WEBVTT - Rerun: What were CGA, EGA and VGA? 0:00:04.440 --> 0:00:07.840 Welcome to text Uff, a production from I Heart Radio. 0:00:12.119 --> 0:00:14.680 Hey there, and welcome to tech Stuff. I'm your host, 0:00:14.760 --> 0:00:17.640 Jonathan Strickland. I'm an executive producer with I Heart Radio 0:00:17.720 --> 0:00:22.040 and how the tech are you. I am currently on vacation, 0:00:22.360 --> 0:00:25.760 which means we're going to have a couple of reruns 0:00:25.800 --> 0:00:29.680 for the rest of this week, and today's episode is 0:00:29.720 --> 0:00:33.479 called what We're c g A, E G A and 0:00:33.920 --> 0:00:38.920 v G A, which originally published on April twenty twenty. 0:00:39.320 --> 0:00:43.440 Hope you enjoy. For today's episode, we're going to learn 0:00:43.479 --> 0:00:48.199 about old computer graphics standards. Don't run away. This is 0:00:48.240 --> 0:00:51.280 actually really interesting. We'll learn how they became standards in 0:00:51.280 --> 0:00:54.280 the first place, and what the company IBM had to 0:00:54.320 --> 0:00:57.440 do with all of this, and why some early decisions 0:00:57.480 --> 0:01:01.000 by IBM would lead to the company x trickating itself 0:01:01.040 --> 0:01:05.120 from the personal computer business altogether a couple of decades later. Now, 0:01:05.200 --> 0:01:08.360 when I was growing up, my family owned a couple 0:01:08.480 --> 0:01:12.040 of personal computers over the course of my childhood. We 0:01:12.040 --> 0:01:15.480 were in that rare small percentage of households with a 0:01:16.000 --> 0:01:19.640 personal computer back in the nineteen eighties, and our first 0:01:19.680 --> 0:01:23.440 computer was an Apple to E with a mono chromatic 0:01:23.560 --> 0:01:28.600 screen that could only display Matrix green style letters. I 0:01:28.640 --> 0:01:31.959 seem to recall that we eventually got a monitor one hundred, 0:01:31.959 --> 0:01:35.280 which is Apple's color monitor, and that was compatible with 0:01:35.360 --> 0:01:37.840 the two E, assuming that you had a to E 0:01:38.040 --> 0:01:42.160 with the appropriate interface card installed. But honestly, that memory 0:01:42.240 --> 0:01:45.520 might be conflated with the second personal computer that my 0:01:45.600 --> 0:01:50.280 dad would purchase. See. Dad got these computers in order 0:01:50.320 --> 0:01:53.320 to work on his novels. He wrote his first couple 0:01:53.360 --> 0:01:56.520 of books on the old Apple to E. I don't 0:01:56.560 --> 0:01:58.960 know if he still has them, but for years he 0:01:59.080 --> 0:02:01.840 had these novels stored on old five and a quarter 0:02:01.920 --> 0:02:05.000 inch floppy disc and those discs could hold about a 0:02:05.040 --> 0:02:08.600 hundred forty kilobytes worth of information each, so to be safe, 0:02:08.880 --> 0:02:12.080 Dad would typically store two to three chapters per disk, 0:02:12.240 --> 0:02:15.200 since his novels were too long to fit onto just 0:02:15.400 --> 0:02:17.880 one five and a quarter inch disc, and the Apple 0:02:17.880 --> 0:02:20.720 to E had no hard drive. Anyway, I digress, but 0:02:21.080 --> 0:02:24.000 I love thinking about those old times. I remember going 0:02:24.040 --> 0:02:29.200 through sleeves of discs and seeing Dad's old novels on there. 0:02:29.880 --> 0:02:33.080 Our second computer that we owned as a family was 0:02:33.160 --> 0:02:36.520 a two eight six. But what does that actually mean? Well, 0:02:36.600 --> 0:02:39.440 it was a personal computer that relied on the Intel 0:02:39.639 --> 0:02:43.960 eight two eight six central processing unit, and it also 0:02:44.040 --> 0:02:48.079 relied on MS DOSS as the operating system. So this 0:02:48.240 --> 0:02:51.720 computer fell into what we would call an IBM compatible 0:02:51.800 --> 0:02:54.839 computer back in the day. It used components and an 0:02:54.880 --> 0:02:58.680 operating system that allowed it to run any software designed 0:02:58.720 --> 0:03:02.119 for those IBM s ccific machines. I think of this 0:03:02.240 --> 0:03:05.040 as an interesting part of personal computer history, and it 0:03:05.080 --> 0:03:09.560 helps illustrate a sharp contrast between IBM S strategy and apples. 