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 Megacomputer - room-sized 16 bit transistor machine 
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Joined: Wed Jan 09, 2013 6:54 pm
Posts: 1280
So far this machine by James Newman has 32 bytes of RAM - also built from transistors. NMOS-style logic with pullup resistors, about 1us per gate, about 25kHz target speed.

It's not a minimal architecture: 16bit parallel bus, four registers. (16-bit internal, 8-bit external.) Details:
http://megaprocessor.com/VitalStatistics.html

Image
http://megaprocessor.com/progress.html

via http://www.theregister.co.uk/2015/06/23 ... processor/
via the discussion at https://news.ycombinator.com/item?id=9755742
"The cost is a rather embarrassing £20k"


Tue Jun 23, 2015 1:27 pm
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Joined: Mon May 25, 2015 12:51 am
Posts: 21
Location: Michigan, USA
That's incredible... remarkable... Sure is pretty.

I wonder what the power budget is going to be?


Wed Jun 24, 2015 2:13 am
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Joined: Wed Jan 09, 2013 6:54 pm
Posts: 1280
He estimates 250W, but that seems low - especially if the gates have resistive pullups.

But, there are more than the minimum number of transistors in the gates, so maybe he's doing something different, perhaps more like CMOS. He has 10 transistors for each bit of RAM - that's more than the minimum, even for a static RAM! But I think he also says that all transistors are the same, so it's a bit of a mystery.


Wed Jun 24, 2015 7:53 am
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Joined: Tue Jan 15, 2013 10:11 am
Posts: 114
Location: Norway/Japan
I saw 500 watts mentioned elsewhere, but he also said that the LEDs caused most of it. And from the pictures those are not power-efficient super-bright LEDs. So the estimated power requirement seems a bit on the low side.


Wed Jun 24, 2015 10:33 am
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Joined: Tue Dec 31, 2013 2:01 am
Posts: 100
Location: Sacramento, CA, United States
BigEd wrote:
He estimates 250W, but that seems low - especially if the gates have resistive pullups.

But, there are more than the minimum number of transistors in the gates, so maybe he's doing something different, perhaps more like CMOS. He has 10 transistors for each bit of RAM - that's more than the minimum, even for a static RAM! But I think he also says that all transistors are the same, so it's a bit of a mystery.

AFAICT, he's using MOS with pull-ups, not CMOS, limiting his clock rate and using a lot of energy heating the pull-ups for every logic 0 in the mix.

Mike B.


Thu Jun 25, 2015 1:16 am
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Joined: Wed Jan 09, 2013 6:54 pm
Posts: 1280
James posted an update with a photo of his room/computer:
http://www.megaprocessor.com/progress.html

Image

Quote:
We now have the four right hand frames running together which are Input & Decoding, Special Purpose Registers, ALU, General Purpose Registers. With the current state of the living room I can't really show them in action. You can get some feel for the conditions from this picture:


via hackaday
Videos within


Wed May 04, 2016 9:58 am
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Joined: Wed Jan 09, 2013 6:54 pm
Posts: 1280
Those videos on hackaday are borked, so here are some more short videos:

Megaprocessor Tour 1 - (fixed audio) - James himself walking you around the machine, as built in his home. The machine has since been moved to the Centre for Computing History in Cambridge where it is on display as a working exhibit - you can play Tetris on it.

Image

MegaProcessor - Computerphile - Jason Fitzpatrick of and at the CCH

Image

The MegaProcessor - James at the CCH

Image


Fri Jun 01, 2018 12:39 pm
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