IMSAI 8080 - You know that computer from War Games

on this channel we've talked a few times about how we've had many computers and micro computers and covered various examples of both to be honest a few more micro computers than minis but what we've not looked at yet is the micro reviews right at the beginning of this the ones that almost had one toe in the mini Computer World so it's time to have a look at the computer from war games no not that one the actual real one but before we get into all of that I would like to thank the sponsor of today's video PCB way PCB way or a manufacturer of pcb's printed circuit rods so if you're the sort of person who likes to design and get manufactured pcbs then they're a company that you can send stuff to over the Internet get your pcbs back in the post I know ideal isn't it especially if you've been joining all your components together with little wires and wondering actually there's a better way to do this now one of the reasons I'm finally looking at the MCI 8080 is I've got a kit version of it now it's not an original one it's a kit that someone's made essentially make a replica version of it that fully emulates the machine and I really wanted an excuse to build it but also I got the kit because I wanted an excuse to talk about the MSI in the video as well so this is very much a virtuous circle for me the company that created the MSI 8080 was IMS Associates Incorporated hence mside no it's founded by William Millard better known as Bill Millard a name that may be familiar to some of you because he also started the company computerland a big computer retailer in the US in the late 60s bill was working for IBM and like many who worked for IBM during this period he left to go start his own business a software publishing company called System Dynamics which unfortunately only lasted about three years however being the sort of person who didn't seem to mind founding new businesses he went on to go start IMS Associates now this started off as a consultancy firm it was doing doing stuff that was much more similar to his role at IBM before he left and that company was started in 1972 And by 1974 he was approached by one of his clients to design a computer system which the client wanted to use in General Motors dealerships now what bill and his chief engineer Joe Killen had in mind was doing much more akin to a mini computer he would have terminals a printer all connected up to One Mini computer that would have a hard drive as well but they stopped development on that design when their heads were turned towards the microprocessor now many computers had processors but they were typically made out of a bunch of TTL logic chips on a board at this point in time what the microprocessor gave you was the entire processor but just on one chip this would give a massive cost advantage to manufacturing machine based around it in the same way that business calculators removed from being out many chip implementation to a single calculation chip implementation now other companies that have been producing these calculated chips was Intel with their 4004 and it was an Intel chip that caught Bill's eye the 80 18. now here is a chip that was offering to do what the 4004 had done for the calculator Market but for the computer market and in fact a calculator manufacturer mitt who previously made calculators based around the 4004 had decided to create a machine based around the 8080 the Altair and it was this Altair machine that they would clone and uses the basis for the mc8018 so why did they make a clone and not just go for their own design well it's all to do with buses with the Altair Mitch had created the bus that would later become known as the S100 bus Now does not there's not a lot to this boss it's basically the CPU signals after the 8080 dumped onto a set of pins of the bus there's also a couple of standard voltage pins as well different voltages that you can use to pull power for your cards with the Altair being the first mass-produced machine to do this or at least mass by early 1970s standards or S100 became the de facto standard bus for 8080 base machines amateurs you're making their own machines there you put the S100 Plus in there companies and individuals who are designing their own cards again they targeted the S100 bus so there was a certain momentum behind this thing so it highly made sense for the MCI 8080 to have that bus and if you're gonna have that bus well there's not much else about the outer left to clone there's essentially the panel at the front and the Altair's panel design let's say it was very heavily inspired by mini computer front panels of the time in fact if you're making a system that was targeting business at the time you're kind of expected to include a front panel like that also if you go with making a clone it is a much easier way to sell your machine particularly if the original machine is popular and for its time the Altair was in fact mitts couldn't make them fast enough which again was another advantage to cloning the thing because if you were the Altair clone well people could come by yours rather than having to wait for the Altair also it's a lot easier to persuade people to buy your thing that's like an Altair but a bit better than it is to say hey see this brand new thing that you'll have to develop different software and hardware for why don't you come and buy that so let's have a look at the MSI 8080 itself now I don't actually have one myself because they will never really sold that much in the UK and they are terrifyingly expensive now but I do have some lovely photos now for a micro computer this thing is very mini computer-like and it is just the computer nothing else and by that I mean this thing does now have a display there is nowhere to plug in a screen or monitor there's no keyboard input it is just the processor some memory and serial interfaces where you can connect printers or terminals so just like a mini computer is designed to be used via a Dom terminal or a tele type so if we open the machine up we'll see that the right one-third of it's