0:03:09.600 --> 0:03:13.200 So let's backtrack a little bit now, before there were 0:03:13.320 --> 0:03:16.520 personal computers, back when you needed to work for a 0:03:16.600 --> 0:03:20.200 special research facility or be enrolled in an engineering course 0:03:20.200 --> 0:03:23.120 in the university, or maybe one of a handful of 0:03:23.160 --> 0:03:25.480 folks who knows about computers and works for a big 0:03:25.520 --> 0:03:28.960 financial company, or maybe you're in the military. Back in 0:03:29.000 --> 0:03:32.200 those days, computers really didn't have monitors at all. Computer 0:03:32.320 --> 0:03:35.920 graphics weren't even a thing yet. The computer would typically 0:03:36.000 --> 0:03:39.800 print out the results of a computational process on some 0:03:39.880 --> 0:03:43.440 sort of paper or paper tape. Richard Garriott, who would 0:03:43.440 --> 0:03:47.040 go on to create the Ultimate Computer Game series before 0:03:47.040 --> 0:03:49.960 You would become one of seven private citizens to visit 0:03:50.000 --> 0:03:53.120 the space station, programmed his first games on a computer 0:03:53.200 --> 0:03:56.400 that would print out each move of his dungeon crawler. 0:03:56.800 --> 0:04:00.600 So imagine a top down view of a done gin crawler, 0:04:00.640 --> 0:04:02.840 except you're not looking at it on a screen. You 0:04:02.920 --> 0:04:07.400 actually have to print out each move. So you make 0:04:07.440 --> 0:04:10.080 a move in the game, the printer would print out 0:04:10.080 --> 0:04:13.240 a new display of what had happened, and all the 0:04:13.280 --> 0:04:16.640 figures were represented by the basic characters that the printer 0:04:16.880 --> 0:04:20.239 could replicate, so it was limited to whatever the printer 0:04:20.320 --> 0:04:25.120 could print, and that was typically stuff like your standard letters, numbers, 0:04:25.120 --> 0:04:28.080 and symbols on a keyboard. So making a move would 0:04:28.120 --> 0:04:30.200 require the whole system to print out a new picture 0:04:30.240 --> 0:04:32.359 showing the results of that move. So playing the game 0:04:32.880 --> 0:04:37.000 took a while. Obviously the refresh rate was terrible, but 0:04:37.480 --> 0:04:40.839 eventually engineers began to create a way for computers to 0:04:40.880 --> 0:04:44.600 display information over a screen. You might connect the computer 0:04:44.680 --> 0:04:47.279 to a regular old television system and you might have 0:04:47.320 --> 0:04:50.320 a little adapter to do that, or, as would later 0:04:50.400 --> 0:04:54.120 become the norm, you would build computer monitors specifically for 0:04:54.200 --> 0:04:57.280 the systems you were creating, and later we would call 0:04:57.360 --> 0:04:59.880 these displays, but I'm so old I still refer to 0:04:59.880 --> 0:05:03.760 the them as computer monitors because that's just how it 0:05:03.880 --> 0:05:07.440 cemented itself in my brain. Obviously, you've got to have 0:05:07.600 --> 0:05:10.160 some sort of bridge for a computer to be able 0:05:10.200 --> 0:05:13.480 to send meaningful information to a display, which will then 0:05:13.560 --> 0:05:17.000 follow the instructions sent by the computer to represent the 0:05:17.000 --> 0:05:19.880 information to the end user. There's got to be some 0:05:20.000 --> 0:05:23.400 sort of interface to make this happen on the computer side, 0:05:23.839 --> 0:05:26.320 as well as a port that allows a user to 0:05:26.320 --> 0:05:28.640 connect the computer to the display. There has to be 0:05:28.680 --> 0:05:31.479 some sort of physical connection between the two, and in 0:05:31.520 --> 0:05:34.599 the early days of personal computers there was no set, 0:05:34.720 --> 0:05:38.480 standardized way to do this. The technology used in one 0:05:38.520 --> 0:05:42.120 computer system wasn't compatible with another, so you couldn't mix 0:05:42.160 --> 0:05:46.479 and match monitors and cables and based systems together. These 0:05:46.480 --> 0:05:49.960 were the wild West days of computing, when making a 0:05:50.040 --> 0:05:53.240 choice as a consumer was complicated because you had no 0:05:53.279 --> 