00:05:58.220 So that gives me the number 8. 00:05:58.220 --> 00:06:01.780 So even though computers only speak 0s and 1s 00:06:01.780 --> 00:06:03.880 and only understand the so-called binary system, 00:06:03.880 --> 00:06:06.760 they can still count as high as we humans can. 00:06:06.760 --> 00:06:10.630 And they fundamentally do it, really, in the same way. 00:06:10.630 --> 00:06:13.510 It's just that they have a smaller vocabulary. 00:06:13.510 --> 00:06:15.600 But why do they have a smaller vocabulary, 00:06:15.600 --> 00:06:17.100 especially when they can do so much? 00:06:17.100 --> 00:06:19.450 Well, it turns out that, in the physical world, 00:06:19.450 --> 00:06:22.701 it's just convenient to be able to represent only two states instead 00:06:22.701 --> 00:06:23.200 of 10. 00:06:23.200 --> 00:06:25.630 And by states, I mean digits, in this case. 00:06:25.630 --> 00:06:27.670 It's a lot easier in the human world, not 00:06:27.670 --> 00:06:31.450 to represent 10 possible values 0 or 9, but just two-- 00:06:31.450 --> 00:06:32.375 0 and 1. 00:06:32.375 --> 00:06:34.750 And we could have called those digits anything we wanted, 00:06:34.750 --> 00:06:36.999 but we humans just standardized our numbers like that. 00:06:36.999 --> 00:06:43.420 But 0 and 1 is nice because if you think of one of these binary digits or bits 00:06:43.420 --> 00:06:46.390 as just being a light bulb-- it's either off or on. 00:06:46.390 --> 00:06:49.380 You can think of a 0 as a light bulb being off 00:06:49.380 --> 00:06:52.270 and a one as being a light bulb being on. 00:06:52.270 --> 00:06:55.750 And light bulbs, of course, in our human world just need electricity to run. 00:06:55.750 --> 00:06:59.320 And so, if we somehow get electricity into our computer laptop, desktop, 00:06:59.320 --> 00:07:03.500 or whatnot coming from the power outlet in the wall or some battery, 00:07:03.500 --> 00:07:06.310 well, that would seem to be sufficient input in order 00:07:06.310 --> 00:07:11.260 to turn a light bulb on or off, to turn a switch, really, on or off. 00:07:11.260 --> 00:07:14.770 And indeed, that's what's inside of our computers-- transistors, 00:07:14.770 --> 00:07:16.060 otherwise known as switches. 00:07:16.060 --> 00:07:19.270 And these transistors, which now number in the billions in the most 00:07:19.270 --> 00:07:22.720 modern of computers are tiny, tiny, tiny little light switches, 00:07:22.720 --> 00:07:28.810 if you will, that, if turned on, allow us to store 1s, if turned off, 00:07:28.810 --> 00:07:31.030 allow us to store 0s. 00:07:31.030 --> 00:07:33.760 And using those many, many, many transistors, 00:07:33.760 --> 00:07:37.270 can we store values, can we store data, can we compute, 00:07:37.270 --> 00:07:41.380 and can we actually do everything we can today with our modern computers. 00:07:41.380 --> 00:07:45.970 Let's make this more real and try out some actual light bulbs. 00:07:45.970 --> 00:07:48.880 So here are some light bulbs clamped into these desk lamps. 00:07:48.880 --> 00:07:51.520 And suppose now that I have these light bulbs here 00:07:51.520 --> 00:07:53.530 to represent bits or binary digits. 00:07:53.530 --> 00:07:56.710 So each of these light bulbs can represent a 0 if it's off 00:07:56.710 --> 00:07:58.310 or a 1 if it's on. 00:07:58.310 --> 00:08:00.880 And if we think about the same system that computers use, 00:08:00.880 --> 00:08:04.330 let's think of this bulb here as being the one's place, this bulb here 00:08:04.330 --> 00:08:08.260 as being the two's place and this bulb here as being the four's place. 00:08:08.260 --> 00:08:10.300 So what number am I currently representing 00:08:10.300 --> 00:08:12.520 if all of these light bulbs are off? 00:08:12.520 --> 00:08:14.575 Well, that's like having 0, 0, 0. 00:08:14.575 --> 00:08:17.950 Since they're all off, so that's the number we humans know in decimal, 00:08:17.950 --> 00:08:20.440 dec meaning 10, as 0. 00:08:20.440 --> 00:08:23.539 What about if I turn on just this one light bulb here? 00:08:23.539 --> 00:08:24.580 What does that represent? 00:08:24.580 --> 00:08:27.930 This, again, is the one's place, the two's place, and the four's place. 00:08:27.930 --> 00:08:30.820 So this, of course, represents the number we know as 1. 00:08:30.820 --> 00:08:34.720 Now, if I go ahead and simultaneously switch these, 00:08:34.720 --> 00:08:37.799 this is still the one's place, the two's place, and the four's place. 00:08:37.799 --> 00:08:38.634 So what is this? 00:08:38.634 --> 00:08:40.960 This, now, is the number we know as 2. 00:08:40.960 --> 00:08:42.610 How do I count as high as 3? 00:08:42.610 --> 00:08:44.470 I don't want to keep going down the line. 00:08:44.470 --> 00:08:49.960 Instead, I want to turn this 1 back on because that means I get a 1 plus a 2. 00:08:49.960 --> 00:08:54.180 I don't need the 4, which is great, because now I have 3. 00:08:54.180 --> 00:08:55.350 How do I get to 4 then? 00:08:55.350 --> 00:08:59.250 Well, let me turn both of these off, turn this one on, and now, of course, 00:08:59.250 --> 00:09:00.420 this is the four's place. 00:09:00.420 --> 00:09:01.620 So this is a 4. 00:09:01.620 --> 00:09:05.250 If I turn this one back on, now we're up to a four's place and a one's place, 00:09:05.250 --> 00:09:06.630 so that gives me 5. 00:09:06.630 --> 00:09:12.420 If I turn this off, this on, that gives me a 4 plus a 2, or a 6. 00:09:12.420 --> 00:09:16.260 And finally, if that turns on, I have now a 7. 00:09:16.260 --> 00:09:18.540 Unfortunately, I can't count as high as 8 00:09:18.540 --> 00:09:20.790 unless I go get myself another desk lamp, 00:09:20.790 --> 00:09:23.416 but for that we just need another bit. 00:09:23.416 --> 00:09:27.330 But this is all very fine and good, but all I can represent thus far, it seems, 00:09:27.330 --> 00:09:29.010 are numbers. 00:09:29.010 --> 00:09:33.240 How, though, do I represent letters of the actual alphabet, A through Z? 00:09:33.240 --> 00:09:35.820 How do I represent words or paragraphs, let 00:09:35.820 --> 00:09:39.529 alone emails, and any number of other features that computers today support? 00:09:39.529 --> 00:09:41.820 Well, for that, we're going to need to make a decision. 00:09:41.820 --> 00:09:44.250 We're going to need to decide what patterns of bits 00:09:44.250 --> 00:09:48.990 to use to represent those higher level notions like letters 00:09:48.990 --> 00:09:50.610 words and paragraphs. 00:09:50.610 --> 00:09:52.050 So for that, I've got an idea. 00:09:55.650 --> 00:09:59.972 So at the end of the day, all computers can store is, indeed, 0s and 1s. 00:09:59.972 --> 00:10:01.680 And from those zeros and ones, of course, 00:10:01.680 --> 00:10:05.950 can we count higher so long as we have a mapping from binary to the numbers 00:10:05.950 --> 00:10:06.900 we know as decimal. 00:10:06.900 --> 00:10:08.990 But, of course, we want our computers to do more. 00:10:08.990 --> 00:10:12.656 We want to be able to express words and even other types of data. 00:10:12.656 --> 00:10:13.530 So how do we do that? 00:10:13.530 --> 00:10:16.950 Well, we need to come up with a standardization, a mapping, 00:10:16.950 --> 00:10:20.610 from 0s and 1s, or really just numbers, to the letters that we want. 00:10:20.610 --> 00:10:24.394 And it turns out, that some years ago what humans decided to do was this. 00:10:24.394 --> 00:10:26.810 Now, at first glance, this might be a little overwhelming. 00:10:26.810 --> 00:10:29.505 This is just a screenshot of a chart from asciichart.com. 00:10:29.505 --> 00:10:34.260 An ASCII chart is a chart of ASCII characters, American Standard 00:10:34.260 --> 00:10:36.270 Code for Information Interchange. 00:10:36.270 --> 00:10:40.410 And this is simply a mapping from decimal numbers to letters. 00:10:40.410 --> 00:10:42.150 And so on let's notice a few of these. 00:10:42.150 --> 00:10:48.690 Notice here that 65 apparently maps to A, 66 maps to B, 67 maps to C, 00:10:48.690 --> 00:10:49.410 and so forth. 00:10:49.410 --> 00:10:55.320 Meanwhile, 97 maps to lowercase a, 98 to lowercase b, 99 to lowercase c, 00:10:55.320 --> 00:10:56.140 and so forth. 00:10:56.140 --> 00:10:58.590 And there's also mappings from punctuation symbols 00:10:58.590 --> 00:11:02.160 to all the letters of the alphabet that you may know. 00:11:02.160 --> 00:11:04.180 So why is this significant? 00:11:04.180 --> 00:11:08.180 Well, it turns out that even though computers only store 0s and 1s, 00:11:08.180 --> 00:11:09.930 we, of course, use them in different ways. 00:11:09.930 --> 00:11:13.860 We have programs like Notepad on PCs, or TextEdit on Mac OS, 00:11:13.860 --> 00:11:17.640 or Microsoft Word on both platforms, or Google spreadsheets, or Google Docs, 00:11:17.640 --> 00:11:18.370 or the like. 00:11:18.370 --> 00:11:20.161 And so we have all these different programs 00:11:20.161 --> 00:11:22.960 that is designed to do one thing or the other. 00:11:22.960 --> 00:11:27.060 And so those programs essentially decide, in their own context, 00:11:27.060 --> 00:11:31.380 whether to display patterns of bits as numbers or as letters 00:11:31.380 --> 00:11:33.120 or, in turn, words and paragraphs. 00:11:33.120 --> 00:11:35.580 So it's entirely context-dependent. 00:11:35.580 --> 00:11:38.610 At the end of the day, all the computer is storing is 0s and 1s, 00:11:38.610 --> 00:11:42.240 but it's up to the program to interpret those 0s and 1s in a certain way. 00:11:42.240 --> 00:11:46.650 And so, if a program like Microsoft Word or Google Docs 00:11:46.650 --> 00:11:54.580 sees a pattern of bits in a file that represents the decimal number 65-- 00:11:54.580 --> 00:11:57.919 it's still pattern of 0s and 1s expressed in binary, 00:11:57.919 --> 00:12:00.460 but of course, we've seen how we can convert that to decimal. 00:12:00.460 --> 00:12:03.300 So if a computer is ultimately storing a pattern of 0s and 1s 00:12:03.300 --> 00:12:06.900 that represents the decimal number 65, the computer, 00:12:06.900 --> 00:12:10.130 in this case Microsoft Word, or Google Docs, and the program running there, 00:12:10.130 --> 00:12:13.650 is going to interpret that pattern, not as the number 65, 00:12:13.650 --> 00:12:18.240 and not as a whole bunch of 0s and 1s alone, but as the capital letter A. 00:12:18.240 --> 00:12:19.990 And that's what you'll see on your screen. 00:12:19.990 --> 00:12:24.022 If it, instead, sees a pattern of bits that represents the decimal number 66, 00:12:24.022 --> 00:12:25.980 Microsoft Word or Google Docs is going to show, 00:12:25.980 --> 00:12:28.530 instead, the capitol letter B. If the pattern of bits 00:12:28.530 --> 00:12:31.680 instead represents the decimal number 97, 00:12:31.680 --> 00:12:35.490 that program is going to display the lowercase letter a or any number 00:12:35.490 --> 00:12:37.630 of other letters from the alphabet. 00:12:37.630 --> 00:12:41.730 And so we just had to decide in advance what mapping to use, 00:12:41.730 --> 00:12:44.850 what code to use that maps numbers to letters. 00:12:44.850 --> 00:12:47.370 And in fact, you'll notice that quite a few characters 00:12:47.370 --> 00:12:48.890 are absent from the screen here. 00:12:48.890 --> 00:12:52.140 In fact, if you speak some language and write some language other than English 00:12:52.140 --> 00:12:53.931 there might be some characters that you can 00:12:53.931 --> 00:12:56.890 express with just this range of values. 00:12:56.890 --> 00:13:00.300 In fact ASCII originally only used 7 bits total. 