WEBVTT - TechStuff Classic: TechStuff Goes to RAMing Speed 0:00:04.120 --> 0:00:07.160 Get in touch with technology with tech Stuff from how 0:00:07.200 --> 0:00:13.600 stuff works dot com. Be there and welcome to tech Stuff. 0:00:13.640 --> 0:00:16.200 I'm your host job in Strickland. I'm an executive producer 0:00:16.200 --> 0:00:19.160 and I love all things tech. And today it's time 0:00:19.200 --> 0:00:22.479 for another classic episode of tech Stuff. We are going 0:00:22.520 --> 0:00:25.919 all the way back to January second, two thousand twelve, 0:00:26.560 --> 0:00:29.920 and we're going to learn about random access memory in 0:00:29.960 --> 0:00:34.280 an episode we called tech Stuff goes to raming speed. 0:00:34.840 --> 0:00:39.599 Chris Palette and I decided to demystify the concept. How 0:00:39.640 --> 0:00:43.040 did we do? Well, let's find out. Today we're gonna 0:00:43.040 --> 0:00:47.279 be talking about memory, computer memory specifically. Yeah, and uh, well, 0:00:47.320 --> 0:00:50.239 you had a lot of people request over over the 0:00:50.360 --> 0:00:52.599 length of tech Stuff. Really the entire time we've been 0:00:52.640 --> 0:00:54.080 doing this, we have a lot of people ask us 0:00:54.080 --> 0:00:57.360 to do a podcast about RAM and to kind of 0:00:57.360 --> 0:00:59.840 talk about what RAM is, why you need it, and 0:01:00.040 --> 0:01:02.320 what does it do and how does it work? Which 0:01:02.360 --> 0:01:04.840 is funny because we kept not doing it because we 0:01:04.880 --> 0:01:07.880 thought we already had it. Turns out not so much. 0:01:07.920 --> 0:01:10.200 I did a search for the word RAM in our 0:01:10.319 --> 0:01:16.000 archives and uh saw a lot of programs but not RAM. 0:01:16.040 --> 0:01:18.319 And I even search for memory and the only memory 0:01:18.319 --> 0:01:20.600 thing we've done is we've talked about hard drives, which 0:01:21.319 --> 0:01:24.480 hard The relationship between hard drives and memory is a 0:01:24.480 --> 0:01:27.199 close one. It's an important one. And Uh, in fact, 0:01:28.000 --> 0:01:31.200 if we did not have RAM, if we if we 0:01:31.240 --> 0:01:34.280 had not developed that, and we were relying solely upon 0:01:34.440 --> 0:01:36.240 the kind of memory that you would find in a 0:01:36.280 --> 0:01:40.720 typical hard drive, you know, the traditional hard drive. UH, 0:01:40.920 --> 0:01:45.399 computer operations would take much longer than what we're accustomed to. Yeah. 0:01:45.440 --> 0:01:47.080 As a matter of fact, I can I can actually 0:01:47.120 --> 0:01:51.559 deliver a personal commentary on that because my very first 0:01:51.600 --> 0:01:55.000 machine was an Amiga one thousand. Many people have known 0:01:55.040 --> 0:01:58.000 because I mentioned it several times in the podcast, and 0:01:58.320 --> 0:02:00.440 that first machine that I had didn't have a hard 0:02:00.520 --> 0:02:04.840 drive on it. Um So Commodore's instructions when you first 0:02:04.880 --> 0:02:07.440 turn the machine on, you would once it it got 0:02:07.480 --> 0:02:10.280 into boot up mode, you would see a copy of 0:02:10.320 --> 0:02:14.399 the Kickstart disc. Kickstart basically loaded the operating system uh 0:02:14.400 --> 0:02:18.480 into RAM, into random access memory, and then once that happened, 0:02:18.520 --> 0:02:22.000 you could launch your workbench, which is the equivalent of 0:02:22.080 --> 0:02:24.800 the desktop in what you would see in Windows Linux 0:02:24.960 --> 0:02:30.080 or the mac os today. Um So, you know, without that, uh, 0:02:30.120 --> 0:02:32.079 you know, when I got my first hard drive computer 0:02:32.120 --> 0:02:34.680 which was an Amigia three thousand UM. It had a 0:02:34.720 --> 0:02:37.080 forty megabyte. Yeah, you can laugh at that hard drive 0:02:38.200 --> 0:02:42.320 which would automatically load the kickstart and get everything started 0:02:42.400 --> 0:02:45.040 up for you. So it worked very much like our 0:02:45.080 --> 0:02:48.680 machines do now. But um, you know that that was 0:02:48.880 --> 0:02:51.400 That's one of those things