0:05:56.320 way of knowing if the computer you chose was going 0:05:56.360 --> 0:05:58.560 to stand the test of time. You could end up 0:05:58.560 --> 0:06:02.120 purchasing a system at rate cost and see the parent 0:06:02.200 --> 0:06:06.440 company crumble and all support for that system would wither away. 0:06:06.640 --> 0:06:09.479 And software developers were affected by this too in a 0:06:09.520 --> 0:06:14.360 big way. Developing software can be an arduous process. Back 0:06:14.360 --> 0:06:18.039 in the early days, it was feasible and even common 0:06:18.440 --> 0:06:21.640 for a single programmer to produce a piece of software 0:06:21.680 --> 0:06:24.479 for a system. But developers had to make the same 0:06:24.520 --> 0:06:27.160 sort of bets that consumers were making. They had to 0:06:27.279 --> 0:06:31.200 choose which systems they would develop four and they would 0:06:31.240 --> 0:06:33.720 hope that they made the right bet, and it often 0:06:33.760 --> 0:06:36.720 been dedicating a lot of their time to learning how 0:06:36.760 --> 0:06:40.960 to program for that particular computers operating system. Since the 0:06:41.040 --> 0:06:44.280 OS of say, an Apple computer was different from that 0:06:44.440 --> 0:06:47.719 of the Texas Instruments trash a D system, which was 0:06:47.720 --> 0:06:51.240 different from the Commodore sixty four, et cetera. So in 0:06:51.279 --> 0:06:54.680 the early days of personal computers, there were many competing 0:06:54.720 --> 0:06:57.920 systems to choose from, both as a consumer and as 0:06:57.960 --> 0:07:01.719 a developer. Apple, Commodo or in Texas Instruments were three 0:07:01.760 --> 0:07:03.840 of the big ones here in the United States, and 0:07:03.920 --> 0:07:06.800 they weren't alone, but they didn't have to contend with 0:07:06.920 --> 0:07:10.000 a really big name in computers for a few years, 0:07:10.360 --> 0:07:14.200 and that was I b M. And that's because initially 0:07:14.600 --> 0:07:19.680 IBM chose to concentrate on its traditional enterprise focused business 0:07:19.840 --> 0:07:22.520 and not really get into the consumer market. They were 0:07:22.520 --> 0:07:26.680 making products and services for other companies, not for end 0:07:26.840 --> 0:07:29.640 users like me and you now. That would change in 0:07:29.760 --> 0:07:34.480 nineteen one when IBM introduced the IBM Personal Computer or 0:07:34.600 --> 0:07:38.960 the fifty one fifty. IBM didn't invent the term personal computer, 0:07:39.280 --> 0:07:42.120 but the fact that this juggernaut had used the phrase 0:07:42.240 --> 0:07:45.800 for its own product would shape the terminology for computers 0:07:45.800 --> 0:07:49.960 in general. We all know that ultimately the two major 0:07:50.040 --> 0:07:53.720 systems to emerge from those early days were Windows based 0:07:53.800 --> 0:07:58.160 PCs and Mac computers from Apple. These would be the 0:07:58.160 --> 0:08:01.440 two big ones for consumers. There are obviously others out 0:08:01.480 --> 0:08:05.239 there there, Linux systems, for example, but for the majority 0:08:05.280 --> 0:08:09.120 of people out there, it's the Windows based PC and 0:08:09.280 --> 0:08:14.640 Apple's Mac. Well, we call the Windows based machines PCs. 0:08:14.640 --> 0:08:18.480 Because of IBM and its influence, a MAC is a 0:08:18.520 --> 0:08:22.040 personal computer, to a Mac is a PC in the 0:08:22.080 --> 0:08:24.240 sense it's a personal computer, but you wouldn't call it 0:08:24.320 --> 0:08:28.920 a PC typically because to us, PCs means a machine 0:08:28.960 --> 0:08:32.680 built upon ibm s approach, and that leads us into 0:08:32.679 --> 0:08:36.080 the choices IBM made that would ultimately contribute to the 0:08:36.120 --> 0:08:39.760 company getting out of the personal computer business. Further down 0:08:39.760 --> 0:08:42.319 the road, it all comes down to how they chose 0:08:42.360 --> 0:08:44.400 to get into it in the first place. You see, 0:08:44.800 --> 0:08:48.319 when IBM was making the personal computer. The company wasn't 0:08:48.320 --> 0:08:52.360 exactly putting its full support behind that effort in order 0:08:52.400 --> 0:08:55.480 to