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Simh/simh: The Computer History Simulation Project (github.com/simh)
55 points by lisper on Nov 23, 2017 | hide | past | favorite | 10 comments



To me, the most amazing thing about old systems was how little resources they needed to do useful work. The first version of Unix was designed to run on a machine with in 24KB (that's kilobytes) of core memory; even the famous and ubiquitous IBM System 360 was quite constrained by today's standards. "The software that controls what happens when you move your mouse on your PC — the mouse driver for Windows — takes more memory than all the NASA supercomputers put together had for Apollo," said Jones."[1]

That's right, they called them "supercomputers."

[1] https://www.techrepublic.com/article/nasas-unsung-heroes-the...


> The first version of Unix was designed to run on a machine with in 24KB (that's kilobytes) of core memory

The very first of UNIX actually ran on a machine that couldn't even address that much memory, the PDP-7 has 13 bit addresses so you can only address 8k words of memory directly (1 word = 18 bits). The UNIX (or rather UNICS) kernel ran in 4k and left the other 4k for a user process; every context switch was a swap! If you want to try it out: https://github.com/DoctorWkt/pdp7-unix


Right. That was "Edition Zero" - naturally, UNIX version count is zero-based!


The most amazing thing about SIMH is that in some form or another it dates back to the mid 1960s, and therefore literally predates UNIX by roughly a decade.


Longtime SIMH user here. The most amazing aspect of this project is the tangential remark visible in its Wikipedia page (https://en.wikipedia.org/wiki/SIMH): has been in development in one form or another since the 1960s: this software predates UNIX by approximately a decade.


I was really disappointed when I clicked through and discovered it's not an attempt to recreate all of human history via a computer simulation.


English is left-associative.


Actually, it isn't. An "automatic donut maker" doesn't make automatic donuts.

Compound adjectives in English should be hyphenated, so strictly speaking, the GP is correct and the headline should have been: "The Computer-History Simulation Project."


Good point about hyphenation, except it should probably be used the other way around: your example should be spelled "automatic donut-maker" (which looks more natural to me than "Computer-History").


Would it be possible to make a libretro version of simh ? Or does that already exist?




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