that the hard drive takes 0:02:51.440 --> 0:02:53.880 care of that you didn't. That you don't have to 0:02:53.919 --> 0:02:56.920 do uh now is load your operating system and all 0:02:56.960 --> 0:02:59.320 that stuff in there. There's also it's also important to 0:02:59.320 --> 0:03:01.880 note the difference between RAM and ROM. I would say 0:03:01.919 --> 0:03:05.720 read only memory or rom UM also has a lot 0:03:05.800 --> 0:03:09.240 of that baked into the chips onto your computer. There 0:03:09.280 --> 0:03:11.840 are some things that are already in your computer that 0:03:11.880 --> 0:03:16.080 are part of the uh um the physical hardware. But 0:03:16.240 --> 0:03:20.040 and and read only memory uh that memory is at 0:03:20.240 --> 0:03:23.840 access sequentially rather than at random, which is how random 0:03:23.840 --> 0:03:26.960 access memory got its name, right, and read only memory, 0:03:27.000 --> 0:03:31.440 as the name implies, you can only read from that memory. 0:03:31.440 --> 0:03:34.800 You can't write to it. So in other words, it's unchanging. 0:03:34.920 --> 0:03:38.360 It is is static. It will always be the way 0:03:38.400 --> 0:03:41.480 it is unless you were to physically remove the chips 0:03:41.520 --> 0:03:45.520 and replace them with other chips or other circuitry, it's 0:03:45.600 --> 0:03:47.560 always going to be the same way. And there's some 0:03:47.600 --> 0:03:51.080 devices that only have read only memory because that's all 0:03:51.120 --> 0:03:54.280 they require, and it's important to have. It's um it's 0:03:54.280 --> 0:03:57.560 a very useful type of memory. But when you're working 0:03:57.600 --> 0:04:01.640 on a project, if you only have ROM and not RAM, 0:04:01.680 --> 0:04:03.520 you would have to burn a new ROM every time 0:04:03.560 --> 0:04:05.560 you wanted to save something. To this I would be 0:04:05.600 --> 0:04:08.200 a real pain. So, for example, if you were to 0:04:08.240 --> 0:04:13.200 look at the good old video game console market, especially 0:04:13.240 --> 0:04:16.560 if you were looking at the old cartridge based consoles, 0:04:17.200 --> 0:04:21.760 the the games, the cartridges you have that you would 0:04:21.760 --> 0:04:26.160 put plug into your console had ROMs on them. That 0:04:26.240 --> 0:04:30.120 was the game itself was a ROM. And that's why 0:04:30.440 --> 0:04:34.039 if you talk about things like the main emulator, and 0:04:34.200 --> 0:04:36.360 I know that's it's kind of like saying a t 0:04:36.520 --> 0:04:40.919 M machine, but the emulator for arcade machines UH that 0:04:41.040 --> 0:04:44.760 you can run on certain computers. The emulator's job is 0:04:44.839 --> 0:04:50.440 to to mimic the circuitry that you would find within 0:04:50.520 --> 0:04:54.039 an arcade machine to run a specific ROM or game. 0:04:54.320 --> 0:04:58.320 So RAMS are used in devices, and in some cases 0:04:58.360 --> 0:05:02.680 are are the only thing within that device. There might 0:05:02.680 --> 0:05:04.840 be some other memory there to do things like keep 0:05:04.880 --> 0:05:06.840 track of a high score. That's a little different. But 0:05:07.839 --> 0:05:11.400 but in general, um, you know, there are certain devices 0:05:11.440 --> 0:05:14.200 that will only have ROM. RAM, however, is very important 0:05:14.240 --> 0:05:17.320 for the way we use computers today. Think of RAM 0:05:17.440 --> 0:05:21.719 as it's a it's a temporary storage fability, yeah, for 0:05:21.839 --> 0:05:24.760 a computer. Right. So it's where you can temporarily store 0:05:24.800 --> 0:05:29.919 instructions and data so that your computers processor doesn't have 0:05:30.000 --> 0:05:32.680 to go hunting through your hard drive system in order 0:05:32.720 --> 0:05:37.360 to find the relevant information to execute a command. Um. 0:05:37.480 --> 0:05:40.120 The way I like to think about this is if 0:05:40.120 --> 0:05:43.839 you're a student, imagine that you have a textbook filled 0:05:43.880 --> 0:05:47.320 with facts, will say physics. It's a physics textbook, all right, 0:05:47.680 --> 0:05:50.560 