produce the system cheaply, which would mean the company 0:08:55.480 --> 0:08:58.360 could sell the manufactured systems at a premium and have 0:08:58.400 --> 0:09:01.280 a really sweet profit margin. And you know, you you 0:09:01.360 --> 0:09:05.160 buy cheap and you sell high. IBM engineers built the 0:09:05.200 --> 0:09:09.319 PC using off the shelf components. The company didn't build 0:09:09.360 --> 0:09:14.080 a custom made microprocessor or anything. Instead, the original IBM 0:09:14.120 --> 0:09:18.920 PC used an Intel eight chip as the CPU. In 0:09:18.960 --> 0:09:22.600 a similar fashion, the engineers used other standard components to 0:09:22.679 --> 0:09:26.360 build out the PC, and they made an arrangement with 0:09:26.480 --> 0:09:30.040 Microsoft to supply the operating system for this new personal computer. 0:09:30.720 --> 0:09:34.120 And the story behind all of that operating system stuff 0:09:34.200 --> 0:09:38.720 gets really super juicy and bonkers. That has betrayal and backstabbing. 0:09:38.720 --> 0:09:41.360 It's like a Game of Thrones episode. For one thing, 0:09:41.720 --> 0:09:45.360 Microsoft was not the company to originally develop DOSS, but 0:09:45.480 --> 0:09:50.560 it sure is. Heck profited from it, but that's another story. 0:09:50.920 --> 0:09:54.880 The operating system that IBM used was called PC DOSS, 0:09:54.880 --> 0:09:59.280 but IBM did not establish an exclusivity agreement with Microsoft, 0:09:59.559 --> 0:10:04.600 and so Microsoft would also develop another OS called MS DOSS, 0:10:04.640 --> 0:10:09.520 which was to all intents and purposes identical to PC DOSS, 0:10:09.600 --> 0:10:13.080 and it would remain so for several versions. Now, all 0:10:13.120 --> 0:10:16.640 the pieces were in place for IBM's eventual decision to 0:10:16.679 --> 0:10:19.800 get out of the consumer PC market, and it was 0:10:20.520 --> 0:10:22.720 just at the point when it was getting in. You see, 0:10:22.800 --> 0:10:26.160 the basic components for the computers were available to anyone, 0:10:26.679 --> 0:10:30.840 and the operating system was likewise available through licensing with Microsoft. 0:10:30.960 --> 0:10:35.800 So an enterprising computer company with much lower operating costs 0:10:35.880 --> 0:10:40.840 than a behemoth like IBM could conceivably swoop in, build 0:10:40.880 --> 0:10:45.679 a reasonable facsimile of an IBM PC machine using similar components, 0:10:46.000 --> 0:10:48.720 and include a licensed version of MS DOSS as the 0:10:48.760 --> 0:10:52.000 operating system. In presto, you have a computer that runs 0:10:52.040 --> 0:10:55.800 just like an IBM PC, including support for all software 0:10:55.840 --> 0:10:59.000 designed for the IBM system, and it's at a fraction 0:10:59.040 --> 0:11:02.240 of the cost. This gave birth to an entire subclass 0:11:02.280 --> 0:11:07.080 of computers called the IBM clones or IBM compatibles. The 0:11:07.080 --> 0:11:08.960 two eight six I mentioned at the top of this 0:11:09.000 --> 0:11:12.760 episode was just such a machine. We didn't known an 0:11:12.800 --> 0:11:16.040 official IBM birstal computer, but rather a machine with the 0:11:16.080 --> 0:11:20.079 same sort of guts inside and running MS DOSS. It 0:11:20.120 --> 0:11:22.160 would take a long time for all of this to 0:11:22.280 --> 0:11:25.319 actually catch up to IBM. Mind you, it's not like 0:11:25.760 --> 0:11:29.320 they were shot and sunk as soon as they launched. 0:11:29.920 --> 0:11:32.800 The company would ultimately pull back from the PC business, 0:11:32.800 --> 0:11:34.520 but it would stick around long enough to make an 0:11:34.720 --> 0:11:38.840 enormous influence on computers and programming, and that includes graphics. 