Interesting. I used Apple II's in elementary school (early 1980's) and then some Macs but I had never even seen a Lisa in person until going to a computer museum about 5 years ago.
I really like having usable, cycle-accurate reimplementations of classic hardware (not to mention modern hardware such as RISC-V). It's the next best thing to running the real hardware, but with minimal storage space and maintenance overhead.
Cycle-accurate software emulators are great (for example people have made drop-in "hardware" CPUs [1,2] which are actually implemented in software on a microcontroller) but FPGA-based implementations are interesting not only in that they create a very realistic and usable version of the hardware, but also because an RTL implementation shows how the logic design could be implemented in hardware.
And modern FPGAs have tons of gates, more than enough to implement an entire system from the 1980s.
What's cool about this is that we're at the point where a committed hobbyist can pull something like this off.
I don't know what's in the FPGA, and I honestly don't know that much about FPGAs, but I imagine it's a pretty much "drag and drop" of the Lisa logic board schematic rendered in whatever FPGA language is used, while leveraging as many, stock, "off the shelf" cores as necessary.
It's telling that they externalized the UART, since they couldn't find a core to use, and weren't comfortable creating one from scratch. Otherwise it's likely a 68000 core, and a bunch of logic gates, or higher level combinatorial logic ICs (directly rendered into FPGA language, or, perhaps, they drag and dropped a, e.g. shift-register IC core).
But the point is that FPGAs are that accessible today.
Add to that the board manufacture. This is no hobbyist through hole exercise. Get the board, break out the soldering iron. No, this was built in a modern electronic assembly facility. Cheap enough to do one off boards, vs runs of 10s or 100s.
Available to the every man.
Impressive achievement for the developer, but impressive we're in a place that this is a practical thing to try and do.
I've recently finished a project that implemented a mc68000 microcomputer board for a 80s industrial control system. It's a great way to do a deep dive into micro computer design, and the older technology makes it possible for 1 person to have a pretty decent understanding of how the system works. Implementing the programmable timer modules was definitely a challenge to get them cycle accurate.
I really want to adapt what I've done into an amiga500 accelerator board.
8 months of work, and it shows. Phenomenal result!
The thing that blew my mind as a kid on the original Lisa was the power button. You pressed it and it didn’t immediately cut the power like a PC, it was a request to cut the power and the OS would first clean up various things on the desktop before finally cutting the power on itself. It just seemed to have agency and a type of control over itself and its environment that gave an impression of intelligence.
Yeah, the soft power feels really magical compared to other systems of the time. And not only can it turn itself on/off in response to a user request from the power button, but you can also set an alarm within the microcontroller that handles soft power and the RTC and it'll automatically power itself on or off whenever the alarm goes off. Pretty neat for 1983.
Sorry, I was expecting it to be seen by like 50 Lisa enthusiasts, and so I didn't put much effort into making it look good. If I had known that it was going to be so popular, I would've taken more time to film it!
Great work! I'll buy one for $250. Will it run AppleTalk?
I didn't correct for inflation but I wanted to buy the Lisa before it was released, it felt around 40000 Dutch guilders, maybe 80 times more expensive than this FPGA?
I did a few more back-of-the-envelope calculations of what I can do with these 2MB SRAMs:
Xerox Alto with Smaltalk-80 and Smalltalk-76 for $4. The Alto was the 1972 machine the Lisa tried to be the sucessor of.
Transputer T414/T800 for $50 but much faster than the original. You would make a supercomputer interconnecting hundreds of Transputers.
Vextrex without display but HDMI output for $50, $8 without the CRT/VGA/Oscilloscope, $100 with the cathode ray tube display built in.
200MB SRAM with 16000 cores 180nm WSI (Wafer Scale Integration) emulating most processors at $1000. It would outperform 2025 Blackwell NVDIA and Apple Silicon M3 Ultra Mac Studio because SRAM is faster than HBM or LPDDR5. It is much cheaper than the 2MB Sram on this Lisa FPGA (it costs around $25 per 2MB (16 Mbit) in batches of 1000 chips).
I do stuff that actually matters too! The FPGA Lisa is just a fun project that I work on in my spare time, but I'm also a PhD student and I like to think that I contribute useful stuff to the body of knowledge of computer engineering through research.
The same person who did this project also worked out how to compile the Lisa Office System code Apple released: https://github.com/alexthecat123/LisaSourceCompilation This took a lot of work because Apple didn't release any of the tooling required to build the code, and the code was actually too big to fit on a stock Lisa hard drive (the hard drive is 10 MB, the code is ~20 MB) so they had to hack the OS to patch in support for higher capacity drives.
It’s neat that there’s such passionate Lisa fans out there. If anyone here is a current day Lisa enthusiast, I’m curious what makes you interested in it.
My interest mainly just comes from the Lisa's unique architecture, both in terms of hardware and software. As I learned during my LOS compilation efforts, the OS was quite advanced for its time, and many of the decisions made in the hardware design (like soft power and the discrete-logic MMU) were quite impressive and advanced for a personal computer. I had already done the software side of things during my LOS compilation project, so I figured that the next logical step would be to recreate the hardware within an FPGA!