And you've got a test coming up, and you've created 0:05:51.160 --> 0:05:54.440 a crib sheet for you to study from, and the 0:05:54.440 --> 0:05:57.480 crib sheet has bulleted points on it about the major 0:05:57.560 --> 0:05:59.880 things you're going to be covering in your next physics test. 0:06:00.600 --> 0:06:02.279 That crib sheet is kind of like RAM in the 0:06:02.320 --> 0:06:04.960 sense that you can make little notes, you can erase stuff, 0:06:05.000 --> 0:06:09.240 you can replace things, and it has a good instruction 0:06:09.360 --> 0:06:11.720 set for you to work from. Now, occasionally you might 0:06:11.800 --> 0:06:14.400 come across a problem. Let's say you're working on some 0:06:14.480 --> 0:06:16.800 homework that's going to prepare you for this test. And 0:06:16.880 --> 0:06:18.839 you've got your crib sheet in front of you, and 0:06:18.839 --> 0:06:21.880 you're working on your homework question, and you realize that 0:06:22.080 --> 0:06:25.240 the information that you need is not on the crib sheet. 0:06:25.279 --> 0:06:27.159 It's just doesn't go that deep. So you have to 0:06:27.160 --> 0:06:30.160 go to the textbook to refer to the right section 0:06:30.200 --> 0:06:32.159 to learn the stuff you need in order to answer 0:06:32.240 --> 0:06:35.360 that question. That's kind of like your computer. Your CPU 0:06:35.520 --> 0:06:38.120 is going to refer back to the memory to see 0:06:38.160 --> 0:06:41.039 if the information it needs is there, and if it's 0:06:41.360 --> 0:06:45.520 if the information goes beyond that little memory, if it's 0:06:45.520 --> 0:06:47.840 something that has to actually access the hard drive, it 0:06:47.839 --> 0:06:51.560 will go to the hard drive. Same sort of idea. Yeah, 0:06:51.600 --> 0:06:54.240 And UM, I would just like to note that when 0:06:54.279 --> 0:06:58.080 I said that ROM could only be access sequentially, that's wrong. 0:06:58.160 --> 0:07:02.040 I was actually thinking of serial access memory or SAM. Right. 0:07:02.160 --> 0:07:05.000 I apologize for that. Yeah, I haven't had enough coffee 0:07:05.000 --> 0:07:08.160 this morning apparently, But yeah, serial access memory is UH 0:07:08.600 --> 0:07:12.320 is another form of memory that's not used nearly as 0:07:12.360 --> 0:07:15.280 often today as it used to be. But back when 0:07:15.360 --> 0:07:18.720 we had tape drives, UM, you know, you used to 0:07:18.760 --> 0:07:20.960 have to go all the way through the tape until 0:07:21.000 --> 0:07:22.880 you got to the part where it had the information 0:07:22.880 --> 0:07:25.920 you needed letter than accessing it. It's just the same 0:07:25.920 --> 0:07:28.520 as if he's had a cassette tape. Right. If you 0:07:28.520 --> 0:07:30.400 had an old cassette tape with music on it and 0:07:30.440 --> 0:07:33.000 you wanted to listen to a specific song, you had 0:07:33.000 --> 0:07:36.760 to fast forward or play through the tape until you 0:07:36.800 --> 0:07:39.120 got to the song you wanted, and then you could 0:07:39.120 --> 0:07:41.560 listen to it. You couldn't just jump right to the song. 0:07:42.160 --> 0:07:44.600 For our younger listeners, this might seem like a completely 0:07:44.640 --> 0:07:48.360 foreign concept, but yes, uh, lots of us used to 0:07:48.360 --> 0:07:51.760 listen to cassette tapes and if you were really lucky, 0:07:52.200 --> 0:07:55.480 you had like the eight track tapes where your options 0:07:55.480 --> 0:07:58.280 were even more limited in order to to navigate to 0:07:58.320 --> 0:08:01.320 the next song. Yes, but ROM doesn't necessarily work that way, 0:08:01.560 --> 0:08:04.720 so I apologize for that. But random axis memory there, 0:08:04.800 --> 0:08:06.920 there's certain there are different kinds of it. One of 0:08:06.920 --> 0:08:10.800 the most common is dynamic RAM. Yeah, that's that's probably 0:08:10.800 --> 0:08:16.080 the most versions of that are probably the most common 0:08:16.480 --> 0:08:19.239 used in computers today. Yeah, and uh, And the way 0:08:19.280 --> 0:08:22.600 that random axis memory, dynamic random access memory