 All right, and welcome everyone, thanks for coming to my talk. So my name is Michel Engel or Michael Engel, whatever you like. I'm working as a professor for systems programming at Bumberg University, and so I thought I'd bring you some of the fun stuff we're working with, so you know, combining your hobby and being paid for it is actually quite nice, and I'm trying to do this, and I thought I'd bring you something. I'm currently working on, so this is work in progress, and we have a great opportunity to actually discuss it this year, because there's an anniversary. So this is ignored, disposed of, revived, four decades of Apple's first computer with a graphical user to Fessi, Lysa, or Lisa, whatever you prefer. And so we have something to celebrate, and of course we're in Berlin, so we have an important anniversary this year. 25 years of Lola rent, oh no, no, that's the wrong one, sorry. Of course we have 40 years of Lysa Loeft, yes. So it's Lysa's 40th anniversary, so most of my students are like half that age, and they started using Windows XP as their first computer, and they cannot imagine that like 20 years before, which is probably when their parents were kids, right? There were computers which had graphical user interfaces, a mouse, and all that stuff they're used to today, and that's great to show it to them, because you know when you do systems programming, you want to dig deeper, you want to show your students like, oh yeah, you see some effect on the high level, you want to know what's going on on the hardware, and this is impossible with modern PCs, not even with a Raspberry Pi, because even on a Raspberry Pi there's a lot of stuff like the GPU, which is not open, which is not documented, so you can't even start reverse engineering without putting like two years of work into it, which my students usually don't have, unfortunately. So, let's talk about Apple. How did it start? You've probably all seen the videos of this new, huge Apple building, which is a circle in this huge park, so a UFO, but it started very small, of course, like all Silicon Valley companies starting from HP in this garage there somewhere in Silicon Valley, and of course these two guys, well, the one looks pretty similar today, this is Steve Wozniak, he's just like 70 something years old now, and the other one probably looks very different today if we could see him, because it's Steve Jobs, and he unfortunately passed away a bit more than 10 years ago, and they started as hackers in the best and worst sense of the world, because they were hackers in the best sense of the world, they wanted to fiddle with technology, they wanted to understand how things work, and the worst thing of the world, because they funded their first electronics projects by selling so-called blue boxes, things which created a special frequency with which you could do free long-distance calls on the American telephone system, and Steve Wozniak had some fun and phoned the Pope in Rome one day, and actually almost got him on the phone before they noticed something's wrong, he's not Henry Kissinger, and so they were interested in that computer stuff, so Steve Wozniak was working for Hewlett Packard back then, as an electronics engineer building pocket-calculated stuff like that, and he's an excellent electronics engineer, and then finally affordable microprocessors came to market, back then you could buy an Intel microprocessor, an 8080, that cost like 400 US dollars, nowadays that would be like two or three thousand dollars in current dollars, and then there's a small company called Moss Technology came to a small computer fair in Western California and presented the 6502 for 25 dollars, and that was affordable, so Woz bought a couple of them and built his first computer, the Apple One. If you happen to have an Apple One, I would be very interested, but I'm afraid I can't afford a quarter of a million dollars these go-for-in auctions today. There were like 666 of them built, and people guessed like 100 up to 200 are in existence. There's one in the Heidz-Nixdorf Forum in Paderborn, if you're interested, they actually managed to get it to work again, so they have a great video on YouTube, but this is distracting because I'm telling you, I want to tell you something about the Lisa. So Apple One was a moderate success, and they managed to earn enough money to build the Apple Two, which is also based on 65 or two, stuff like color graphics, and it built in basic interpreter and stuff like that, and this was a huge success, not because the hardware was so great. It was okay, but it was nothing special. Everyone could have built this, maybe not as compact as Woz did it, but yeah, there were no secrets, and there were lots of Apple clones around back then. I know some students in Karlsruhe and their student dormitories built Apple clones and sold them cheaply. I think I have one of those, and well, it gave them enough money to continue with follow-up projects. What was the success of Apple? It was software, software that wasn't even written by Apple, but by two economics researchers, and they built the first spreadsheet called Wizikalk. So office applications, something wasn't never was interested in because he wanted to play games on his computer as he built, right? That was actually the thing that managed to push Apple to this big company we have today initially, and so they thought, like, oh yeah, of course, we should build some follow-up stuff. All of the computers until the early 80s used the same 6502 CPU, so an 8-bit CPU running at 1 MHz to 1.8 MHz, and then the Apple II became a bit long in the tooth, so essentially something new needed to come, and Electronics was rapidly developing back then, so of course they were interested in everything new that was coming out. And since they were in Silicon Valley, there were so many other great companies around, and of course engineers know each other, and there are no company limits when it comes to technology. It's just the managers think they are. And so they knew the guys sitting a bit further away in Palo Alto, that's where Stanford University is, and they're from a company called Xerox. It's a central research lab, so you might know Xerox from photocopiers. That's actually the only thing that ever made money for that company, but they managed to fund a large research lab, and they wanted to try to invent the office of the 1980s, in the 1970s, so you might have heard the, well, once in my age, or some of you might have heard of this vision of the paperless office. That didn't really work out, especially not for Xerox, which built copiers, right? So they had more paper. Anyways, they funded a lot of great researchers, including people like Alan Kay, and they, in the early 70s, thought about how do I make office work digital? And they built machines like this thing. This is the first machine with a graphical screen, bitmap screen, and a mouse down there, and of course a keyboard. You see the computer is this big thing below here, which had a lot of PCBs here and a large 14-inch disk platter for the operating system and application, and that was, yeah, well, an innovation, because they invented stuff like user interfaces. They invented using the mouse, which was built in Stanford before, by Doug Engelbart a couple of years before that, and they continued to develop it. Now, unfortunately, Xerox management was a bit brain dead, because the only thing they could do is sell copiers. They didn't know how to sell computers, so these machines were like $100,000. Nobody bought them, or nobody could afford them, but they still continued to develop that stuff for like a couple of years. So in 1979, a follow-up machine, which was much faster, but very similar in principle, came out the Xerox Star, but still this one costs more than $100,000. So nothing you would put on your secretary's desk unless you're a very rich company. And they also built other things which really other companies made money with, like Ethernet came from Xerox, laser printers were invented there. And another thing they invented was something called Smalltalk, just a show of hands. Who have you heard of Smalltalk before? Excellent. So Smalltalk is one of the very early, one of the first two object-oriented languages, what we call today. The other one is similar from the research lab in Norway in Oslo, and Smalltalk was a system. So really they tried to start like, how can we get normal people, whatever a normal person is, to program a computer? So let's make it easier. Back then you programmed on punched cards in assembly. They thought like, can we do it in objects in human-like language? And of course approachable, so no command lines, but user interfaces showing graphics, little icons where you can click on, little windows you can move around the screen. So Smalltalk was developed over the course of many years in the Xerox park by Alan Kay and his colleagues, and it ran on the Alto and on all the successive machines. And Smalltalk, you can see here, is a system that has windows, it has bitmap fonts, so nothing you've seen in normal computers in the 1970s. And something interesting happened. And this is that a couple of Apple engineers knew a couple of people at Xerox, and so they got a tour of all the innovations at Xerox Labs in 1979. So they were shown the Alto and maybe the Star already. They were shown this graphical user interface. They were also shown Ethernet and laser printing, but they didn't get why this would be relevant until a couple years later. So the one thing that really stayed in their mind is graphical user interfaces are the way to build future computers. And you see this. So this is a Smalltalk window, and this is just a screenshot, so that's why it looks so crumbled of a prototype of the Liza operating system or even the first Mac operating system. And if you look at the font, this is a very specific font that was designed for Smalltalk. It was supposed to be easy to read. It wasn't, so they replaced it later. And the font used here is exactly the same one. So there is more than just inspiration. They really took over some ideas from Smalltalk at Apple. So they were