00:13:00.300 --> 00:13:04.350 Or if you round up, 8 bits total, for what's called the extended ASCII. 00:13:04.350 --> 00:13:09.930 And it turns out, that's not nearly enough patterns of bits, 256 maximally, 00:13:09.930 --> 00:13:12.240 that you can use to express characters that you might 00:13:12.240 --> 00:13:15.900 see in certain Asian languages or symbols that just simply are not 00:13:15.900 --> 00:13:17.880 depicted even yet on the screen here. 00:13:17.880 --> 00:13:19.770 So there are other systems, not just ASCII. 00:13:19.770 --> 00:13:23.400 Something called Unicode, for instance, is a superset of what you see here. 00:13:23.400 --> 00:13:26.190 And that actually allows us to express any number of characters 00:13:26.190 --> 00:13:29.550 from English and Asian languages and beyond and, in fact, even 00:13:29.550 --> 00:13:32.739 things like the emoji characters-- the smiley faces, 00:13:32.739 --> 00:13:35.280 and other such characters that you might now use increasingly 00:13:35.280 --> 00:13:37.170 on your phone, your desktop, or laptop. 00:13:37.170 --> 00:13:40.287 Those two are expressed ultimately as just patterns of bits. 00:13:40.287 --> 00:13:42.120 And the world, for the most part, has simply 00:13:42.120 --> 00:13:44.820 standardized on what pattern of bits represents 00:13:44.820 --> 00:13:48.450 a happy face, what pattern of bits represents a sad face, 00:13:48.450 --> 00:13:51.750 and beyond, in that system there is Unicode. 00:13:51.750 --> 00:13:53.740 So let's take an example. 00:13:53.740 --> 00:13:57.450 Suppose that you see this pattern of bits somewhere in a file. 00:13:57.450 --> 00:14:00.840 And you, in this context, say are Microsoft Word, or Google Docs, 00:14:00.840 --> 00:14:04.560 or some program designed to display, not numbers like a calculator, 00:14:04.560 --> 00:14:08.310 but words and letters like a word processor or a text editor. 00:14:08.310 --> 00:14:10.140 Well, what is this pattern of bits? 00:14:10.140 --> 00:14:12.000 Well, we haven't seen this many bits before, 00:14:12.000 --> 00:14:16.230 but it looks to be like two patterns of eight. 00:14:16.230 --> 00:14:20.580 And in fact, it turns out that anytime you have eight bits here or eight bits 00:14:20.580 --> 00:14:24.810 here, humans generally refer to this as a byte, B-Y-T-E. 00:14:24.810 --> 00:14:26.730 So a byte is just eight bits. 00:14:26.730 --> 00:14:28.920 And it's a slightly more useful measure because it's 00:14:28.920 --> 00:14:32.980 a lot bigger than a single bit, which can, of course, only represent 0 or 1. 00:14:32.980 --> 00:14:35.260 A byte can actually count higher. 00:14:35.260 --> 00:14:38.640 So what are the columns here if we look only at this number at left? 00:14:38.640 --> 00:14:48.000 This is my 1's place, 2's, 4's, 8's, 16's, 32's, and 64, and then 128. 00:14:48.030 --> 00:14:53.520 So 64 plus 8, if I do that arithmetic, that gives me 72. 00:14:53.550 --> 00:14:56.160 Now let's consider the pattern of bits on the right. 00:14:56.160 --> 00:15:05.250 Again, my 1's place, 2's place, 4's 8's, 16's, 32, 64, 128. 00:15:05.250 --> 00:15:08.370 Now notice, these patterns are actually almost identical. 00:15:08.370 --> 00:15:12.340 We've got a 1 in the 64's place, we've got a 1 in the 8's place, 00:15:12.340 --> 00:15:15.690 but we've also got an extra one in the 1's place. 00:15:15.690 --> 00:15:21.750 So if this was 72, and this pattern is identical except for this last bit 00:15:21.750 --> 00:15:27.842 here, which adds 1, this must be 72 followed by 73. 00:15:27.842 --> 00:15:29.550 And I've put a space here, visually, just 00:15:29.550 --> 00:15:32.216 to separate the fact that these are, indeed, two separate bytes. 00:15:32.216 --> 00:15:35.550 And I claim now that, yes, while you could interpret these 00:15:35.550 --> 00:15:42.510 as two decimal digits, 72 and 73, it turns out, per the ASCII system, 00:15:42.510 --> 00:15:46.890 we could map 72 and 73 to alphabetical letters. 00:15:46.890 --> 00:15:48.150 What might those letters be? 00:15:48.150 --> 00:15:51.780 Well, if we consider our chart again, 72 apparently 00:15:51.780 --> 00:15:55.290 gives us a capital H. 73 gives us the capital I. 00:15:55.290 --> 00:15:59.700 And, voila, 72 followed by 73 in a computer's memory, apparently, 00:15:59.700 --> 00:16:02.700 is how a computer would express HI. 00:16:02.700 --> 00:16:07.050 And of course, if we used more bytes, and therefore more bits, and therefore 00:16:07.050 --> 00:16:11.550 more numbers, we could represent even larger words than just H I, or HI. 00:16:11.550 --> 00:16:14.710 But that's exactly how a computer, underneath the hood so to speak, 00:16:14.710 --> 00:16:17.700 would store a word like HI. 00:16:17.700 --> 00:16:21.000 Now what is indeed using these patterns of bits? 00:16:21.000 --> 00:16:24.240 And what is a computer actually doing at the end of the day? 00:16:24.240 --> 00:16:28.200 Well, for that, we need to take a look under the hood, so to speak. 00:16:28.200 --> 00:16:31.470 This is what Intel inside means. 00:16:31.470 --> 00:16:37.680 If your Mac or your PC comes with an Intel Inside, 00:16:37.680 --> 00:16:41.360 as goes the marketing slogan, that means that your computer has inside of it 00:16:41.360 --> 00:16:46.216 a CPU, a Central Processing Unit that looks a little something like this. 00:16:46.216 --> 00:16:47.340 It's a pretty small device. 00:16:47.340 --> 00:16:48.705 It's not quite as big as this. 00:16:48.705 --> 00:16:50.159 This, of course, is not to scale. 00:16:50.159 --> 00:16:52.619 It wouldn't fit in your actual laptop or desktop. 00:16:52.619 --> 00:16:54.000 But what you see is two sides. 00:16:54.000 --> 00:16:56.444 This is just a mental case and a nice big logo there. 00:16:56.444 --> 00:16:58.860 And then, if you flip this around, you see the other side, 00:16:58.860 --> 00:17:01.740 which generally has a whole bunch of golden pins 00:17:01.740 --> 00:17:05.879 that actually interconnect to a device inside of the computer. 00:17:05.879 --> 00:17:08.010 And now what is that device? 00:17:08.010 --> 00:17:11.419 Well, that device, we'll soon see, is something called the motherboard. 00:17:11.419 --> 00:17:14.490 A motherboard is a circuit board, so a big piece 00:17:14.490 --> 00:17:17.910 of silicon or plastic-like material that has 00:17:17.910 --> 00:17:20.640 a lot of lines running back and forth on it, 00:17:20.640 --> 00:17:23.880 and often has sockets, essentially, a bunch of tiny little holes 00:17:23.880 --> 00:17:28.890 into which devices like this fit so that you can put this inside of a computer 00:17:28.890 --> 00:17:31.110 and actually have it clamped down on something. 00:17:31.110 --> 00:17:32.970 Now what does it mean to be a CPU? 00:17:32.970 --> 00:17:34.846 Well, the CPU is the brains of your computer. 00:17:34.846 --> 00:17:36.553 It's the thing in your computer that does 00:17:36.553 --> 00:17:38.100 all of the work, all of the thinking. 00:17:38.100 --> 00:17:40.230 Now what kind of thinking does a computer need to do? 00:17:40.230 --> 00:17:41.850 Well, if you're feeding it all of these numbers, 00:17:41.850 --> 00:17:43.710 and you're feeding it all of these letters, 00:17:43.710 --> 00:17:46.500 you want to maybe perform math on those numbers. 00:17:46.500 --> 00:17:49.096 You might want to display those letters on the screen. 00:17:49.096 --> 00:17:50.970 You might want to add or delete those letters 00:17:50.970 --> 00:17:53.640 if the user is using a word processor and typing new characters 00:17:53.640 --> 00:17:54.570 or hitting delete. 00:17:54.570 --> 00:17:58.320 And so a computer needs to do all of that thinking and work for the human. 00:17:58.320 --> 00:18:01.740 And the peace inside of the computer that does most of that work 00:18:01.740 --> 00:18:05.520 is, indeed, this device here called the CPU. 00:18:05.520 --> 00:18:10.020 Now, it turns out, that CPUs today are actually getting pretty fancy. 00:18:10.020 --> 00:18:14.990 And inside of a CPU, typically, is one or more cores, so to speak. 00:18:14.990 --> 00:18:17.640 And a core is really what's doing the work. 00:18:17.640 --> 00:18:21.090 And it is the device inside of this device that actually 00:18:21.090 --> 00:18:24.060 can do addition, and subtraction, and multiplication, and division, 00:18:24.060 --> 00:18:27.030 and other operations still loading information from memory, 00:18:27.030 --> 00:18:28.770 saving information to memory. 00:18:28.770 --> 00:18:33.570 And so a CPU like this might have one, or two, or four or more cores, 00:18:33.570 --> 00:18:38.110 which means it can do one, or two, or four or more things at a time. 00:18:38.110 --> 00:18:40.560 And that's great because, these days on my Mac or my PC, 00:18:40.560 --> 00:18:42.420 I might double-click a whole bunch of icons. 00:18:42.420 --> 00:18:43.980 I might be running multiple programs. 00:18:43.980 --> 00:18:45.720 I might be chatting with a friend over here. 00:18:45.720 --> 00:18:47.553 I might be working on my homework over here. 00:18:47.553 --> 00:18:50.940 And so I might have a lot of programs and a lot of files open simultaneously. 00:18:50.940 --> 00:18:55.650 And thanks to multiple cores inside of a CPU, can each of those programs 00:18:55.650 --> 00:18:57.564 continue running in parallel. 00:18:57.564 --> 00:18:59.480 Maybe one is printing something to my printer. 00:18:59.480 --> 00:19:01.380 Or maybe one is playing back a video. 00:19:01.380 --> 00:19:03.090 Maybe one is spell-checking a file. 00:19:03.090 --> 00:19:07.480 Any number of operations can literally be happening simultaneously. 00:19:07.480 --> 00:19:10.620 Now moreover, it turns out that the fanciest of use today, 00:19:10.620 --> 00:19:14.250 from Intel especially, also support something called hyperthreading, 00:19:14.250 --> 00:19:17.040 which means you might just have one CPU or one core, 00:19:17.040 --> 00:19:21.270 but thanks to some technology built into the CPU itself, 00:19:21.270 --> 00:19:24.960 it will present itself to the computer, to the operating system, 00:19:24.960 --> 00:19:27.900 Mac OS or Windows-- more on those in a bit-- 00:19:27.900 --> 00:19:31.200 as though it's actually two CPUs or two cores. 00:19:31.200 --> 00:19:35.100 And so, thanks to technology, can your computer actually 00:19:35.100 --> 00:19:38.290 think it has even more computational power than it actually has, 00:19:38.290 --> 00:19:41.170 thereby allowing it to take advantage of downtime 00:19:41.170 --> 00:19:44.500 or slow running programs that might still allow you 00:19:44.500 --> 00:19:47.290 to run multiple things simultaneously. 00:19:47.290 --> 00:19:49.690 But we'll come back to that in just a bit. 00:19:49.690 --> 00:19:54.010 Now, not all devices have just a CPU connected to a motherboard. 00:19:54.010 --> 00:20:00.310 Some devices, instead, have a CPU and more all interconnected all at once. 00:20:00.310 --> 00:20:02.830 And these things are generally known as systems on a chip. 00:20:02.830 --> 00:20:06.790 And they're especially popular in things like tablets or iPads these days, 00:20:06.790 --> 00:20:10.720 game consoles like Xboxes or even things like the Raspberry Pi, 00:20:10.720 --> 00:20:14.170 which is a very small computer that looks pretty much like this. 00:20:14.170 --> 00:20:17.080 Also not to scale, this thing could fit in the palm of my hand. 00:20:17.080 --> 00:20:20.530 And this has, not only one of these silicon circuit boards-- 00:20:20.530 --> 00:20:24.520 generally green, and you'll see there's very fine lines or traces that 00:20:24.520 --> 00:20:26.680 interconnect all of the chips and technology 00:20:26.680 --> 00:20:28.870 that's plugged into this thing-- and it also has, 00:20:28.870 --> 00:20:30.350 well, first and foremost, no case. 00:20:30.350 --> 00:20:33.224 There's no pretty plastic case that protects all of these components. 