is is 0:08:23.080 --> 0:08:27.440 arranged is that you can imagine a grid, right, and 0:08:27.880 --> 0:08:31.200 the columns there are columns, and there are rows, and 0:08:31.200 --> 0:08:36.839 where these intersect you have memory cells. Now, a memory cell, 0:08:37.280 --> 0:08:41.280 the most basic memory cell is essentially a transistor and 0:08:41.440 --> 0:08:45.280 a capacitor, and the capacitor can hold a charge. If 0:08:45.280 --> 0:08:47.520 the capacitor is holding a charge, the memory cell is 0:08:47.559 --> 0:08:50.480 registering as a one. If the capacitor is not holding 0:08:50.480 --> 0:08:54.120 a charge, it's registering as a zero. The transistor access 0:08:54.200 --> 0:08:59.320 a switch that allows the various things. It allows the 0:08:59.320 --> 0:09:02.240 computer to be a to read those particular cells and 0:09:02.280 --> 0:09:05.400 also to recharge those cells. Because here's the thing about capacitors, 0:09:05.880 --> 0:09:09.480 they do drain. Yeah, they can hold a charge. There. 0:09:09.520 --> 0:09:13.400 They're sort of like a battery, though they are not identical, 0:09:13.480 --> 0:09:16.080 so don't assume that that's the same thing, but there 0:09:16.160 --> 0:09:20.520 they fulfill similar functions. Capacitors usually release their energy in 0:09:20.559 --> 0:09:25.520 a burst as opposed to over a prolonged time. But yeah, 0:09:25.520 --> 0:09:28.040 the capacitors the the energy drains from the capastors, so 0:09:28.040 --> 0:09:33.280 they have to be recharged regularly and rapidly in order 0:09:33.320 --> 0:09:36.280 for them to maintain that charge and hold onto what 0:09:36.320 --> 0:09:39.680 we call a state, the state of that memory cell. 0:09:39.760 --> 0:09:41.520 So the state is either a one or a zero. 0:09:41.559 --> 0:09:44.360 If it's a one, the computer has to continually send 0:09:44.520 --> 0:09:47.160 energy to that UH cell in order for it to 0:09:47.200 --> 0:09:50.640 maintain a one until the memory needs to be written over, 0:09:50.679 --> 0:09:52.719 in which case it might be a one again or 0:09:52.760 --> 0:09:54.440 it might be a zero. It all depends on what 0:09:54.480 --> 0:09:57.640 the information is. And you've got the like I said, 0:09:57.679 --> 0:10:01.760 you've got columns and you've got rows, and uh, the 0:10:01.840 --> 0:10:04.040 way the computer works, it has all these different little 0:10:04.120 --> 0:10:10.000 UM components to it that will detect what the current 0:10:10.080 --> 0:10:12.960 state is of all those different memory cells in order 0:10:12.960 --> 0:10:16.320 to be able to uh to to pull the right information. 0:10:16.320 --> 0:10:18.960 And in fact, the computer keeps a record of which 0:10:19.040 --> 0:10:21.079 memory you sell it needs to go to because you 0:10:21.120 --> 0:10:23.280 can think of the intersection of that column in that 0:10:23.400 --> 0:10:26.120 row as an address. Yeah, if you think about it 0:10:26.160 --> 0:10:29.800 as a piece of graph paper. Yeah, kind of the 0:10:29.800 --> 0:10:33.360 computer just basically keeps track of, uh, you know, where 0:10:33.360 --> 0:10:36.440 each item is in that memory. Yeah. If you think 0:10:36.480 --> 0:10:38.959 of the columns is like things like A, B, C, D, E, F. 0:10:39.360 --> 0:10:41.280 You know, sort of like think of it kind of 0:10:41.320 --> 0:10:44.160 like a game of battleship. That's exactly what I was thinking. Yeah, 0:10:44.160 --> 0:10:46.040 you got that. You've got the columns that are maybe 0:10:46.080 --> 0:10:49.360 A through Z, and then you have one through twenty 0:10:49.440 --> 0:10:51.880 six as the rose and you want to look at 0:10:52.360 --> 0:10:55.280 a four, well, then you know exactly where to go 0:10:55.920 --> 0:10:58.080 to to pull up that information. You don't have to 0:10:58.120 --> 0:11:00.400 you don't have to go through the entire ce quence 0:11:00.520 --> 0:11:03.360 of memory cells in order to get that information. That's 0:11:03.520 --> 0:11:06.080 a very simplistic way of saying what is happening with 0:11:06.120 --> 0:11:10.880 this dynamic