If you wish to make a computer from scratch...
April 24, 2016 7:17 PM Subscribe
The Megaprocessor is a 16-bit computer made almost entirely from discrete electronic components (individual transistors, diodes, resistors, capacitors and LEDs). When finished it will measure 14m wide x 2m tall.
Some videos of the machine in action can be found on the progress page. The total cost of the project is "now nudging over £40,000."
Additional coverage from The Register and the BBC.
Many more projects can be found at the Home-Built Computers Web-Ring.
Homebrew computers featured previously [1, 2, 3].
Some videos of the machine in action can be found on the progress page. The total cost of the project is "now nudging over £40,000."
Additional coverage from The Register and the BBC.
Many more projects can be found at the Home-Built Computers Web-Ring.
Homebrew computers featured previously [1, 2, 3].
What's he got against vacuum tubes?
posted by gwint at 7:20 PM on April 24, 2016 [9 favorites]
posted by gwint at 7:20 PM on April 24, 2016 [9 favorites]
Realistically, he should be using sets of 3 leds for his monitor and it should be the size of a jumbotron. Because when I got to that monitor of his, I was let down.
posted by Nanukthedog at 7:21 PM on April 24, 2016 [2 favorites]
posted by Nanukthedog at 7:21 PM on April 24, 2016 [2 favorites]
First message on booting up: " Upgrade now to Windows 10! Your system is fully compatible!"
posted by TheWhiteSkull at 7:28 PM on April 24, 2016 [16 favorites]
posted by TheWhiteSkull at 7:28 PM on April 24, 2016 [16 favorites]
Upgrade now to Windows 10! Your system is fully compatible!
I have a Commodore 64 which told me that the other day, and when I let it go it turned into a Coleco Adam.
posted by Bringer Tom at 7:39 PM on April 24, 2016 [5 favorites]
I have a Commodore 64 which told me that the other day, and when I let it go it turned into a Coleco Adam.
posted by Bringer Tom at 7:39 PM on April 24, 2016 [5 favorites]
From The Register link:
"When completed, the Mega Processor will have more than 100,000 connections. Soldering in and hooking up the circuitry has not been easy, and Newman acknowledges that finding and replacing dying components will be a major headache."
You don't say.
"""The potential for unreliability is deeply scary. There is no built in defence for broken circuitry. My main strategy is to design a test method which allows me to isolate the various subsystems and check their operation matches expectations," he said.
"I'm expecting some disappointment and a lot of frustration.""
Something about this is so British.
posted by Kevin Street at 7:49 PM on April 24, 2016 [19 favorites]
"When completed, the Mega Processor will have more than 100,000 connections. Soldering in and hooking up the circuitry has not been easy, and Newman acknowledges that finding and replacing dying components will be a major headache."
You don't say.
"""The potential for unreliability is deeply scary. There is no built in defence for broken circuitry. My main strategy is to design a test method which allows me to isolate the various subsystems and check their operation matches expectations," he said.
"I'm expecting some disappointment and a lot of frustration.""
Something about this is so British.
posted by Kevin Street at 7:49 PM on April 24, 2016 [19 favorites]
Hah! I was just last week doing some back-of-the-envelope calculations to assess the feasibility of doing almost exactly this, although I was thinking of using SMD and multi-layer boards for a cheaper and more compact build. I'm glad people out there are way ahead of me, at least it confirms my aging mind is still capable of producing relevant ideas :)
posted by memetoclast at 7:53 PM on April 24, 2016
posted by memetoclast at 7:53 PM on April 24, 2016
Minecraft is only $26.95, if you don't care about doing this in physical space.
posted by dilaudid at 8:02 PM on April 24, 2016 [9 favorites]
posted by dilaudid at 8:02 PM on April 24, 2016 [9 favorites]
Vacuum tubes, crap, it's like we're amateurs. I've seen pictures of Danny Hillis with his tinkertoy tic-tac-toe machine. What's Ghost Charles Babbage have to say about this?
posted by ostranenie at 8:06 PM on April 24, 2016
posted by ostranenie at 8:06 PM on April 24, 2016
Bah, doesn't count without hand blown vacuum tubes. Using LED diodes for memory is pretty darned cool, would love to see a video stepping through a loop.
posted by sammyo at 8:36 PM on April 24, 2016 [1 favorite]
posted by sammyo at 8:36 PM on April 24, 2016 [1 favorite]
What's Ghost Charles Babbage have to say about this?
Ghost Ada Lovelace is still waiting to tell us.
posted by TheWhiteSkull at 8:36 PM on April 24, 2016 [3 favorites]
Ghost Ada Lovelace is still waiting to tell us.
posted by TheWhiteSkull at 8:36 PM on April 24, 2016 [3 favorites]
But does it run Minix?
posted by LogicalDash at 8:39 PM on April 24, 2016
posted by LogicalDash at 8:39 PM on April 24, 2016
Ah, gwint beat me to the tube snark :-)
But how perfect is it that the archaic computer guys have a "web ring"!
posted by sammyo at 8:40 PM on April 24, 2016 [4 favorites]
But how perfect is it that the archaic computer guys have a "web ring"!
posted by sammyo at 8:40 PM on April 24, 2016 [4 favorites]
Realistically, he should be using sets of 3 leds for his monitor and it should be the size of a jumbotron.