00:20:33.224 --> 00:20:34.990 It really is just a raw piece of hardware 00:20:34.990 --> 00:20:39.670 that computer technophiles like to use to build their own machines 00:20:39.670 --> 00:20:41.530 and programs. 00:20:41.530 --> 00:20:43.270 But it has a whole bunch of ports-- 00:20:43.270 --> 00:20:45.490 as we'll return to in a bit-- a whole bunch of places 00:20:45.490 --> 00:20:47.750 you can connect other devices. 00:20:47.750 --> 00:20:49.780 But these systems on a chip all come together. 00:20:49.780 --> 00:20:54.190 And they do many things beyond just the CPU's task alone. 00:20:54.190 --> 00:20:55.990 But what else is inside of your computer? 00:20:55.990 --> 00:20:57.700 Well, the CPU is the brain. 00:20:57.700 --> 00:21:01.370 And the CPU on a system on a chip is thereto the brain. 00:21:01.370 --> 00:21:04.209 But there's other components necessary inside of a computer 00:21:04.209 --> 00:21:05.250 so we can do actual work. 00:21:05.250 --> 00:21:09.190 And one of those things is called memory or random access memory. 00:21:09.190 --> 00:21:13.135 And random access memory looks, physically, like this. 00:21:13.135 --> 00:21:19.150 This is a chip that you might slide into a little slot inside of your computer 00:21:19.150 --> 00:21:23.050 specifically on the so-called motherboard, again, a big greenish 00:21:23.050 --> 00:21:25.779 board into which all of your computer's components connect. 00:21:25.779 --> 00:21:28.570 And there's usually a little divot here, a little bump to make sure 00:21:28.570 --> 00:21:31.611 you put it in the right way-- instead this way, instead of, for instance, 00:21:31.611 --> 00:21:32.260 that way. 00:21:32.260 --> 00:21:35.440 And then on this green circuit board are all these various chips 00:21:35.440 --> 00:21:37.510 that actually store your data. 00:21:37.510 --> 00:21:42.700 Specifically, they store your data in a volatile way, only when the power is 00:21:42.700 --> 00:21:45.190 on, when your laptop has battery and is running 00:21:45.190 --> 00:21:47.740 or when your laptop is plugged in and is running. 00:21:47.740 --> 00:21:50.260 Which is to say, when you double-click an icon on the screen 00:21:50.260 --> 00:21:54.220 or run some program, open some file, those files 00:21:54.220 --> 00:21:59.050 are loaded into the little black chips that you see on this stick here. 00:21:59.050 --> 00:22:01.750 They're loaded into RAM or Random Access Memory. 00:22:01.750 --> 00:22:03.370 And this memory is pretty fast. 00:22:03.370 --> 00:22:05.920 And it is where those files and programs live, 00:22:05.920 --> 00:22:09.250 so long as you are using them at a given moment in time. 00:22:09.250 --> 00:22:12.370 Now other devices have slightly different looking sticks of RAM. 00:22:12.370 --> 00:22:14.500 This is a smaller stick here that's actually 00:22:14.500 --> 00:22:18.550 found, typically, in laptops or certain desktop models, but it's the same idea. 00:22:18.550 --> 00:22:20.510 It's simply a different form factor. 00:22:20.510 --> 00:22:23.020 Now you can actually see in your Mac or PC 00:22:23.020 --> 00:22:25.169 sometimes exactly how much RAM you have, especially 00:22:25.169 --> 00:22:27.460 if you bought the computer without knowing this concept 00:22:27.460 --> 00:22:29.930 or were given the computer and didn't think to ask. 00:22:29.930 --> 00:22:33.910 In fact, on Windows, if you open up the so-called Task Manager 00:22:33.910 --> 00:22:38.110 and look at the CPU tab, you might see a little something like this. 00:22:38.110 --> 00:22:41.380 You'll see one, a nice little chart that shows you what your CPU has 00:22:41.380 --> 00:22:43.120 been doing over the past few seconds. 00:22:43.120 --> 00:22:44.950 And the higher these peaks are, the busier it was. 00:22:44.950 --> 00:22:47.033 Maybe you double-clicked an icon or played a video 00:22:47.033 --> 00:22:49.570 or sent a really big email or something like that. 00:22:49.570 --> 00:22:52.990 But more interesting, down here, is the speed of your CPU. 00:22:52.990 --> 00:22:55.600 This one is 1.9 for gigahertz. 00:22:55.600 --> 00:22:59.800 And a gigahertz means 1 billion things per second. 00:22:59.800 --> 00:23:04.360 So a you that's 1.9 for gigahertz means that this computer, this CPU 00:23:04.360 --> 00:23:08.590 can do 1.94 billion things per second-- 00:23:08.590 --> 00:23:10.330 additions, subtractions, multiplications, 00:23:10.330 --> 00:23:13.040 printing to the screen, any number of other things. 00:23:13.040 --> 00:23:17.500 But if we look, odds are this is marketed, frankly, as 2 gigahertz, 00:23:17.500 --> 00:23:20.020 and maybe it has burst technology whereby it can actually 00:23:20.020 --> 00:23:23.140 go even a little faster, maximum speed 2.81 00:23:23.140 --> 00:23:28.242 gigahertz by maybe using a little more energy for some amount of time 00:23:28.242 --> 00:23:29.950 and therefore generating a bit more heat. 00:23:29.950 --> 00:23:33.730 But you'll see that there's only one socket in the computer from which I 00:23:33.730 --> 00:23:36.560 took this screenshot from Windows, which means there's one CPU. 00:23:36.560 --> 00:23:40.720 But that CPU has two cores, which means that the computer can do literally 00:23:40.720 --> 00:23:44.987 two things at once because it has really two brains inside of that device 00:23:44.987 --> 00:23:46.570 that we saw a picture of a moment ago. 00:23:46.570 --> 00:23:48.880 But logically, it actually seems four. 00:23:48.880 --> 00:23:54.160 So this particular windows computer has a CPU with two cores, each of which 00:23:54.160 --> 00:23:56.650 supports that technology called hyperthreading, which 00:23:56.650 --> 00:24:01.120 means that each of those cores will present itself to the Windows operating 00:24:01.120 --> 00:24:02.590 system as though it's two. 00:24:02.590 --> 00:24:05.770 Which is to say each core will do two things simultaneously, 00:24:05.770 --> 00:24:10.120 thereby giving me four logical processors or, really, the ability 00:24:10.120 --> 00:24:12.410 to do 4 total things at once. 00:24:12.410 --> 00:24:15.220 So perhaps lower level detail than is perhaps germane, 00:24:15.220 --> 00:24:18.550 but these are the kinds of things that you end up paying for in a store 00:24:18.550 --> 00:24:20.444 or when you buy a computer online. 00:24:20.444 --> 00:24:23.110 This is what distinguishes a less expensive computer from a more 00:24:23.110 --> 00:24:27.400 expensive computer is just how fast the CPU or CPUs are 00:24:27.400 --> 00:24:30.460 and just how many cores the CPU has and, therefore, 00:24:30.460 --> 00:24:34.480 just how much work you can get done at a given moment in time 00:24:34.480 --> 00:24:36.930 or just how quickly you can work more generally. 00:24:36.930 --> 00:24:40.100 Now, in a Mac, if you open up your System Profiler, 00:24:40.100 --> 00:24:43.310 you'll see a different kind of interface, but similar information. 00:24:43.310 --> 00:24:45.560 This is taken here from a MacBook Pro. 00:24:45.560 --> 00:24:50.750 You can see that this CPU is 3.1 gigahertz, so faster, 00:24:50.750 --> 00:24:55.010 but it has one processor, total number of cores is two. 00:24:55.010 --> 00:24:59.240 And so, here, we see no mention of hyperthreading, which generally windows 00:24:59.240 --> 00:25:03.560 is a bit more detailed on, but this does mean that this CPU is pretty darn fast, 00:25:03.560 --> 00:25:05.990 3.1 billion things per second. 00:25:05.990 --> 00:25:10.970 And it actually has two cores, so it can do at least two things at once. 00:25:10.970 --> 00:25:11.570 All right. 00:25:11.570 --> 00:25:15.170 So that's my CPU, which does all the thinking and all of the work. 00:25:15.170 --> 00:25:18.620 That's RAM or random access memory where all of my data and programs 00:25:18.620 --> 00:25:21.690 are stored while I am using them. 00:25:21.690 --> 00:25:23.550 So what else do I need? 00:25:23.550 --> 00:25:27.200 Well, where are those programs and files stored when the power is not on 00:25:27.200 --> 00:25:31.800 or when my battery is dead or when my computer is not even plugged in. 00:25:31.800 --> 00:25:35.570 Now, odds are, if your computer is like mine, you don't lose all of your files 00:25:35.570 --> 00:25:37.880 and all of your programs just because your battery dies 00:25:37.880 --> 00:25:40.505 or you move a computer, and therefore, unplug it from the wall. 00:25:40.505 --> 00:25:42.320 It would not be a very useful device. 00:25:42.320 --> 00:25:46.850 Computers do have nonvolatile memory that sticks around 00:25:46.850 --> 00:25:49.910 even when the power is lost, but it uses a different technology 00:25:49.910 --> 00:25:51.350 than RAM for that. 00:25:51.350 --> 00:25:55.160 It tends to use a disk or a hard disk, as in this case. 00:25:55.160 --> 00:25:59.540 So this is a device that a PC desktop or Mac desktop might have inside of it. 00:25:59.540 --> 00:26:03.350 And it actually stores quite a bit more information than a stick of RAM. 00:26:03.350 --> 00:26:08.360 A stick of RAM might store one gigabyte, two gigabytes, maybe even 16 gigabytes. 00:26:08.360 --> 00:26:11.810 But a hard drive, as this thing is called, 00:26:11.810 --> 00:26:16.940 will actually store 256 gigabytes, or maybe 1,000 gigabytes, 00:26:16.940 --> 00:26:21.740 AKA a terabyte or even two terabytes or four terabytes, which 00:26:21.740 --> 00:26:25.292 is an order of magnitude more than our sticks of RAM. 00:26:25.292 --> 00:26:27.500 Inside of this device, though, meanwhile is something 00:26:27.500 --> 00:26:29.100 that feels kind of old school. 00:26:29.100 --> 00:26:32.900 It's actually one or more metal platters that literally 00:26:32.900 --> 00:26:35.630 physically spin around mechanically. 00:26:35.630 --> 00:26:38.610 And on those platters is your data actually stored. 00:26:38.610 --> 00:26:41.600 So in RAM, there were no moving parts. 00:26:41.600 --> 00:26:44.750 There is no fan, there's no motor, there's nothing to move back and forth. 00:26:44.750 --> 00:26:46.070 It's entirely electronic. 00:26:46.070 --> 00:26:48.350 It's all electrons at the end of the day. 00:26:48.350 --> 00:26:51.992 But a hard drive is a mechanical device that actually has one or more 00:26:51.992 --> 00:26:54.200 of these platters spinning and spinning and spinning. 00:26:54.200 --> 00:26:56.075 And that's what allows the computer to access 00:26:56.075 --> 00:26:57.740 different areas of those platters. 00:26:57.740 --> 00:27:00.650 And, in fact, you'll see one or more of these little reading heads, 00:27:00.650 --> 00:27:03.020 not unlike old school phonograph or record 00:27:03.020 --> 00:27:05.240 players that actually move back and forth 00:27:05.240 --> 00:27:08.060 and read the data from that device. 00:27:08.060 --> 00:27:11.810 And what's nice about this device is that it's nonvolatile. 00:27:11.810 --> 00:27:17.810 It uses tiny, tiny magnetic particles, little specks of magnetic particles, 00:27:17.810 --> 00:27:20.540 that, if you orient them this way might represent a 1. 