
Simh/simh: The Computer History Simulation Project - lisper
https://github.com/simh/simh
======
Koshkin
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...](https://www.techrepublic.com/article/nasas-unsung-heroes-the-apollo-
coders-who-put-men-on-the-moon/)

~~~
aap_
> 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](https://github.com/DoctorWkt/pdp7-unix)

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

------
qubex
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](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.

------
Glyptodon
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.

~~~
Koshkin
English is left-associative.

~~~
lisper
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."

~~~
Koshkin
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").

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

