 Today we're going to be taking a look at 86DOS, which was recently uploaded to the internet on archive.org. I'll leave a link to it in the description of this video. This is the earliest known copy of 86DOS in existence and probably will be the earliest copy we ever get because it's literally serial number 11. Okay, so there's probably only 10 other disc out there in the world that came before it. And this was originally developed, you know, 86DOS, also known as QDOS, was originally developed for the Seattle computer products Intel 8086 based computer kit and was later sold to Microsoft who made some changes to it. And of course they renamed that operating system to MSDOS, which many consider to be the first widely successful home operating system. But this version of DOS, 86DOS, QDOS, whatever you want to call it, is from a year prior to that Microsoft acquisition. And it really gives us some insight into vintage home operating systems. So to give you an idea of just how old this computer is, here's some pictures of a gazelle system that might have ran 86DOS or QDOS. Okay, this is a desktop probably about the size of a small file cabinet with this hefty looking terminal on top. Let's get a better picture of it. Yeah, here we go. These two guys standing beside it right comes up to about hip height on an average size, ma'am. I really like this pick too, just with like the tablecloth and everything. It's such a like blast from the past nostalgia trip. But anyway, you know, this bad boy under the hood, it might have a whole megabyte of RAM inside of it, right? Like, this is early 80s computers, you know, compare that to current gen DDR5 builds that could have a whole terabyte or more of RAM in them. But anyway, let's get this thing running, right? Speaking of modern systems, let's let's emulate 86DOS on my Threadripper real quick. I mean, you don't need a Threadripper any Linux system will do for running this. Now there are a couple of things that you're going to need, you're going to need open SIMH or, you know, any type of SIMH will probably do personally open SIMH is the one that I'm using. Now, this is a basically like a simulator or an emulator for different computer systems, like, you know, you've got the Altair on here, you know, HP's, you've got the Vax system, right? But the only system that we're really going to need from this group is the Altair Z80. So that's just a quick tip, you know, if you're going to download this from GitHub and compile it like I did, the only one that you actually have to compile is the Altair Z80. So that's going to save you quite a bit of time not having to compile all these additional things here. And of course, you're going to also need that image file, you know, that ISO image, which you can download right here, 250K. They don't make operating systems like that anymore, folks. And you're also going to need some additional helper files. Basically, it's a startup script and 86mon.bin, which can be downloaded from this link here. I'm going to try to leave this link in the description as well. But it's a direct link to a zip file. So I don't know if YouTube's going to be weird about something like that. But yeah, this is if that doesn't work, then I'll just leave a link to this website, which has the link and hopefully that gets past YouTube's filters. So I've got all these files here inside of this directory. So this is the original file name that you get when you download 86DOS from that archive.org link. And this is actually the first change I'm going to make here. I'm going to rename this because it's just really long and annoying to just 86DOS.img. All right, so when you unzip, actually, let me just do this, make things a little bit more clear and concise. So when you inflate the zip file, there's a few other files you're going to get in it. There's something like IMD, or like it's not an IMG file. It's got a slightly different file extension, but that's not a needed file. I'm not even quite sure what it is. I kind of thought that this person might have just packaged up 86DOS with it, but I ran a diff between the one from archive.org and the one that came in the zip and they were different. So I just got rid of that file that came in the zip. So then inside of this 86DOS startup file, you want this to pretty much match exactly what I have here. I think I'll probably, I got a sim link, vim to nvim. Anyway, you pretty much want this to match exactly what I have here, and I'll probably just cat this file out and put it in the description as well. So the important things to note are online 26. You want to make sure after attcromfdc0, that this string here, 86DOS.img, matches exactly the name of the 86DOS file that you just saw me rename. And then up here, below line, or actually, no, it's right here on line 12. Just take note how 86mon.bin, this matches the file here, 86mon.bin. So you want to make sure both this file and this file are in the same directory as the startup script in that they have the same names matching in that startup script on the lines that you saw. So once everything is in place there, you can then run the Altair binary that you compiled in that simh download, z80. So you run that program and then you point it to the 86DOS startup script. And then from here, you just have to read and follow the instructions here in the prompt. So press return to get the monitor prompt and then press B to boot, or sorry, capital B to boot, and boom, we're in 86DOS version 0.11 copyright 1980, Seattle computer products incorporated. We just traveled back in time folks, 44 years. Now if you've played around in something like the Windows command prompt, for example, this here might be throwing you off a little bit, right? Because it's kind of familiar. We're used to seeing C on the Windows command prompt, you know, C colon, but we're not used to seeing A colon, right? So what's going on with this drive letter A? Well, long ago, back