random access memory. One of the disadvantages here, though, 0:11:11.000 --> 0:11:15.760 is that having to refresh that memory constantly means that 0:11:15.840 --> 0:11:21.760 you're essentially slowing down the memory. UM, which is you 0:11:21.800 --> 0:11:24.880 know a problem. It's it's something that that requires a 0:11:24.920 --> 0:11:28.360 lot of energy. It requires uh that you're constant constantly 0:11:28.400 --> 0:11:31.920 refreshing it and slows down your memory. Now, um, having 0:11:31.960 --> 0:11:35.480 more memory and your computer is a good thing. UM. 0:11:35.559 --> 0:11:37.880 You remember when we talked about thirty two bit and 0:11:37.920 --> 0:11:42.240 sixty four bit systems. Um. You know, your your operating 0:11:42.280 --> 0:11:45.440 system and your computer, depending on how they work together, 0:11:45.559 --> 0:11:51.520 can address a certain amount of computer memory. UM. And 0:11:51.679 --> 0:11:54.720 uh you know with if you have if you are 0:11:54.800 --> 0:11:59.120 not taking advantage of the maximum capacity of memory or 0:11:59.120 --> 0:12:01.160 at least you know, the as much as your computer 0:12:01.240 --> 0:12:05.040 can hold. UM. Not only is it having to uh 0:12:05.040 --> 0:12:07.880 fit whatever programs you're trying to run on top of 0:12:07.920 --> 0:12:10.920 the operating system in that amount of memory, it's also 0:12:11.720 --> 0:12:15.040 dealing with uh constantly having to refresh that memory, so 0:12:15.080 --> 0:12:18.160 it can really slow your computer down. We're gonna take 0:12:18.160 --> 0:12:20.160 a quick break to thank our sponsor, and then when 0:12:20.160 --> 0:12:30.440 we come back more about RAM. Going back to the 0:12:30.480 --> 0:12:35.520 grid really quickly. The the columns along this grid are 0:12:35.559 --> 0:12:40.080 called bit lines, the rows are called word lines, and 0:12:40.120 --> 0:12:43.319 then the the intersection is the memory cell address. So, 0:12:43.880 --> 0:12:46.880 UH though, what when you are WIN, when you want 0:12:46.920 --> 0:12:49.280 to write information or when your computer needs to write 0:12:49.280 --> 0:12:52.000 information to your RAM in order for the CPU to 0:12:52.040 --> 0:12:54.440 be able to have access to it to make things 0:12:54.520 --> 0:13:01.440 run smoothly. First it starts sending electricity through the column area, 0:13:02.040 --> 0:13:07.440 so through the bitline UM individual bitline, and then the 0:13:07.480 --> 0:13:13.640 computer sends electricity through the appropriate wordlines the right rose. 0:13:14.000 --> 0:13:16.720 So let's say that you you know that you're you're 0:13:16.880 --> 0:13:20.439 you're activating column D that's the one that's being UM 0:13:20.640 --> 0:13:23.640 that electricity is running through right now. And you know 0:13:23.760 --> 0:13:29.360 that Rose five, twelve, and twenty three need to have 0:13:29.679 --> 0:13:33.080 need to be activated because those memories, the memory cells 0:13:33.080 --> 0:13:37.319 at those addresses at the intersection of column D UH 0:13:37.600 --> 0:13:39.840 need to be active in order for the information to 0:13:39.840 --> 0:13:43.199 be there. The computer sends this information, the transistor allows 0:13:43.280 --> 0:13:48.720 the capacity turns to take on that that charge. And 0:13:48.760 --> 0:13:55.079 then there's a little um sensor actually since amplifier as well, 0:13:55.400 --> 0:13:59.840 that receives the signal that says this capacitor has has 0:13:59.880 --> 0:14:03.040 a state of one, and that's what allows the computer. No, 0:14:03.559 --> 0:14:05.719 you know if it's a one or zero, and collectively 0:14:05.760 --> 0:14:09.280 all those ones and zeros give it the information it needs. Now, 0:14:09.760 --> 0:14:13.000 all of this happens in a manner of a few nanoseconds, 0:14:13.520 --> 0:14:17.000 So don't think like this is taking ages. It's it's 0:14:17.080 --> 0:14:20.640 it's billions of a second for this stuff. When I 0:14:20.720 --> 0:14:22.920 say slow, I would put that in quotes. It's slow, 0:14:23.280 --> 0:14:27.160 right slow, like the way we feel when we put 0:14:27.200 --> 0:14:29.720 something in the microwave for a minute and we're thinking, 0:14:29.800 --> 0:14:32.800 why isn't it done yet? That kind of slow slow 0:14:32.920 --> 0:14:36.240 as relative. Yes, it's not slow as in you put 0:14:36.240 --> 0:14:39.000 something in the oven and four days later you've got turkey. 