[TUHS] UNIX testing / error injection

[Marc Rochkind via TUHS]

When you use the phrase "UNIX engineers," to whom are you referring? At the
beginning and for years afterwards, UNIX was a research project. If there
was engineering, it came along much later.

On Tue, Apr 14, 2026, 10:41 PM Adam Koszek via TUHS <tuhs at tuhs.org> wrote:

> Hello,
>
> A friend told me that UNIX engineers went through great pains to test
> software. I heard a story about bubble gum wrapper being stuck into IDE
> disk cable to short some lines to inject errors, and see if the filesystem
> would handle/survive this.
>
> Were there any more examples of this?
>
> After UNIX was already running many program, were any of the complex
> pieces of system code ever developed in the user-space first?
> Filesystems/schedulers/networking are inherently hard to get right, and the
> compile -> boot -> see kernel fail wasn’t ever fun cycle for me, and it had
> to be hell on slow machines..
>
> How was all this good code delivered? :)
>
> I’ve learnt a buzzword: “deterministic simulation testing”. It’s when you
> stub everything and run program in a fully controllable virtual world, and
> can inject faults etc. These days I can build mini datacenter in a single
> Golang program, but I’m wondering how the software that came before was
> developed.
>
> Adam