0:11:39.480 --> 0:11:44.040 When the IBM PC debut in the company offered two 0:11:44.040 --> 0:11:47.880 options when it came to graphics. Each was a type 0:11:47.920 --> 0:11:50.880 of circuit board that could be plugged into the motherboard 0:11:51.000 --> 0:11:54.960 of the computer, the sort of an expansion slot. These 0:11:55.000 --> 0:11:58.080 types of cards were called add in boards or A 0:11:58.240 --> 0:12:00.600 I B s, and they represent in the ways to 0:12:00.640 --> 0:12:05.280 add capabilities to a base computer model. Sometimes those abilities 0:12:05.320 --> 0:12:09.520 were fairly simple additional features. Sometimes, like in this case, 0:12:09.600 --> 0:12:12.520 they were required in order to send images to an 0:12:12.520 --> 0:12:15.040 external display. So without one of these two cards you 0:12:15.040 --> 0:12:19.079 wouldn't have any way of sending information to a computer monitor. 0:12:19.679 --> 0:12:22.640 The first of the two was called the Monochrome Display 0:12:22.760 --> 0:12:26.600 Adapter or m d A. This was a video card 0:12:26.640 --> 0:12:30.800 installed on the PC that would output monochromatic signals to 0:12:31.120 --> 0:12:34.920 the monitor. Furthermore, it didn't do so in a pixel 0:12:35.000 --> 0:12:38.200 addressable way. So wait, wait, wait, what does that mean 0:12:38.400 --> 0:12:42.000 All right. So let's remember that the images we see 0:12:42.000 --> 0:12:45.880 on displays and monitors and screens like on smartphones are 0:12:45.920 --> 0:12:49.160 made up a little points of light. By changing the 0:12:49.160 --> 0:12:52.160 brightness and color of those points of light, you can 0:12:52.240 --> 0:12:56.040 create full images. It's not that different from the technique 0:12:56.160 --> 0:12:59.880 used by the famous painter George Serat in his fame 0:13:00.040 --> 0:13:03.959 its work A Sunday Afternoon on the Island of Lagrange Jatt. 0:13:04.679 --> 0:13:08.560 In that painting, all the images consist of tiny dots 0:13:08.600 --> 0:13:10.920 of paint, but when you view it from a distance, 0:13:11.679 --> 0:13:14.480 they form the shapes of people spending a lovely day 0:13:14.480 --> 0:13:17.720 at a park along the Sin River. It's an example 0:13:17.760 --> 0:13:19.720 of a style called point to lists, and it's perhaps 0:13:19.800 --> 0:13:22.960 the most famous version of this of all time. But 0:13:23.400 --> 0:13:27.480 television's computer monitors and electronic displays like the one smartphones 0:13:27.559 --> 0:13:31.040 use have a similar technique, except they use points of 0:13:31.160 --> 0:13:34.959 light rather than points of paint. Now, as I mentioned, 0:13:35.280 --> 0:13:39.760 the m d A wasn't pixel addressable, and addressability refers 0:13:39.800 --> 0:13:45.120 to the capacity to separately access individual units of something, 0:13:45.200 --> 0:13:49.320 so in this case pixels. A pixel addressable approach allows 0:13:49.320 --> 0:13:52.680 the computer system to send specific instructions to each and 0:13:52.960 --> 0:13:57.120 every pixel, which, in turn, let's computers send full images 0:13:57.200 --> 0:14:00.360 and graphics to a connected monitor, but m d A 0:14:00.920 --> 0:14:04.480 didn't have that capability, so you couldn't send a black 0:14:04.520 --> 0:14:07.800 and white photo to display on a connected monitor. The 0:14:08.000 --> 0:14:12.400 m d A was dedicated purely to text mode. The 0:14:12.440 --> 0:14:15.400 screen consisted not of pixels so much as it did 0:14:15.559 --> 0:14:19.680 of character cells. So imagine a box that's large enough 0:14:19.720 --> 0:14:23.440 to hold the largest text character, like an uppercase G 0:14:23.880 --> 0:14:28.120 or W or something. Now imagine that the entire screen 0:14:28.600 --> 0:14:31.920 is a grid of those boxes. Each box is exactly 0:14:31.960 --> 0:14:34.280 the same shape, so it can a lot for the 0:14:34.400 --> 0:14:37.880 largest of characters inside of it, but that's all they 0:14:37.880 --> 0:14:40.840 can fit inside. Each box is one character. You couldn't 0:14:40.880 --> 0:14:45.000 create more complex images, only pictures that consisted of those 0:14:45.040 --> 0:14:48.560 basic characters, just like the old printers that I mentioned 0:14:48.560 --> 0:14:51.560 earlier that Richard Garriott had been playing with. Well, with 0:14:51.680 --> 0:14:57.120 these displays, you could get really good resolution on those characters, 0:14:57.160 --> 0:15:00.240 so the images were crisp and clear. The picture here's 0:15:00.280 --> 0:15:03.440 the text was incredibly clear to read. It was very 0:15:03.600 --> 0:15:06.960 simple too. With these displays. You could get really good 0:15:07.040 --> 0:15:10.720 resolution on those characters. The text is crisp and clear. 