Linked by Thom Holwerda on Sun 4th Nov 2007 15:45 UTC
OSNews, Generic OSes "Bill Buzbee offered the first public demonstration of the Minix OS - a cousin of Linux [I beg your pardon?] - running on his homebrew minicomputer, today at the Vintage Computer Festival in Mountain View, Calif. Magic-1, built with 74-series TTL ICs using wire-wrap construction, implements a homebrew, 8086-like ISA."
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RE: Hard path
by transputer_guy on Mon 5th Nov 2007 16:31 UTC in reply to "Hard path"
transputer_guy
Member since:
2005-07-08

I did wire wrapping TTL before I became a chip designer, I really would not ever want to work at that level again. Signal conditions are just awefull in TTL, a few MHz is doing well. A better approach if low level gates is a must is to use CMOS 7400 equivalents or better use ECL, both will have much better signals and ECL can also give pretty good speeds too.

Also using FPGAs is still a really good idea, prototype in the Spartan or Cyclone on one of the widely available edu boards and if you can get the architecture to work then redo the correct logic in gate level logic of choice. One might expect to reach logic speeds closer to 50-100MHz and use SDRAM memory. Several homebrew FPGA cpus run GNU tool chains and some can boot Linux.

That allows you to use a modern language like Verilog or VHDL and when high level RTL code works, rewrite the code to use lower gate level primitives to the same effect. The synthesized gate logic in Luts will then be much closer to wired gates on a board. The tools are essentially free to use from Xilinx, Altera, Lattice etc when low end target FPGAs are used even if you retarget to logic gates.

In the hobby world of true homebrew computers though it is rare to see someone with the deep software skills this Transmeta guy has, most of these machines get to run far less code.

Also ofcourse the Z80 and early 8086 were pretty close cousins both being revamped 8080s, 1 in the 8 bit direction, the other 16bit. And this guy has an inside track on the 86 architecture nuances so it is hardly surprising what he produced!

BTW, almost all the early micro processors were designed with pencil & paper tools with only a minimal use of CAD. Even the 68K and 8086 were done that way IIRC. These were usually prototyped with TTL or CMOS gate chips although the silicon for them arrived before the wirewrap proto's even worked so their usefullness was limited. After that it was CAD all the way.

On Lisp, there is a project to redo the Symbolics design in FPGA.

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