0:14:39.120 --> 0:14:44.200 Uh the I put an old boot in there. There's 0:14:44.200 --> 0:14:48.280 a turkey. That's the way it worked, isn't it. No? Oh, 0:14:48.480 --> 0:14:51.440 I need to go home after this podcast, but at 0:14:51.520 --> 0:14:55.400 least I'll have some warm boots Uh yeah, so this 0:14:55.400 --> 0:14:59.280 this is all taking just nanoseconds for each individual transaction, 0:14:59.280 --> 0:15:03.520 no seconds the whole thing. So, but it's happening repeatedly 0:15:03.680 --> 0:15:06.280 until that memory is getting rewritten, and it's happening. You know, 0:15:06.280 --> 0:15:10.720 it's changing rapidly because that's the nature of memory. If 0:15:10.720 --> 0:15:13.520 you're running a lot of different applications, and uh, your 0:15:13.520 --> 0:15:17.520 memory might be filling up pretty quickly with all this information. 0:15:17.920 --> 0:15:21.040 That's why the more applications you run, if you're if 0:15:21.040 --> 0:15:23.920 you're using an older machine and you're running a lot 0:15:23.920 --> 0:15:26.880 of different applications, you might feel like you're everything's kind 0:15:26.920 --> 0:15:30.680 of sluggish. And that's why people will tell you like, oh, well, 0:15:30.720 --> 0:15:33.440 you need to close some of these applications because it's 0:15:33.480 --> 0:15:35.560 taking up space in the memory and the CPU is 0:15:35.600 --> 0:15:38.520 having to work harder to get the information it needs 0:15:38.880 --> 0:15:43.360 to act to execute your commands. So uh, you know 0:15:43.480 --> 0:15:46.400 that that's how that all plays in. That's why people say, oh, 0:15:46.520 --> 0:15:48.040 if you want a computer to go faster, you need 0:15:48.040 --> 0:15:50.720 more memory, because then you can you can actually run 0:15:50.800 --> 0:15:53.640 more applications. That tends to be a very common problem 0:15:53.760 --> 0:15:56.560 that people run into, right They're like, my computer is 0:15:56.560 --> 0:15:58.560 so slow, and you look at it and you're like, well, 0:15:58.600 --> 0:16:01.560 you've got fifteen applications open, and three of them are 0:16:01.560 --> 0:16:05.160 pretty heavy duty, um, you know, or graphics intensive or whatever, 0:16:05.320 --> 0:16:08.960 something that's going to require a lot of processing. That 0:16:09.000 --> 0:16:12.240 would be why it's both processor speed and the amount 0:16:12.280 --> 0:16:14.640 of memory you have. The two are very much important. 0:16:14.920 --> 0:16:18.520 And also when we talk about Moore's law, Moore's law 0:16:18.560 --> 0:16:23.440 plays into the into memory as well, because dynamic random 0:16:23.440 --> 0:16:26.200 access memory the nice thing about it is that, well 0:16:26.200 --> 0:16:29.560 two nice things about is that it's relatively inexpensive, and 0:16:29.720 --> 0:16:32.560 it's it doesn't take up a lot of physical space 0:16:32.640 --> 0:16:36.240 when you're designing memory chips. There are other types of 0:16:36.320 --> 0:16:40.280 random access memory, not just dynamic their static random access memory. 0:16:40.840 --> 0:16:45.240 And static random access memory uses uh something a logic 0:16:45.760 --> 0:16:49.320 construction called a flip flop. Yes, not a standal I 0:16:49.440 --> 0:16:52.640 was gonna say, you're gonna oven and it comes out 0:16:52.680 --> 0:16:57.120 as chicken already know that doesn't work. Well, the static 0:16:57.320 --> 0:17:01.520 random access memory, Um yeah, I mean it one of 0:17:01.560 --> 0:17:05.000 the benefits of us now flip flops. Actually we uh 0:17:05.080 --> 0:17:09.280 you go back to the Boolean logic um reference. But 0:17:10.119 --> 0:17:15.919 basically a static RAM has the benefit of being a 