0:15:11.440 --> 0:15:14.080 And that was a big drop because a lot of 0:15:14.120 --> 0:15:17.240 these computers were meant to go towards small businesses, where 0:15:17.640 --> 0:15:21.880 presumably the applications you're running are mostly text based. There 0:15:21.920 --> 0:15:24.520 were some trade offs. Because the screen was made up 0:15:24.600 --> 0:15:27.720 of a grid of equal sized boxes, and each of 0:15:27.800 --> 0:15:32.360 those boxes could contain one character, every letter would use 0:15:32.480 --> 0:15:36.320 up the same amount of space on the screen. So 0:15:36.480 --> 0:15:39.400 an upper case W, which is about as wide as 0:15:39.440 --> 0:15:42.320 it gets, would take up the same amount of space 0:15:42.560 --> 0:15:44.600 as an upper case I. Now I don't mean that 0:15:44.720 --> 0:15:48.320 the upper case I would be wide, but rather it 0:15:48.360 --> 0:15:52.000 would occupy a spot that would be surrounded by an 0:15:52.040 --> 0:15:56.120 invisible box the same size as the invisible box that 0:15:56.200 --> 0:15:58.480 goes around the upper case W. So you get this 0:15:58.560 --> 0:16:02.320 weird spacing between letters in the same word. If you're 0:16:02.400 --> 0:16:06.440 using a collection of wide and narrow letters, it would 0:16:06.480 --> 0:16:11.680 just look off. H It's called monospace font. It's it's 0:16:11.720 --> 0:16:13.720 the same sort of thing that you would see with 0:16:14.440 --> 0:16:18.160 a lot of printers and typewriters because they were limited 0:16:18.280 --> 0:16:21.720 to having all of their stamps at the same size, 0:16:21.840 --> 0:16:25.560 even if the letters were different sizes. In contrast, most 0:16:25.600 --> 0:16:29.360 fonts we use today are proportional fonts, which means individual 0:16:29.480 --> 0:16:32.880 characters are given space proportional to their own size, so 0:16:32.960 --> 0:16:35.560 you don't get these odd gaps between letters that should 0:16:35.600 --> 0:16:37.680 be right next to each other. But that was just 0:16:37.840 --> 0:16:40.760 one option for the IBM PC. The other option had 0:16:40.840 --> 0:16:44.600 direct addressability for pixels. It also had support for colors, 0:16:44.640 --> 0:16:47.560 so you could have color graphics with this version, and 0:16:47.680 --> 0:16:50.800 it was called c g A, and we'll talk about 0:16:50.840 --> 0:17:01.760 it more after the break. So c g A stands 0:17:01.880 --> 0:17:06.120 for Color Graphics Adapter, and describing this technology will also 0:17:06.200 --> 0:17:08.359 require us to examine a couple of other sets of 0:17:08.480 --> 0:17:11.320 standards that affected the graphics that displayed on old c 0:17:11.520 --> 0:17:16.280 g A systems. C g A had big limitations had 0:17:16.359 --> 0:17:20.800 compared to graphics cards today, they seem absolutely stone age. 0:17:21.200 --> 0:17:25.440 The c g A system could support four different modes officially, 0:17:25.760 --> 0:17:29.640 but clever programmers figured out ways to boost this. We'll 0:17:29.680 --> 0:17:33.240 get into that. There were two text modes and two 0:17:33.400 --> 0:17:37.560 graphic modes for the c g A card. The first 0:17:37.760 --> 0:17:41.520 text mode supported four bit color and could display up 0:17:41.560 --> 0:17:45.440 to forty characters per line, with twenty five lines making 0:17:45.520 --> 0:17:48.760 up the total screen space, so twenty five like you 0:17:48.800 --> 0:17:52.200 could stack twenty five vertically or you could stack forty 0:17:52.560 --> 0:17:57.600 horizontally across the screen. The pixel aspect ratio was one 0:17:57.920 --> 0:18:01.320 to one point two. But what that mean, Well, these 0:18:01.359 --> 0:18:06.000 pixels were not perfect squares. They were actually taller than 0:18:06.080 --> 0:18:09.760 they were wide. With that ratio of one for width 0:18:10.080 --> 0:18:12.920 to one point two for height, this would mean that 0:18:13.040 --> 0:18:16.120 the visual resolution of the screen was more like three 