00:27:20.540 --> 00:27:24.420 If you orient them this way it might represent a 0-- so north to south pole, 00:27:24.420 --> 00:27:27.350 south to north pole if you remember some of your electronics. 00:27:27.350 --> 00:27:31.310 But all that is to say is there's tiny, tiny, tiny little particles on here, 00:27:31.310 --> 00:27:35.330 billions or more perhaps, that, depending on their orientation up 00:27:35.330 --> 00:27:37.990 or down, represent a 1 or 0. 00:27:37.990 --> 00:27:39.740 And if you have enough of those particles, 00:27:39.740 --> 00:27:43.880 you can represent bytes or megabytes or gigabytes or terabytes 00:27:43.880 --> 00:27:46.040 or more or anything in between. 00:27:46.040 --> 00:27:50.300 And so you have the ability to store data this way 00:27:50.300 --> 00:27:52.400 or this way, even when the power is off. 00:27:52.400 --> 00:27:56.900 The power is used just to read the data or to write or change the data. 00:27:56.900 --> 00:28:00.770 It doesn't need to stick around to persist the data. 00:28:00.770 --> 00:28:03.410 So in fact, why don't we take a look at what this motor looks 00:28:03.410 --> 00:28:06.350 like when actually running. 00:28:06.350 --> 00:28:09.890 This is a short video from the Slow Mo Guys, which gives us 00:28:09.890 --> 00:28:12.770 a sense of what the hard drive looks like when its lid is indeed 00:28:12.770 --> 00:28:13.790 removed like that there. 00:28:13.790 --> 00:28:27.810 [VIDEO PLAYBACK] 00:28:27.810 --> 00:28:28.310 [END VIDEO] 00:28:28.310 --> 00:28:29.060 DAVID J. MALAN: Fascinating. 00:28:29.060 --> 00:28:29.750 I know. 00:28:29.750 --> 00:28:33.470 Well, now let's actually take the hood off of an actual hard drive, 00:28:33.470 --> 00:28:38.450 albeit via animation, and actually see and hear what it is that's going on. 00:28:38.450 --> 00:28:41.720 And in this depiction here, you'll see that the magnetic particles ultimately 00:28:41.720 --> 00:28:45.020 are represented as red-blue, or blue-red particles, which 00:28:45.020 --> 00:28:47.420 represent precisely those magnetic particles that 00:28:47.420 --> 00:28:49.410 represent your 0s and 1s. 00:28:49.410 --> 00:28:50.760 [VIDEO PLAYBACK] 00:28:50.760 --> 00:28:54.960 - The hard drive is where your PC stores most of its permanent data. 00:28:54.960 --> 00:28:57.900 To do that, the data travels from RAM along 00:28:57.900 --> 00:29:02.340 with software signals that tell the hard drive how to store that data. 00:29:02.340 --> 00:29:07.300 The hard drive circuits translate those signals into voltage fluctuations. 00:29:07.300 --> 00:29:10.470 These, in turn, control the hard drive's moving parts-- 00:29:10.470 --> 00:29:14.200 some of the few moving parts left in the modern computer. 00:29:14.200 --> 00:29:18.390 Some of the signals control a motor which spins metal-coated platters. 00:29:18.390 --> 00:29:21.700 Your data is actually stored on these platters. 00:29:21.700 --> 00:29:26.970 Other signals move the read-write heads to read or write data on the platters. 00:29:26.970 --> 00:29:30.840 This machinery is so precise that a human hair couldn't even 00:29:30.840 --> 00:29:33.590 pass between the heads and spinning platters. 00:29:33.590 --> 00:29:35.725 Yet, it all works at terrific speeds. 00:29:35.725 --> 00:29:36.615 [END VIDEO] 00:29:36.615 --> 00:29:38.490 DAVID J. MALAN: So where are those particles? 00:29:38.490 --> 00:29:41.850 Well, for that, we're going to have to zoom in even closer because they're not 00:29:41.850 --> 00:29:43.350 visible to the human eye. 00:29:43.350 --> 00:29:45.030 [VIDEO PLAYBACK] 00:29:45.030 --> 00:29:48.000 - Let's look at what we just saw in slow motion. 00:29:48.000 --> 00:29:51.510 When a brief pulse of electricity is sent to the read-write head, 00:29:51.510 --> 00:29:55.260 it flips on a tiny electromagnet for a fraction of a second. 00:29:55.260 --> 00:29:58.350 The magnet creates a field which changes the polarity 00:29:58.350 --> 00:30:00.840 of a tiny, tiny portion of the metal particles 00:30:00.840 --> 00:30:03.240 which coat each platter surface. 00:30:03.240 --> 00:30:06.240 A pattern series of these tiny charged up areas on the disk 00:30:06.240 --> 00:30:10.860 represents a single bit of data in the binary number system used by computers. 00:30:10.860 --> 00:30:13.770 Now, if the current is sent one way through the read-write head, 00:30:13.770 --> 00:30:16.211 the area is polarized in one direction. 00:30:16.211 --> 00:30:18.210 If the current is set in the opposite direction, 00:30:18.210 --> 00:30:20.310 the polarization is reversed. 00:30:20.310 --> 00:30:22.740 How do you get data off the hard disk? 00:30:22.740 --> 00:30:24.451 Just reverse the process. 00:30:24.451 --> 00:30:26.700 So it's the particles on the disk that get the current 00:30:26.700 --> 00:30:28.440 in the read-write head moving. 00:30:28.440 --> 00:30:30.870 Put together millions of these magnetized segments, 00:30:30.870 --> 00:30:32.490 and you've got a file. 00:30:32.490 --> 00:30:35.460 Now, the pieces of a single file may be scattered 00:30:35.460 --> 00:30:40.450 all over a drive's platters kind of like the mess of papers on your desk. 00:30:40.450 --> 00:30:43.860 So a special extra file keeps track of where everything is. 00:30:43.860 --> 00:30:45.790 Don't you wish you had something like that? 00:30:45.790 --> 00:30:48.199 [END VIDEO] 00:30:48.199 --> 00:30:50.490 DAVID J. MALAN: Now, anytime you have a physical device 00:30:50.490 --> 00:30:53.280 like this that's spinning all day long or for months 00:30:53.280 --> 00:30:56.640 on end, if you use your computer a lot and for quite a long period of time, 00:30:56.640 --> 00:30:58.060 something could go wrong. 00:30:58.060 --> 00:31:02.100 Maybe you accidentally bump the desktop or the laptop, the result of which 00:31:02.100 --> 00:31:04.890 is that this reading head might actually strike the platter 00:31:04.890 --> 00:31:07.980 and make a dent in it or some kind of scratch which actually will corrupt, 00:31:07.980 --> 00:31:10.270 not only some of the data perhaps, but might even 00:31:10.270 --> 00:31:14.250 stop the whole device from working if the reading head no longer functions 00:31:14.250 --> 00:31:14.920 properly. 00:31:14.920 --> 00:31:17.280 Moreover, anything that's physical like this 00:31:17.280 --> 00:31:20.520 isn't going to spin all that fast at the end of the day. 00:31:20.520 --> 00:31:24.250 Now technically, a hard drive like this might spin 7,200 times per minute 00:31:24.250 --> 00:31:28.560 or even 10,000 times per minute, but that's much, much slower 00:31:28.560 --> 00:31:31.200 than the speed with which electrons travel 00:31:31.200 --> 00:31:33.357 as they would in something like RAM. 00:31:33.357 --> 00:31:35.190 Well, fortunately, it turns out that there's 00:31:35.190 --> 00:31:39.070 something in between those technologies that doesn't have moving parts, 00:31:39.070 --> 00:31:43.740 but that's not quite as fast as RAM, but that is non-volatile, 00:31:43.740 --> 00:31:46.350 whereby it will store your data persistently 00:31:46.350 --> 00:31:47.820 even when the power is off. 00:31:47.820 --> 00:31:53.280 And this is so-called flash memory or a Solid State Disk, SSD, in this case 00:31:53.280 --> 00:31:53.790 here. 00:31:53.790 --> 00:31:57.660 It's a smaller device, whereas typical hard drives that have moving parts 00:31:57.660 --> 00:32:00.300 are very often 3 and 1/2 inches, although 2 and 1/2 inch 00:32:00.300 --> 00:32:03.210 versions do exist as well, in diameter. 00:32:03.210 --> 00:32:08.490 A solid state drive tends to be only 2.5 inches in width 00:32:08.490 --> 00:32:11.220 so that it actually fits inside of computers in the same slots 00:32:11.220 --> 00:32:14.580 that older more mechanical hard drives might fit. 00:32:14.580 --> 00:32:16.020 But it doesn't have moving parts. 00:32:16.020 --> 00:32:19.144 In fact, if we open it up, you'll see something very reminiscent of the RAM 00:32:19.144 --> 00:32:19.860 we saw earlier. 00:32:19.860 --> 00:32:24.390 But the technology inside of this device is such that the data persists, 00:32:24.390 --> 00:32:27.720 even when your battery dies or you unplug your laptop or desktop. 00:32:27.720 --> 00:32:33.990 But the upside of an SSD, being entirely electronic, is that it's much faster. 00:32:33.990 --> 00:32:35.790 And so this means that your programs will 00:32:35.790 --> 00:32:38.250 load faster when you double-click them, your files 00:32:38.250 --> 00:32:40.410 will open up faster when you double-click on them. 00:32:40.410 --> 00:32:44.160 Anything you might do or save to your hard drive or solid state drive, 00:32:44.160 --> 00:32:46.920 in this case, will actually get saved much more quickly, which 00:32:46.920 --> 00:32:50.801 means you might see a little hourglass or spinning beachball much less 00:32:50.801 --> 00:32:51.300 frequently. 00:32:51.300 --> 00:32:55.230 And your computer is going to behave and certainly feel faster. 00:32:55.230 --> 00:32:58.830 Now the catch is that solid state drives, theoretically, 00:32:58.830 --> 00:33:02.340 won't necessarily last as long, depending on the quality of the brand 00:33:02.340 --> 00:33:04.470 and the technology being used whereby they only 00:33:04.470 --> 00:33:06.030 have a finite number of writes. 00:33:06.030 --> 00:33:09.070 You can read from them nearly as much as you want. 00:33:09.070 --> 00:33:12.600 But over time, they'll degrade in terms of how many times 00:33:12.600 --> 00:33:13.830 you can keep writing to them. 00:33:13.830 --> 00:33:15.570 Now, for many people this might be a non-issue, 00:33:15.570 --> 00:33:18.690 but to mitigate against this, has the industry also introduced what are 00:33:18.690 --> 00:33:20.170 called hybrid drives-- 00:33:20.170 --> 00:33:23.850 hard drives that might be the same size as this or the same size 00:33:23.850 --> 00:33:26.820 as a 3 and 1/2 inch drive like the spinning mechanical device we 00:33:26.820 --> 00:33:30.540 saw a moment ago in our animated form-- 00:33:30.540 --> 00:33:33.330 but they might have both some solid state memory 00:33:33.330 --> 00:33:38.010 and some mechanical hard drive memory so that you might have a few megabytes 00:33:38.010 --> 00:33:40.470 or gigabytes of solid state memory. 00:33:40.470 --> 00:33:44.220 And you might have a few gigabytes or terabytes of traditional hard disk 00:33:44.220 --> 00:33:44.910 space. 00:33:44.910 --> 00:33:48.870 And the device itself moves your data around in a clever way 00:33:48.870 --> 00:33:51.360 so that it tries to keep as much of the data that you 00:33:51.360 --> 00:33:55.170 want to use, at a given moment, on the solid state part of the device 00:33:55.170 --> 00:33:57.300 so that it's readily accessible for you. 00:33:57.300 --> 00:33:59.970 And the data that you might not need, right then and there, 00:33:59.970 --> 00:34:02.340 stays on the slower, more mechanical device 00:34:02.340 --> 00:34:04.920 where, nonetheless, you have a lot more storage. 00:34:04.920 --> 00:34:07.860 Now flash memory is something you might have heard about before now, 00:34:07.860 --> 00:34:09.920 but in the form of these things here, USB 00:34:09.920 --> 00:34:12.971 sticks that might store 1 gigabyte or 16 gigabytes or more. 00:34:12.971 --> 00:34:15.720 But it's data that you might want to carry around on your keychain 00:34:15.720 --> 00:34:18.030 or in your pocket or keep around on your desk simply 00:34:18.030 --> 00:34:20.519 for transferring files from one computer to another 00:34:20.519 --> 00:34:22.339 or keeping some data with you. 00:34:22.339 --> 00:34:24.630 They tend to be slower though, than solid state drives. 