inspired, but of course the stuff in Xerox didn't license that thing. And of course, Apple would never have been able to sell a computer that costs $100,000. I mean, they're still trying today with the Mac Studio, but no. And so they thought, like, can we build our own system that's cheaper? And of course, back then the first more capable microprocessors came to market. So we had the Intel 8088 and the 8086, which causes all the mess we're using today with X86 and Windows. We had Motorola with much more advanced CPU. The Motorola 68000 you've all heard of if you ever had an Amiga or an Atari or an early Mac, of course. These processes weren't exactly cheap. So I remember seeing an old magazine. So I was bought in 1970. So in 1979, at that time I never saw a computer in my life. The first one was an 83, a Commodore 64, but anyways. So I found some old magazines and a 68000 process cost around marks back then. So not exactly cheap, but much more affordable. So the Apple II was old. Apple needed something new to sell. Even if the Apple II was selling very well they knew they had to come up with something new because the competition was pretty strong back then. You had Commodore you had Tandy, Radio Shack and of course you had the IBM PC by 1981. So in 1978 two new projects as Apple started. Both named after girls, Sarah. Sarah is the name of the daughter of one of the Apple II developers. He developed the Apple II successor. Also as a business system, but still mostly a text based system, but with an advanced operating system intended for small business. This is what became the Apple III. So still a 6502 based machine, but advanced more memory, 80 characters screen advanced operating system. Nobody bought that thing. And then there was Lisa. Why is it called Lisa? Now there's a story. So if you look at the official Apple explanation of why it's called Lisa, you will read somewhere it's called Local Integrated Systems Architecture. Now this is what we call a background. So back then Steve Jobs had a daughter out of wedlock which he never admitted back then and this daughter was called Lisa. Actually he didn't even pay the substance money to the mother of that child, even though he was a millionaire by that time. But anyways so many people assume that actually Lisa is still because Steve Jobs' daughter was called Lisa. We will never know. We can't ask him anymore. So the idea of the Lisa was to really take it further. So you see a prototype here with a really big screen. That's one of the first Lisa prototypes. We have no idea where these pictures come from, but well they showed up on BitSaver's luckily. And this was ambitious. So they wanted to realize a low-cost version of the Xerox Alto running something with a graphical user interface. So this should be much more ambitious, more expensive, easy to use, the next generation office computer with this revolutionary back then, graphical user interface. So here's a screenshot of the very first test drawing bitmap. So it's a proportional font and they took Polaroid pictures back then of their progress. And they're all on a site called folklore.org where all the old Apple developers working on the early Lisa and Mac actually post stories. Really interesting to read. So we have some documentation of the very early development. So after a couple of years, like five years of development, with lots of changes, discussions, all of that, whatever, the Lisa is born. In January 19th, on January 19th, 1983, the first model of the Lisa, the Lisa 1, was introduced. So 40 years ago and a couple of months now. And this was able to use this great new Motorola 68000 processor running at 5 MHz. Doesn't sound very convincing, right? But back then, this was the thing powering microcomputers used for multi-user systems on tunics. So the first sun machine, the sun one, the first SGI graphics machine, the Iris machine, and the first Apollo workstations were all based on the same Motorola 68000 processor and they were intended to run like 10 or 20 users at the same time on terminals. And here Apple dared to use this expensive high-end CPU for a single user doing text processing. Wow. They're pretty crazy, right? And the hardware specs for that time were really great. So it had a megabyte when your standard computer came with 64 kilobytes, so 16 times as much. A bit of ROM, just a little because most is in RAM. It had a large 12-inch screen with a very specific feature. If you look at your computer screen, you notice your pixels on your screen are usually square. So vertical size equals horizontal size. The Lisa had rectangular pixels with a ratio of 2 to 1. So pixels were twice as high as they were right. Why did they do this? Well, first it's Apple, of course, they're doing their own stuff always. But the thing is they wanted to display 80 characters on the screen in a very good readable font. So 720 pixels by 80 characters is 9 pixels per character if you have a non-proportional font and the Lisa already had proportional fonts. So that would be nice. So why didn't they increase the vertical resolution also? Well, because there's a limited bandwidth from the memory to your graphics. So RAMs can only deliver data whatever with a certain speed and of course these old DRAMs were pretty slow. So when you increase the vertical resolution, you need to read more lines per frame. And each frame has to be displayed 60 times a second because you need a screen refresh rate that's easy on your eyes, right? So if you would have increased the vertical resolution also then the CPU would have had no more time left over to access the memory which is not a good idea. So that's why we have rectangular pixels on the Lisa and adjusted, well, rule of thumb calculation like already with this monochrome resolution we need to move 2 megabytes per second to our display which is quite a lot for a machine slow as this. Now Apple loves to do stuff on their own so the Apple 2 had standard floppy drive mechanisms from Seagate or from Alps with 140 kilobytes. So 35 tracks GCR encoding with variable rotation rates but 140 kilobytes is not a lot when you have a megabyte of memory in your machine. So they needed something to store more data on and they developed their own floppy drives, 500 quarter inch floppy drives which look vaguely familiar so this is one of the floppies called fileware so you see you have one slot for a read write hat and what the heck is the other thing? That's another slot for a read write hat. So Triggy drives had two read write hats one on each side and the idea was that you could read two tracks at once with this so you increase, you double the data rate from the floppy now the problem was that the Apple guys were good or great electronics engineers, they were great software engineers, they were not so great mechanical engineers I guess. So these things were horribly unreliable. You had to readjust them like every two months and they failed ever so often so essentially that was a big problem these so called Triggy drives because they have two of those and Triggy was a model which was very slim in the 1970s or something they were a failure luckily Apple also had the idea of like storing data on disks is actually a pretty stupid idea because you can't put that much on it so let's put a hard disk on it and Apple again did the same thing well let's build our own hard disk now they were a bit more intelligent here so they bought the hard disk mechanism from Seagate a 5 megabyte mechanism an ST412 the original drive but they didn't buy the electronics from Seagate but they thought oh we can do electronics we build the electronics ourselves and this is actually an intelligent hard disk so compared to the regular MFM hard disk which needed a lot of controller hardware this was controlled by its own Z8 microcontroller inside of the program drive and the disk was connected over an 8-bit parallel bus which is vaguely similar to what we have in SCSI nowadays or head later then but again 5 megabytes were horribly expensive I think the hardest mechanism alone was like $2,000 so you can imagine you have a big screen, you have a high resolution you have an expensive CPU you have specially designed disk drives which nobody else uses and you have a 5 megabyte hard disk so essentially this computer wasn't exactly cheap so the introductory price for that machine was $9,995 or around $25k today you could have bought a very nice car back then for that amount of money so the Lisa 1 wasn't exactly a success now luckily Apple wasn't itself critical and said like maybe, maybe, maybe and Steve Jobs was absolutely against this but the engineers wanted this maybe we should ask someone who actually has experience in building disk drives and there was this Japanese company called Sony you might have heard of it they don't only build audio equipment, no that brought a new disk drive the first 3.5 inch disk drive to market nowadays 3.5 inch disk drives and those were the first ones they stored 80 tracks single-sided which resulted in 400 kilobytes of capacity so much less than the Triggy drives which had 860 kilobytes and we had two of them but since you had a hard disk it didn't matter so much and these drives are pretty reliable back then at least nowadays they're pretty unreliable unfortunately I'm trying to fix one at the moment that is the same drive that was later on used in the Mac128 and Mac512k so they could buy them in larger volumes and these worked pretty reliable so the follow-up machine was the Lisa2 and you had two variants with a 5 megabyte profile hard disk sitting on top like we've seen in the previous slide add a new one with a 10 megabyte drive and that was sitting in the place of the second disk drive here inside of the machine which made it much smaller and easier to handle now unfortunately this so-called widget drive, the 10 megabyte drive Apple then decided with like oh well it can't hurt to try and build our own hard disk again and this time we're also building the mechanics this is a horrible failure so this thing has three D8 microcontrollers which distributedly control the read-write head, the stepper motor the rotational motor and the