dominated by what a dunkingly huge power supply but at the time it was quite a good high quality power supply particularly if you compared it to the one in the outer the left two thirds is dominated by the backplane or the bus which is just a PCB with a number of slot connectors on it there really isn't very much to this thing electrically speaking although this is another area where the M side gets a bit better than the outer and it had 22 slots on the version they shipped with as opposed to the Thor on the Altair all the actual things that make up the working part of the computer well they're all on cards including the CPU so the MSI originally shipped with a board labeled mpua which was the board that carried the CPU and actually does not much else on that bust as the CPU the clock generator and some line drivers for the bus that's that's basically it oh and of course the connector for the front panel so to get a working computer you're going to need a few more cards in your boss than just that one you would need some memory cards so the CPU actually had some memory it could use and you'd need at least one i o card so you could plug a terminal into it now later on MSI was producer board known as mpub which is the replacement for mpua and this board had the CPU and a few more things on it as well so as well as your CPU clock generator bus line drivers Etc you also had serial and parallel i o so you could have a printer and a terminal came with a very small amount of RAM and you'd averaging one to 4k on there and a 1K ROM as well we'll come back to that ROM later with mpub you had a more or less very basic working machine with just one card although very few people just had the one card in there typically you'd see people adding at least another Ram card in there and they might want some more i o cards to have more serial ports or slightly more exciting things like you could set into Facebook or if you had all the money a floppy Drive controller and if you had even more money than all the money a hard drive controller and if you're a Matthew Broderick you had a speech synthesizer board that you'd use to try and impress your rugby girlfriend so what was it like to try and use one of these things well with the very first version of this thing the answer is not a lot like using a model computer that's for darn sure and this is where we're going to come to the switches on the front because these switches on the front that's how you got code into this thing or at least initially now things change a little bit when we get that mpub board you know the one with the 1K ROM on it as that contains some firmware for the machine a bit of software that can be run initially when the machine first powers on and that gives us something that well helps a little bit in that it gives us a monitor program and all that monitor program does is let us do at the serial Port via a terminal what we can do with the switches on the front fire a few typed commands now this may sound like not very much and that's because this is not a significant Improvement but it does make life a little bit easier for us because the problem with toggling in data at the front panel is it's very very time consuming and you have to do it manually every single time with the serial Port version well we don't necessarily have to do it by hand you see a lot of people at the time were using tele-type devices and a number of these teletype devices had a paper punch reader and writer which meant that you could record onto paper tape what comes down the serial Port you can also play that paper tape back again and it's almost like you're typing it in at the keyboard live only you know steady repeatable and reliable so if you combine this with the monitor run we can actually automatically type everything in off paper tape so we could have all our program pre-recorded on paper tape play it through the Telly typing it will essentially type it in in an automated fashion into the monitor ROM for us we could then just run the code and this is a huge leap forward from toggling Little switches at the front repeatedly of course if you want the more advantages of one of these vt100 terminals or 52 terminals you know the glass TTY well then you didn't have a paper tape reader on that thing but people started to create cassette tape interfaces an example of one of these is the ac30 now this device you plug your serial terminal in one end your computer in the other end and you could also plug in a regular tape recorder you could then record the output of the computer to type and then play that back into the computer again essentially doing what the paper tape reader did only with audio tape you would also get cassette interface cards that could go directly on the M size bus and these were fake being a Serial port and you'd use a a bit of Koji toggling on the front panel to get it to use that serial Port rather than the one your terminal was plugged into to read the data from I've of course as we've got more and more i o options we also got improved firmware ROMs that could boot software directly off these storage devices like the tape and if you have more money the disk drive now it's this level of machine that our replica seeks to emulate so this feels like a pretty good time to bring the thing out and start telling you about it the kits created by the high nibble as he's known on Twitter or Dave who's based out in Australia so if you order one of these kits and you don't live in Australia it's going to take a little while to get to you or in my case it'll take a little while for Royal Mail to send someone to your house while you're out fail to leave any indication that they've been like a card or anything and then they will keep hold of your parcel and refuse to give it to you because you don't have the card that they apparently definitely gave you although they didn't at which point your kit will go back to Australia and Dave will be nice enough to send it again and assuming this time that Royal Mail uses a postman and not a ninja you will eventually find out that your parcel has arrived