00:34:24.630 --> 00:34:26.340 They tend to be less reliable. 00:34:26.340 --> 00:34:29.420 But they also tend to be much less expensive, but also smaller 00:34:29.420 --> 00:34:30.330 in capacity. 00:34:30.330 --> 00:34:33.152 But the technology is very similar in spirit. 00:34:33.152 --> 00:34:34.860 If you need more storage space than that, 00:34:34.860 --> 00:34:38.272 you might actually carry around with you a solid state drive externally. 00:34:38.272 --> 00:34:40.480 So it might be a little bigger, and a little heavier, 00:34:40.480 --> 00:34:42.605 and not something you want to put on your keychain. 00:34:42.605 --> 00:34:46.620 But this might store 256 gigabytes of space 00:34:46.620 --> 00:34:51.570 or even a terabyte of space, all of which is now carried around externally. 00:34:51.570 --> 00:34:54.180 And via some kind of cable can you plug this device 00:34:54.180 --> 00:34:57.540 into your laptop or desktop or maybe a friend or colleague's computer 00:34:57.540 --> 00:35:00.930 so that you can share files without having a local network. 00:35:00.930 --> 00:35:04.590 If you need even more storage than that, 1 terabyte, 2 terabytes, 4 terabytes, 00:35:04.590 --> 00:35:08.130 or more, you might actually have another type of external hard drive 00:35:08.130 --> 00:35:11.910 inside of which is one of those older more traditional mechanical drives, 00:35:11.910 --> 00:35:17.250 the 3 and 1/2 inch disk devices, that might store much, much, much more data. 00:35:17.250 --> 00:35:20.050 But the price you pay is that it's a mechanical device. 00:35:20.050 --> 00:35:22.390 It might be, therefore, a little bit slower. 00:35:22.390 --> 00:35:24.540 And so ultimately, there's this trade-off 00:35:24.540 --> 00:35:27.600 between how much space you get, how much money you're spending, 00:35:27.600 --> 00:35:31.957 and how quickly you can get data from and to that external device. 00:35:31.957 --> 00:35:35.040 In fact, there's this whole series of trade-offs that we've seen thus far. 00:35:35.040 --> 00:35:37.200 And you can actually think of these various types 00:35:37.200 --> 00:35:40.200 of memory inside of a computer like a funnel of sorts 00:35:40.200 --> 00:35:44.310 whereby you have a pretty big opening where you keep a lot of your data 00:35:44.310 --> 00:35:45.930 on the biggest of your devices. 00:35:45.930 --> 00:35:49.380 But the goal is to get that data closer and closer and closer 00:35:49.380 --> 00:35:52.690 to your computer's brain where it can do some actual work. 00:35:52.690 --> 00:35:55.740 Indeed, if you think of the CPU as being at the bottom of this funnel, 00:35:55.740 --> 00:35:58.560 that's to whom you want to get all of this data. 00:35:58.560 --> 00:36:02.010 So throughout this funnel, you might have your hard disk or your solid state 00:36:02.010 --> 00:36:05.190 disk up here which stores a lot of your files a lot of your programs 00:36:05.190 --> 00:36:09.120 persistently in a nonvolatile way so that it's permanent even when 00:36:09.120 --> 00:36:11.910 the power or battery no longer works. 00:36:11.910 --> 00:36:16.740 But that hard disk or solid state disk ultimately feeds information down 00:36:16.740 --> 00:36:18.600 to your computer's RAM. 00:36:18.600 --> 00:36:21.480 But the ram is not the last stop before the computer's CPU. 00:36:21.480 --> 00:36:24.150 It turns out that there's other types of memory 00:36:24.150 --> 00:36:28.420 that a computer has that you might even see mentioned on your computer screen. 00:36:28.420 --> 00:36:30.930 So if up here you have your disk, whether it's 00:36:30.930 --> 00:36:33.930 a hard disk drive or a solid state disk drive, 00:36:33.930 --> 00:36:36.060 you might have quite a bit of this. 00:36:36.060 --> 00:36:41.550 This might be in the order of gigabytes or terabytes, billions of bytes 00:36:41.550 --> 00:36:43.080 or trillions of bytes. 00:36:43.080 --> 00:36:48.330 That gets fed into, ultimately, your computer's RAM, which probably exists 00:36:48.330 --> 00:36:51.600 on the order of these days of gigabytes, but fewer gigabytes 00:36:51.600 --> 00:36:52.810 than your actual disk. 00:36:52.810 --> 00:36:55.140 Down here you're going to have your CPU. 00:36:55.140 --> 00:36:58.410 And indeed, the goal is to get your data to the CPU. 00:36:58.410 --> 00:37:00.660 And the CPU, of course, is measured not in bytes 00:37:00.660 --> 00:37:02.790 but in gigahertz-- the number of billions of things 00:37:02.790 --> 00:37:05.520 it can do per second with that data. 00:37:05.520 --> 00:37:09.030 But there's also tends to be something in between RAM and CPU. 00:37:09.030 --> 00:37:14.130 There's often something called Level 3 cache, which might 00:37:14.130 --> 00:37:16.590 exist in the form of megabytes worth. 00:37:16.590 --> 00:37:19.980 Then it goes into what's called Level 2 cache, which 00:37:19.980 --> 00:37:21.840 is another type of memory, which also might 00:37:21.840 --> 00:37:26.610 be in the kilobyte or thousands of bytes or megabyte range. 00:37:26.610 --> 00:37:30.570 And then there might be L1 cache, which doesn't quite 00:37:30.570 --> 00:37:31.680 fit on this on the screen. 00:37:31.680 --> 00:37:32.310 But that's OK. 00:37:32.310 --> 00:37:35.460 Because it hints at just how small of a physical device this is, 00:37:35.460 --> 00:37:38.637 which might be on the order of, say, kilobytes. 00:37:38.637 --> 00:37:39.720 So these values will vary. 00:37:39.720 --> 00:37:42.160 And they'll certainly change over time. 00:37:42.160 --> 00:37:45.480 And so what's the pattern, then, among these various types of memory 00:37:45.480 --> 00:37:47.130 leading to the CPU? 00:37:47.130 --> 00:37:49.770 Well, the disk, whether a hard disk or solid state disk, 00:37:49.770 --> 00:37:52.800 is not only nonvolatile-- sticks around permanently, 00:37:52.800 --> 00:37:56.640 and it's where your files and your programs are stored when the power is 00:37:56.640 --> 00:37:57.391 off-- 00:37:57.391 --> 00:37:59.640 that's the biggest of these various types of memories, 00:37:59.640 --> 00:38:00.960 but it's also the slowest. 00:38:00.960 --> 00:38:04.520 Even solid state is slower than some of these other memories 00:38:04.520 --> 00:38:06.510 below it on the funnel here. 00:38:06.510 --> 00:38:10.170 Meanwhile, RAM tends to exist, still on the order of gigabytes, 00:38:10.170 --> 00:38:13.260 but maybe 1 gigabyte, 4 gigabytes, 16, maybe more 00:38:13.260 --> 00:38:15.300 if you've splurged on a really nice computer. 00:38:15.300 --> 00:38:17.610 But RAM recall is where programs and files 00:38:17.610 --> 00:38:21.750 live when you double-clicked or opened them in order to use them 00:38:21.750 --> 00:38:23.610 on your computer at a given moment. 00:38:23.610 --> 00:38:26.190 Meanwhile though-- and this is values you don't really 00:38:26.190 --> 00:38:28.509 control because they tend to be associated closely 00:38:28.509 --> 00:38:30.300 with the CPU or the motherboard that you've 00:38:30.300 --> 00:38:35.460 bought as part of your computer-- that RAM feeds information into Level 3 00:38:35.460 --> 00:38:41.820 and/or Level 2 and/or Level 1 cache in turn so that it's less memory there, 00:38:41.820 --> 00:38:43.860 but it's super, super fast. 00:38:43.860 --> 00:38:46.960 And that ensures that, even though there's less of this memory-- 00:38:46.960 --> 00:38:50.490 Level 1 cache exists in smaller quantities than Level 3-- 00:38:50.490 --> 00:38:52.230 that funnel is just always filled. 00:38:52.230 --> 00:38:54.396 There's always something at the bottom of the funnel 00:38:54.396 --> 00:38:55.740 ready to be fed into the CPU. 00:38:55.740 --> 00:38:59.820 So the CPU never, theoretically, has to wait for any data-- 00:38:59.820 --> 00:39:03.720 to get numbers to crunch, or text to display, or the like. 00:39:03.720 --> 00:39:07.230 Meanwhile, there exists, turns out, tiny little pieces 00:39:07.230 --> 00:39:11.040 of memory in a computer that we'll give a name to called registers. 00:39:11.040 --> 00:39:16.740 And these registers typically only hold 1 byte or 4 bytes or 8 bytes total. 00:39:16.740 --> 00:39:18.930 So they're the smallest unit of memory. 00:39:18.930 --> 00:39:22.620 But it's in those registers that the CPU stores values 00:39:22.620 --> 00:39:27.100 like numbers like those decimal numbers we discussed earlier. 00:39:27.100 --> 00:39:29.644 And if it wants to perform arithmetic of any sort, 00:39:29.644 --> 00:39:32.560 it stores those values in these registers, actually performs the math, 00:39:32.560 --> 00:39:35.190 stores the result in another register, so it's, then, ready 00:39:35.190 --> 00:39:39.210 to be loaded back through this funnel into something like the computer's RAM 00:39:39.210 --> 00:39:41.850 or ultimately saved back to disk. 00:39:41.850 --> 00:39:43.500 But there's another trade-off here. 00:39:43.500 --> 00:39:47.100 Besides the top of this funnel being bigger and slower, 00:39:47.100 --> 00:39:50.036 and the bottom of this funnel being smaller and faster, 00:39:50.036 --> 00:39:52.410 the bottom of the funnel also tends to be more expensive, 00:39:52.410 --> 00:39:54.870 which also explains, in part, why you see less 00:39:54.870 --> 00:39:56.900 of this memory inside of a computer. 00:39:56.900 --> 00:39:59.239 The Level 1 cache might be more expensive than ram, 00:39:59.239 --> 00:40:01.530 so you have less of it and, technically, you don't even 00:40:01.530 --> 00:40:03.696 need as much of it so long as there's enough to keep 00:40:03.696 --> 00:40:05.700 data waiting for the CPU. 00:40:05.700 --> 00:40:08.520 But cost is certainly another trade-off as well. 00:40:08.520 --> 00:40:11.746 But the types of numbers that you, as a consumer, might care about, really, 00:40:11.746 --> 00:40:13.620 would be how big the disk in your computer is 00:40:13.620 --> 00:40:16.229 and how much data and programs and files you can store, 00:40:16.229 --> 00:40:17.520 how much RAM your computer has. 00:40:17.520 --> 00:40:19.920 Because that correlates with just how much work 00:40:19.920 --> 00:40:22.160 you can do at once, how many files and programs you 00:40:22.160 --> 00:40:25.450 can keep running simultaneously without having to quit any of them. 00:40:25.450 --> 00:40:28.830 And so cache, finally, which is more closely 00:40:28.830 --> 00:40:32.380 tied to the CPU and the motherboard in your computer and, therefore, 00:40:32.380 --> 00:40:35.610 isn't really a number you have as much control over as the consumer, 00:40:35.610 --> 00:40:38.730 just ensures that the data is actually ready. 00:40:38.730 --> 00:40:40.760 Now this might all sound fairly technical. 00:40:40.760 --> 00:40:44.220 But these caches, whether Level 3 or 2 or 1 are actually 00:40:44.220 --> 00:40:47.230 quite similar to techniques that we humans use in the real world, 00:40:47.230 --> 00:40:51.200 for instance, even at your local candy store. 00:40:51.200 --> 00:40:53.300 Here's my candy store, and I'm open for business. 00:40:55.860 --> 00:40:56.880 SPEAKER: Candy, please? 00:40:56.880 --> 00:40:58.630 DAVID J. MALAN: Let me get you some candy. 00:40:58.630 --> 00:41:00.250 [FOOTSTEPS] 00:41:05.381 --> 00:41:05.880 Thank you. 00:41:05.880 --> 00:41:07.816 Come again. 00:41:07.816 --> 00:41:10.190 Now that was not very efficient to have to go all the way 00:41:10.190 --> 00:41:12.330 and back into the store room to get the candy. 