interface and if one of them is just off by a single cycle or so your hard disk crashes yes, luckily only in software but later on due to mechanical failures so the break mechanism in the disk was too weak to actually break a high-speed rotating disk actually most of them broke down mechanically or electronically or both so repairing a widget is a nightmare luckily there are solutions for that anyways they managed to build these machines but were still very much expensive and Apple of course tried to build their own stuff in any possible way so on the left-hand side you see an original Xerox mouse which has three mouse buttons and in small talk each of these mouse buttons has a defined function one selects one enables you to open a context menu like the right mouse button today and the third one actually enables you to move windows to do window manipulation and stuff like that and Apple thought this is too complicated for our users they will never figure out which of the buttons does what so what did they do well they just threw away two of the mouse buttons and this is the first Lisa mouse which had a single mouse button you can't go wrong with a single button right I mean the later ones had zero buttons but they had a touch field so that's the thing and also these Xerox mouse mice didn't have the usual mouse ball and the two rollers on the side but they had two separate rollers which moved so they were very awkward to move in a diagonal way so Apple actually helped building and this is from the patent application the mouse we were used to before optical mice were common so with a rubber ball which moved these two cylindrical things on the side and then you essentially had an LED and a photo transistor figuring out how far the mouse has moved and this signal was directly translated and transmitted to the Lisa which could handle it now the thing is if you look at the schematics of Lisa there's actually three mouse buttons supported so they weren't too sure about it so that's one thing I need to try to connect the three button mouse to build one and see if it's actually supported that would be interesting so this is a very special model which was a bit it was square like a bit of a size of a pack of cigarettes not that ergonomically so later Lisa's were actually delivered with the mouse that was also used for the first Macintosh model so there is some crossover in hardware already so the protocol and connector is identical and some of you might know that Atari, ST and Amiga mice also work on the same principle so you just need a plug adapter if you don't have an old Mac mouse you can use an Atari ST or an Amiga mouse on these systems so we already talked about the hard disks so the profile used this Apple the cigarette mechanism and the rest built by Apple it also worked on the Apple 3 which was nice this proprietary parallel interface was simple and the widget interface was just a mess because of the mechanics built by Apple but the nice thing is this is an Apple system that's actually easy to maintain easy to repair because it's based on a modular construction so this is the back side of Lisa with the back panel removed and you see on the right hand side there is a power supply which is encapsulated obviously for safety reasons but there's a thumbscrew so you don't even need a screwdriver to open it you can just pull it out it's connected using a plug-in connector on the back so you don't need to unplug any cables or stuff like that and then the rest of the electronics is actually on a tray so here you see it's a baseboard with a number of slots and you can also see it here of course because I brought one so here's a baseboard and the different cards just plugged in so here we see the CPU board so this is the large slot for a 68000 processor in front of here would be two RAM boards and behind the CPU board on the other side is the IO board the nice thing is both have the ICs facing out so if you need to measure something because you want to see which IC went bad you can just attach your oscilloscope and you can read what's going on so you don't have to fiddle around on the back side of a PCB and then count the pins oh is it is it oh no it's mirrored oh I got the wrong one again yes so that's pretty nice but of course you would expect something like this from a machine costing ten thousand dollars because they should be serviced by like office technicians who were used to servicing typewriters or Xerox copyers or whatever and safety was built in so as soon as you either remove this back panel here there was a little pin that went into the power supply and it closed the micro switch as soon as you remove the back panel the micro switch opened and the power supply turned off so there was no way of running a Lisa with an open back panel unless of course you shorted switch which was common for service technicians and there was another one you could also remove the front panel there was another interlock safety switch and it was an expandable machine you wish you'd have that in the Mac today right so it had two RAM slots usually Lisa's came with 512k or megabyte of RAM and you had three you can't see them here but you can see them here we couldn't get the connectors so far because they're very strange and rare three expansion slots for stuff like more parallel interfaces for more hard disks or a SCSI controller or even network controllers all sorts of stuff even a sound card was available back then that was pretty nice so it's a machine that's approachable and if we look closer we see the modules again serve the CPU board here we see the big 68k processor we see two ROMs which just contained like startup firmware that can boot from different devices and do some diagnostics but compared to many other computers at that time the Lisa had a memory management unit so it could do memory relocation and protection already which is important for stability of your software there's a question 68k 68k yeah do you have a microphone for the questions or that's a trick and the trick is before you access a page you execute an instruction that accesses this memory location but it's recoverable like a test instruction test.byte so before you know before you try to access a page you really insert and that's a compiler operation instruction which when it fails just gives you a result which can be ignored and then then you can page in the page because you got a fault you're back in the operating system you can page it in and then you can continue the test operation will fail but you don't need the result anyways and then you can continue with your reload and start operation that was also used by the first sun machines actually by the sun one which also had a 68000 all this stuff was fixed in the 68010 but that was not available back then when Lisa was designed it's actually somebody tried to put a 68010 in there and actually it boots LisaOS but there's really some strange effects because the 010 also had a loop cache which meant that self modifying code which was sometimes used I guess did behave a bit differently but yes and most Lisa stuff actually didn't use the MMU but the original Lisa operating system used the MMU for protection because it was but we'll come to this later a multitasking system which was also pretty uncommon back then so we have an MMU and we also have the video signal generation so somewhere there's a shift register hiding which moves the pixels to the screen and also the signal generation for the dynamic rems so dynamic rems need don't get their addresses for the bits they want to address in one piece but in two pieces so it's essentially a matrix for memory cells which is addressed using a row and a column address so they're sent in two pieces which makes the rems cheaper to build because you need less pins, fewer pins on the chips and so this is usually on the remboard but Apple put it on the CPU board already which means they could build remboards with much smaller connectors here so this is one of the remboards these are identical these are 512k each built from 64 kilobit rems so it's a rems and so they could get away with a small connector because all the multiplexing already happened on the CPU and you actually needed it because the video and the CPU needed to access to the same memory because Apple was not putting a separate video memory on the Lisa so they shared the memory like well most later machines from Apple also did unless they invented Nubus cards and there's some multiplexers here we just had a look at those really shift between video RAM access and CPU access which is interesting because you can look at the schematics they're all on bit savers and you can try to figure out because it's all standard 74 series chips how that stuff works so we have our CPU board here we have the memory boards already here and then we have the IO board and this IO board was a bit more sophisticated actually because the Lisa uses IO co-processors two of them actually one up here is a 6504 which is a 6502 just in a 28 pin housing instead of 40 pin so it has fewer address pins and no interrupts and this is hence the floppy drive who have you have ever taken a closer look at the Apple 2 floppy controller by Steve Wozniak so you might remember this was a very small controller only consisting of six chips one was boot ROM for the CPU so you could boot from floppy drives one was another prom with a state machine and the rest was just some multiplexes and TTL ICs so back then the IBM floppy controller for the IBM PC was such a huge board which had like 100 ICs on that so Wozniak actually used a very clever software method to actually handle the data stream in real time so the Apple 2 didn't use interrupts so you could just do polling of the bits as they came from the disk so the 5542 executes well around a million instructions per second and so the bits really came exactly in that speed from the floppy disk so the CPU was a very tight loop without any timing left over could read the bits shift them over and move them into a buffer and that's also the reason why blocks on the Apple 2 are always only 256 bytes wide because they had a counter bytes large because they