0:18:16.240 --> 0:18:20.600 twenty by two forty. In actuality, it was three twenty 0:18:20.760 --> 0:18:23.880 by two hundred. So why the three two forty. Well, 0:18:24.320 --> 0:18:28.760 because the pixels were longer than they were wide. If 0:18:28.840 --> 0:18:32.200 you were clever with the way you create your computer graphics, 0:18:32.640 --> 0:18:35.480 it would seem almost like you had stacked more pixels 0:18:35.600 --> 0:18:38.520 vertically and you could take advantage of things and make 0:18:38.560 --> 0:18:41.080 a picture that had that sort of look as if 0:18:41.160 --> 0:18:44.359 it was a resolution of three twenty by two forty. However, 0:18:44.960 --> 0:18:47.840 if you needed to cut things short and the ratio 0:18:48.000 --> 0:18:50.760 just wasn't working for you, it would become a detriment, 0:18:50.920 --> 0:18:53.560 not an asset. However, if you do the math, you'll 0:18:53.560 --> 0:18:56.800 see that this means every character on screen would have 0:18:57.000 --> 0:19:00.520 eight pixels dedicated to it. And here how I did that. 0:19:00.600 --> 0:19:03.720 You just take the resolution with that's three twenty pixels. 0:19:04.119 --> 0:19:06.040 You divide that by the number of characters that could 0:19:06.040 --> 0:19:09.560 fit on one line. Remember it's forty characters across, so 0:19:09.720 --> 0:19:12.880 three twenty divided by forty you get eight. The same 0:19:13.000 --> 0:19:16.199 is true vertically. You can have twenty five characters stacked 0:19:16.240 --> 0:19:18.840 from top to bottom on the screen, and the vertical 0:19:18.920 --> 0:19:22.240 resolution is two hundred pixels top to bottom. Two hundred 0:19:22.280 --> 0:19:27.360 divided is eight, So each character and the adapter supported 0:19:27.400 --> 0:19:32.000 two fifty six different characters could use eight pixels for 0:19:32.160 --> 0:19:36.760 display purposes. The four bit color part also needs explaining. 0:19:36.920 --> 0:19:40.800 So a bit is a single unit of computer information, 0:19:41.040 --> 0:19:43.840 and we represent it as either a zero or a one, 0:19:44.840 --> 0:19:47.920 So that means a bit has one of two possible 0:19:48.000 --> 0:19:50.320 states at any given time. You can think of it 0:19:50.400 --> 0:19:55.360 as off or on, zero or one. We have four 0:19:55.520 --> 0:19:57.840 bits for four bit color, so that means we can 0:19:57.880 --> 0:20:01.880 think of having to the possible number of states per bit. 0:20:02.480 --> 0:20:06.159 Raised to the power of four, that's equal to sixteen. 0:20:06.640 --> 0:20:11.320 So four bit color could support sixteen different colors total, 0:20:11.760 --> 0:20:17.359 not all at once, but total. Like, that's the number 0:20:17.440 --> 0:20:22.720 of colors this display could show. In text mode, programmers 0:20:22.800 --> 0:20:26.440 could choose a foreground and background color, choosing from those 0:20:26.600 --> 0:20:30.879 sixteen pre made colors. In addition, a bit for the 0:20:30.960 --> 0:20:33.640 foreground color could be dedicated to make the character blink, 0:20:33.720 --> 0:20:37.159 so you can have blinking text in the foreground. The 0:20:37.400 --> 0:20:42.080 blinking bit, the bit responsible for that blinking command, was 0:20:42.160 --> 0:20:45.239 repurposed for the background color, and it's served as an 0:20:45.320 --> 0:20:50.320 intensity bit instead. Intensity essentially means how dark or bright 0:20:50.640 --> 0:20:54.440 that particular color happens to appear. The second text mode 0:20:55.000 --> 0:20:58.840 was an eighty by twenty five four bit color mode, 0:20:59.520 --> 0:21:03.320 so that meant you could fit eighty letters across in 0:21:03.400 --> 0:21:08.600 a line twenty five lines per screen. These letters were 0:21:08.680 --> 0:21:11.600 half as wide as the forty by twenty five versions. 