00:41:12.330 --> 00:41:15.270 Much more efficient would be to keep it closer to me 00:41:15.270 --> 00:41:19.770 in a place that's faster to access much like a cache of candy right here 00:41:19.770 --> 00:41:20.520 on the counter. 00:41:20.520 --> 00:41:22.394 In fact, let me go ahead and ready that cash. 00:41:22.394 --> 00:41:24.496 [FOOTSTEPS] 00:41:28.490 --> 00:41:33.106 And now, with this cache of candy am I open for business again. 00:41:33.106 --> 00:41:34.390 SPEAKER: Candy, please? 00:41:34.390 --> 00:41:35.473 DAVID J. MALAN: Thank you. 00:41:35.473 --> 00:41:36.550 Come again. 00:41:36.550 --> 00:41:38.950 Now this is a small cache of candy, but it's fast. 00:41:38.950 --> 00:41:42.850 And, with it, can I provide my customers or really my CPU with information 00:41:42.850 --> 00:41:44.230 much more quickly. 00:41:47.250 --> 00:41:50.900 Now we can actually see the sizes of these caches in that same output 00:41:50.900 --> 00:41:53.404 that we saw earlier from Windows and Mac OS. 00:41:53.404 --> 00:41:55.820 For instance, if we look again at the Windows Task Manager 00:41:55.820 --> 00:41:59.630 and look down here, you can actually see that this particular laptop 00:41:59.630 --> 00:42:03.800 had L1 cache on the order of 128 kilobytes or thousands of bytes. 00:42:03.800 --> 00:42:09.170 It had 512 kilobytes of L2 cache, and 4 megabytes of L3 cache. 00:42:09.170 --> 00:42:12.240 Meanwhile, if we take a look at that same MacBook Pro from earlier, 00:42:12.240 --> 00:42:17.450 you'll see that it has 256 kilobytes of cache, 4 megabytes of L3 cache, 00:42:17.450 --> 00:42:21.260 doesn't happen to mention L1 cache, but odds are, it's indeed there on the CPU, 00:42:21.260 --> 00:42:24.230 just not reported by this program. 00:42:24.230 --> 00:42:28.130 Now what else is inside or really outside of a computer? 00:42:28.130 --> 00:42:31.370 In fact, let's start to take a look at things, perhaps, more familiar. 00:42:31.370 --> 00:42:35.930 Now these are just graphical depictions of connectors or sockets 00:42:35.930 --> 00:42:39.590 on the back of your computer into which you might have very well plugged 00:42:39.590 --> 00:42:41.040 in various devices. 00:42:41.040 --> 00:42:43.910 In fact, this collection of ports here are all 00:42:43.910 --> 00:42:46.610 related to monitors or displays. 00:42:46.610 --> 00:42:49.100 So a computer, like a desktop computer, tends 00:42:49.100 --> 00:42:50.940 not to come with a monitor built in. 00:42:50.940 --> 00:42:54.290 And if it does, indeed not, you might need to plug-in an external monitor 00:42:54.290 --> 00:42:56.870 using something like mini DisplayPort-- 00:42:56.870 --> 00:43:00.050 very commonly found on laptops, especially if you want to have, 00:43:00.050 --> 00:43:01.820 not just your primary laptop display, but 00:43:01.820 --> 00:43:04.430 a secondary, a bigger monitor on your desk-- 00:43:04.430 --> 00:43:07.340 DisplayPort, which is the same idea, but a larger connector 00:43:07.340 --> 00:43:10.430 that you might typically have on a desktop plugging into a monitor-- 00:43:10.430 --> 00:43:13.730 HDMI, which you might have, not only on your laptop or desktop, 00:43:13.730 --> 00:43:17.390 but possibly even on your TV at home because this is also the type of cable 00:43:17.390 --> 00:43:20.960 that you would use to plug a TV into some kind of set-top device 00:43:20.960 --> 00:43:21.830 in your living room. 00:43:21.830 --> 00:43:23.020 And then, lastly, VGA-- 00:43:23.020 --> 00:43:24.770 still on the list, even though it's super, 00:43:24.770 --> 00:43:28.520 super old and not nearly as featureful as these other technologies. 00:43:28.520 --> 00:43:31.610 But you'll very often find at universities like this and companies 00:43:31.610 --> 00:43:38.330 that have long had projectors installed in their rooms, this older technology, 00:43:38.330 --> 00:43:41.430 and so it, too, is still pretty common. 00:43:41.430 --> 00:43:44.730 Now, what else might we want to plug into a computer? 00:43:44.730 --> 00:43:48.980 Well, any number of devices as well-- in fact, if you've ever seen this symbol, 00:43:48.980 --> 00:43:52.840 that means you have a port on your computer, desktop or laptop, into which 00:43:52.840 --> 00:43:55.090 you can plug a whole range of devices. 00:43:55.090 --> 00:43:58.100 If you've ever needed to plug a printer into your computer, 00:43:58.100 --> 00:44:02.450 you might use the port label with this-- a scanner, a digital camera, 00:44:02.450 --> 00:44:06.380 any number of other peripheral devices might be connected to your computer 00:44:06.380 --> 00:44:07.790 by way of this device here. 00:44:07.790 --> 00:44:10.780 Even your mouse and your keyboard, if they're not already wireless, 00:44:10.780 --> 00:44:12.860 would be plugged in with this device here. 00:44:12.860 --> 00:44:15.189 And it might actually take any number of shapes, 00:44:15.189 --> 00:44:17.730 though thankfully, some of these are more common than others. 00:44:17.730 --> 00:44:19.660 This is the universal serial bus-- 00:44:19.660 --> 00:44:22.040 where a bus as a term technologically that 00:44:22.040 --> 00:44:25.970 refers to some kind of medium along which data can travel, much like a bus 00:44:25.970 --> 00:44:27.380 travels down a street. 00:44:27.380 --> 00:44:31.730 So USB has a whole bunch of different connectors as depicted here. 00:44:31.730 --> 00:44:34.490 And the most common of which is just this rectangular one that, 00:44:34.490 --> 00:44:38.120 rather annoyingly, only 50% of the time do you, if you're like me, 00:44:38.120 --> 00:44:42.470 plug the cable in the right way because it can only go in one certain way. 00:44:42.470 --> 00:44:43.970 So you might have to flip it around. 00:44:43.970 --> 00:44:46.345 But on the other end of that cable might be another type, 00:44:46.345 --> 00:44:50.960 not USB A, but USB B, which is commonly used 00:44:50.960 --> 00:44:54.080 to plug into the back of scanners and printers and beyond. 00:44:54.080 --> 00:44:57.590 More recently, though, have companies like Apples and others 00:44:57.590 --> 00:44:59.660 started using using USB C-- 00:44:59.660 --> 00:45:03.920 a third type of connector that, thankfully, can go either top down 00:45:03.920 --> 00:45:07.280 or bottom up, thereby, not having to think as much when 00:45:07.280 --> 00:45:08.640 you want to plug in a device. 00:45:08.640 --> 00:45:11.723 But there's any number of other variants of these connectors commonly seen 00:45:11.723 --> 00:45:15.830 on cell phones, in fact, for chargers and data cables, all of which support 00:45:15.830 --> 00:45:16.730 USB. 00:45:16.730 --> 00:45:19.310 Now the USB standard, itself, has evolved over time. 00:45:19.310 --> 00:45:22.970 So the latest and greatest version of USB devices and connectors 00:45:22.970 --> 00:45:26.930 are actually much faster than some of the historically older devices 00:45:26.930 --> 00:45:27.530 and cables. 00:45:27.530 --> 00:45:30.440 And so it actually does matter what kind of cable you have 00:45:30.440 --> 00:45:33.920 and what device you have as to whether or not it will transfer data 00:45:33.920 --> 00:45:35.390 as fast as you might like. 00:45:35.390 --> 00:45:36.690 Now why is this important? 00:45:36.690 --> 00:45:41.600 Well, one of the devices you can connect to a computer, typically via USB cable, 00:45:41.600 --> 00:45:43.430 is something like an external hard drive. 00:45:43.430 --> 00:45:46.820 And even if you have a super fast external hard drive that 00:45:46.820 --> 00:45:49.880 is, say, an SSD underneath the hood, if you're 00:45:49.880 --> 00:45:52.512 using a slower older USB cable or technology, 00:45:52.512 --> 00:45:54.470 you might not, nonetheless, be able to transfer 00:45:54.470 --> 00:45:58.790 that data off a very fast device over a slow cable to your computer. 00:45:58.790 --> 00:46:03.020 So keeping an eye out for the latest versions of these technologies like USB 00:46:03.020 --> 00:46:05.180 can actually be quite important. 00:46:05.180 --> 00:46:08.600 But, of course, you might not need cables at all for certain devices. 00:46:08.600 --> 00:46:12.110 Of course, if you want to use Wi-Fi or wireless internet in your home, 00:46:12.110 --> 00:46:16.070 in the airport, in Starbucks, or elsewhere, your computer just 00:46:16.070 --> 00:46:19.382 needs to support Wi-Fi, which odds are, it very much does these days. 00:46:19.382 --> 00:46:21.590 And you might see a symbol somewhere in your computer 00:46:21.590 --> 00:46:23.750 like this depicting as much. 00:46:23.750 --> 00:46:26.330 But not everything operates over Wi-Fi. 00:46:26.330 --> 00:46:30.260 In fact, devices that you might want to plug into or connect to your computer 00:46:30.260 --> 00:46:32.900 without a cable would tend to use not Wi-Fi, 00:46:32.900 --> 00:46:35.300 but another wireless technology called Bluetooth 00:46:35.300 --> 00:46:39.119 that Windows computers and Macs alike support these days. 00:46:39.119 --> 00:46:40.910 So in fact, if you have a wireless keyboard 00:46:40.910 --> 00:46:43.910 at home or at work, or a wireless mouse, or if you 00:46:43.910 --> 00:46:47.900 have any number of other devices that, somehow, are wirelessly communicating 00:46:47.900 --> 00:46:51.376 with your computer, perhaps even your headphones these days, odds are, 00:46:51.376 --> 00:46:53.750 those are using a technology called Bluetooth, which have 00:46:53.750 --> 00:46:56.160 a limited range of just so many feeds. 00:46:59.150 --> 00:47:02.330 They don't afford you nearly as much distance as something like Wi-Fi does, 00:47:02.330 --> 00:47:03.460 but that's a good thing. 00:47:03.460 --> 00:47:05.210 Because generally, this technology is used 00:47:05.210 --> 00:47:08.720 to interconnect your personal devices to your personal computer 00:47:08.720 --> 00:47:11.810 and not really to others around you. 00:47:11.810 --> 00:47:14.960 So with all of these various devices inside of and, potentially, 00:47:14.960 --> 00:47:17.041 connected outside of my computer, what is 00:47:17.041 --> 00:47:19.165 it that ensures that they can all intercommunicate? 00:47:19.165 --> 00:47:21.580 And what is it that ensures that all of this works? 00:47:21.580 --> 00:47:23.580 Well, at the end of the day it's the, so-called, 00:47:23.580 --> 00:47:26.300 operating system whether it's Mac OS or Windows, 00:47:26.300 --> 00:47:29.390 which is simply software, that either you or, more likely, 00:47:29.390 --> 00:47:32.930 some manufacturer pre-installed on the computer that you bought. 00:47:32.930 --> 00:47:36.320 And that software is installed on your hard drive or your solid state disk 00:47:36.320 --> 00:47:37.876 so that it's there persistently. 00:47:37.876 --> 00:47:40.250 And so that, even when you unwrap that shrink-wrapped box 00:47:40.250 --> 00:47:43.430 that has had no power for some time, the operating system is ready to go. 00:47:43.430 --> 00:47:46.304 And, indeed, when you hit the power button on your laptop or desktop, 00:47:46.304 --> 00:47:51.170 it's the operating system, ultimately, that is loaded into RAM from disk, 00:47:51.170 --> 00:47:52.949 and is what you ultimately see. 00:47:52.949 --> 00:47:55.490 In fact, it's the operating system that gives you, literally, 00:47:55.490 --> 00:47:58.010 the graphical windows that you see and the icons and the buttons 00:47:58.010 --> 00:47:58.850 that you can click. 00:47:58.850 --> 00:48:01.220 But more importantly, it's the operating system 00:48:01.220 --> 00:48:03.862 that knows how to talk to your keyboard and your mouse. 