had a counter and it's a native CPU counting up to 12 would mean you have to handle carry somewhere and this would have messed your timing well interesting so why I'm telling you stuff about the Apple 2 floppy controller because well Apple thought we have a great floppy controller why should we build another one let's just use the Apple 2 CPU or a 65 or 2 as a close related one put most of the stuff from the floppy controller driver in this EEP ROM give it a kilobyte of ROM and have this co-processor essentially run a mini Apple 2 in the Apple Lisa to handle floppy drives and then just talk to the 68k CPU whenever it wants to read or write something from floppy pretty cool isn't it the other things here in the middle are a couple of parallel ports so for example to connect to your hard disk or also the connection to the floppy controller and to that other chip which I'm talking about in a minute is handled by these and there's a serial chip using two serial standard RS232 lines for modems or printers or stuff like that but this is a Xilok 8530 SCC chip which can also handle synchronous serial transfers up to a megabit using HDLC encoding which means this thing can run Apple talk or local talk so you could network Lisa which was great and finally of course we have the backplane which is mostly passive I think there's a couple of resistor arrays and there's one I see I think containing a couple of NOR gates to do the slot selects for the RAM so it's modular that's nice we have all the circuit diagrams which is also nice and we'll see why this is important in a minute so I already told you we have advanced features so we have interestingly no custom ASICs used in the machine so there's no chip which was only built for Apple almost let's see so most of the logic is 74 series TTL logic you can go to Sega electronics here in Berlin and just buy the stuff over the counter just reserve some time if you meet the boss of the company because you'll have an interesting talk with him last time I was there I chatted with him for 3 hours we have some very large large scale integration chips of course the 68000 CPU the parallel port chips which the Commodore users of you might know from the 5041 floppy driver from the VIC20 so these are standard 6522 VRs and the Xilox serial chip we have two bipolar prompts one the same one almost as used in the Apple 2 floppy controller the other one doing the video state machine for generating the video signals on time now the interesting thing is without complex additional chips they managed to build this memory management unit I mentioned before which is also built using discrete components so I brought you a piece of the Lisa CPU board schematic here and these are essentially 6 chips here these are 3 s-rems so if you know a bit of computer architecture you know a memory management unit needs something like a TLB a translation logicide buffer which is a cache for the mapping entries so you map a virtual address to a physical address so here we have a virtual address the 68000 has 24 address bits here and we want to get a different physical address out of it to be able to allocate code and memory without rewriting the code so hardware does it for us and this can be done by just moving a part of the address into a separate RAM and these are the rams here and then the RAM contains the translation for these bits so if you can write these rams you put one address in you get another one out and there's a software controllable by the CPU actually you can shift blocks around so the blocks are 512 bytes in size so these significant 9 bits here are unchanged so 512 byte blocks and the rest can be mapped if you know modern MMUs they enable paging using multi-level paging so you split the rest of the address in 2 or 3 pieces and then you have a multi-level page table and if you have a page miss on most CPUs some hardware starts and reads the TLB entries into the TLB RAM from main memory because page tables can be huge so you cannot afford to put them on the CPU chip now there's no such thing in the Lisa so this is all handled in software so this is a software TLB software managed TLB and well on the Lisa it's a segment based MMU so it doesn't do paging just relocating segments giving you some base address which can be added and so the adders are the things you see here on the right so this is the excerpt from the patent Apple got up for that MMU and this is really how you can see it so they're not lying to you which is rare enough Sun built something similar for the first Sunworks station the Sun1 but this was much more sophisticated than the Sun machines and the Sun engineers actually used to make jokes about that lame Lisa MMU because they knew each other of course they did so and as already mentioned the IO co-processors here were 6504 which is the tiny Apple II lookalike which has the floppy and then we need to handle some other IO namely keyboard and mouse obviously because we need them and the Lisa is one of the first machines featuring a soft power mechanism so you might know when you use the Windows 95 or 98 machine you shut it down what was the last thing you see it's now safe to turn off your computer famous last words better to turn it on again if it's running Windows no anyways so Lisa had soft power off so and on so the power supply generated a 5W standby current that supplied a separate microcontroller which is called a COPS 421 with standby power this also handled the real-time clock which is very convenient so you had real-time on your machine and when you push the power button in front of the machine well the machine started up but the good thing is when you push it again to shut it down you didn't need to select shut down the machine now no the microcontroller actually instructed the 6800 to shut down to save all the stuff to disk you know open buffers open files whatever and then the microcontroller shut the power supply down great of course you have stuff like that in ATX power supplies for PCs nowadays but this is 40 years ago so of course Lisa local integrated software architecture or Steve Jobs' daughter whatever had a lot of software and that was the other interesting part here we've seen all the software developed at Xerox so it's a small talk system Apple actually didn't get small talk they just thought like no we're going to program in Pascal they had UCSD Pascal on the Apple II already which was very popular especially for education well and they thought let's build an operating system in Pascal this stuff was all written in assembler because running Pascal code on the 65 or 2 is pretty slow but as 68K was fast enough and so they want to build something supporting their office system because they want to sell it to companies doing office stuff so it's the Liza office system or Liza operating system and they well thought like okay I'll need to do text processing I need to do whatever spreadsheet calculations I need to use a little database with addresses for like serial letters and stuff like that so we should actually enable our users to use all these things at once so they built something which was very uncommon in PCs for regular users back then they built a multitasking system of course Unix had this because you need to support like dozens or hundreds of users but the IBM PC and MS-DOS obviously didn't so they implemented something called multitasking it's an interesting question why we haven't solved this this is still an open discussion so cooperative multitasking means well an application must relinquish access to the CPU so it's use of the CPU to the operating system itself so when application crashes or runs in an endless loop without relinquishing this control of the CPU which is called yield operation if you ever took an operating systems course well then your application continues to run or is crashed but the rest of the applications won't run the other thing which is used today is so called preemptive multitasking preemptive means there's a timer interrupt which ticks regularly like every millisecond or every 10 milliseconds depending on the machine this interrupts the currently executing code your application it traps to the operating system and the operating system can see okay we're going to switch to another process no matter what the first process interrupt it was doing so preemptive multitasking is what we do today this is in Windows terms Windows 3.11, 95, 98 used also this cooperative multitasking Windows NT used preemptive multitasking from the start and of course it was able to protect virtual memory so we have several applications and of course we didn't have something like Rust back then but Pascal allowed you to address every address in your memory and of course you shouldn't be allowed to override neither other applications memory so they would actually use the MMU to protect the memory of an application against excesses of other applications of course if you tried it anyways you would get a fault and then your application would be killed because you were doing something that was not allowed also file management was rather advanced so the first Mac only had a single level a flat file system Lisa already had a hierarchical file management of course MS-DOS also had this couple of years later so what were the innovations actually brought to the Xerox software the first thing is something we don't usually think about this is the thing on top of the menu bar some people hate it, some people love it now the thing is they actually try to do some user interface research back then and there's something in user interface research called Fitt's law and that is how easy it is to target something on the screen with your mouse or with some pointer and usually when you need to position somewhere in the middle of the screen like on the icon you need to control your mouse very precisely on the horizontal and on the vertical axis to really hit your target and the smaller the target is the more difficult it is to get it now with the menu bar the first thing you need is you push your mouse to the back so to the upper side of the screen as far as possible and it didn't wrap around in small talk it wrapped