Probably says that that once that most people that ran UNIX purchased the FP option and did not run the simulated FP and those that did clearly didn't use tcsh ;-)

Fred Brook's bug's curves really are amazing but are so true. Some really major bugs just take years to be discovered because no one ever looked and when you do. It can be like this one -- 'wow!'

Clem

On Sat, Jun 10, 2017 at 10:24 AM, Noel Chiappa <jnc@mercury.lcs.mit.edu> wrote:

> From: "Walter F.J. Mueller"

> the kernel panic after tcsh here documents is understood.

Very nice detective work!

> The kernel panic is due to a coding error in mch_fpsim.s. ... After
> fixing the "$SIGILL." ... and three similar cases

I'm fairly amazed that apparently nobody has run across one of these 4 before!
(Or, at least, not bothered to report it.)

I wonder how long that bug has been in the code?

Noel