00:48:03.862 --> 00:48:05.570 It's your operating system that knows how 00:48:05.570 --> 00:48:07.222 to display information on the screen. 00:48:07.222 --> 00:48:08.930 It's your operating system that knows how 00:48:08.930 --> 00:48:12.380 to move things around in memory and disk and reading and writing 00:48:12.380 --> 00:48:13.877 all of that information. 00:48:13.877 --> 00:48:16.460 And that's all thanks to software that comes with an operating 00:48:16.460 --> 00:48:18.500 system called device drivers-- 00:48:18.500 --> 00:48:22.580 special software designed to talk to a certain model of printer, 00:48:22.580 --> 00:48:25.449 to a certain model of camera, or scanner, and the like. 00:48:25.449 --> 00:48:28.490 And, in fact, even when Windows or Mac OS or Linux or any other operating 00:48:28.490 --> 00:48:32.300 system doesn't recognize some device-- maybe because it didn't exist when 00:48:32.300 --> 00:48:36.059 Windows or Mac OS or Linux was installed on your computer-- 00:48:36.059 --> 00:48:38.600 well, you can very often download new software device drivers 00:48:38.600 --> 00:48:41.510 from the manufacturer's website of the manufacturer that 00:48:41.510 --> 00:48:42.960 made that new technology. 00:48:42.960 --> 00:48:46.610 And that can teach Windows and Mac OS and Linux and others 00:48:46.610 --> 00:48:48.280 to understand that new hardware. 00:48:48.280 --> 00:48:51.800 And so there is a future-proofing built into these operating systems 00:48:51.800 --> 00:48:54.230 because, at the end of the day, they're just software. 00:48:54.230 --> 00:48:56.480 And so it's this intersection of hardware and software 00:48:56.480 --> 00:48:59.660 that makes these computers just so powerful. 00:48:59.660 --> 00:49:02.870 Now, it's all fun and good to talk about hardware 00:49:02.870 --> 00:49:04.730 and see it depicted on the screen. 00:49:04.730 --> 00:49:07.880 But let's actually get our hands dirty here and actually enter 00:49:07.880 --> 00:49:10.940 into our own laboratory and take a look on the outside 00:49:10.940 --> 00:49:14.510 and inside of some actual computers. 00:49:14.510 --> 00:49:18.354 I'm here now with Dr. Colton Ogden for a look inside a couple of computers. 00:49:18.354 --> 00:49:20.270 COLTON OGDEN: Happy to be with you guys today. 00:49:20.270 --> 00:49:23.057 We have an IBM ThinkPad laptop here. 00:49:23.057 --> 00:49:24.640 Nobody really needs to use it anymore. 00:49:24.640 --> 00:49:27.681 So I figured we'd show you guys what a computer looks like on the outside 00:49:27.681 --> 00:49:29.910 before we start digging in on the inside. 00:49:29.910 --> 00:49:33.110 So you want to start off by maybe showing what some of these ports 00:49:33.110 --> 00:49:34.100 are here on the laptop? 00:49:34.100 --> 00:49:34.320 DAVID J. MALAN: Yeah. 00:49:34.320 --> 00:49:34.820 Sure. 00:49:34.820 --> 00:49:36.320 So here's one of those older ports. 00:49:36.320 --> 00:49:37.861 And, indeed, this is an older laptop. 00:49:37.861 --> 00:49:41.600 This is a so-called VGA port into which you would plug a cable to connect it, 00:49:41.600 --> 00:49:44.390 either to an external monitor, or more realistically, on a campus 00:49:44.390 --> 00:49:45.420 or in a workplace. 00:49:45.420 --> 00:49:47.960 It's like a projector so that other people can see. 00:49:47.960 --> 00:49:52.170 If you can believe it, this is an RJ11 jack for an old school modem or a phone 00:49:52.170 --> 00:49:52.670 cable. 00:49:52.670 --> 00:49:55.430 So that you could actually dial up to AOL. 00:49:55.430 --> 00:49:56.660 COLTON OGDEN: Old school. 00:49:56.660 --> 00:49:58.760 DAVID J.MALAN: Here's an RJ45 connector, which 00:49:58.760 --> 00:50:02.450 actually looks like this here, as sort of a fat network cable. 00:50:02.450 --> 00:50:06.080 And that's what you would use to get online with wired internet. 00:50:06.080 --> 00:50:09.620 Here, we have a microphone jack, if you have an external mic, headphone jack 00:50:09.620 --> 00:50:13.940 if you want to listen to music at work, USB to connect 00:50:13.940 --> 00:50:16.010 any number of external devices. 00:50:16.010 --> 00:50:16.520 And oh. 00:50:16.520 --> 00:50:18.040 What's this one we've got over here? 00:50:18.040 --> 00:50:20.390 COLTON OGDEN: It looks like we've got a DVD port. 00:50:20.390 --> 00:50:21.640 You don't see these very often anymore. 00:50:21.640 --> 00:50:23.681 It's not going to work because the laptop is off. 00:50:23.681 --> 00:50:26.070 But we also have a couple of USB ports here on the side. 00:50:26.070 --> 00:50:28.460 And I think that's pretty much all we have on this guy. 00:50:28.460 --> 00:50:28.570 DAVID J. MALAN: Yeah. 00:50:28.570 --> 00:50:31.430 A DVD or CD drive is what's known as optical storage. 00:50:31.430 --> 00:50:34.700 And it really is just a piece of plastic, the CD or DVD, 00:50:34.700 --> 00:50:37.850 with some reflective material on it and little divots or pits that 00:50:37.850 --> 00:50:40.760 are created with a laser that gets, then, read with the laser 00:50:40.760 --> 00:50:43.220 so that you can actually write 0s and 1s by, 00:50:43.220 --> 00:50:45.770 essentially, having a smooth surface or little bumps. 00:50:45.770 --> 00:50:49.920 But it's increasingly falling into disuse as Flash Media of various sorts 00:50:49.920 --> 00:50:51.260 is being used instead. 00:50:51.260 --> 00:50:53.330 Well, why don't we not gut this, although, I do 00:50:53.330 --> 00:50:55.640 see it's power cable sitting here. 00:50:55.640 --> 00:50:59.330 So you'll notice that most laptops like this have power cables that one 00:50:59.330 --> 00:51:02.330 go into the wall, then some other proprietary or standard connector that 00:51:02.330 --> 00:51:03.890 goes into the laptop, and then a brick. 00:51:03.890 --> 00:51:05.473 Sometimes that gets a little bit warm. 00:51:05.473 --> 00:51:07.730 And what this brick is doing is it's actually 00:51:07.730 --> 00:51:11.750 converting the 120 volts or 240 volts coming out of your wall 00:51:11.750 --> 00:51:15.920 to far fewer volts that your laptop can actually tolerate. 00:51:15.920 --> 00:51:18.020 Shall we take a look at the desktop next? 00:51:18.020 --> 00:51:18.380 COLTON OGDEN: Yeah. 00:51:18.380 --> 00:51:18.740 Perfect. 00:51:18.740 --> 00:51:21.989 So let's go ahead and take a look at the internals of a computer with this guy 00:51:21.989 --> 00:51:22.850 here. 00:51:22.850 --> 00:51:27.540 So I'm going to go ahead and just take off the casing's lid here. 00:51:27.540 --> 00:51:29.340 DAVID J. MALAN: And this is an older PC-- 00:51:29.340 --> 00:51:29.620 COLTON OGDEN: Yes. 00:51:29.620 --> 00:51:30.170 DAVID J. MALAN: --desktop right? 00:51:30.170 --> 00:51:31.700 An older Windows PC. 00:51:31.700 --> 00:51:34.817 And so you find that Mac computers aren't so readily taken apart. 00:51:34.817 --> 00:51:36.650 In fact, that's one of the features of Apple 00:51:36.650 --> 00:51:39.245 computers is that they have far fewer user serviceable parts, 00:51:39.245 --> 00:51:41.120 but the price you pay, of course, is that you 00:51:41.120 --> 00:51:43.905 can't upgrade them or reconfigure them, often using magnets to. 00:51:43.905 --> 00:51:44.780 COLTON OGDEN: Indeed. 00:51:44.780 --> 00:51:45.190 DAVID J. MALAN: All right. 00:51:45.190 --> 00:51:46.600 So what do we have inside of here? 00:51:46.600 --> 00:51:46.830 COLTON OGDEN: OK. 00:51:46.830 --> 00:51:48.870 So we have, in here, a lot of the parts you were just 00:51:48.870 --> 00:51:50.120 talking about in your lecture. 00:51:50.120 --> 00:51:53.024 We have a CPU with its heat sink here, right in the middle. 00:51:53.024 --> 00:51:54.690 DAVID J. MALAN: That's a huge heat sink. 00:51:54.690 --> 00:51:55.525 And that does what? 00:51:55.525 --> 00:51:56.900 COLTON OGDEN: It dissipates heat. 00:51:56.900 --> 00:51:58.170 A CPU is very hot. 00:51:58.170 --> 00:51:59.670 It's oscillating very fast. 00:51:59.670 --> 00:52:04.080 And so the purpose of this is to, with all of these planes, disperse 00:52:04.080 --> 00:52:08.370 the heat equally and then get rid of it alongside the fan 00:52:08.370 --> 00:52:10.150 as well, which acts in tandem with it. 00:52:10.150 --> 00:52:10.320 DAVID J. MALAN: Yeah. 00:52:10.320 --> 00:52:12.420 It's a big fan, like you would have in the summertime. 00:52:12.420 --> 00:52:12.900 COLTON OGDEN: Oh, yeah. 00:52:12.900 --> 00:52:13.401 Definitely. 00:52:13.401 --> 00:52:14.483 DAVID J. MALAN: All right. 00:52:14.483 --> 00:52:15.960 And what about these green sticks? 00:52:15.960 --> 00:52:17.850 COLTON OGDEN: These green sticks, we only have one in this laptop. 00:52:17.850 --> 00:52:20.760 But this is actually a stick of RAM, so random access memory 00:52:20.760 --> 00:52:23.209 where computers' programs are stored as they're loaded. 00:52:23.209 --> 00:52:24.000 DAVID J. MALAN: OK. 00:52:24.000 --> 00:52:26.776 And that's connected to this bigger green sheet, which is-- 00:52:26.776 --> 00:52:29.150 COLTON OGDEN: This bigger green sheet is the motherboard. 00:52:29.150 --> 00:52:31.230 It's sort of like the central hub for all the parts 00:52:31.230 --> 00:52:32.688 working together with the computer. 00:52:32.688 --> 00:52:35.160 It acts as sort of a messaging interface for everything. 00:52:35.160 --> 00:52:35.420 DAVID J. MALAN: OK. 00:52:35.420 --> 00:52:37.890 And now, doctor, can I take a look at that piece of RAM? 00:52:37.890 --> 00:52:38.530 Do you need it? 00:52:38.530 --> 00:52:39.090 COLTON OGDEN: Absolutely. 00:52:39.090 --> 00:52:39.220 No. 00:52:39.220 --> 00:52:40.230 Let's take it out of here. 00:52:40.230 --> 00:52:40.410 DAVID J. MALAN: All right. 00:52:40.410 --> 00:52:42.045 So that just snaps right out. 00:52:42.045 --> 00:52:42.650 COLTON OGDEN: Snaps right out. 00:52:42.650 --> 00:52:43.441 DAVID J. MALAN: Ah. 00:52:43.441 --> 00:52:46.542 So it looks pretty much like the image we had earlier 00:52:46.542 --> 00:52:48.500 with a bunch of black chips here, each of which 00:52:48.500 --> 00:52:51.250 store some number of megabytes or gigabytes probably. 00:52:51.250 --> 00:52:54.000 And then the little gold pin, so to speak, that could actually get 00:52:54.000 --> 00:52:54.420 plugged in. 00:52:54.420 --> 00:52:55.720 And they can only go a certain way. 00:52:55.720 --> 00:52:58.320 In fact, I've done this blindly before where I've accidentally 00:52:58.320 --> 00:53:01.320 plugged it in the wrong way, only to realize, it actually goes this way. 00:53:01.320 --> 00:53:03.895 And that's why this little divot here is asymmetric. 00:53:03.895 --> 00:53:04.770 COLTON OGDEN: Indeed. 00:53:04.770 --> 00:53:06.940 DAVID J. MALAN: I'm done with this, doctor. 00:53:06.940 --> 00:53:07.440 OK. 00:53:07.440 --> 00:53:08.370 We're not going to put that back in. 00:53:08.370 --> 00:53:10.500 And what's this big thing in the back of a PC? 00:53:10.500 --> 00:53:12.677 COLTON OGDEN: So this is the Power Supply or PSU. 00:53:12.677 --> 00:53:15.760 It essentially just powers everything up with electricity in the computer. 00:53:15.760 --> 00:53:16.100 DAVID J. MALAN: I see. 00:53:16.100 --> 00:53:18.630 And so if this is the extent to which you've actually 00:53:18.630 --> 00:53:21.338 played with the inside of your computer before-- this, of course, 00:53:21.338 --> 00:53:22.381 is the power cable. 00:53:22.381 --> 00:53:25.380 And this is actually a standardized plug that goes back into the device. 