around amazingly amazingly so it just stuck here on the top and then you just need to move it left or right so these menus are much faster to use or were much faster to use in the experience Apple did with regular users, office users then menus which are attached to a window like in windows for example so that's why they built a menu bar the other thing which is a bit uncommon if you use a Lisa is that it uses a task oriented workflow so essentially you didn't start an application that opened the menu and choose new document which is a bit of a mess right but there's so called stationary documents so templates for documents which are just inside of the file system and you can see them here so here's a Lisa right paper which is a template and if you double clicked on this it created a new empty copy of that file and started your application so this is a document centric application or environment which is of course appropriate for an office environment because I just need a new sheet of paper with my letterhead on it the secretary knew how to do it and so there's a letterhead of my company template and I just click on it and I get a new one which I can put my letters in one something that was also not very common back then is that Lisa is internationalized so the OS and applications were localized not just to US English but also to British English yes of course that's important if you want to sell something in the UK but also to French, German so my Lisa at home speaks German with me Italian, Spanish and some Scandinavian language I think it's actually all three common ones so Danish, Swedish and Norwegian I don't think they built a nice landing version and of course no Finnish version that's a bit more difficult and that's nice how does the Lisa figure out it's a German Lisa did they build special machines for the German market? No but they built special keyboards of course because every language has its own keyboard layout so the keyboard of course knows which language it has so the Lisa operating system can ask the keyboard which language are you and if it says oh I'm a German keyboard then it switches automatically to German even in the ROM from start-up in the self-test and everything that's pretty cool and something that's really interesting to see is like the Apple engineers got a tour of Xerox PARC and they saw all the technologies but Xerox didn't tell them all the details or how they built stuff because well they wanted to sell their stuff themselves I guess so something you need when you build overlapping windows is so called regions so for example if you have this window here and you have a window beneath it and you want to move this window here to the left then something is uncovered from the document below and you need to redraw it and you should do it efficiently because you don't want to redraw your complete screen but only the affected regions and that's what regions are called and the guy doing this is Atkinson, Bill Atkinson he actually had an idea of how Xerox did it and thought oh that must be the way Xerox did it and he implemented it and it was pretty fast and then he showed it to some Xerox engineers and they said like oh that's the cool stuff we never thought of that we're doing it much more inefficiently so they did a lot of innovation here and a lot of stuff which was a bit accidentally but nice yeah so there were applications so Lisa came with seven applications for the office stuff by default it's also called the 7.7 office system so a text processor a spreadsheet, a drawing and a graph program so putting bar graphs and stuff like that a project management thing you know using Gantt diagrams and things a list manager for for Xerox letters, main merge and the terminal emulation because maybe you had a unix machine sitting somewhere connected anyways but the only thing that didn't exist or one of the things was a compiler or something or a programming language so you couldn't use the original Lisa operating system the office system to write programs for the Lisa damn what did I do well there was a separate development OS you needed which was called the Lisa workshop and this is what you see on top no graphical user interface and if you ever used the UCSD Pascal on Apple too it looks very familiar not by coincidence to be honest so you had to put a completely different operating system to develop software for your Lisa which is like a bit crazy and since this was so complicated there was not a lot of third party software support because you know most of the applications were already delivered with the system the programmers weren't used to these new paradigms with windows and mouse they were inexperienced so there's some stuff that was available some companies built programming languages which run on Lisa OS like basic there's also a cobalt version it was a business machine after all but amazingly if you look for third party software on the net there's not a lot to be found which is a bit of a shame and gets worse so there's some stuff I really don't like about Lisa because Apple thought like all these people copying our software for the Apple too that's not good we need to earn money on this so Lisa introduced a version of simple copy protection so floppy disks were delivered to the customer there's a serial number of zero on the floppy disk and as soon as you inserted the floppy disk and installed the software to hard disk so Lisa couldn't run applications from floppies usually well Lisa wrote the serial number also its own serial number to the disk and whenever you try to use this disk to install the software on the next Lisa they checked like oh there's another serial number on that disk well that's not my serial number so I'm going to refuse you to install it so that's what we see here like the Lisa is about to make the first copy of Lisa calc this copy and all future copies can only be used on this Lisa is that really what you want because of course if the serial number matched you could reinstall software using your floppy but you couldn't just borrow floppy from your neighbor because that didn't work the serial number was very well hidden it was stored in one of these prompts in the video state prompt and you could read it by actually some strange timing variants so essentially something very similar to such an attack nowadays so people actually couldn't figure out for more than a decade how this worked well of course finally they did and there's nowadays deserialization tools available so you essentially have to change for every floppy bytes at address 5a 42, 3, 4 and 5 resets them to 0 voila you have a fresh install disk the good thing about Lisa is it was no architecture so people knew how to program it so there were alternative operating systems so essentially since we had an MMU we could run unix and I said these machines were usually so 68K machines were usually used as multi-user unix machines so we could use a Lisa to run unix so we can run Microsoft and SCO Zenix so Microsoft operating system for Lisa right it wasn't that popular but yes there was another system 3 and system 5 port by Unisoft which were the experts in porting unix to 68K machines they also built the first Sunways for Sun there was a small talk 80 version finally and this is described in one of the famous small talk books which are now available online by Stefan Dukas in Lille in France he's an old small talk researcher and actually Apple built a prototype small talk 80 system running on the Lisa on that bad and there was also a version of CPM which is usually for the 80 machines there was a 68K variant which was also available so here you see small talk so this is a typical small talk 80 screen which looks quite different so you have no menu bar on top the menu the window handles look different but this font is familiar again with the one we seen in the beginning and then of course you see well it's a unix machine so it has a text screen so this is running an emulation here sorry I couldn't get it it's a real machine and this is actually a screenshot of the Apple Lisa Unix but this was actually connecting using a terminal because Lisa of course had a black and white no green screen so you could use it for many purposes and one of the strangest purposes was actually software development for Atari so if you know your Atari ST it was running an operating system called GemDOS which was closely related to CPM 68K and back on top of that also from digital research there was an interface called Gem well this was pretty nice the Atari ST was also later called the Jackintosh so Jack Tramiel as the guy who bought or well who had Atari back then after he sold Commodore well he tried to build a low cost Mac so actually a Mac was expensive and Atari ST was much more affordable and it also had a mouse, it had windows and stuff like that and yeah but well they need the machine to develop that stuff on and for many years it was rumors from old Atari engineers yes we had Apple Lisa's but well yeah they can tell me a lot and then like 15 years or 25 years ago actually most of the gem source code was open sourced by well Caldera which bought digital research a number of years ago and it's subsidiarily Neo and embedded Linux actually and people took a closer look at what's actually inside all these dumbed archives that they gave us and there was like a Gem development toolkit and people figured out wait there's drivers for the Apple Lisa in there and people really spend a lot of time reconstructing that stuff compiling code on the Atari STs so now you can download a bootable Gem disk for your Lisa it runs it runs perfectly and you can run your Atari ST applications on your Lisa if you want well we have ones of course not directly accessing hardware but it's open sourced so there's yet another OS and there's more now the problem is the Mac the original ones in 128K came out a year after the Lisa and these were competing groups inside of Apple with different target markets and this was one of the reasons why they kicked out Steve Jobs a year later because they couldn't just stand him anymore and so the Mac was a quarter of the price of the Lisa so it was only $2,500 of course it was much more primitive so it didn't have IO co-processors it had 128K of RAM it had a small 9 inch screen but it cost a quarter of the money so nobody bought Lisa anymore so that was a problem Apple sat on a huge stack of unsold Lisa's and they had two incompatible operating systems because the Lisa OS was so complex you couldn't put it on a Mac because it would run out of memory immediately so actually what they did is they took their Mac operating system and ported it to the Lisa so they exchanged a lot of drivers the CPU was the same luckily and so all the remaining Lisa's which was a 210 version so the one with a megabyte RAM and 10 megabyte hard disks were re-bedged as Macintosh XL the extra large Macintosh and sold for a cheaper price but the hardware is absolutely identical a Mac has square pixels a Lisa as we remember has rectangular pixels so when you run Mac software on your Lisa everything's squished horizontally your circles are oval squares are rectangles so there was a hardware modification consisting of two new firmware prompts and this video state PAL and the new transformer because something changed about the frequencies to modify the Lisa to use square pixels you actually have that installed by a field technician in your Lisa and then the resolution changed from 720 by 360 to 608 by 431 still quite a bit more than the original Macintosh which had 512 by 342 the unlucky thing is that as soon as you install this modification your original Lisa OS didn't work anymore because this required rectangular pixels and it didn't work with a new firmware so we tried to sell the Lisa as MacXL it was great tech but yeah, actually it was still expensive now still there were a lot of Lisa's out there and there was a lot of unsold inventories of Lisa's out there so what did they do? so Apple thought like oh yeah well maybe somebody wants to take them but we don't want them anymore there was a small company in the I think in the north east of the US on micro systems we thought oh yeah we take the Lisa's off your hand for the scrap metal price and we sell them again so this is a MacXL and they sold not for $9995 but for $995 a couple of years later and they also built accessories to expand the Lisa's so there were accelerators with CPUs up to 18 MHz they had a 2 Mb memory card which finally used the first 256K sim modules there was an upgrade to 800K floppies even a 20 Mb SCSI hard disk and they even improved this emulation of the Mac called MacWorks to support newer macOS versions up to the last system 7 version even which was supported on a 68K 755 so people could use the Lisa for quite some years more and it was not worse than a mac plus or a mac SE and they already had that machine that was great 7.6K doesn't run on a 68K needs a 0.20 sorry and well that's great nowadays we have some more useful hardware if we want to still run a Lisa so one of the things is these floppies are mechanically unreliable after 40 years I have one I tried getting to work now the mechanics work but the electronics is broken thank you and so a guy in the US with a nice website called bigmassofwires.com but a floppy emulator for all Apple hardware for Apple IIs for Macs and for the Lisa we know the floppy controller was almost identical and this is called floppy emu it's an AVR controller where you can put in an SD card like all the floppy controls it's $150 so it's a bit expensive but there's great support and this guy is great and it works and this has a Lisa floppy disk emulation mode as we see here now we said the hard disks were also unreliable what could you do well there's an emulator the first one was built by Patrick Schäfer who is an engineer at Arviter Aachen and lives in Dortmund we met him because I was living in Dortmund for a couple of years and he built the IDE file which is an 8051 microcontroller emulating this parallel protocol and then you could just connect your regular IDE hard disk or compact flash card nowadays to emulate your hard drive there's also a project that tries to do it on an AVR which is very simple up here which you can build cheaply it's open source on github this is unfortunately not open source now the AVR file works with a Lisa 2-5 but not with a 210 because they changed a bit about the signal integrity and it's now too fast for the AVR to catch up so there's some problem here which is some critical timing there's also a commercial emulator which is like $350 called the X-Profile and there's also replacements for this stupid IO controller which is unobtainable so the keyboard and mouse controller is a master program controller which was only built for Apple it's a standard controller but with a special program in there so if you want to replace that one well you have a problem and luckily these controllers can also be had with an external e-prom so Patrick Schäffer again who built the IDE file also built that adapter here which you can just plug in and mouse controller breaks which can happen if your power supply acts up and there's also a keyboard emulator because these keyboards might be hard to find and are unreliable nowadays so you can connect either an original Mac keyboard which is much easier to find or even a USB keyboard using an Arduino as an interface so if you have a Lisa what do you have to do to make it happy or to keep it happy the first thing that's the problem is the real-time clock and the real-time clock if the machine is really not powered so you unplug the cable well it needs some sort of backup to keep the time and this is usually done by batteries now this is a nickel-cadmium battery pack and as you know if you're taking care of old computers the first thing you need to do is take out the stupid battery because it tends to leak and what it leaks is corrosive acid so as you see here there's some blue regions here there's some dirty regions here this is all the copper that was disintegrated by the acid from a leaking battery and that usually destroyed your I.O. board here where this was located and it destroyed your base board so your Lisa was actually broken then another common problem is the Rifa capacitors so Rifa capacitors are used to stabilize the incoming voltage from the net so 110 or 220 volts and these are paper-based capacitors so there's paper inside there which is not that bad but unfortunately the plastic they encased it is very brittle after 40 years so it tends to break and when air comes in they go up in a nice cloud of white smoke this is what happened to my Lisa because I want to turn it on on her 40th birthday because there was this live transmission from the computer history museum about the open sourcing and I said it would be nice to have the Lisa running and then well I got some nice white smoke and it stank like hell so that was when I need to repair my power supply and my Lisa so that's a common problem also for very many other power supplies Rifa's tend to break they're just crap hope nobody from Rifa listens to this and sues me the Sony floppies tend to get stuck because the grease hardens after 40 years so you have to use a lot of WD-40 or isopropyl alcohol to un-grease them but still the capacitors also are a problem here with the other capacitors in the system electrolytic capacitors tend to leak also it's not as bad as the leaking batteries but you have to replace them we also said the heart breaks easily and the heart to repair especially the widgets and the keyboard is another special case so this keyboard actually uses capacitive sensing so beneath each key there's a pet of foam which you see here and on top and on bottom of the foam pieces of whatever aluminum foil or something are glued so when you depress a key the capacitance of this capacitor you build from this piece of foam which is non-conductive and the two conductive elements changes and you can sense that a key was pressed pretty nice idea you don't have mechanical components that can break unfortunately of course foam after 40 years tends to get very brittle so to get your keyboard working again you need to get these little foam bits somebody built a special metal tool with a foam again you need to glue conductive foil on top of bottom and you need to do this for all the 80-something keys of a Lisa oh my goodness I have to do this for mine because mine is also no broken or you use a keyboard emulator but you can do it, it's all manageable because this machine is serviceable and it's simple well so Lisa's were sold to some micro remarketing but of course there were more and more recent Macintosh models so nobody bought Lisa's anymore and in 1985 there were still lots of Lisa's like 5-7 thousand of them in stock even though some micro some remarketing acquired the rights to sell the Lisa's they still remained Apple's property so they were just like a broker for the hardware so it's a consignment and the problem is in 1989 most of the unsold Lisa's were still on Apple's books so they're accounted as unsold inventory for tax purposes so they're quite expensive so Apple decided let's get rid of the remaining ones 2700 once and so we have to write them off so we're burying them in a Utah landfill and that's a photo of a Lisa which just got scratched by this bulldozer there and so they really buried 2700 remaining machines somewhere in Utah, actually people try to find it you may have heard the story of this ET game for the Atari 2600 which was uncovered on a landfill because it was such a horrible game that it didn't sell and the Atari buried hundreds of thousands of cartridges these were recovered and the Lisa's are broken beyond repair because if you bulldoze a CRT there's not much left unfortunately and Apple actually made a quite nice amount of money from this so it got about 34 dollars of tax break for every 100 dollars of depreciated value and of course they said of course these machines were 95 dollars initially yes so that made them unfortunately quite a lot of money it's sad I could have used this keyboard here so this is the end, no it's not my talk is still going on, I hope I'm not running out of time because I forgot to take a clock here so is there still hope first if you want to run