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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.
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.
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.
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.
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).
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!
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.
Xenix is the best operating system Microsoft ever shipped, but they gave up on it because there was no way they could use their PC leverage to corner the Unix market.
Small correction: "utility validation" is redundant -- utility is a form of validation. But you're right that the original comment assumes "matters" means societal impact, when clearly it already mattered to the person building it.
But who decides what "really matters"? The implicit assumption is that intelligence is most valuable when pointed at legible, economically-validated problems. Some of the people you're describing might just have a different ledger for what counts.
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.
My personal philosophy on this is that in the grand scheme of things, there is almost nothing that "really matters". So you might as well spend as much of your time as is reasonable doing something fun.
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!
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.
Same. The Lisa was the future that didn't ship in time. By '84 when Mac launched at a third the price, the Lisa was already a ghost. Still ran circles around everything else on the desk, though.
Cycle-accurate reimplementation is harder than software emulation and arguably more valuable for preservation - software emulators abstract away timing dependencies that original software sometimes relied on. The Lisa's memory management was unusually sophisticated for 1983; it may have been one of the first personal computers with hardware-enforced memory protection between processes. Getting that right in HDL is nontrivial.
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.