0:17:15.920 --> 0:17:19.520 lot faster than dynamic RAM. Well, for one thing, what 0:17:19.640 --> 0:17:22.200 it does. Once it has a state, it will hold 0:17:22.240 --> 0:17:24.439 that state until you tell it to change. So it 0:17:24.480 --> 0:17:28.600 doesn't it doesn't, it doesn't require to be recharged, doesn't 0:17:28.640 --> 0:17:32.560 have a capacitor that is leaking energy and has to 0:17:32.600 --> 0:17:36.159 be refilled. So so once you once you set a 0:17:36.160 --> 0:17:38.040 flip flop to one, it's going to stay a one 0:17:38.080 --> 0:17:40.720 till you tell it to be a zero. So that 0:17:40.760 --> 0:17:43.680 sounds great. Why don't we use static RAM instead of 0:17:43.760 --> 0:17:47.040 dynamic RAM for our you know, main RAM in our computers? 0:17:47.040 --> 0:17:50.320 Two reasons. One, it takes up more space, so you 0:17:50.800 --> 0:17:53.520 end up having problems like especially with things like mobile 0:17:53.520 --> 0:17:57.520 devices or or laptop computers, you start running into the 0:17:57.520 --> 0:17:59.680 problem of while you can only fit so much into 0:17:59.680 --> 0:18:02.239 a four in factor before he gets clunky, right right, 0:18:02.280 --> 0:18:05.360 you need more transistors for static RAM. Yeah, yeah, four 0:18:05.400 --> 0:18:08.400 to six for each flip flop. So that's and each 0:18:08.400 --> 0:18:13.439 flip flop is is representing one memory cell. So and 0:18:13.880 --> 0:18:16.719 granted these transistors that we're talking about are on the 0:18:16.840 --> 0:18:20.200 nanoscale at this point, you know, we're talking about tiny, tiny, 0:18:20.240 --> 0:18:23.000 tiny transistors. But even so those add up if you 0:18:23.040 --> 0:18:25.520 need to have the amount of memory that you're accustomed to, 0:18:26.160 --> 0:18:28.680 so they are they take up more space, and they're 0:18:28.680 --> 0:18:32.400 more much more expensive. So static RAM is not something 0:18:32.440 --> 0:18:35.600 you're gonna find in every single kind of device, although 0:18:36.240 --> 0:18:39.359 as you know, as the technologies improved, those prices do 0:18:39.480 --> 0:18:41.760 tend to go down, so we do see more and 0:18:41.800 --> 0:18:44.159 more of that, but dynamic RAM is still probably I 0:18:44.160 --> 0:18:47.560 would say the most popular by far. Um. There there's 0:18:47.560 --> 0:18:54.000 another potential change coming up, a new development that could 0:18:54.040 --> 0:18:56.760 really uh impact this, which we can get into in 0:18:56.800 --> 0:18:59.400 a little bit. Okay, Yeah, I was gonna mention too though, 0:18:59.400 --> 0:19:02.040 that that's attic RAM can be found in your computer, 0:19:02.400 --> 0:19:07.920 probably because um, if you've seen a list of computer specifications, 0:19:07.920 --> 0:19:10.320 perhaps when you're shopping for a new machine and you 0:19:10.359 --> 0:19:14.320 see the cash referred to, um, your computer's cash is 0:19:15.200 --> 0:19:18.760 uh probably static ram. Yeah. A lot of CPUs have 0:19:18.920 --> 0:19:22.439 this built in, uh, A lot of the ones that 0:19:22.520 --> 0:19:27.560 use multi threading, that have multi core processors. A lot 0:19:27.600 --> 0:19:31.879 of these CPUs have their own sections of memory built 0:19:31.960 --> 0:19:34.560 And it's not it's not your computer's RAM. It's something 0:19:34.560 --> 0:19:37.760 that's specifically part of the CPU chip set that is 0:19:38.400 --> 0:19:42.720 there to help make make those those data transfers even 0:19:42.760 --> 0:19:46.560 faster so that it makes it very efficient and for 0:19:46.720 --> 0:19:52.120 the the most commonly used commands, uh, those would be 0:19:52.440 --> 0:19:57.639 stored within the cash. So in that crib sheet example 0:19:57.720 --> 0:20:00.000 I gave, let's say that you even had a little 0:20:00.119 --> 0:20:03.119 note card next year, a crib sheet that had the 0:20:03.280 --> 0:20:06.159 four formulas you're going to use them most frequently in 0:20:06.200 --> 0:20:10.080 that physics test, and so you've got those there. Because 0:20:10.119 --> 0:20:12.560 this way, no matter what you know, you just have 0:20:12.640 --> 0:20:15.080 to glance at the at the note card like that's 0:20:15.200 --> 0:20:17.000 that's the formula I need, and you plug it in 0:20:17.119 --> 0:20:19.440 and you make it, you make it work and whatever. 