in like 1980 and before, most computers didn't have any hard drive in them at all. You only had one floppy disk drive that you would run your whole operating system off of your whole OS would be run off of a floppy disk and you would save all your files to it. And that floppy disk would be maybe one megabyte in capacity, right? That was your A drive. And if you were a really cool guy, you might have had a second floppy drive in your computer that you could copy stuff to, you know, you could run two floppy drives at once. Oh my gosh. And that would have been your B drive. So we're basically emulating a floppy disk A here. And still to this day, I'm pretty sure on Windows, the first, what we would call a hard disk is C, so that they can have backwards compatibility with those old school floppy drive systems. And speaking of file systems, right? Let's do a dir command so that you can get an idea of what the file system output looks like. So the one used here is basically a very early version of fat 12, probably the earliest ever version of fat 12, because I think it's missing things that like are considered standard in the actual fat 12 standard. So you're limited to a volume size of I think 16 megs. And that's also going to be the theoretical maximum for your file sizes as well, which honestly is freaking huge considering that we're in floppy disk world. And I think floppy disk only got up to like a meg, maybe a meg and a half in size. So this 12 bit fat doesn't support date or timestamps, right? So there's no like created or last modified timestamps for any of the files here. And you also don't get file sizes. Right? So when we do a dir command, all you see are the names of the files, and the file types. Okay, so dot doc, of course, is a document. And com, I think is short for command, because these are the names of all of the external commands that we can run on 86 dots. And then in addition, there's some internal commands not listed, which are rename, erase, copy, type, and of course, dir, that you already saw. Oh, and clear, clear, just delete all the whole operating system, right? Maybe we'll do that at the end. But we're not going to do that right now. So let's let's list out our external commands again, and just kind of go over what's on here, right? Because this is what like just over a dozen commands in total, including the internal commands. So of course, command is our command interpreter. rd CPM can read files from CPM disks, and then copy them over to our fat format disk, because DOS was not able to do that natively at this stage in its life. Hex to bin, let's us change assembled programs into com files that we can actually run in our operating system. Asm is our assembler, right? Because that's what we do on here, right? We do everything in assembly. And this assembler was written by Seattle computers, not by Microsoft. Trans takes Z80 source code, and it converts it to 8086 source code. CIS is used to copy a bootable copy of this system onto another disk. So this would probably be used by those cool guys that we were talking about that had two floppy drives in their computers. And Edlin is the line editor. We're going to take a look at this in a moment. Who boy, you thought them was a not great text editor or a hard text editor to use, right? You thought Nano, you thought Emacs was difficult. Let me show you Edlin. I'm an Edlin noob. I mean, I had to read the user manual just to figure out how to do what I'm going to show you guys in a minute and I'm still probably going to screw it up. And then we have chess, right? We have chess com and we have chess doc. So what's going on with this? Well, you know, chess, why don't I just run chess, right? So, you know, choose our color and depth one. And then, you know, we start entering places to move to, I guess. Oh, wait, no, that's an invalid move. E2, E4, that's an invalid move to. Clearly, I don't know how to play chess on the command line. But chess com, that's our chess game, right? And then chess doc, actually, why don't we just read chess doc, right? So I'm going to type type to output it chess doc. And then that'll just send or output the text from this document to our command line kind of like the cat command. So let's see. Okay. Oh, okay. So I see how to do it. E2 to E4. All right, cool. So maybe later on, if I want to, I could play some 1980s chess on 86 dots. That'd be pretty cool. But anyway, let's edit or end the video with a little bit of file editing, something that I actually read the user manual on. So dur, list all my files, right? Let's make a copy of this chess document. So we'll change it from chess dot doc to I'll just call it chess one dot doc. So I do dur again, boom, you see, I've got this chess one dot doc. And if I type it out, it's got all the same text as the first one, right? Well, I want to edit the instruction of this, I'm going to create the instructions for my version of chess. So we'll Edlin chess one dot doc. So on this screen, this is kind of like, I guess, kind of like Vim's normal mode, right? Or maybe Vim's command mode. So L list out all of our lines and all the stuff that's on them. So let's see. I think I'm going to edit three lines here, right? So I'm going to actually delete line five. I'm going to delete line six. And I'm going to, and let me just do an L real quick to show you, right? So we deleted those. And I think now I'm going to edit line five. And let's, let's make this more my game of chess, right? Knock over all the pieces. And now I win. Yeah, there we go. That's how to do it. So now we list that. And you can see now line five contains my ultimate unbeatable strategy to win at chess. And then he saves and closes our file and exits us out of Edlin. And then type chess one dot doc and boom, you have my instructions here for how to always win a chess. So that is 86 dots. Hope you guys enjoyed this brief introduction to it. And have a great rest of your night.