24x80 Nixie tubes!
posted by Slap*Happy at 9:01 PM on April 24, 2016 [9 favorites]
24x80 Nixie tubes!
posted by Slap*Happy at 9:01 PM on April 24, 2016 [9 favorites]
Back in 1990 a couple of guys in my third year electronics engineering class built an 8 bit 8080 out of discrete gates, flip-flops and a whack of red LEDs. They didn't even implement the full instruction set and it ended up being over 3' square. As far as I know it's still up there on the wall in school, mounted in a huge shadow box and looping through some basic math.
posted by CynicalKnight at 9:31 PM on April 24, 2016 [3 favorites]
posted by CynicalKnight at 9:31 PM on April 24, 2016 [3 favorites]
The original Cray was built out of discrete components. They implemented ECL with discrete transistors, and a lot of the design effort went into figuring out how to cool it so it didn't catch fire.
posted by Chocolate Pickle at 11:10 PM on April 24, 2016
posted by Chocolate Pickle at 11:10 PM on April 24, 2016
Something about this is so British.
What, is it positive-ground?
posted by 7segment at 11:15 PM on April 24, 2016 [4 favorites]
What, is it positive-ground?
posted by 7segment at 11:15 PM on April 24, 2016 [4 favorites]
Expecting some disappointment and a lot of frustration: Metafilter?
posted by alex_skazat at 11:37 PM on April 24, 2016 [1 favorite]
posted by alex_skazat at 11:37 PM on April 24, 2016 [1 favorite]
His budget line 'not sure where the rest went' speaks for all of us, I think.
posted by dowcrag at 1:48 AM on April 25, 2016 [3 favorites]
posted by dowcrag at 1:48 AM on April 25, 2016 [3 favorites]
This makes me think my idea of building a computing fabric out of 4x4 bit lookup tables might not be so crazy after all.
posted by MikeWarot at 4:34 AM on April 25, 2016 [1 favorite]
posted by MikeWarot at 4:34 AM on April 25, 2016 [1 favorite]
Back in the day, building an 8-bit processor out of 74 series ICs was part of the core computer science curriculum at MIT. Every student was issued a large breadboard and power supply built into a small suitcase (usually called a "nerd kit") where, over the course of the semester, you would build your processor.
In the late 90s "Bunnie" Huang designed a new FPGA based nerd kit, but in the end for one reason or another it was abandoned and the switch was made to software simulation.
The nerd kit was probably was never really necessary to teach the concepts, but having that completed kit at the end of the semester with all of the wires flat and neat was a feeling of satisfaction and accomplishment you don't get from a simulator.
posted by Lazlo Hollyfeld at 6:26 AM on April 25, 2016 [6 favorites]
In the late 90s "Bunnie" Huang designed a new FPGA based nerd kit, but in the end for one reason or another it was abandoned and the switch was made to software simulation.
The nerd kit was probably was never really necessary to teach the concepts, but having that completed kit at the end of the semester with all of the wires flat and neat was a feeling of satisfaction and accomplishment you don't get from a simulator.
posted by Lazlo Hollyfeld at 6:26 AM on April 25, 2016 [6 favorites]
Some of the photos gave me a Factorio vibe--which seems appropriate and fitting.
posted by tehjoel at 7:29 AM on April 25, 2016
posted by tehjoel at 7:29 AM on April 25, 2016
This makes me think my idea of building a computing fabric out of 4x4 bit lookup tables might not be so crazy after all.
Already been done. Four-bit lookup tables are the basic architecture of Xilinx and Altera FPGAs. There are lots of commercial implementations of 8, 16 and 32 bit CPUs implemented within FPGAs. These is used for System on Chip designs that include the processor implemented in FPGA logic and then all of peripherals like serial ports and video using the remaining FPGA logic.
You can find lots of open-source VHDL and Verilog CPU designs on the FPGA forums.
posted by JackFlash at 8:08 AM on April 25, 2016 [1 favorite]
Already been done. Four-bit lookup tables are the basic architecture of Xilinx and Altera FPGAs. There are lots of commercial implementations of 8, 16 and 32 bit CPUs implemented within FPGAs. These is used for System on Chip designs that include the processor implemented in FPGA logic and then all of peripherals like serial ports and video using the remaining FPGA logic.
You can find lots of open-source VHDL and Verilog CPU designs on the FPGA forums.
posted by JackFlash at 8:08 AM on April 25, 2016 [1 favorite]
In the late 90s "Bunnie" Huang designed a new FPGA based nerd kit, but in the end for one reason or another it was abandoned and the switch was made to software simulation.