0:21:11.960 --> 0:21:14.760 Makes sense, right, you could fit twice as many across 0:21:14.840 --> 0:21:17.159 the screen. They must be half as wide as the 0:21:17.240 --> 0:21:21.560 forty by twenty five. The pixel ratio that this would 0:21:21.680 --> 0:21:25.560 create for a visual representation of the resolution was six 0:21:25.720 --> 0:21:29.240 forty by four eighty. Now, in reality, those pixels again 0:21:29.320 --> 0:21:32.040 were taller than they were wide. In fact, they were 0:21:32.200 --> 0:21:36.520 notably taller than they were wide, so the real resolution, 0:21:36.600 --> 0:21:39.320 the true resolution was six forty by two hundred, but 0:21:39.440 --> 0:21:43.399 it looked like six forty eight. More programs were written 0:21:43.600 --> 0:21:47.239 in this mode because that you could fit way more 0:21:47.320 --> 0:21:49.600 text on a screen than you could with the forty 0:21:49.800 --> 0:21:53.440 twenty five mode. It was less chunky, but most text 0:21:53.520 --> 0:21:57.680 based programs relied on the eighty by twenty five approach. 0:21:58.640 --> 0:22:00.920 If you were using a word process or something, this 0:22:01.160 --> 0:22:03.879 was the style that you were most likely looking at. 0:22:04.080 --> 0:22:06.159 That being said, the resolution of text on a c 0:22:06.320 --> 0:22:08.960 g A machine was lower than what you would have 0:22:09.040 --> 0:22:12.760 found on the monochromatic m d A computers, so it 0:22:12.920 --> 0:22:15.480 was a tradeoff. You could have a c g A 0:22:16.400 --> 0:22:20.320 ibm PC running on this eight by twenty five text 0:22:20.400 --> 0:22:23.760 mode for a specific program and it'd be fine. It 0:22:23.840 --> 0:22:26.760 just wouldn't be as crisp and clear as the monochromatic 0:22:27.040 --> 0:22:32.359 m d A text specific machines. Onto the graphics modes, however, 0:22:32.560 --> 0:22:35.120 that's what we're really interested in, right, What actually made 0:22:35.600 --> 0:22:41.160 the images, not just the text on these computers. Well, 0:22:41.680 --> 0:22:44.320 the graphics mode for the c g A machine had, 0:22:44.680 --> 0:22:47.480 like I said, two different modes to it, two different 0:22:47.520 --> 0:22:50.959 official modes to it. One was a three twenty by 0:22:51.040 --> 0:22:54.879 two hundred resolution, but the pixel ratio was one to 0:22:55.000 --> 0:22:57.360 one point two, so again it looked more like three 0:22:57.800 --> 0:23:00.960 by two forty. This mode could just lay up to 0:23:01.280 --> 0:23:04.640 four colors at any one time using one of two 0:23:04.840 --> 0:23:08.240 pre selected palettes. This is why if you ever look 0:23:08.280 --> 0:23:10.600 at old c G A games, they all start to 0:23:10.680 --> 0:23:14.160 look really similar. They're all using the exact same colors. 0:23:14.320 --> 0:23:18.520 For colors, the programmers were working under some really tight restrictions. 0:23:18.880 --> 0:23:23.639 The first palette of colors included black, green, red, and yellow. 0:23:23.960 --> 0:23:27.920 This was palette zero. The second palette, a k A 0:23:28.119 --> 0:23:33.159 Palette one had black, cyan, magenta, and white. Now, as 0:23:33.200 --> 0:23:36.640 you can imagine, it's pretty tough to create good graphics 0:23:36.720 --> 0:23:40.040 with this limited color selection. Now, on top of that, 0:23:40.280 --> 0:23:45.399 programmers could use low intensity or brightness or high intensity 0:23:45.840 --> 0:23:49.680 or brightness. So that would add another variation. And I've 0:23:49.720 --> 0:23:53.600 seen the same screen presented in both palettes at both 0:23:53.680 --> 0:23:58.479 levels of intensity, and there are differences, like you can 0:23:58.560 --> 0:24:01.200 get a very different effect going from one to the other. 0:24:01.800 --> 0:24:04.359 So programs had a little bit of flexibility, but not 0:24:04.480 --> 0:24:09.080 by much. In both palettes, black is color zero, and 0:24:09.200 --> 0:24:13.000 color zero was actually customizable. You could swap it out. 0:24:13.720 --> 0:24:17.240 You could choose one of the other fifteen colors that 0:24:17.400 --> 0:24:20.880 c g A supported and use that as color zero. 0:24:21.200 --> 0:24:23.600 Black would no longer be used. The flip side of 0:24:23.680 --> 0:24:26.640 this is that the new color would replace color zero 0:24:26.720 --> 0:24:29.320 in all of the image. So if you wanted the 0:24:29.400 --> 0:24:32.760 image to have black in it, it would get replaced 0:24:32.800 --> 0:24:36.119