Youtuber Ben Eater is uploading a series of instructional videos on building a programmable 8-bit computer from digital logic circuits on breadboards. No soldering required. The series is ongoing, updated weekly.
I don't question the security, but correctness... really...? On breadboards? With so much stray capacitance and inductance and lousy connections? Perhaps it will be correct if you run it on hundred kilohertz clock frequency but I wouldn't bet for more.
Have a look at the Intel 4004 replica project [4004.com]. It's a 41 x 58 cm (1.3 x 1.9 ft) 130x scale replica of the 4-bit and 2300 transistor CPU.
The Motorola 68020 which is MMU and FPU expandable uses 190 000 transistors and would using the same method require 20 m² (215 ft²). The Intel 80386 requires 28 m² (306 ft²).
But one could target the MOS 6502 with 3510 transistors which would require 0.36 m² (3.9 ft²) ie something like 60 x 60 cm. And compensate for the 8-bits by increasing the clock frequency. Assembly done by a pick & place robot will make this task efficient and the different types of components will be limited so a big spool of transistors will push the price down.
There are of course even easier methods for a secure computer depending on the amount of trust you have. Or skills to thwart any would be spies.
(Score: 4, Insightful) by Arik on Monday May 08 2017, @02:07PM (2 children)
If laughter is the best medicine, who are the best doctors?
(Score: 2) by c0lo on Monday May 08 2017, @05:28PM
I don't question the security, but correctness... really...? On breadboards? With so much stray capacitance and inductance and lousy connections?
Perhaps it will be correct if you run it on hundred kilohertz clock frequency but I wouldn't bet for more.
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 3, Interesting) by kaszz on Monday May 08 2017, @06:43PM
Have a look at the Intel 4004 replica project [4004.com]. It's a 41 x 58 cm (1.3 x 1.9 ft) 130x scale replica of the 4-bit and 2300 transistor CPU.
The Motorola 68020 which is MMU and FPU expandable uses 190 000 transistors and would using the same method require 20 m² (215 ft²). The Intel 80386 requires 28 m² (306 ft²).
But one could target the MOS 6502 with 3510 transistors which would require 0.36 m² (3.9 ft²) ie something like 60 x 60 cm. And compensate for the 8-bits by increasing the clock frequency. Assembly done by a pick & place robot will make this task efficient and the different types of components will be limited so a big spool of transistors will push the price down.
There are of course even easier methods for a secure computer depending on the amount of trust you have. Or skills to thwart any would be spies.