Hence, the oft repeated phrase "I don't need to build it -- I've simulated it!"
posted by JackFlash at 8:15 AM on April 25, 2016
Hence, the oft repeated phrase "I don't need to build it -- I've simulated it!"
posted by JackFlash at 8:15 AM on April 25, 2016
Are we still doing "Beowulf Cluster?"
posted by Cookiebastard at 9:07 AM on April 25, 2016 [2 favorites]
posted by Cookiebastard at 9:07 AM on April 25, 2016 [2 favorites]
There are some more photos here but none that really capture all the pieces set up together unfortunately.
posted by Spacelegoman at 10:38 AM on April 25, 2016
posted by Spacelegoman at 10:38 AM on April 25, 2016
JackFlash, he seems to know this and wants and FPGA with no routing fabric? not sure what he's on about.
Lazlo - hell yah, i came thru berkeley in the late 80s... as you probably know berkeley's EECS/CS departments had styled themselves after MIT, so we also built narrow processors or other digital circuits (like answering machines) out of 74 series parts. however our computer architecture classes were already using schematic capture and simulation by then which kinda sucked.
posted by joeblough at 11:56 AM on April 25, 2016
Lazlo - hell yah, i came thru berkeley in the late 80s... as you probably know berkeley's EECS/CS departments had styled themselves after MIT, so we also built narrow processors or other digital circuits (like answering machines) out of 74 series parts. however our computer architecture classes were already using schematic capture and simulation by then which kinda sucked.
posted by joeblough at 11:56 AM on April 25, 2016
Interesting choice to go for a mixed 16-bit internal/8-bit external architecture; I wonder how much extra complexity and construction that caused over a pure 8-bit arch?
This reminded me strongly of the relay-computer FPP a few years ago; linked as the 3rd "previously".
posted by We had a deal, Kyle at 12:47 PM on April 25, 2016
But one of the darker memories seared on my soul is the yards of assembler code you need to write to for an 8 bit processor to do not much at all.My memory of 6502 coding was that there was more pain in dealing with the constant discipline of shuttling data in and out of the A, X, and Y registers. He has 4 GPRs which is a little better, but still...
This reminded me strongly of the relay-computer FPP a few years ago; linked as the 3rd "previously".
posted by We had a deal, Kyle at 12:47 PM on April 25, 2016
Interesting choice to go for a mixed 16-bit internal/8-bit external architecture; I wonder how much extra complexity and construction that caused over a pure 8-bit arch?
The Intel 8088 was 16-bit internal and 8-bit external. It was used in the original IBM PC and a lot of early CP/M computers. The 8088 CPU core was identical to the external 16-bit 8086 but with a different memory interface that used two memory cycles to fetch 16-bit opcodes and access 16-bit data. So no added complexity, just reduced performance.
posted by JackFlash at 1:32 PM on April 25, 2016
The Intel 8088 was 16-bit internal and 8-bit external. It was used in the original IBM PC and a lot of early CP/M computers. The 8088 CPU core was identical to the external 16-bit 8086 but with a different memory interface that used two memory cycles to fetch 16-bit opcodes and access 16-bit data. So no added complexity, just reduced performance.
posted by JackFlash at 1:32 PM on April 25, 2016
Something about this is so British.
What, is it positive-ground?
More likely it just page faults every time it rains.
posted by CynicalKnight at 2:34 PM on April 25, 2016
What, is it positive-ground?
More likely it just page faults every time it rains.
posted by CynicalKnight at 2:34 PM on April 25, 2016
The Intel 8088 was 16-bit internal and 8-bit external. It was used in the original IBM PC and a lot of early CP/M computers. The 8088 CPU core was identical to the external 16-bit 8086 but with a different memory interface that used two memory cycles to fetch 16-bit opcodes and access 16-bit data. So no added complexity, just reduced performance.
Right, but the 8088 was a variant of the preceding 8086 design; he's building his design from the ground up.
I was thinking that if he'd gone for 8-bit internal / 8-bit external (ie, something more like a 8080 than an 8088) he would have saved himself quite a lot of construction effort because most of his internals would have been half the width.
But really though: what a magnificent "I've got to scratch this crazy itch" thing this is.
posted by We had a deal, Kyle at 7:01 PM on April 25, 2016 [1 favorite]
Right, but the 8088 was a variant of the preceding 8086 design; he's building his design from the ground up.
I was thinking that if he'd gone for 8-bit internal / 8-bit external (ie, something more like a 8080 than an 8088) he would have saved himself quite a lot of construction effort because most of his internals would have been half the width.
But really though: what a magnificent "I've got to scratch this crazy itch" thing this is.
posted by We had a deal, Kyle at 7:01 PM on April 25, 2016 [1 favorite]
The 8088 wasn't used in a lot of early CP/M computers; that was the 8080, which was succeeded by the Z80. The 8088 was introduced in 1979, rather late in the CP/M era, and as a 16-bit processor, used a different OS (CP/M-86, and of course MS/PC-DOS).
posted by lhauser at 9:39 PM on April 25, 2016 [2 favorites]
posted by lhauser at 9:39 PM on April 25, 2016 [2 favorites]
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