00:53:25.380 --> 00:53:28.160 You can actually use this or any number of other cables on your own computer. 00:53:28.160 --> 00:53:28.610 COLTON OGDEN: Indeed. 00:53:28.610 --> 00:53:28.770 DAVID J. MALAN: All right. 00:53:28.770 --> 00:53:31.890 So where is my data stored when not in RAM persistently? 00:53:31.890 --> 00:53:35.470 COLTON OGDEN: When not in RAM, you have, here, an external Hard Drive, an HDB, 00:53:35.470 --> 00:53:37.220 or an internal hard drive in this context. 00:53:37.220 --> 00:53:38.011 DAVID J. MALAN: OK. 00:53:38.011 --> 00:53:41.641 So this is older and bigger probably than something like an SSD? 00:53:41.641 --> 00:53:42.390 COLTON OGDEN: Yes. 00:53:42.390 --> 00:53:47.879 Older and larger, but probably stores less since this is an older computer. 00:53:47.879 --> 00:53:50.920 And it's connected to the motherboard using what's called the SATA cable, 00:53:50.920 --> 00:53:52.860 S-A-T-A, which hooks right into the motherboard. 00:53:52.860 --> 00:53:53.190 DAVID J. MALAN: Oh, yeah. 00:53:53.190 --> 00:53:55.510 Can we can we pull that out without that much damage here? 00:53:55.510 --> 00:53:55.900 COLTON OGDEN: Yeah. 00:53:55.900 --> 00:53:56.399 Absolutely. 00:53:56.399 --> 00:53:59.429 So it's a pretty small cable, it plugs right into the motherboard there. 00:53:59.429 --> 00:54:00.220 DAVID J. MALAN: Ah. 00:54:00.220 --> 00:54:00.855 OK. 00:54:00.855 --> 00:54:05.280 So it's got kind of a nice angled shape so that it only goes, in it would seem, 00:54:05.280 --> 00:54:05.990 one way. 00:54:05.990 --> 00:54:06.490 All right. 00:54:06.490 --> 00:54:08.400 And actually, it looks like a different type of cable 00:54:08.400 --> 00:54:09.660 is used for this older technology. 00:54:09.660 --> 00:54:11.530 We seem to have another DVD or CD drive up there? 00:54:11.530 --> 00:54:12.000 COLTON OGDEN: We do. 00:54:12.000 --> 00:54:12.500 We do. 00:54:12.500 --> 00:54:14.520 We have a DVD drive. 00:54:14.520 --> 00:54:16.350 And actually it does you SATA as well. 00:54:16.350 --> 00:54:16.762 DAVID J. MALAN: Oh, Yes. 00:54:16.762 --> 00:54:18.280 COLTON OGDEN: It plugs right in with the hard drives. 00:54:18.280 --> 00:54:18.560 DAVID J. MALAN: Oh. 00:54:18.560 --> 00:54:20.750 But it has a special power cable that drives that. 00:54:20.750 --> 00:54:21.500 COLTON OGDEN: Yep. 00:54:21.500 --> 00:54:21.630 Exactly. 00:54:21.630 --> 00:54:23.796 DAVID J. MALAN: --just like the hard drive does too. 00:54:23.796 --> 00:54:26.350 So actually, we have, in advance, taken apart 00:54:26.350 --> 00:54:30.175 and 3.5 inch mechanical hard drive that you previously 00:54:30.175 --> 00:54:32.550 had a whole bunch of screws on it and probably previously 00:54:32.550 --> 00:54:34.202 had a whole bunch of data on it. 00:54:34.202 --> 00:54:35.910 But now that we've exposed it to the air, 00:54:35.910 --> 00:54:38.400 and therefore all of the dust particles here in the theater, 00:54:38.400 --> 00:54:40.358 probably not going to be very reliable anymore. 00:54:40.358 --> 00:54:43.980 But what's really cool now is that we took off all but one of the screws 00:54:43.980 --> 00:54:48.190 so we can actually pull this off. 00:54:48.190 --> 00:54:52.870 And you can see what's been inside your own hard drive perhaps all this time. 00:54:52.870 --> 00:54:55.380 So this is, again, is 3 and 1/2 inches across, 00:54:55.380 --> 00:54:58.980 which is a standard size, at least, for these older larger mechanical drives. 00:54:58.980 --> 00:55:01.830 There's also a 2.5 inch version of this commonly found in laptops 00:55:01.830 --> 00:55:04.320 or even higher-end desktops these days. 00:55:04.320 --> 00:55:07.170 And there's that mechanical arm that won't move now because there's 00:55:07.170 --> 00:55:08.520 no power going into this. 00:55:08.520 --> 00:55:11.670 But if there were, we'd be plugging it in to the back of the device 00:55:11.670 --> 00:55:15.330 here and then that SATA cable, which actually runs the power. 00:55:15.330 --> 00:55:19.140 And how many-- it looks like there's two platters here. 00:55:19.140 --> 00:55:19.710 Two platters. 00:55:19.710 --> 00:55:22.110 So the data store probably on the top, on the bottom, 00:55:22.110 --> 00:55:24.176 and then on the other top, and the other bottom, 00:55:24.176 --> 00:55:25.800 thereby fitting even more data in here. 00:55:25.800 --> 00:55:27.660 And if this were an even newer bigger hard drive, 00:55:27.660 --> 00:55:30.360 we could probably fit even more platters, and therefore more data. 00:55:30.360 --> 00:55:33.090 And increasingly, is the data being stored closer and closer together, 00:55:33.090 --> 00:55:35.790 so all those magnetic particles are packed ever more densely, 00:55:35.790 --> 00:55:37.890 which also means we can store more bits and thus 00:55:37.890 --> 00:55:40.181 bytes and thus files and programs. 00:55:40.181 --> 00:55:40.680 All right. 00:55:40.680 --> 00:55:43.390 So what we also have here a motherboard. 00:55:43.390 --> 00:55:46.000 Can we take a closer look at this outside of the box? 00:55:46.000 --> 00:55:47.125 COLTON OGDEN: Yes. 00:55:47.125 --> 00:55:49.500 DAVID J. MALAN: So this one looks a little bit different. 00:55:49.500 --> 00:55:51.840 And, in fact, I don't see a CPU. 00:55:51.840 --> 00:55:52.889 Where's our CPU gone? 00:55:52.889 --> 00:55:54.930 COLTON OGDEN: Well, this one does not have a CPU. 00:55:54.930 --> 00:55:56.221 It's been taken out in advance. 00:55:56.221 --> 00:55:58.740 But most of the other components are still in place here. 00:55:58.740 --> 00:56:02.111 We have RAM, we have a heat sink, and we have a lot of other ports 00:56:02.111 --> 00:56:04.860 and such that we've seen on the other motherboard and was looking. 00:56:04.860 --> 00:56:07.170 DAVID J. MALAN: And these internal ports, what gets plugged into those? 00:56:07.170 --> 00:56:08.850 COLTON OGDEN: So these are PCI slots. 00:56:08.850 --> 00:56:11.880 You'll see oftentimes graphics cards, sound cards-- 00:56:11.880 --> 00:56:15.180 other things that aren't necessarily always with a computer, 00:56:15.180 --> 00:56:17.639 but are optional-- those get plugged into these ports here. 00:56:17.639 --> 00:56:20.846 DAVID J. MALAN: And it looks like if we plug this into the back of a computer 00:56:20.846 --> 00:56:23.820 just right, these things should stick out the back of the plastic case? 00:56:23.820 --> 00:56:24.150 COLTON OGDEN: Yes. 00:56:24.150 --> 00:56:26.340 These are ports that are often user-facing, 00:56:26.340 --> 00:56:31.530 so you can plug-in peripherals such as keyboards, mice, 00:56:31.530 --> 00:56:36.450 monitors with VGA ports, maybe headphones or speakers with these ports 00:56:36.450 --> 00:56:40.719 here, headphones, microphones line out, and a few other ports, maybe-- 00:56:40.719 --> 00:56:43.760 DAVID J. MALAN: Do you want to talk to them in some of these older ports? 00:56:43.760 --> 00:56:44.980 These are really from my day. 00:56:44.980 --> 00:56:46.813 So the parallel port, which is where we used 00:56:46.813 --> 00:56:49.320 to put our printers or serial ports-- 00:56:49.320 --> 00:56:51.820 I don't know what voice that is-- but our serial ports where 00:56:51.820 --> 00:56:55.930 we used to put our joysticks for playing the games, a VGA port, of course, 00:56:55.930 --> 00:56:59.410 and then a whole bunch of USB ports there, which we can actually 00:56:59.410 --> 00:57:00.670 take a closer look at a cable. 00:57:00.670 --> 00:57:03.460 So here's a common end of a USB cable. 00:57:03.460 --> 00:57:06.640 This is Type A, and so that's probably the most common type. 00:57:06.640 --> 00:57:09.757 But the white plastic on the inside suggests that this is an older cable. 00:57:09.757 --> 00:57:11.590 If you look at newer cables, you'll actually 00:57:11.590 --> 00:57:14.560 see that the inside is blue, which means its USB 3.0, which generally 00:57:14.560 --> 00:57:17.530 means faster, which means you can move data back and forth all the more 00:57:17.530 --> 00:57:18.190 quickly. 00:57:18.190 --> 00:57:20.440 But on the other ends of these USB cables-- 00:57:20.440 --> 00:57:22.330 you see, like the Type B connector here-- 00:57:22.330 --> 00:57:26.160 this is commonly found in the back of a printer or a scanner. 00:57:26.160 --> 00:57:27.865 So it's a slightly different plug. 00:57:27.865 --> 00:57:30.140 It keeps one end straight from the other. 00:57:30.140 --> 00:57:32.740 But you will actually see sometimes smaller cables 00:57:32.740 --> 00:57:35.410 like this one here, mini or micro USB, commonly 00:57:35.410 --> 00:57:37.750 found on phones or just smaller devices where 00:57:37.750 --> 00:57:40.446 it would be annoying to try to plug-in something as big as this. 00:57:40.446 --> 00:57:42.820 Well, I think we have just a couple of other things here. 00:57:42.820 --> 00:57:44.662 Here we have-- this came from a computer. 00:57:44.662 --> 00:57:46.870 No CPU attached, but this is one of those heat sinks? 00:57:46.870 --> 00:57:47.430 You were talking about? 00:57:47.430 --> 00:57:48.263 COLTON OGDEN: It is. 00:57:48.263 --> 00:57:50.620 It's a combo of a heat sink and a fan for a CPU. 00:57:50.620 --> 00:57:51.536 DAVID J. MALAN: I see. 00:57:51.536 --> 00:57:54.440 So Intel Inside might also mean you have an Intel fan, it would seem, 00:57:54.440 --> 00:57:55.090 and heat sink. 00:57:55.090 --> 00:57:58.510 And then lastly, we've got one of these things here. 00:57:58.510 --> 00:57:59.440 What's this here? 00:57:59.440 --> 00:58:01.398 COLTON OGDEN: This is a solid state hard drive, 00:58:01.398 --> 00:58:06.370 which actually uses flash memory very akin to microSDs, if you're familiar. 00:58:06.370 --> 00:58:08.290 It's essentially what a hard drive is. 00:58:08.290 --> 00:58:11.290 But instead of having a movable mechanical arm that 00:58:11.290 --> 00:58:14.700 looks at the different bits on the platters, as we talked about, 00:58:14.700 --> 00:58:15.670 it's almost like RAM. 00:58:15.670 --> 00:58:18.790 It's just storing the data in electricity, 00:58:18.790 --> 00:58:20.397 hence solid state, no moving parts. 00:58:20.397 --> 00:58:21.730 DAVID J. MALAN: But permanently. 00:58:21.730 --> 00:58:22.646 COLTON OGDEN: But yes. 00:58:22.646 --> 00:58:24.610 It's nonvolatile, which means, unlike RAM, you 00:58:24.610 --> 00:58:27.640 can actually store this whether or not you turn your laptop off or whatever. 00:58:27.640 --> 00:58:28.150 DAVID J. MALAN: All right. 00:58:28.150 --> 00:58:29.858 And it looks like-- and I'm told I've got 00:58:29.858 --> 00:58:32.720 to be extra careful with this-- this is a 4 terabyte SSD. 00:58:32.720 --> 00:58:35.600 So this is a huge amount of data, 4 trillion bytes. 00:58:35.600 --> 00:58:38.350 So we're just going to put this safely over here. 00:58:38.350 --> 00:58:40.770 Less expensively, though, we have this little USB stick. 00:58:40.770 --> 00:58:43.057 It's still 128 gigabytes, but it's a little gimmicky. 00:58:43.057 --> 00:58:44.890 But this thing slides out here, and then you 00:58:44.890 --> 00:58:47.470 can plug it into your laptop or desktop or really any device. 00:58:47.470 --> 00:58:49.345 And it's a really convenient way, ultimately, 00:58:49.345 --> 00:58:52.100 just like moving files back and forth between each other. 00:58:52.100 --> 00:58:52.600 All right. 00:58:52.600 --> 00:58:54.010 Well, Dr. Ogden, thank you so much. 00:58:54.010 --> 00:58:57.218 I'm sure you're going to want to take care of putting this all back together. 00:58:57.218 --> 00:58:59.430 And this was hardware.