in the UK and get a hold of it and then one year after that you'll have the time available to finally assemble the thing and make a video about it of course your experience of this may vary from mine so the kit is based around an esp32 that microcontroller then does all the emulation of the MCI 8080 and I must say it does a lovely job I'll get to show you that off in a minute and the rest of the replica kit consists of what we need to make the front panel which is a lot of Twitches some very nice looking Plastics a PCB and a bag full of components so it's time to get soldering so let's fire up the solder Montage Music by poke the first bit unfortunately involves doing some surface mount components and I hate doing surface mount soldering I really do because it's difficult and I'm not brilliant at it but here's my GT method of doing it you use a lot of flux but a tiny bit of solder on the end of your iron and just dab the PIN secure the first pin to hold the chip in place and then you do the second pin at the opposite corner again hold the thing in place then you can solder all the rest of the pins you get something that hopefully doesn't Bridge any of the pins but does a good enough contact and I just about manage it this time unfortunately this Ram chip isn't the only bit of surface mounting I also have to do an SD card holder as well which has all the problems of the first component are in the additional one if you can't Bridge the soldiers of the metal shielding on the outside otherwise you show up the PIN to ground this is harder than it sounds did I mention they hate doing surface mount work I mean I really hate doing surface mount [Music] s that I'm running out of deck [Music] unfortunately all the rest of the components are through home and here I'm doing one of the sets of the many LEDs that we're going to install luckily the kits provided this nice spacing tool that we can put under the legs of the LEDs to get them just the right distance off the PCB and all neatly aligned and this bit that goes on top that helps us get the LED alignment just spot on when you need me I'll always be a sovereign [Music] Christmas [Music] and at this point during the build I discovered where I'd left my side Cutters so funny got to start tidying up some of the back of the board [Music] laughs [Music] we got a number of sockets for all our dip chips so we'll get those all salted on [Music] [Music] foreign [Music] after we've done a bit of off-camera testing for this board it's time to finally assemble it together with all its various panels and Plastics so it looks really nice [Music] and finally we have all the toggle switches to do [Music] thank you [Music] thank you [Music] so here we go the Finish kit and as did say in Australia it's a Butte or at least I'd assume they would say that due to my watching of Neighbors when I was a child now if you're gonna buy one of these don't use my video as your assembly guy because I really did rush through this just to show you how it's built and give you some idea as to what it's like to put one together there's a lot of testing steps I did that are not on camera the person who's made it has actually done some detailed assembly guide video so if you're building one yourself much better that you look at those than watch this so what happened to MSI in the 8080 well well very iconic it's not the highest selling of the Altair clones I mean that was probably the cremenko at which the higher nibble also does a kit off as well by the way but certainly it was selling well enough and they tried to develop the product further and further by creating new cards for it one thing they created was a card that is essentially a text based video system which made it much more likely to expect the computer to be these days that you could looking at monitoring the keyboard to it and this replaced the need for an external terminal cremenko even did a graphics board known as the dazzler that you could add directly to this thing as well but as the 70s wore on we started to see the release of much more Friendly Computers for your average users the likes of the Apple II The Commodore pet the TRS-80 these machines are much more likely to expect them to be and that you could plug them into a TV or a monitor just switch them on you've got a keyboard you've got graphics Etc amsite did try to develop a machine like this themselves in the form of the vdp-40 which they released in 1977 and this was essentially an MCI 8080 only using an 8085 processor with 32 or 64k in memory and it came with two floppy drives you're still adding S100 bus and it had a built-in monitor as well and the nice fancy graphics card okay well fancy for 1977 anyway the problem is it was very expensive for the time at 10 000 and those other manufacturers had a lot more scale and money for advertising and stuff like that they were also based on more modern processes as well as many use xylog z80 chip which is essentially an improved clone of the 8080 that could run a bit faster and add more stuff built into it or they were based on the 6502 which was again an improved and cheaper version of the Motorola 6800 by the time we hit 1979 unfortunately MSA Associates Inc had gone bust but fortunately for Bill Millard who started it well he'd founded computer land in 1976 which went on to be one of the largest computer retailers in the US until it went defunct in 1999 at which point I'm hoping that bill Millard got a very well-earned retirement although we now know what happened to MSI what we've not been able to see is what using this machine's actually like now I was hoping to show you this with the serial terminal plugged in and using it like you would have used it back then but unfortunately my vt220 is not particularly well um it seems to have a bit of a vertical sync problem so I'm not even going to turn it on for the video because it well to say it flickers would be a bit of an understatement fortunately we can see this thing in action without owning a Serial terminal after all creating a new modern version of a retro machine and forcing you to use