Lisa software you don't have a real machine or your machine is broken there's two emulators available development started for the first one in 1979 the Lisa M which you'll see here and this is a fancy emulator so this is the screen that actually shows up it looks like a real Lisa you have to push this power button to power it on and it even makes real floppy noises and the power light goes on and off this is fun giving you the real experience another one was started in 2006 the idle because well back then Lisa M could run the Lisa OS but none of the alternative OS is because the emulation was incomplete because well back then not all the documentation was available well idle tried to make this better but the author was a bit more humble it said idle is the incomplete draft of the Lisa emulator now both are open source both can run Lisa OS and the Mac work XL Mac emulation now support for other OS it depends so I had problems getting anything else to run but I know with earlier version stuff ran maybe it's a problem here on my M1 Mac nowadays with arm and 64 bit something like that I need to figure it out that's when I was running out of time and even in recent memes so the multi arcade machine emulators there's some support for emulating Lisa and some of that code is actually exchanged between the emulators like peripheral emulation which is nice I mean it's open source people should collaborate so is this the end well luckily not so one interesting thing is that happened earlier this year but was started a couple of years earlier before that is that the computer history museum I actually approached some people at Apple and said like now you're finally not going to earn any money more with Lisa software right are you? I know probably not unfortunately Apple couldn't find it so they lost their source code until somebody found a backup tape and that was happening like in 2000 and something in the 2010s so we have it and the computer history museum got a copy unfortunately they also got a letter from Apple's lawyers like if you publish this we'll sue you to the ground and it took them like five years to actually get permission to publish it it didn't get better due to Covid I guess so what they actually managed and that was coincident with the 40th anniversary of the Lisa which was of course very nice to release the complete source code of the operating system the Lisa OS and all the seven office applications and of course the development toolkit all the libraries you need to build software in source code so it is mostly Pascal source code and of course a bit of assembly code 68k assembly, here's just some examples and well unfortunately it's not open source at least not in the common definition of open source because there's constraints so this is so called Apple academic license so you can use it for non-commercial academic research, educational teaching and personal study purposes only and there's another paragraph that says you're only allowed to run it on your hardware so not in the cloud I guess I don't have a Lisa in the cloud do I and if you look at the source code of course without source code it wasn't scrutinized as badly as modern source code for swear words and stuff so here in one file which is the source code implementing the main window for the preferences app like welcome to the all create preferences window so with the extensive use of hallucinogens I have found truth and beauty however those same hallucinogens have also made me incapable of getting to dodge rich to sell reclaimed ski wax in the parking lot so they must have had some good stuff back then in California I guess and I encourage you you can download it you have to register with a name but that's perfectly fair and you can dig through the source code maybe you find some other interesting stuff if you do please let me know I'm always looking for these Easter eggs so we have the source code which is nice we can build our own modifications to Lisa OS you need Lisa to do this right and that's a good thing about it we can do this now so I said that this battery tends to leak and if you see something like this on the PCB so the stuff which was originally gilded copper now turns into oxidized copper like this green nasty stuff like you see on old church roofs and also and stuff like that well this is due to acid leaking into there and this usually destroys the contacts and the PCB so this is the original battery pack and you see this also already started leaking here somewhere and this is just a huge mess so people had working Lisa's even in the 2020s but with broken IO boards and broken mainboards so they need a replacement and that's where people started there was a company even doing this called Sapient Technologies they still sell stuff relatively expensively and the right to the products developed by sundry marketing so the SCSI boards SIM memory boards all the extensions we've seen were transferred to company vintage micros and they cooperated in building replacement parts for Lisa unfortunately they're pretty expensive and now they ran out of original manufactured stuff so it's hard to get stuff so people start to say well this hardware isn't too complicated let's build our open source ones I mean we have the schematic diagrams we have the thick pictures of the original boards how hard can it be famous last words I know and they started last year and actually it's online so you can build your own app Lisa now so initially the IO and the mainboard were recreated because those were the things broken in real Lisa's these are simple, these are two layer boards so just the front and back side so you can just take a photo of an empty board and essentially redraw it in your PCB layout program and then of course somebody said like okay we have an IO and a mainboard so let's do a CPU board and then we have a complete machine right so the CPU board is more complex at four layers so you need something like an x-ray machine to really look inside but well you can find an x-ray machine at your doctor's office right so all of these were recreated you can get the schematics the CPU board is available in Altium and Easy EDA format the IO and mainboard unfortunately only as PDFs because I guess they redrew them by hand in the drawing program and also the Gerber files so the files needed to manufacture your PCB once you send to your PCB manufacturer to have it built and these are all available and downloadable on Github the only thing missing are the memory boards because nobody wants to solder a memory board with 12864 kilobit chips so we need a replacement for this but that can be done and one of the challenges as I said is this microcontroller handling mouse keyboard and power so this is unobtainium you need to take it from a broken Lisa main board well for people with defective IO boards where the battery was sitting there but it was leaking in that direction because this is just rotated 90 degrees maybe they were lucky and could take the working controller from their board maybe not we have two of these bipolar prompts we set the one for the floppy controller the other one for the video and serial number these are available you can buy 6309 or something similar people are from nowadays for couple of euros being able to program them is a bit more difficult because they need like 27 watts of program voltage and most modern e-promos actually don't support this so you need an old one for the memory management unit for this TLB we need very fast static ramps so 1k by 4 ramps are easily available 2114 from your Commodore VIC20 or something would be useful but they have an access time of like 200 to 400 nanoseconds the MMU is in the critical path from the CPU to the RAM so it needs to be as fast as possible so they used 55 nanosecond ramps these are harder to find I found some on eBay in Poland and they actually sent them they are still in ceramic cases not even plastic cases so pretty nice the RAM boards have not been recreated yet but most of the Lisa's came with a megabyte of RAM so if you have a working one you can take one of the two RAM boards out 502fk and put it in your replica to test it already the video was very special because due to the high horizontal resolution it had a high line frequency so the usual frequency is like 15.652 kilohertz for a TV signal the Lisa uses like 22 kilohertz so you need a multi-screen capable of doing this or there's a solution using a Raspberry Pi called RGB to HDMI so RGB signal to HDMI converter using a Raspberry Pi which can be configured to also accept Lisa's signals there's a small CPLD on it if you have a broken power supply there's also a replacement available building this with the standard ATX power supply parts now but you need 33 volts to supply some voltage for the CRT so you need to add some components but this is also available on the Github sites where the other boards are available so yeah and people have first prototypes working so this one's here you'll see it's obviously not yet working because it's not populated because I was running out of time I have two boards which are populated with all the passive components and the sockets but I haven't started testing them yet so this will unfortunately take some time I would have loved to take your working clone here so this is just empty boards but you can easily have like the Chinese producers or of course a local one have the boards manufactured and I had them built at JLCPCB and the CPU board because it's four-layered because like $12 the IO board was 650 and the backplate is a bit smaller it was $4.50 so that's actually affordable some other stuff is a bit more expensive like some of the components like these special connectors here cost like $30 each because well nobody else uses them but there's luckily still a company building them and so some of these special chips depending on where you buy them might be a bit more expensive so if you buy a new $68,000 from Kessler Electronics for example it will set you back like $20 or 17 euros or something like that but it's still reasonable of course somebody built it and there's a prototype in CNC cut plexiglass with a multi-sync monitor and