Yeah from a technical perspective it's really impressive for its era. OS written in a high level language, preemptive multitasking, memory protection, stuff like that. I just wish there was more software available for the Lisa. It's a shame that Apple gave this all up for the Mac, it severely limited that platform as the computers grew over time. It would have been neat if Apple had based their larger computers (Mac II, etc) on Lisa OS and provided some sort of compatibility layer that programs intended for classic Macs would run inside.
> and the code was actually too big to fit on a stock Lisa hard drive (the hard drive is 10 MB, the code is ~20 MB) so they had to hack the OS to patch in support for higher capacity drives.
Then how was it originally developed? Did Apple also patch their own OS?
Apple hooked up the Lisa to a much larger larger external hard disk, the Priam Datatower. It could hold ~84 MB. The Datatower is extremely rare and AFAIK nobody with the skills to figure out how it works for emulation or cloning has a working one with a Lisa interface card.
The OS did, but the disk driver for the Lisa ProFile hard drives (which was distributed as part of the OS) did not. All existing emulation only supports the ProFile drives, not the DataTower. If you're actually interested, I think it would be a better use of your time to look at the readme file for the repo I linked (which goes over the patch) instead of nitpicking my comments.
Hi everyone, I'm Alex, the creator of the LisaFPGA project. A couple people pointed me to this thread, so I figured I'd come over here and answer any questions that people might have. Let me know if there's anything you're curious about!
27 comments
[ 3.2 ms ] story [ 67.1 ms ] threadCycle-accurate software emulators are great (for example people have made drop-in "hardware" CPUs [1,2] which are actually implemented in software on a microcontroller) but FPGA-based implementations are interesting not only in that they create a very realistic and usable version of the hardware, but also because an RTL implementation shows how the logic design could be implemented in hardware.
And modern FPGAs have tons of gates, more than enough to implement an entire system from the 1980s.
[1] https://microcorelabs.com
[2] https://eaw.app/picoz80/
I don't know what's in the FPGA, and I honestly don't know that much about FPGAs, but I imagine it's a pretty much "drag and drop" of the Lisa logic board schematic rendered in whatever FPGA language is used, while leveraging as many, stock, "off the shelf" cores as necessary.
It's telling that they externalized the UART, since they couldn't find a core to use, and weren't comfortable creating one from scratch. Otherwise it's likely a 68000 core, and a bunch of logic gates, or higher level combinatorial logic ICs (directly rendered into FPGA language, or, perhaps, they drag and dropped a, e.g. shift-register IC core).
But the point is that FPGAs are that accessible today.
Add to that the board manufacture. This is no hobbyist through hole exercise. Get the board, break out the soldering iron. No, this was built in a modern electronic assembly facility. Cheap enough to do one off boards, vs runs of 10s or 100s.
Available to the every man.
Impressive achievement for the developer, but impressive we're in a place that this is a practical thing to try and do.
I really want to adapt what I've done into an amiga500 accelerator board.
The thing that blew my mind as a kid on the original Lisa was the power button. You pressed it and it didn’t immediately cut the power like a PC, it was a request to cut the power and the OS would first clean up various things on the desktop before finally cutting the power on itself. It just seemed to have agency and a type of control over itself and its environment that gave an impression of intelligence.
Yeah, the soft power feels really magical compared to other systems of the time. And not only can it turn itself on/off in response to a user request from the power button, but you can also set an alarm within the microcontroller that handles soft power and the RTC and it'll automatically power itself on or off whenever the alarm goes off. Pretty neat for 1983.
I didn't correct for inflation but I wanted to buy the Lisa before it was released, it felt around 40000 Dutch guilders, maybe 80 times more expensive than this FPGA?
I did a few more back-of-the-envelope calculations of what I can do with these 2MB SRAMs:
Xerox Alto with Smaltalk-80 and Smalltalk-76 for $4. The Alto was the 1972 machine the Lisa tried to be the sucessor of.
Transputer T414/T800 for $50 but much faster than the original. You would make a supercomputer interconnecting hundreds of Transputers.
Vextrex without display but HDMI output for $50, $8 without the CRT/VGA/Oscilloscope, $100 with the cathode ray tube display built in.
200MB SRAM with 16000 cores 180nm WSI (Wafer Scale Integration) emulating most processors at $1000. It would outperform 2025 Blackwell NVDIA and Apple Silicon M3 Ultra Mac Studio because SRAM is faster than HBM or LPDDR5. It is much cheaper than the 2MB Sram on this Lisa FPGA (it costs around $25 per 2MB (16 Mbit) in batches of 1000 chips).
1. Wow! That's so cool!
2. Why didn't someone this smart spend that time to build something that really matters?
I'm typing here on HN this morning. I could've been doing something more useful.
I'm about to put this down and play Animal Crossing. That isn't something that matters.
You could reasonably argue that I'm not as smart as this person, but I'm 100% behind his desire to have hobbies he enjoys.
It’s neat that there’s such passionate Lisa fans out there. If anyone here is a current day Lisa enthusiast, I’m curious what makes you interested in it.
Then how was it originally developed? Did Apple also patch their own OS?