a 1980 serial terminal would be a bit awkward no this thing has a nice web interface so by default when you first power it on it actually sets up as a wireless access point and you can connect to that and then use your web browser to connect to the machine and use it you can also reconfigure that so it just joins your wireless network as well right let's have a look at this web interface down the left hand side of the screen you'll see all our inputs and output devices starting with dty dty is essentially that serial terminal device it's emulating a vt100 in this particular case next you see we have a device labeled CRT that's emulating msi's own card which is essentially a terminal on a card that you could put in and just clog up to a CRT monitor the idea being that this card would save you having to have an external serial terminal now although this card was made available for the mc8018 really this was developed for their VDP 40. after that we have ltp which is the printer we then have our various disk drives a today and these are meant to emulate an 8-inch disk drive which is the standard of the time which is why it has an icon that looks like that after that we have dry VI which is a hard drive which of course barely anyone had at that point in time we then have Libs which is the folder containing all our disk images which we can use to mount into any of the floppy drives or hard drive images into drive I we then have man which is just a handy copy of all the manuals for this stuff we then have says that shows us how our machines currently configured CPL uses access to the control panel at the front or at least a very small part of it it allows us to hit the stop run clear reset buttons those sorts of things we then have the output of the cremenco dasler card which is an early graphics card we'll come back to that in a bit later and let you see some very early computer games with graphics and the last couple of devices are the Cyclops camera which is again made by cremenko and you can think it was like a very early web camera I'll need you know there's no web and it's black and white and Incredibly low resolution and as for its frame rate you kind of feel like the plural might be inappropriate in terms of how this is emulated well it hooks up to your webcam through your web browser and the final devices joystick which I've not yet figured out how to use which will become very evident later on I also should mention because it's been on screen the whole time is there's a paper tape emulator as well which is what that yellow rectangle is which allows us to load in paper tape images and use our machine like it's a proper old school early 70s box right let's get this TTY fighting to full screen so you can see this thing running CPM as you can see we're left with this a prompt because we are on drive a yes thus and windows did steal the disk labeling system used by CPM thus users will also notice we got some.com files there and Yep they're exactly what you think they are because again does borrow the extension used by CPM although you won't see dot exe because that was a Dos thing let's change over to drive B and run super calc while not the first ever spreadsheet program for CPM in fact that would be the first spreadsheet program physical it did run on a much wider variety of CPM machines so it pretty much took over from physical very quickly and it's pretty much what you'd expect for a spreadsheet program it does a lot of things a modern spreadsheet program does and spreadsheets were the killer application for the micro computer it's what really drove forward the early adoption of these machines of course one of the other big business uses for these machines was word processing and here we have word star which is time is one of the most popular word processing applications now earlier I mentioned the dazzler and the possibility of games well it's finally got to that point prepared to be underwhelmed here we have space war or at least the implementation for the dazzler now this is not going to be the most inspiring um footage parsley because I can't get the joystick interface to work and therefore all these ships are going to do is repeatedly crash into the stage due to the fact that gravity is pulling it in and the other reason you won't be particularly impressed as well it's not particularly impressive or at least even by graphic standards two or three years after this when I say this is an early graphics card I mean this is one of the first graphics cards so at the time it would have been quite a thing to see but even by 1980 graphically this would not have been that impressive I'll move on to the next game I've got to show you for the dazzler dogfight which is where two planes duel each other in the skies or what do if you had a working joystick so in this instance two planes will sit on the ground of course most MSI 8080 owners never had the dazzler as that was cremenko's card but they did have some games to play even if those games had to be text based and no games more Tech space than the text Adventure game I mean the clue is very much in the title and in that genre at the time one of the most popular series of them were Zork in fact we had zork's one two and as we have here free now I'm not really gonna sit and play this here in front of you because for the purposes of a video a text Adventure game is really not very exciting if you got all the way to the end I'd like to say thank you very much for watching I would also like to thank Richard Masters and poke for letting us borrow the soldering Montage tune if you enjoyed this video why not click that little thumbs up button that YouTube has created to indicate that fact and if you'd like to help the channel out then feel free to hit that subscribe Button as it really does make a huge difference as to whether YouTube can be bothered sharing these videos to other people thank you [Music]

Channel: RetroBytes

Views: 81,652

Keywords: imsai 8080, intel 8080, war games, imsai, s100 bus

Id: fmnX0bJjVew

Length: 26min 36sec (1596 seconds)

Published: Sat Jul 29 2023