an adapter Mac Plus keyboard here already running by one user and there's on mastodon and twitter some other users so we have I think three machines already running in the world most in the US and the fourth one hopefully later this year so what are we doing with this because I didn't build the PCBs I didn't design anything I was just fascinated like let's do this and this came from a motivation that you know I'm teaching operating systems design, virtualization technology at Bamberg University by the way sorry for the embarrassment we're hiring if you want to do a PhD we know we have an open position fully funded so students who took my OS course so we start writing a small preemptive multitasking was from scratch in C or Rust for risk 5 in my course and these students asked me like oh can't we also do some hardware stuff we want to do some hands-on soldering and stuff and I thought yes sure good idea always want to support this and I started with there are some other open source hardware clones, Sinclair clones 1980's microcomputers, Sinclair ZX81 and Spectrum and these were recreated first in the 80's and 90's in the former eastern block states and of course nowadays you have modern copies and these are all also open source.github so you can download the files, have them manufactured for a couple of dollars and you can buy all the components because the Z80 is still manufactured you can buy them for a dollar in China or for seven dollars by Ed Reichelt for example and the rest is TTL chips, Static-Rams and E-Proms so we had an event organized by the local Hacker Space in Bamberg, the Backspace what a nice name, which is also the local chaos group in Bamberg and they organized a large three or four day event each year called the Eager the Intergalactic Experience Reise, the Intergalactic Experience Trip and I thought let's offer a workshop, a soldering workshop here and not only my students but also some other people came, registered and built their own ZX81 which is a bit more simple or there's the Spectrum clone which is a bit more complicated so we need some soldering experience to build this in a reasonable amount of time and I thought that's nice but it's not a challenge for me because my copies I built worked on the first try so I need something that doesn't work on the first try so I thought let's build a Lisa clone and yeah I like Apple hardware I have a huge collection of stuff including an original Lisa too which I unfortunately couldn't take here for this meeting and a couple of necks and stuff like that and so I thought yeah that would be a cool idea and maybe I can also use it for teaching because this is a machine where now every bit of hardware I have the source code to all bits of software so I can explain it to my students and my students can explore stuff themselves that would be nice we are trying to so my students build these Sinclair clones and then they ask me okay can you teach us how to design a PCB like how to use KiCat or something yeah sure that would be interesting so of course we need a project to do this like maybe we could build an SMD version of the Lisa maybe fitting it into a laptop case so we built the first portable Lisa which doesn't weigh 20 kilos in CMOS so it uses much less power or we could also do an FPGA version there's FPGA versions of several mechs for example for the Mr. FPGA emulation board what I already did is these people are prompts because I didn't have a programmer for these or I do have but I couldn't find it to be honest I replaced these with gods so these first generation programmable chips and this was fascinating because usually you put in your inputs and your outputs and then you let the optimization program do the optimization when I tried to do this it told me it won't fit I didn't believe it so I spent a whole night until 4 am in the morning doing the optimizations by hand on the machine I could fit it just need to test it but it should work simulation is wide we're trying to replace this stupid microcontroller which is unobtainable so this cops microcontroller handling keyboard, mouse and power with an AVR microcontroller we have the source code for the code running on this cops 421 this is just a kilobyte of code and well what we're trying is we do a static translation so we assume this assembler code but it's source code for some language and we're translating it to AVR machine code unfortunately this is a bit more complicated than it sounds so not just replacing an instruction that whatever is called load with move on the other one but it has to be timing exact because Apple didn't use interrupts on that thing but they used timing loops and of course they timed even GPIO pins so the keyboard protocol and stuff using these loops so that is a bit more of a challenge but one of my students want to work on this so that's a bit of research we're doing here replacing essentially ancient unobtainable components which you need to run and obtain with modern stuff and of course we're trying to develop a RAM board obviously not with 128 discrete RAMs because 2 megabytes of RAM are a single 5 dollar chip nowadays these are mostly static RAMs as I told you before the addresses are multiplexed on the RAM board so we need to demultiplex them again to access a static RAM but that's possible that's easy enough and of course it would be nice to analyze use and improve the lisa hardware to analyze the OS to figure out why on earth didn't it use preemptive multitasking but just cooperative and some projects with students who want to learn about system level programming about hardware design hardware software interface because that's what we're doing in my workgroup in Bamberg and if you're interested well that's almost all I thought I'd give you some visions of what people thought the lisa future might be so the first one here is a portrait screen actually and that was a design by Frockdesign so Frockdesign is a design company founded by Hartmut Esslinger here in Germany and he built some famous machines like the later MEC2 series starting from the MEC SE and MEC2 and the Apple 2C and also the next cube for example but he also decided the Sony Walkman so he's one of the best industrial designers out there or his company and they built a prototype for Apple like what might a future lisa look like well this was obviously never built so it's also not a working prototype it's built of wood and foam but it looks pretty nice I think and if you know later apples this might be the inspiration for the portrait display which was available for the MEC later on so you had a full A4 page available on your screen and there's another thing I found by an Italian designer called Antonio, is he Italian? I don't know sounds more Spanish right? Antonio de Rosa Lisa he thought like oh yeah let's combine this modern Apple aluminium style with the old hardware so this is the idea of well we don't need a CRT just a flat screen and LCD right so it's actually the whole back part of the lisa is missing but the rest looks pretty much the same and I guess that was inspired by something by a German design company called Curve Labs which took the inspiration from the original MEC and then built such an aluminium profile model here but it's also just a mock-up. Building this in real would also be nice but I guess we need an advanced CNC machine to do this if somebody wants to donate one for our hackerspace let me know okay so finally Lisa of course and the MEC are related as we've seen the MEC as I said was a quarter of the price but the hardware was significantly weaker it had no memory protection little RAM, no hard disk, just floppy and it already used programmable ICs which took a quite a long time to realize and whereas engineer the first one who did this in the 80s was a Brazilian engineer and they actually built they had built Apple 2 clones before and they built a series of MEC clones until they were sued out of existence by Apple because Apple pushed the American government to actually forbid fruit import from Brazil if they continue building MEC clones and so the Brazilian government just killed that company I guess but information on that is available so we now know how the parts of the original MEC works but the MEC Plus there's still two unreversed reverse engineered parts and the problem is while the MEC had so little memory you couldn't actually develop software on a MEC you had to buy a Lisa to develop software for a MEC using this Lisa workshop this primitive system initially so that's probably why Apple sold a number of Lisa's anyways because they were developers who wanted to write software for a MEC so to write software for your fancy $2,500 computers you need to invest another $10,000 plus the cost of the software which was also not free and some stuff is shared like quick draw by Bill Atkinson which is the these advanced graphics routines which were fast which were using these regions to draw windows these were originally written for the Lisa and then easily adapted in one night to the MEC because they needed a demo for some shareholders or something like that the source code of quick draw and the first drawing program MEC Paint was published a number of years before in 2010 also by the Computer History Museum and it's very interesting to look at this is mostly hand optimized assembler code with a bit of Pascal intertwined and the MEC system was much more primitive so it was single tasking it had a non-hierarchical file system originally the MFSE MEC file system and it had large parts in ROM so there were initially no alternative operating systems for the MEC compared to the Lisa nowadays things look a bit different and you can even run linux on our MEC but that's like well 40 years later I guess so thanks for listening I hope Apple tries to invent the personal computer again and if not we're going to do it based on the Lisa right so I hope you found this interesting thanks for listening and here's a lot of references that are probably hard to read but of course we'll publish the slides later on if you want to dig deeper and of course if you have questions ask no now or later or just get in touch thanks a lot