0:20:19.440 --> 0:20:23.240 The problem is. Your CPU is really really good at 0:20:23.280 --> 0:20:28.480 executing operations upon data, but it's stupid in the sense 0:20:28.520 --> 0:20:30.320 that as soon as it's as soon as it's finished 0:20:30.320 --> 0:20:33.080 doing that, it's forgotten. There's no Yeah, it has no 0:20:33.200 --> 0:20:36.639 memory of its own other than this this cash that 0:20:36.640 --> 0:20:39.879 we're talking about. A CPU on its the very basic 0:20:39.920 --> 0:20:44.080 CPU has no memory, so it can do stuff, but 0:20:44.119 --> 0:20:46.199 as soon as the task is done, it's like a 0:20:46.280 --> 0:20:50.160 blank slate all over again. That's that's why we have 0:20:50.280 --> 0:20:53.520 to have memory in order to get this to work. 0:20:53.560 --> 0:20:57.200 If if the CPU could somehow remember on its own, 0:20:57.720 --> 0:21:00.359 then you'd have other issues like well, now needed to 0:21:00.359 --> 0:21:03.280 do something new, So how do you write over what 0:21:03.400 --> 0:21:06.000 you had before? Do you just add to it? If 0:21:06.040 --> 0:21:08.400 you add to it, how long until you reach capacity? 0:21:08.440 --> 0:21:10.320 And you can't do anything with that CPU other than 0:21:10.359 --> 0:21:13.040 the stuff that you've already done. So you know, this 0:21:13.119 --> 0:21:16.320 is why the whole idea of the random actis memory 0:21:16.359 --> 0:21:19.560 that could be rewritten very quickly was so important because 0:21:19.600 --> 0:21:23.840 otherwise you limit the functions that your computer is capable 0:21:23.880 --> 0:21:27.000 of doing. You know, this computer is great at adding 0:21:27.000 --> 0:21:30.480 and subtracting and dividing, and after that you can't do 0:21:30.520 --> 0:21:34.240 anything else because that's I was about to install Pacman, 0:21:34.400 --> 0:21:38.480 but darn it, I already took up all of its 0:21:38.520 --> 0:21:41.560 space with these three functions. Well, yeah, so you've got 0:21:42.400 --> 0:21:45.600 and and we're we're sort of filling out the whole computer. 0:21:45.640 --> 0:21:47.680 So you've got your your CPU, and you've got a 0:21:47.760 --> 0:21:50.280 cash to help it remember stuff that it needs to 0:21:51.040 --> 0:21:54.359 do basic operations, right, and then you've got your your memory, 0:21:54.520 --> 0:21:57.760 your RAM, your dynamic RAM that that's over here managing 0:21:57.800 --> 0:22:00.600 the stuff that you've got going on, your word pressing, 0:22:00.760 --> 0:22:06.960 your word uh processor uh stuff, and your your graphics program, 0:22:07.040 --> 0:22:09.760 the stuff that you have brows your browser, your your 0:22:09.800 --> 0:22:14.200 email program. But you also have UH in your modern computer, 0:22:14.320 --> 0:22:17.240 you've got your graphics processor chip. And in a lot 0:22:17.280 --> 0:22:20.880 of cases, UM, and I'm just hedging my bets here 0:22:20.880 --> 0:22:23.080 that somebody has some weird computer that doesn't have this 0:22:23.440 --> 0:22:27.320 also has its own RAM UM to help it pro 0:22:27.520 --> 0:22:32.119 specifically process graphics. UM. So that RAM in general is 0:22:32.200 --> 0:22:35.480 off limits to the rest of the machine because it's 0:22:35.480 --> 0:22:38.480 saying no, no, no no. This memory is specifically to 0:22:38.560 --> 0:22:41.720 help us render graphics on the screen so that the 0:22:41.840 --> 0:22:46.000 user can UH see everything that he or she wants 0:22:46.040 --> 0:22:50.080 to see from the other programs. So it's not handling programs, 0:22:50.119 --> 0:22:53.280 it's handling graphics. We have we have seen some processors 0:22:53.400 --> 0:22:57.520 recently that are able to tap into the graphics processing 0:22:57.600 --> 0:23:01.480 units as well and be able to to utilize those 0:23:01.520 --> 0:23:06.800